Water and Major Minerals

Calcium Absorption

Calcium absorption occurs throughout the length of the intestines, with the greatest absorption in the duodenum. Calcium is absorbed in the duodenum through active transport, a process that requires calcium-binding protein. Vitamin D in the form of calcitriol stimulates synthesis of calcium-binding protein. Adult humans absorb approximately one-third of the calcium in food. Absorption rates are higher in newborn infants (55%), children (50%), and pregnant women (65%).

Trace Minerals

Chromium (Cr) Fluoride (F-) Copper (Cu) Iodine (I) Iron (Fe) Manganese (Mn) Molybdenum (Mo) Selenium (Se) Zinc (Zn)

Dietary Adequacy of Zinc

Currently, there is no established method for assessing zinc status in the body. Humans do not store zinc, so the trace mineral needs to be consumed daily. Adult RDAs for zinc range from 8 mg to 11 mg/day. In the United States, the average intake of zinc is 9.3 mg/day for women and 13.2 mg/day for men.

Food Sources of Phosphorus

Dairy foods, meat, and cereal grains are the primary sources of phosphorus in the typical American diet. The bioavailability of phosphorus is dependent on whether the nutrient is from plant or animal foods and if it is present in the organic or inorganic form. Plant foods, such as seeds and beans, generally contain organic phosphorus, including phytate. Phytate inhibits the absorption of phosphorus from such foods. Inorganic phosphorus, which is predominately in animal foods, is more bioavailable than the organic forms.

Functions of Fluoride

Dental erosion can lead to tooth decay (dental caries or cavities), but fluoride can remineralize the tooth surface and prevent cavities from developing. In children under 12 years of age, dietary fluoride helps the body build teeth that are resistant to decay. For people with fully formed teeth, fluoride from the diet becomes incorporated in the saliva, which further protects against tooth decay as it bathes the teeth. Fluoride also encourages bone development, and the mineral becomes incorporated into bone tissue. Thus, adequate intake of fluoride is important for optimal bone health.

Dehydration

Despite the body's mechanisms to balance its water content, some fluid is constantly being lost, primarily via the skin and lungs. If a person does not consume enough fluids to replace that water, dehydration can occur.

Reducing the Risk of Osteoporosis

Efforts to reduce the risk of osteoporosis should begin early to maximize peak bone mass. Proper diet and regular exercise are especially important from early childhood through late adolescence because the body actively builds bone during these life stages. Exposing skin to sunlight can stimulate the body's ability to form vitamin D, but some people will need to take calcium and vitamin D supplements. Exercise training, especially performing weight-bearing activities, increases bone mass because contracting muscles keep tension on bones, which stimulates bone-building activity

Sources of Chromium

In general, meat, broccoli, whole-grain products, yeast, spices, fruits, and vegetables are good sources of chromium. As with selenium, the amount of chromium in plant foods reflects the chromium content of soils where the crops are grown.

Potassium Deficiency

Individuals suffering from excessive sweating, vomiting, diarrhea, or kidney diseases that increase potassium excretion are at risk for potassium depletion (hypokalemia). Signs and symptoms of hypokalemia generally include loss of appetite, muscle cramps, confusion, constipation, and increased urinary calcium excretion. The condition is life-threatening, and treatment should be initiated immediately to prevent serious complications, including death.

Magnesium Toxicity

Magnesium toxicity, hypermagnesemia, rarely occurs from eating too much magnesium-rich food. The toxicity is more likely to occur from ingesting excessive magnesium from laxatives, antacids, or dietary supplements that contain the mineral. Thus, the UL for the micronutrient (350 mg/day) is for magnesium-containing medications and not food sources. A person who ingests too much magnesium often develops diarrhea as a result.

Molybdenum (Mo)

Major Functions in the Body: Component of certain coenzymes Adult RDA/AI 45 μg Major Dietary Sources: Liver, peas, beans, cereal products, leafy vegetables, low-fat milk Major signs and symptoms of deficiency of this mineral: None in healthy humans Major toxicity signs and symptoms: UL = 2000 μg/day Rarely occurs from usual dietary sources Overdoses of dietary supplements containing molybdenum may cause joint pain and swelling of feet or lower legs.

Zinc (Zn)

Major Functions in the Body: Component of numerous enzymes Adult RDA/AI Women: 8 mg Men: 11 mg Major Dietary Sources: Seafood, meat, whole grains Major signs and symptoms of deficiency of this mineral: Skin rash Diarrhea Depressed sense of taste and smell Hair loss Poor growth and physical development Major toxicity signs and symptoms: UL = 40 mg/day Intestinal upset Depressed immune system function Supplement use can reduce copper absorption.

Phosphorus (P)

Major functions in the body: -Structural component of bones and teeth -Maintenance of acid-base balance -Component of DNA, phospholipids, and other organic compounds Adult RDA/AI: 700 mg Major Dietary Sources: Dairy products, processed foods, soft drinks, fish, baked goods, meat Major Deficiency Signs and Symptoms: None reported Major Toxicity Signs and Symptoms: UL = 4 g/day Poor bone mineralization

Sulfur (S)

Major functions in the body: Component of organic compounds such as certain amino acids and vitamins Adult RDA/AI: None Major Dietary Sources: Protein-rich foods Major Deficiency Signs and Symptoms: None reported Major Toxicity Signs and Symptoms: Unlikely from dietary sources

Manganese Function

Manganese is an important component and activator of many enzymes in the body. These manganese-dependent enzymes play roles in wound healing, metabolism, bone and cartilage formation, and antioxidant function.

Determining Iron Status

Measuring blood (serum) ferritin concentration (saturation) is the most commonly used method to assess a person's iron status. Total body iron is the ratio of blood transferrin receptor to ferritin. Determining a person's total body iron is the best method of assessing iron status.

Sources of Potassium

Overall, fresh fruits, fruit juice, and vegetables are good dietary sources of potassium. Milk, whole grains, dried beans, and meats are also major contributors of potassium to American diets. While processed foods are often concentrated sources of sodium, most processed foods are poor sources of potassium. Potassium is also found as a part of the salt substitute potassium chloride and the artificial sweetener acesulfame-K. People can raise their potassium intakes by increasing their consumption of fruits, vegetables, whole-grain breads and cereals, and low-fat and fat-free milk and milk products.

sulfur food sources

Protein-rich foods, including meat, poultry, fish, eggs, milk, cheese, legumes, and nuts, provide ample sulfur to diets. Deficiencies are rare and occur only with severe protein deficiency, which is uncommon in the United States.

Categories of Blood Pressure

Systolic (mm Hg) - Diastolic (mm Hg) Normal < 120 and < 80 Prehypertension 120-139 or 80-89 Hypertension ≥ 140 or ≥ 90

Dietary Adequacy

The adult RDA for calcium ranges from 1000 to 1200 mg/day. For children and adolescents between the ages of 9 and 18, the RDA is higher (1300 mg/day) to allow for increases in bone mass during growth and development. In the United States, average calcium intakes were 1086 mg/day for men and 852 mg/day for women in 2013-2014.

Iodine Absorption

The body absorbs nearly all (85 to 90%) of the iodine that is in food. Some plant foods such as cassava, turnips, cabbage, Brussels sprouts, cauliflower, and broccoli, contain goitrogens. These compounds inhibit iodide metabolism by the thyroid gland and, as a result, reduce thyroid hormone production. Soy products also contain a compound that inhibits thyroid hormone production.

Diet for Iron

The following suggestions can add iron to your diet and increase its absorption: Eat lean meat, poultry, or fish with plant sources of iron. Combine soybeans with tomatoes or tomato sauce. Sprinkle lemon or lime juice on cooked beans, or serve the beans with salsa. Add orange segments, strawberries, or chopped tomatoes to spinach salads or cooked spinach. Add chopped onions and green peppers to peas or beans. Add lemon or lime juice to salad dressing. Serve sweet potatoes with fresh orange segments or dried apricots. Add raspberries, strawberries, raisins, or dried apricots to cereal. Drink orange juice when eating sandwiches made with nut butter. Consume watermelon, dried plums, dried apricots, or raisins for snacks.

Kidneys and Water Balance

The kidneys are the major regulator of the body's water content and ion concentrations. In a healthy person, the kidneys maintain proper hydration by filtering excess ions from blood as it flows through the kidneys. When the kidneys remove ions such as sodium, water follows and becomes the main component of urine. If more watery fluids are consumed than the body needs, the kidneys excrete the excess water in urine. Kidneys also remove waste products, such as urea, from the bloodstream. Sometimes, minerals and waste products collect into crystals that enlarge and form a hard mass called a kidney stone. Pain management and hydration are important in the treatment of kidney stones. However, a kidney stone that is large enough to block the urinary tract requires emergency treatment to remove or break it down.

chloride food sources

The majority of chloride consumed in the typical American diet is in table or sea salt (sodium chloride). Most salt substitutes are comprised of potassium chloride. Many vegetables also contain chloride. Seaweed, rye, tomatoes, celery, and olives are considered excellent sources of the mineral.

Other sources of minerals

The tap water in many communities may be a source of minerals that people may overlook. "Hard" water naturally contains a variety of minerals, including calcium, magnesium, sulfur, iron, and zinc. Water with high mineral content often tastes and smells unpleasant. Many people drink bottled water as a substitute for tap water because they think bottled water tastes better and is safer. Dietary supplements are another source of minerals. A daily multiple vitamin and mineral supplement is generally safe for healthy people, because a dose of this type of supplement does not provide high amounts of minerals. However, people need to be careful when taking dietary supplements that contain individual minerals, such as iron or selenium. Single-mineral supplements are usually unnecessary unless they are medically prescribed to treat a specific condition, including iron deficiency. An excess of one mineral can also interfere with the absorption or metabolism of other minerals.

Risk factors for Hypertension

-Family history -Advanced age -African-American ancestry -Obesity -Physical inactivity -Consuming excess sodium -Cigarette smoking -Consuming excess alcohol -Type 2 diabetes

Functions of Water

-Is a solvent -Is a major component of blood, saliva, sweat, tears, mucus, and joint fluid -Removes wastes -Helps transport substances -Lubricates tissues -Regulates body temperature -Helps digest foods -Participates in many chemical reactions -Helps maintain proper blood pH

Non-weight-bearing Activities

-Lying in bed -Swimming -Water Aerobics -Cycling -Space flight

chloride deficiency

A chloride deficiency disorder is unlikely because of the excessive intake of table salt by most Americans. However, deficiencies may be seen in cases of extreme vomiting, diarrhea, and/or sweating, as well as with diuretic use. Prolonged vomiting causes increased loss of HCl in gastric juice, resulting in an acid-base and fluid imbalance. Fatigue and loss of appetite are common symptoms of chloride deficiency.

Risk Population for Zinc Deficiency

Alcoholics have high risk of zinc deficiency because alcohol reduces zinc absorption and increases excretion of the mineral in urine. Furthermore, many people who suffer from alcoholism do not consume nutritious diets. People with chronic diarrhea or digestive tract diseases can also develop zinc deficiency.

Copper Deficiency and Toxicity

Although copper deficiency is fairly rare in the United States, infants born too soon (prematurely), infants fed cow's milk, and people with malabsorption disorders may be at risk of developing the condition. As a result of this defect, the person's body does not synthesize enough ceruloplasmin, so anemia develops. Poor bone health, abnormal skin pigmentation, impaired neurological and immune system functioning, and poor growth also result from copper deficiency. Infants who have Menkes syndrome, a rare inherited metabolic disorder, can absorb copper, but their cells are unable to metabolize the trace mineral properly. Babies with the syndrome have a variety of physical signs, including brittle, kinky hair; bone defects; and plump, rosy cheeks. Children with Menkes syndrome do not live for more than a few years.

Chromium Function

Chromium enhances the effect of insulin. Recall that cells require insulin to obtain glucose from the bloodstream. Chromium may enhance insulin's action on cell membranes and, in a way, help to "hold the door open" for glucose to enter cells. Chromium is also important for carbohydrate, fat, and protein metabolism and storage. For people who are trying to lose weight, chromium supplementation may contribute to a small amount of weight loss. Can people who have diabetes experience better blood glucose regulation by taking chromium supplements? Supplementation with chromium improves blood glucose control in people who have diabetes. Additionally, chromium supplementation may improve blood triglyceride and HDL levels in those with diabetes.

Copper

Cuproenzymes are a group of enzymes that contain copper. Copper, for example, is a component of ceruloplasmin, a protein that is needed for copper transport and iron metabolism. Antioxidant activity Energy metabolism Collagen formation (connective tissue and bone health) Iron storage and transportation Synthesis and metabolism of neurotransmitters Formation of myelin that surrounds parts of certain nerve cells Synthesis of melanin, the pigment in hair, skin, and eyes Gene expression

Zinc Lozenges and the Common Cold

Zinc lozenges or gels may inhibit multiplication of the common cold virus in the nasal or oral cavity and thereby reduce the severity or duration of colds.

Heme

Heme is the iron-containing structure in two very important proteins, hemoglobin and myoglobin. In red blood cells (RBCs), hemoglobin enables oxygen uptake and transport.

Sources of Water

How much water is necessary to drink for good health? Contrary to popular belief, there is no "rule of thumb" recommendation that specifies how many glasses of water to consume each day. 2 Factors such as environmental temperatures, health conditions, physical activities, and dietary choices influence individual water requirements. Thus, total water intake varies widely. The Adequate Intake (AI) for total water intake is approximately 11 cups (2.7 L) for young women and approximately 15.5 cups (3.7 L) for young men. Total water intake refers to water ingested by consuming beverages, including drinking water, and foods. Other sources of water include fruit juice, milk, soup, coffee, tea, soft drinks, and flavored bottled water. In addition to the water in beverages and foods, a considerable amount of water enters the digestive tract daily through secretions from the mouth, stomach, intestine, pancreas, and gallbladder. The intestinal tract absorbs most of this water. Each day, only about 0.4 to 0.8 cup (100 to 200 mL) of the water that enters the digestive tract is not absorbed. The body eventually eliminates the unabsorbed water in feces.

Dietary Adequacy

Humans require only about 180 mg of sodium per day, but the AI for adults under 51 years of age is 1500 mg/day. The AI for sodium does not apply for people who perspire heavily, such as marathon runners, or people who work in extremely hot conditions. weat contains small amounts of sodium, chloride, and some other minerals. Thus, people who perspire heavily can lose large amounts of these minerals in their sweat.

Water balance and Hydration

Hydration is another term for the body's water status. If hydration becomes altered, such as in dehydration (body water depletion), an individual can suffer serious consequences.

Sources of Magnesium

Magnesium is a critical component in chlorophyll, the green pigment in plants. Therefore, plant foods such as spinach, green leafy vegetables, whole grains, beans, nuts, seeds, and chocolate are the richest sources of magnesium. Animal products such as milk and meats also supply some magnesium.

Sources of Minerals

Most foods contain small amounts of minerals; In general, a mineral's bioavailability increases during periods of growth, such as infancy and puberty, and during pregnancy and breastfeeding. Compared to plant foods, animal foods tend to be more reliable sources of minerals, such as iron and calcium. Why? Animal products often have higher concentrations of these minerals, with the exception of magnesium and manganese. Although plants foods may contain minerals, these foods may often contain phytic acid or oxalic acid, naturally occurring substances that interfere with mineral absorption. Phytic acid is a compound in whole grains and in certain seeds and beans. Spinach, collard greens, and sweet potatoes have high amounts of oxalic acid. In fact, rhubarb leaves are toxic because they contain such high amounts of this chemical.

Myoglobin

Myoglobin in muscle cells helps oxygen enter the cells. The oxygen carried by hemoglobin and myoglobin is critical for energy metabolism.

Does water give you energy?

No, water does not provide energy.

Dietary Sources of Copper

Organ meats, shellfish, whole grains, nuts, and seeds are good sources of copper. The adult RDA for copper is 0.9 mg/day, and Americans typically consume 10 to 70% more than this amount.

Sources of Selenium

Rich food sources of selenium include seafood and organ meats, such as liver and kidneys. In the United States, meat, poultry, fish, eggs, nuts, and whole grains are the primary dietary sources of selenium.

Signs and Symptoms of Iron Deficiency Anemia

-Fatigue and weakness -Shortness of breath -Dizziness -Headache -Coldness in the hands and feet -Pale skin -Chest pain

Weight-Bearing Activities

-Low Impact Aerobics -Basketball -Running or jogging -Walking -Jumping Rope -Dancing -Hiking -Stair climbing -Strengths training with weights -Tennis and other racket sports

Most Common Signs of Dehydration

-Rapid weight loss -Dry or sticky mouth -Low or no urine output -Dark urine -No tears -Sunken eyes -Confusion -Heart palpitations (heart feels like it is jumping or fluttering) -Weakness

Iron Absorption, Storage, and Transport

A healthy body carefully regulates its iron status to avoid obtaining excessive amounts of the trace mineral. The body uses iron to make ferritin, the major storage form of iron. The liver, spleen, and bone marrow are the main sites for iron storage. In the absorptive cells of the small intestine, ferritin helps regulate iron absorption. When the body has adequate iron stores, the absorptive cells make ferritin, which blocks more iron from being absorbed. If the body lacks iron, ferritin levels drop. When the absorptive cells lack ferritin, they allow more iron to enter the bloodstream. Intestinal cells are constantly being shed into the lumen, and as a result, any ferritin that is stored in the absorptive cells is also shed. Thus, some iron is always needed by the body to replace that which is lost. Transferrin is a protein in blood that transports iron. When transferrin reaches cells, the protein binds to a receptor on the cell membrane called the transferrin receptor. If a cell needs more iron, it increases the number of transferrin receptors on its membrane. A version of transferrin receptor is in the bloodstream in an amount that is proportional to number of membrane-bound receptors. The level of transferrin receptors in the bloodstream increases when the body's iron stores become low.

Iron Deficiency

After RBCs die, the body breaks them down and conserves most of the iron that was in hemoglobin. By doing so, the body can recycle the trace mineral to make hemoglobin for new RBCs. Despite the body's efforts to maintain iron, some of the trace mineral is lost each day via the gastrointestinal tract, urine, and skin. Any form of bleeding, including menstruation, also contributes to iron losses. If such losses are excessive and the affected person is unable to replace the iron, iron deficiency occurs. Iron deficiency is a condition characterized by abnormally low iron levels in the body. The deficiency usually results from losing blood, consuming diets that lack iron, or being unable to absorb adequate amounts of dietary iron. Anemia is a condition in which the body does not have enough healthy RBCs and oxygen transport in blood is impaired. Approximately 25% of the world's population has anemia, and many cases of the condition are due to iron deficiency. In the first two stages of iron deficiency, the body's iron stores are lower than normal. A drop in the body's ferritin level is a sign that iron stores are becoming depleted. In the second stage, RBC production is reduced, but the reduction is not enough to be considered anemia. The third stage, iron deficiency anemia, is a condition that occurs when the body lacks enough iron to make the hemoglobin needed for producing healthy RBCs. As a result, the body forms hypochromic (pale red), microcytic (small cell) RBCs. Iron deficiency anemia has widespread negative effects on the body, including interfering with normal growth, behavior, immune system function, and energy metabolism. In children, iron deficiency anemia may interfere with the development of cognitive (thought processes) functioning.

Population at Risk of Magnesium Deficiency

Alcoholics, people with poorly controlled diabetes, or persons who use certain medications (such as diuretics) that increase urinary excretion of magnesium have higher risk of magnesium deficiency. Older adults are also at risk of magnesium deficiency because their bodies absorb less of the mineral and urinary losses increase with advancing age.

Trace Mineral

Although the body requires each trace mineral in very small amounts (generally less than 100 mg/day), these minerals perform vital roles in the body, and obtaining adequate amounts of them from food can be difficult

Water Balance

An average healthy adult consumes and produces approximately 2.5 quarts (2500 mL) of water daily. The body eliminates about 2.5 quarts of water in urine, exhaled air, feces, and perspiration. Thus, a healthy person's average daily water input equals his or her average daily losses (output). A number of factors influence a person's fluid input and output. Environmental conditions such as temperature, humidity, and altitude can affect body water losses. Physiological conditions, especially fever, vomiting, and diarrhea, as well as lifestyle practices such as exercise habits and sodium and alcohol intake, can also alter the body's fluid balance.

Hormones, Enzymes, and Water Balance

Antidiuretic hormone (ADH) and aldosterone are two hormones that participate in the body's efforts to maintain fluid balance. In response to dehydration, the posterior pituitary gland in the brain releases antidiuretic hormone. Antidiuretic hormone stimulates the kidneys to conserve water. Additionally, the adrenal glands secrete aldosterone. Aldosterone signals the kidneys to reduce the elimination of sodium in urine, and as a result, the kidneys return this mineral to the general circulation. Because water follows sodium, it is conserved as well. The renin-angiotensin system also regulates blood volume and blood pressure. The kidneys secrete the enzyme renin in response to low blood volume and falling blood pressure. Renin then activates the conversion of a protein synthesized in the liver, angiotensinogen, to angiotensin I. Angiotensin I is inactive and must be converted to angiotensin II, a reaction that primarily occurs in the lungs through the action of angiotensin-converting enzyme (ACE). Angiotensin II (1) stimulates the release of aldosterone from the adrenal glands and (2) acts as a vasoconstrictor, a substance that contributes to the constriction of blood vessels, which causes an increase in blood pressure.

Resistant Hypertension

Approximately 13% of adults with high blood pressure suffer from resistant hypertension. People with resistant hypertension have blood pressure that remains uncontrolled while taking three medications or is controlled only through the continued use of four or more medications. African-Americans, non-black Hispanics, males, obese individuals, and older adults are more likely to develop resistant hypertension than other people. Individuals with resistant hypertension have a higher-than-average risk of experiencing heart and kidney complications such as coronary artery disease and kidney damage. Regular screening and early treatment are recommended to minimize the risk of such serious complications.

Food Sources of Iron

Because meat contains hemoglobin and myoglobin, beef, fish, and poultry contain more iron (heme iron) than most plant foods. The remaining iron in meat, as well as all the iron in vegetables, grains, dietary supplements, and fortified or enriched foods, is nonheme iron. More heme iron than nonheme iron is absorbed in the intestinal tract. Absorption of iron from a mixed diet that includes heme iron is approximately 14 to 18% and from a vegetarian diet that includes nonheme iron is 5 to12%.

Diuretics and Dehydration

Caffeine is a diuretic, a substance that increases urine production. Coffee, tea, "energy" drinks, and soft drinks often contain caffeine or caffeine-related compounds. However, the water consumed in caffeinated beverages is not completely lost in urine, so drinking these fluids can still contribute to meeting a person's water needs. Alcohol is also a diuretic. Normally, ADH signals the kidneys to conserve water. Alcohol, however, inhibits ADH secretion from the pituitary gland in the brain, enabling the kidneys to eliminate more urine than normal. Alcohol consumption actually results in urinary water losses that are greater than the volume of fluid consumed. Therefore, alcohol contributes to dehydration.

Major Minerals

Calcium (Ca) Chloride (CI-) Magnesium (Mg) Phosphorus (P) Potassium (K) Sodium (Na) Sulfur (S)

Fluoride

Fluoride (F−) is not considered an essential nutrient because it is not required for growth or to sustain life. However, regular fluoride intake helps mineralize teeth and bones, and can prevent tooth decay. The average adult has about 2.6 g of fluoride in his or her body; 95% of the trace mineral is located in calcified tissue such as bones and teeth.

Calcium, Heart Disease, and Weight Control

Calcium-rich diets may have beneficial effects on heart disease risk factors, including hypertension, insulin resistance, chronic inflammation, and abnormal blood lipid levels. Although dietary calcium may protect against heart disease, calcium supplements have actually been associated with an increased risk of cardiovascular disease (CVD). Dietary sources of calcium may also be associated with successful weight loss and improved body composition. A high-calcium diet may increase fat breakdown, accelerating fat loss. More research needs to be done.

% Water Food by Weight

Food Water % by Weight Lettuce 95 Tomato 95 Watermelon 91 Milk, 1% fat 90 Apple, with skin 86 Avocado (Florida) 79 Potato, white, baked with skin 75 Banana 75 Chicken, white meat, roasted 65 Ground beef, 80% lean, broiled 56 Bread, whole wheat 39 Margarine, stick 16 Crackers, saltines 5 Vegetable oil 0

Iodine

Elemental iodine (I2) is a poison, but the iodine in foods is in the form of compounds and salts containing the trace mineral. In the body, the compounds and salts break apart and release the iodide ion (I−), which is the form of iodine that the body absorbs and uses. Most of the iodide in an adult's body is located in the thyroid gland. Goiter is an enlargement of the thyroid gland that is not the result of cancer. Goiters often occur among populations living in areas that lack the mineral iodine in locally produced foods. In general, these regions are inland and far from an ocean. If people in these communities limit their diets to locally produced foods, they might not have enough iodine in their diets.

Functions of Minerals

Essential minerals have many roles in the body. Some minerals form inorganic structural components of tissues, such as calcium and phosphorus in bones and teeth. Minerals may also function as inorganic ions, substances that have negative or positive charges. For example, calcium ions (Ca2+) participate in blood clotting, and sodium ions (Na+) help maintain fluid balance. Some ions, such as magnesium (Mg2+) and copper (Cu2+), are cofactors. A cofactor is an ion or small molecule that an enzyme requires to function. Many minerals are components of enzymes, hormones, or other organic molecules, such as cobalt in vitamin B-12 and iron in hemoglobin. Although cells cannot metabolize minerals for energy, certain minerals are involved in the chemical reactions that release energy from macronutrients.

Fluoride Toxicity: Fluorosis

Excessive fluoride intakes during tooth development can cause dental fluorosis, abnormal changes in the appearance of tooth enamel. Children under the age of 8 are at risk for dental fluorosis. Fluorosis can range from white specks on the teeth to severe discoloration and pitting. Dental fluorosis can occur in children who routinely swallow toothpaste and dental rinses. To reduce young children's exposure to excess fluoride, adults should teach youngsters how to use a pea-sized amount of toothpaste on their brush, rinse with water, and spit out the excess fluid. Long-term consumption of high amounts of fluoride can lead to skeletal fluorosis, a condition characterized by excess fluoride buildup in bones. Skeletal fluorosis changes bone structure, causing joint stiffness and bone pain. The condition also increases the risk of bone fractures. Because of these consequences, fluoride supplements should be used with caution and only under the supervision of a dentist or physician.

Sources of Fluoride

Fluids such as fluoridated water, coffee, tea, soft drinks, beer, and juice are Americans' main dietary sources of fluoride. In addition, fish and shellfish such as crab, shrimp, and clams are a good source of fluoride. Nonfood sources of fluoride include toothpaste, mouthwash, and dental treatments.

Potassium Toxicity

Food consumption of potassium does not lead to potassium toxicity; therefore, there is no UL for the mineral. However, taking potassium supplements can lead to high blood potassium levels, a toxic condition known as hyperkalemia. If a person's kidneys are not able to eliminate the excess potassium from the supplements, the mineral accumulates in his or her blood and can cause the heart to stop beating. To avoid toxicity, individuals should not take potassium supplements unless they are under a physician's care.

Food Source of Manganese

Food sources of manganese include leafy vegetables, whole grains, nuts, and tea. Additionally, small amounts of manganese are in natural sources of water.

Iron Content Lost in Frozen vegetables

Frozen vegetables may lose up to half of their iron content due to processing and cooking. In contrast, fresh vegetables that have been boiled may retain as much as 65% of their iron content, depending on the type of vegetable. To achieve a healthy iron intake, people should consider eating a variety of vegetables, including raw, frozen, and canned forms.

Sodium and Hypertension

Hypertension, a condition characterized by persistently elevated blood pressure, is a serious public health problem in the United States. Compared to people with normal blood pressure, hypertensive individuals have greater risk of CVD, especially heart disease and stroke, as well as kidney failure and damage to other organs. Approximately one in three adult Americans, about 70 million people, has hypertension. Children can also develop hypertension; among U.S. adolescents, 22% of boys and 10% of girls have high blood pressure. Hypertension is often called the "silent killer" because high blood pressure generally does not cause symptoms until the affected person's organs and blood vessels have been damaged. The best way to detect hypertension is to have regular blood pressure screenings. Because children can develop hypertension, their blood pressure should also be checked regularly, beginning at 3 years of age.

Iron Deficiency Anemia

In cases of iron deficiency anemia, not enough RBCs are available to carry oxygen efficiently, or the RBCs do not contain enough hemoglobin. When oxygen is lacking, the body's cells cannot release considerable amounts of energy from macronutrients. This leads to symptoms of anemia, including lack of energy and weakness. Furthermore, the heart of a person with anemia has to work harder to circulate oxygen-poor blood throughout the body. Over time, anemia can cause rapid or irregular heartbeat, chest pain, an enlarged heart, and even heart failure.

Magnessium

Magnesium plays an essential role in many important metabolic and physiological activities, including contraction and relaxation of muscles, enzyme function, energy production, and DNA and protein synthesis. Magnesium participates in more than 300 chemical reactions in the body. This essential mineral also helps regulate normal muscle and nerve function, as well as blood pressure and blood glucose levels. Additionally, the body needs magnesium to maintain strong bones and a healthy immune system. Magnesium may help prevent and treat diabetes, hypertension, metabolic syndrome, CVD, and asthma. In addition, magnesium may be useful in the treatment and management of migraine headaches and reduce risk of death from CVD. Normally, humans absorb about 40 to 60% of the magnesium in their diets, but as much as 80% of the magnesium in food may be absorbed when the body is lacking the mineral. The kidneys regulate blood concentrations of magnesium and can reduce urinary losses when the body's magnesium level is low.

Iron Deficiency: High Risk Populations

In the United States, iron deficiency is the most common nutritional deficiency and the leading cause of anemia. According to a 2012 report, 10 to 19% of American females between the ages of 12 to 49 years are iron deficient in contrast to only 1% of males in that age group. Substantial blood loss that results from severe injuries and serious intestinal conditions, such as colon cancer, is a common cause of iron deficiency anemia. Additionally, women with heavy menstrual blood losses are especially prone to iron deficiency anemia. Young women are also at risk for iron deficiency and iron deficiency anemia because they may exclude meat and enriched bread and cereal products from their diets. Iron needs increase during pregnancy and periods of rapid growth. A pregnant woman's need for iron increases as her blood supply expands and new tissues are added to both her body and that of her fetus. Pregnant women who suffer from iron deficiency anemia have a higher risk of dying during pregnancy than healthy pregnant women. Anemic pregnant women are also more likely to give birth to premature or low-birth-weight infants, who are more likely to die during their first year of life. Because of their rapid growth rates, infants and toddlers have higher needs for iron than older children. Furthermore, iron appears to be necessary for normal nervous system functioning, including proper brain development. Iron-deficient infants can experience delays in the development of normal motor and mental functions

Selenium

In the body, selenium functions as a component of several enzymes referred to as selenoproteins (sell′-in-oh-pro′-teens). Glutathione peroxidase is a family of selenoproteins that act as antioxidants, protecting the body from free-radical damage. Other selenoproteins are necessary for the normal functioning of thyroid hormone and the immune system. In addition, selenium is important for reproduction and DNA synthesis.

Fluoridation of Public Water Supplies

In the last 60 years, numerous municipalities in the United States have added healthful amounts of fluoride to the public water supply (fluoridation). In 2014, about 75% of the U.S. population had access to drinking water that contained optimal fluoride levels.

Dietary Adequacy of Phosphorus

Individuals who eat greater amounts of protein-rich foods tend to consume the most phosphorus. Phosphorus deficiencies are rare. However, when present, a phosphorus deficiency leads to bone loss and decreased bone mineralization and strength. Children who are deficient in phosphorus experience symptoms of rickets. Poor appetite, weight loss, fatigue, muscle pain, weakened immune system, and bone pain are also typical signs and symptoms of phosphorus deficiency. Cases of phosphorus toxicity are also rare, but consuming excess phosphorus can lead to hyperphosphatemia, elevated blood levels of the mineral. Hyperphosphatemia can cause calcium-phosphate deposits to form in body tissues, including blood vessels, which contributes to CVD progression. Individuals with chronic kidney disease often experience abnormal blood levels of phosphorus, calcium, or both as a result of hyperphosphatemia. In this population, synthesis of calcitriol, the most metabolically active form of vitamin D, is decreased because calcitriol is made in the kidneys. Thus, kidney-disease patients often need to monitor and regulate their phosphorus intake to avoid hyperphosphatemia. Avoiding meat, poultry, fish, dairy foods, nuts, carbonated soft drinks, and cereals is generally among the dietary recommendations for patients with chronic kidney disease.

Iron Major functions of the body

Iron is necessary for energy metabolism, growth, reproduction, wound healing, and immune function. Oxygen transport and energy metabolism Needed for production of hemoglobin (red blood cells), myoglobin (muscle cells), and cytochromes (most body cells) Cell division Required by an enzyme needed for DNA production Immune system Needed for production of lymphocytes (a type of white blood cell) Enables neutrophils (another type of white blood cell) to destroy bacteria Nervous system Needed to help maintain the myelin sheath that covers parts of certain nerve cells Needed for the production of neurotransmitters (e.g., dopamine, epinephrine, and norepinephrine) that regulate brain and muscular activity

Wilson Disease

It is a rare inherited disorder characterized by the accumulation of toxic amounts of copper in the body, especially in the liver, brain, kidneys, and eyes. Normally, the liver removes excess copper from the bloodstream, stores the trace mineral, or adds it to bile for elimination. In cases of Wilson disease, the liver does not make enough ceruloplasmin, a protein that transports copper in the bloodstream. As a result, the liver's ability to remove copper from storage is severely impaired, so the mineral accumulates in the organ, causing damage. Eventually, the liver releases excess copper into the circulation, and the trace mineral is picked up by other organs. People with Wilson disease usually develop signs of chronic liver disease, including yellowing of the skin and whites of the eyes (jaundice), fluid accumulation in the abdominal region, and enlargement of the liver. Patients may also develop signs and symptoms of nervous system damage, such as impaired muscular coordination and behavioral changes. Physicians can diagnose the disease by measuring copper and ceruloplasmin levels in the blood, and by noting copper deposits in the eyes called Kayser-Fleischer rings. A Kayser-Fleischer ring is a greenish-brown or rusty-brown ring that forms around the edge of each iris (the pigmented part of the eye), where it meets the cornea (the clear outer membrane of the eye).

Iron (Fe)

Major Functions in the Body: -Component of hemoglobin and myoglobin that carries oxygen -Energy generation -Immune system function Adult RDA/AI Women: 18 mg Men: 8 mg Major Dietary Sources: Meat and other animal foods, except milk; whole-grain and enriched breads and cereals; fortified cereals Major signs and symptoms of deficiency of this mineral: Fatigue upon exertion Small, pale red blood cells Low hemoglobin levels Poor immune system function Growth and developmental retardation in infants Major toxicity signs and symptoms: UL = 45 mg/day Intestinal upset Organ damage Death

Manganese (Mn)

Major Functions in the Body: Cofactor for certain enzymes, including some involved in carbohydrate metabolism Adult RDA/AI Men: 2.3 mg Women: 1.8 mg Major Dietary Sources: Nuts, oats, beans, tea Major signs and symptoms of deficiency of this mineral: None in humans Major toxicity signs and symptoms UL = 11 mg/day Abnormal nervous system function

Selenium (Se)

Major Functions in the Body: Component of an antioxidant system Adult RDA/AI 55 μg Major Dietary Sources: Meat, eggs, fish, seafood, whole grains Major signs and symptoms of deficiency of this mineral: Muscle pain and weakness Form of heart disease Major toxicity signs and symptoms: UL = 400 μg/day Nausea Vomiting Hair loss Weakness Liver damage

Iodine (I)

Major Functions in the Body: Component of thyroid hormones Adult RDA/AI 150 μg Major Dietary Sources: Iodized salt, saltwater fish, dairy products Major signs and symptoms of deficiency of this mineral: Goiter Cretinism (intellectual impairment and poor growth in infants of women who were iodine deficient during pregnancy) Major toxicity signs and symptoms: UL = 1100 μg/day Reduced thyroid gland function

Chromium (Cr)

Major Functions in the Body: Enhances insulin action Adult RDA/AI Men: 30-35 μg Women: 20-25 μg Major Dietary Sources: Egg yolks, whole grains, pork, nuts, mushrooms Major signs and symptoms of deficiency of this mineral: Blood glucose level remains elevated after meals Major toxicity signs and symptoms: Unknown but currently under scientific investigation May interact with certain medications

Fluorine

Major Functions in the Body: Increases resistance of tooth enamel to cavity formation Stimulates bone formation Adult RDA/AI Men: 4 mg Women: 3 mg Major Dietary Sources: Fluoridated water, tea, seaweed Major signs and symptoms of deficiency of this mineral: No true deficiency, but increased risk of tooth decay Major toxicity signs and symptoms: UL = 10 mg/day Stomach upset Staining of teeth during development Bone deterioration

Copper (Cu)

Major Functions in the Body: Promotes iron metabolism Component of antioxidant enzymes Component of enzymes involved in connective tissue synthesis Adult RDA/AI 0.9 mg Major Dietary Sources: Liver, cocoa, legumes, whole grains, shellfish Major signs and symptoms of deficiency of this mineral: Anemia Reduced immune system function Poor growth and development Major toxicity signs and symptoms: UL = 10 mg/day Vomiting Abnormal nervous system function Liver damage

Potassium (K)

Major functions in the body: -Maintenance of proper fluid balance -Transmission of nerve impulses -Maintenance of acid-base balance Adult RDA/AI: 4700 mg Major Dietary Sources: Fruits, vegetables, milk, meat, legumes, whole grains. Major Deficiency Signs and Symptoms: Irregular heartbeat and muscle cramps Major Toxicity Signs and Symptoms: No UL has been determined. Slowing of heart rate that can result in death

Sodium (Na)

Major functions in the body: -Maintenance of proper fluid balance -Transmission of nerve impulses -Muscle contraction -Transport of certain substances into cells. Adult RDA/AI: 1500 mg (19-50 years of age) Major Dietary Sources: Table salt; luncheon meats; processed foods; pretzels, chips, and other snack foods; condiments; sauces Major Deficiency Signs and Symptoms: Muscle cramps Major Toxicity Signs and Symptoms: UL = 2300 mg/day Contributes to hypertension in susceptible individuals Increases urinary calcium losses

Magnesium (Mg)

Major functions in the body: -Strengthens bone -Cofactor for certain enzymes -Heart and nerve functioning Adult RDA/AI: Men: 400-420 mg Women: 310-320 mg. Major Dietary Sources: Wheat bran, green vegetables, nuts, chocolate, legumes Major Deficiency Signs and Symptoms: Muscle weakness and pain. Poor heart function Major Toxicity Signs and Symptoms: UL = 350 mg/day medication-related Diarrhea

Calcium (Ca)

Major functions in the body: -Structural component of bones and teeth -Blood clotting -Transmission of nerve impulses -Muscle contraction -Regulation of metabolism Adult RDA/AI: 1000-1200 mg Major Dietary Sources: Milk and milk products, canned fish, tofu made with calcium sulfate, leafy vegetables, calcium-fortified foods such as orange juice. Major Deficiency Signs and Symptoms: Increased risk of osteoporosis. May increase risk of hypertension Major Toxicity Signs and Symptoms: UL = 2.0 to 2.5 g/day Intakes > 2.5 g/day may cause kidney stones and interfere with absorption of other minerals.

Chloride (CI-)

Major functions in the body: -Maintenance of proper fluid balance -Production of stomach acid -Transmission of nerve impulses -Maintenance of acid-base balance Adult RDA/AI: 2300 mg (19-50 years of age) Major Dietary Sources: Processed foods, salty snacks, table salt Major Deficiency Signs and Symptoms: Convulsions (observed in infants) Major Toxicity Signs and Symptoms: UL = 3600 mg/day Hypertension (because of the association with sodium in sodium chloride [table salt])

Major Minerals and why are they called major

Major minerals are called "major" not because of their relative importance to health, but because they are needed in greater amounts in the diet and are stored in larger quantities in the body than are trace minerals. The human body has higher concentrations of calcium and phosphorus than other minerals. In addition to calcium and phosphorus, sodium, potassium, magnesium, chloride, and sulfur are also classified as major minerals.

Sources of Iodine

Major sources of iodine include saltwater fish; seafood; seaweed; some plants, especially the leaves of plants grown near oceans; milk; eggs; and iodized salt. A half teaspoon of iodide-fortified salt supplies the adult RDA for iodine. Adding iodide to salt is voluntary in the United States, so not all salt has the trace mineral added to it.

Calcium Supplements

Many adults have difficulty consuming enough milk products and other calcium-rich foods to achieve adequate intake of the mineral. Thus, taking calcium supplements or antacids that contain calcium has become a common practice, especially among older adults. Dietary supplements containing calcium carbonate are the most commonly used products, and supplements made with calcium citrate are also available. The body absorbs both forms of calcium to about the same extent, however, products that include vitamin D enhance calcium absorption. Taking only 500 mg of calcium at a time and ingesting the supplement with meals also improves the mineral's absorption.

Sources of Calcium

Milk products, such as fluid milk, yogurt, and cheese, provide most of the calcium in American diets. Moreover, the calcium in milk products is well absorbed and used by the body. Not all products made from milk are rich sources of calcium. Milk loses about half of its calcium content when it is processed to make cottage cheese. Good plant sources of calcium include broccoli and leafy greens, especially kale, collard, turnip, bok choy, and mustard greens. Nevertheless, the calcium in plant foods is generally not as bioavailable as the calcium in milk and milk products. Calcium is added to a variety of foods, including fortified orange juice, margarine, soy milk, cereals, and breakfast bars. Another source of calcium is soybean curd (tofu) that is made with calcium sulfate.

Molybdenum Function, Food Source and Deficiency.

Molybdenum is a trace mineral required by all life forms. This essential mineral is a cofactor of four enzymes in humans, including sulfite oxidase and xanthine oxidase. Legumes such as beans, lentils, and peas are high in molybdenum, and grains and nuts are also good sources. The adult RDA for this mineral is 45 μg/day, and most Americans consume plentiful amounts of this essential mineral. A deficiency of molybdenum has not been reported in healthy individuals, and there is limited evidence of molybdenum toxicity in people who are healthy

Dietary Adequacy

Most Americans consume more than the RDA for selenium. Selenium deficiency is uncommon in the United States, but the condition may occur in people who have serious digestive tract conditions that interfere with the mineral's absorption. Selenium deficiency reduces thyroid gland activity, which can worsen an iodine deficiency and lead to goiter or cause cretinism. The deficiency also causes male infertility, depresses immune system function, and may contribute to the development of specific forms of heart disease and cancer. In parts of China where the soil lacks selenium and the population consumes only locally produced foods, diets are typically inadequate in selenium. Keshan disease, a cardiomyopathy (disease of the heart muscle), was common in selenium-deficient regions of China before food in the area was fortified with selenium. In areas of China, Tibet, Siberia, and North Korea, a form of osteoarthritis called Kashin-Beck disease develops as a result of selenium deficiency. Kashin-Beck disease is a degeneration of the cartilage between joints, which leads to deformity and dwarfism. The UL for selenium is 400 μg/day. In the United States, selenium toxicity (selenosis) is rare. Chronic selenosis, however, can occur from drinking well water that contains naturally high levels of selenium. Selenium toxicity can develop by taking megadoses of dietary supplements. In humans, signs and symptoms of chronic selenosis include brittle fingernails, loss of hair and nails, garlicky body odor, nausea, vomiting, and fatigue.

Causes of Hypertension

Most cases of hypertension do not have simple causes, but advanced age, African-American ancestry, obesity, physical inactivity, smoking cigarettes, and excessive use of alcohol, and high sodium intake are among the major risk factors for the condition. Blood pressure usually increases as a person ages, probably in part because of stiffening (arteriosclerosis) of the blood vessels. Healthy arteries are flexible tubes that expand with each heartbeat and recoil in between beats. Arteriosclerotic arteries are less flexible and cannot expand as much as healthy arteries. As a result, the heart must work harder to pump blood, and blood pressure becomes chronically elevated.

Sodium Toxicity

Most of the typical American's sodium intake comes from food bought in grocery stores, convenience stores, and restaurants. Only 10% of Americans' sodium intake is from salt added at home during food preparation and consumption. A high-sodium diet is associated with increased risk of hypertension, and in some cases, such diets can be a cause of hypertension. A person who is sodium sensitive is more likely to develop hypertension as a result of consuming a high-sodium diet than an individual who lacks this sensitivity. The kidneys of a sodium-sensitive person may be unable to eliminate excess sodium as effectively as the kidneys of a healthy person. The excess sodium causes the body to retain water, and blood volume and pressure increase as a result.

Food Sources of Sodium

Most uncooked vegetables, raw meats, and grain products are naturally low in sodium. Thus, most of the sodium Americans consume is from foods available from restaurants and the salt that is added to food during processing, during preparation, or at the table. As a food additive, salt enhances flavors and can prevent the growth of microorganisms responsible for food spoilage. Other common sodium-containing food additives include sodium nitrate, sodium citrate, and monosodium glutamate (MSG), a seasoning that may be added to foods served in Chinese restaurants. Salted snack foods, French fries, canned and dried soups, sauces and gravies, hot dogs and deli meats, cheeses, and pickled foods are high in sodium. Frequent consumption of these foods often leads to higher-than-recommended intakes of sodium. Although sodium is an essential mineral, diets that contain high amounts of sodium are associated with increased risk of hypertension.

Zinc Toxicity

The UL for zinc is 40 mg/day. Zinc intakes that exceed the UL can reduce beneficial HDL cholesterol levels. Ingesting more than 100 mg of zinc per day can also result in diarrhea, cramps, nausea, vomiting, and depressed immune system function. Additionally, megadoses of zinc may interfere with copper absorption and metabolism.

Calcium Toxicity

Normally, the small intestine prevents too much calcium from being absorbed. However, taking too many calcium-containing antacids or supplements or drinking too much vitamin D-fortified milk can result in excessive calcium absorption and hypercalcemia. It is a condition characterized by a higher-than-normal concentration of calcium in blood. Signs and symptoms of hypercalcemia include kidney stones, bone pain, muscle weakness, fatigue, and hypertension. Treatment for hypercalcemia may include avoiding vitamin D and calcium supplements to reduce calcium absorption.

Calcium Deficiency

Osteoporosis is a chronic disease characterized by low bone mass and reduced bone structure. People with osteoporosis have osteopenia, weak bones that are susceptible to fractures. In the United States, osteoporosis is a major public health problem. Over 53 million Americans either have osteoporosis or are at a high risk for the disease because they have low bone mass. Most people with osteoporosis are older adult women. Fractures, especially hip fractures, can be devastating events for older adults. Only about 15% of older people who break their hip can walk without assistance 6 months after the fracture occurred.21 Moreover, about 25% of older Americans who experience a broken hip die within 1 year of the injury. Most deaths result from complications after surgery to repair the broken hip.

Function of Iodine

People require iodine for normal thyroid function and for the production of different thyroid hormones, which are collectively referred to as thyroid hormone. Thyroid hormone controls the rate of cellular metabolism, that is, the rate at which cells use energy. If iodine intake is too low, the thyroid gland enlarges in an attempt to remove as much iodide as possible from the bloodstream. However, an enlarged thyroid gland can also be a sign of certain diseases and conditions that are not related to iodine intake, such as Graves' disease. In cases of Graves' disease, the thyroid gland produces and secretes too much thyroid hormone, causing hyperthyroidism. Signs and symptoms of hyperthyroidism include rapid heart rate, sweating, anxiety, and weight loss despite increased appetite. In some cases of the disease, the person's eyeballs bulge out of their normal position. Treatment may involve removal of part or all of the thyroid gland, as well as medications that reduce thyroid hormone production.

Treating Dehydration

People who are sick, especially children with fever, vomiting, diarrhea, and increased perspiration, may need to be given specially prepared solutions of water and electrolytes, called oral rehydration therapy, to prevent dehydration. More serious cases of dehydration require intravenous (IV) fluids. The immediate goals of both oral rehydration therapy and IV fluids are to restore blood volume, correct tissue fluid balance, and maintain rehydration.

People at Risk of Iron Toxicity

People with hereditary hemochromatosis (HH) absorb too much iron. The body has no way to eliminate the excess iron, so the mineral accumulates in tissues and can cause joint pain; abnormal bronze skin color; and damage to the liver, heart, adrenal glands, and pancreas. The organ damage that results from HH can lead to cirrhosis, liver cancer, diabetes, or cardiac arrhythmias (irregular heartbeats). Common signs and symptoms of HH include fatigue, lack of energy, abdominal pain, loss of sex drive, and heart problems. Even though people with HH begin accumulating iron early in life, they often do not report any signs and symptoms of the disease until they are over 30 years of age.

Phosphorus

Phosphorus is the second most abundant mineral in the body, making up about 1% of a person's total body weight. Approximately 85% of phosphorus is found in combination with calcium as part of bones and teeth. Although phosphorus is concentrated in the skeleton, the mineral is essential for every cell in the human body. Phosphorus is needed to: Synthesize adenosine triphosphate (ATP) and creatine phosphate, substances that are essential for energy production; Synthesize phospholipids, DNA, and RNA; Regulate acid-base balance; and Activate many enzymes and hormones necessary for energy metabolism.

Potassium

Potassium is the primary positively charged ion in the intracellular fluid. Most of the body's potassium is in cells. All cells need potassium, but nerve and muscle cells contain high amounts of the mineral. Like sodium, potassium plays a key role in maintaining proper fluid balance. Unlike sodium, potassium is associated with lower, rather than higher, blood pressure values. Potassium is also necessary for transmitting nerve impulses, contracting muscles, and maintaining normal kidney function.

Signs of Dehydration explanation

Rapid weight loss is one of the primary and initial signs of dehydration. Every 16 ounces (about 0.5 L) of water that the body loses represents a pound of body weight. When an individual loses 1 to 2% of his or her usual body weight in fluids, the person feels fatigued and thirsty. For example, if a woman weighs 150 pounds and her weight drops 3 pounds after exercising in hot conditions, she has lost 2% of her body weight, primarily as water weight. Thirst is the primary regulator of fluid intake in most people.1 The thirst response alerts the person to replenish water that was lost by sweating and other means, before severe dehydration occurs. The majority of healthy people meet their AI for water by letting thirst be their guide. However, people who are dehydrated and older than 60 years of age do not sense thirst as accurately as younger adults. Furthermore, older adults may be more susceptible to developing dehydration than younger persons because as kidneys age, they become less able to conserve water when fluid intakes are low. Therefore, it may be necessary to remind older adults to drink more fluids, especially when they are physically active or in warm conditions.

Sodium

Salt is the primary source of sodium in American diets. The chemical commonly called "table salt" or simply "salt" is actually sodium chloride, a compound comprised of two minerals, sodium and chloride. A teaspoon of table salt supplies 2325 mg of sodium. The human digestive tract absorbs almost all of the sodium that is in foods and beverages. As mentioned in the "Water" section of this chapter, sodium plays a major role in maintaining normal fluid balance. This mineral is also necessary for the transmitting impulses by nerves, normal functioning of muscles, and transporting small substances such as glucose and amino acids into cells.

Causes of Osteoporosis

Several factors contribute to bone loss and osteoporosis. Family history of osteoporosis, cigarette smoking, and excessive alcohol consumption are associated with increased risk of the disease. Loss of bone mass begins in mid-adulthood as levels of testosterone and estrogen ("sex hormones"), which are needed for normal bone development and maintenance, begin to decline. In women, however, the rate of bone loss increases significantly after menopause; that is, after menstrual cycles have ceased. At this time of life, women have the highest risk of osteoporosis. After menopause, a woman's ovaries produce less estrogen, and as a result, her rate of bone loss exceeds the rate of bone replacement. A simple way to monitor bone mass is by tracking height. Losing an inch or more of adult height may be the first sign that a person has experienced tiny fractures of the spine due to osteoporosis. If osteoporosis is suspected, a person can undergo painless x-ray bone testing to determine the extent of bone loss. People who are at high risk or who already have osteoporosis may require prescription medication to reduce their rate of bone loss.

Can minerals be destroyed?

Several minerals, including lead and mercury, are often found in the human body, but they are environmental contaminants that have no known function and can cause toxicity. Unlike vitamins, minerals are indestructible. Because minerals cannot be destroyed, heating a food or exposing it to most other environmental conditions does not affect the food's mineral content. However, minerals are water soluble, and they can leach out of a food and into cooking water. By using the cooking water to make soups or sauces, minerals from the food can be retained that would otherwise be discarded.

Possible Essential Minerals

Some minerals, including arsenic, boron, lithium, nickel, silicon, and vanadium, are found in small amounts in the body, but their roles in health are unclear. At present, this group of minerals is not classified as essential nutrients. Consumers can help lower their intake of dietary sources of inorganic arsenic by: Rinsing rice grains before cooking; Cooking rice using 6 cups of water for every 1 cup of rice and draining the remaining fluid, once the rice is cooked; Limiting apple juice consumption to 4 to 6 ounces/day for children under 6 years of age and 8 to 12 ounces/day for everyone else; and Consuming a variety of grains such as wheat, oats, quinoa, and millet.

Sulfur

Sulfur is a component of several organic compounds, including the amino acids methionine and cysteine, the vitamins biotin and thiamin, and the vitamin-like substance lipoic acid. Some foods and beverages, such as white wine, contain inorganic forms of sulfur (e.g., sulfites), which have been added to preserve the items. Sulfur is essential to the activity of many enzymes and as part of antioxidant molecules, including glutathione, a major antioxidant in the body.

Manganese Deficiency

The AI for manganese is 2.3 mg/day for adult men and 1.8 mg/day for adult women. Manganese deficiency rarely occurs in humans. Some experts suspect that the mineral may have a role in preventing osteoporosis, diabetes, and epilepsy. In laboratory animals, manganese deficiency interferes with reproduction, impairs growth, alters carbohydrate and lipid metabolism, and causes skeletal abnormalities.

Iodine Toxicity

The UL for iodine is 1.1 mg/day. Over time, consuming very high amounts of iodine can cause goiter and hypothyroidism. These outcomes are the same as those that occur when diets are deficient in iodine. In some cases, iodine toxicity causes hyperthyroidism. Also, excess iodine is associated with an increased risk of a form of thyroid cancer. It is difficult for someone to reach the upper limit for iodine intake from food alone. However, in regions where seaweed is a common component of the diet, such as in northern Japan, people have been known to consume more than 50 times the UL for iodine.

Iron Toxicity

The UL for iron is 45 mg/day. Iron overload occurs when toxic amounts of iron supplements are ingested, but toxicity also results from certain genetic conditions. Excess iron in the blood acts as an oxidant. Oxidants are free radicals that damage cell membranes, proteins, and DNA.

Dietary Adequacy of Chromium

The adult AIs for chromium are 25 μg for young women and 35 μg for young men. Well-balanced diets typically contain these amounts of chromium. On average, American adults consume diets that meet or exceed their AIs for chromium. Chromium deficiency can lead to impaired glucose tolerance, which often precedes the development of type 2 diabetes. In addition, elevated blood cholesterol and triglyceride levels can occur with a chromium deficiency. The mechanism by which chromium influences cholesterol metabolism is not known, but it may involve enzymes that control the body's cholesterol production. Cases of chromium deficiency have been reported in people maintained on special-formula diets that did not contain the trace mineral, as well as in severely malnourished children.

Dietary Adequacy

The adult RDA for iodine is 150 μg/day. Although most Americans have adequate iodine intakes, many young, American women have iodine intakes that are marginally adequate. Because iodine needs increase during pregnancy and lactation (milk production), some medical experts recommend that young women take a multivitamin and mineral supplement that provides 150 μg of iodine daily before pregnancy and during pregnancy and lactation.

Sources of Zinc

The bioavailability of zinc is enhanced when foods that contain the mineral are eaten with proteins, especially those with sulfur-containing amino acids Other factors that influence the bioavailability of zinc include the body's need for the mineral and the presence of large amounts of certain other metals. During times when a healthy body needs zinc, such as during pregnancy, the small intestine absorbs more. However, the presence of excess copper or iron in the small intestine interferes with zinc absorption. Thus, iron supplements should be taken between meals instead of with them to avoid suppressing zinc absorption.

Calcium: Maintaining Normal Blood Calcium Levels

The body has complex hormonal systems that maintain calcium homeostasis. The thyroid and parathyroid glands secrete certain hormones that help regulate blood calcium levels. In response to falling blood calcium levels, the parathyroid glands secrete parathyroid hormone (PTH), which signals special bone cells called osteoclasts to break down bone tissue. This process releases calcium from bones so the mineral can enter the bloodstream. PTH also works with vitamin D to increase intestinal calcium absorption and reduce calcium excretion in urine. When the level of calcium in blood is too high, the thyroid gland secretes the hormone calcitonin calcitonin signals another type of bone cell (osteoblasts) to remove excess calcium from blood and build bone tissue. Bone formation involves the incorporation of a crystalline structure that contains calcium and phosphorus, called hydroxyapatite, on the framework of bone tissue. As this process of bone mineralization continues, bone tissue gains strength and rigidity.

Water Distribution: Intracellular and Extracellular Water

The body has two major fluid compartments: intracellular water and extracellular water. Intracellular water is inside cells. Extracellular water surrounds cells (tissue or interstitial fluid) or is the fluid portion of blood (plasma). About two-thirds of the body's water is in the intracellular compartment. The body maintains the balance of compartmental fluids primarily by controlling concentrations of ions in each compartment. Ions are mineral elements or small molecules that have electrical charges, such as sodium, potassium, phosphate, and chloride ions. These ions are also called electrolytes. Maintenance of intracellular water volume depends to a large extent on the intracellular concentration of potassium and phosphate ions. In contrast, maintenance of extracellular water volume depends primarily on the extracellular concentration of sodium and chloride ions. Changes in the normal concentrations of these ions can cause water to shift out of one compartment and move into the other. For example, extracellular fluid that has fewer-than-normal sodium ions can cause water to move from the extracellular compartment into cells. When this occurs, the cells swell and can burst. In the opposite situation, extracellular fluid that has an excess of sodium ions can cause water to move out of cells. As a result, the cells shrink and die because they lack enough intracellular fluid to function.

Chloride

The concentration of chloride in extracellular fluid helps to regulate fluid balance. When extracellular chloride levels are low, extracellular fluid concentrations decrease as fluid moves into the cell. Cells then swell. In addition to regulating fluid balance, the negatively charged chloride and positively charged sodium ion provide electrolytic balance in the extracellular fluid. Chloride is also important for: Hydrochloric acid production (stomach); Regulation of acid-base balance; Transmission of nerve impulses; and Immune fighting response of the white blood cells. The chloride ion can be formed from the toxic gas chlorine (Cl2) when it reacts with sodium or hydrogen. Chlorine, but not chloride, is commonly used to disinfect pools, purify water, and clean clothes and household surfaces because Cl2 is highly toxic to cells.

Essential Minerals

The essential minerals are classified into two groups: major minerals and trace minerals. If the average adult needs 100 mg or more of a mineral per day, the mineral is classified as a major mineral; otherwise, the micronutrient is a trace mineral. The body also contains very small amounts of other minerals, such as nickel and arsenic. The essential nature of this particular group of minerals has not been fully determined.

Iron Deficiency Population At Risk

Vegetarians have a higher risk of iron deficiency than people who eat meat because meat provides heme iron. To avoid iron deficiency and iron deficiency anemia, vegetarians need almost twice as much iron as people who eat meat, up to 14 mg/day for men and 32 mg/day for premenopausal women. Vegetarians should be aware of dietary factors that can enhance or inhibit iron absorption from plant sources. Athletes who regularly perform long-distance running may lose iron during the high-impact activity. The iron in hemoglobin can be lost when RBCs rupture in feet as they pound the pavement. Also, runners experience increased blood loss in the gastrointestinal tract due to the jarring the body undergoes during running. Therefore, long-distance runners may need 30% more iron than people who are not as vigorously active.

Hydration Status

The simplest way to determine if an individual is consuming enough water is to observe the volume of his or her urine. When fluid intake is adequate, the kidneys produce enough urine to maintain fluid balance. If fluid consumption is more than needed, the kidneys eliminate the excess, and the body produces plenty of urine. If fluid intake is limited or the body loses high amounts of fluid, such as through heavy perspiration, the kidneys produce only small amounts of urine. In addition to urine volume, the color of urine may be a useful indicator of hydration status. Straw-colored (light yellow) urine can indicate adequate hydration, whereas dark-colored urine may be a sign of dehydration. However, the color of urine is not always a reliable guide for judging a person's hydration status. It is important to recognize that having a urinary tract infection or ingesting certain medications, foods, and dietary supplements, especially those containing the B vitamin riboflavin, can alter urine's color.

Dietary Adequacy of Fluoride

There is not enough information concerning human fluoride requirements to set an RDA for the trace mineral. The Food and Nutrition Board, however, set the Adequate Intake (AI) at 4 mg/day and 3 mg/day for adult men and women, respectively. Because fluoride is not an essential nutrient, it is unlikely that negative consequences will occur from having a low intake of this trace mineral. Nevertheless, people in communities with fluoridated water have 15 to 40% fewer dental caries than fluoride-deficient populations.

Iodine Deficiency

Throughout the world, millions of people are at risk of iodine deficiency. Goiter is often the first sign of iodine deficiency. Iodine-deficient people develop hypothyroidism, which is characterized by low blood levels of thyroid hormone. Other signs or symptoms of hypothyroidism include reduced metabolic rate, elevated blood cholesterol level, fatigue, difficulty concentrating on mental tasks, weight gain, constipation, and dry skin. Adequate iodine status is extremely important during pregnancy. Pregnant women who are iodine deficient have higher risk of stillbirths (giving birth to a dead infant) or having low-birth-weight babies. During fetal life, thyroid hormone is crucial for normal brain development. Thus, the fetus of an iodine-deficient woman is likely to be born with a condition called cretinism. Babies with cretinism have permanent brain damage, reduced intellectual functioning, and growth retardation. Worldwide, iodine deficiency is the most common cause of preventable intellectual disability. Pregnant women can reduce the risk of giving birth to infants with cretinism by consuming adequate amounts of iodine throughout pregnancy.

Treatment of Hypertension

Treatment for hypertension usually includes following dietary modifications; making some other lifestyle changes, such as managing stress; and taking prescription medications. In the United States, three in four individuals with hypertension are treated with prescription medications, and in many cases, patients require a combination of multiple medications. Such combination therapies have been shown to help hypertensive individuals meet their blood pressure goals. The Dietary Approaches to Stop Hypertension (DASH) diet is low in sodium, total fat, saturated fat, and cholesterol, and high in fruits, vegetables, and low-fat dairy products. Research indicates that people can lower their blood pressure and reduce their risk of CVD by following the DASH diet, losing excess body fat, and increasing their physical activity level.

Treating Iron Deficiency

Treatment for iron deficiency anemia generally includes iron supplements and the addition of iron-rich foods to the diet.

Iron Supplementation

Treatment for iron deficiency may include use of iron supplements. Because of the risk of iron toxicity, an iron supplement should only be taken if it has been recommended by a physician. If men and postmenopausal women take a multivitamin/multimineral supplement, they should choose one with a maximum of 10 mg of iron. Iron supplements can cause gastrointestinal distress, including stomach irritation, nausea, vomiting, diarrhea, or constipation

Iron Absorption

Under normal conditions, the body closely regulates iron absorption and conservation. The digestive system of healthy people absorbs only 5 to 8% of the iron that is in a typical diet. However, the intestinal tract can absorb more iron when the body's need for the trace mineral increases. For example, absorption of nonheme iron can be as high as 23% in women who are iron deficient. Calcium and iron compete for absorption in the small intestine, so a meal with high calcium content can inhibit iron absorption. Therefore, people should consume a variety of food sources of iron throughout the day. Some plant foods, such as spinach, contain nonheme iron, but oxalic acid in spinach binds to the mineral, reducing its absorption. Other naturally occurring compounds that reduce iron absorption include polyphenols, phytic acid (or phytates), and soy protein. Polyphenols are present in tea, coffee, wine, and some fruits and vegetables. Phytates are in several foods, including whole grains, rice, and legumes. Absorption of iron from phytate-containing legumes, such as soybeans, black beans, lentils, and split peas, may be as little as 2%.1 Soy protein, including the kind used to make tofu, also reduces iron absorption. Foods that are high in vitamin C increase intestinal absorption of the trace mineral. Adding a source of vitamin C to meals can increase the absorption of nonheme iron by 20%.5 People can also increase their absorption of nonheme iron by combining a small amount of heme iron (from meat) with foods that contain nonheme iron. In addition to heme iron, meat, fish, and poultry contain a factor (sometimes called "MFP factor") that enhances the intestinal tract's ability to absorb nonheme iron.

Water and Membrane Transport

Water helps transport water-soluble substances within and outside cells. A selectively permeable membrane is a barrier that allows the diffusion of certain substances and prevents the movement of other substances through it. Osmosis is the diffusion of a solvent, usually water, through a selectively permeable membrane, such as the plasma membrane of a human cell. The concentration of substances dissolved in the water, such as sodium ions or glucose, influences osmosis. Water moves from a region that has less material dissolved in it (is dilute) to a region that has more material dissolved in it. The diffusion stops when the concentrations of the material on either side of the plasma membrane are equal. To survive, a human cell carefully controls the passage of substances through its plasma membrane.

Water Intoxication

Water intoxication, however, can occur when an excessive amount of water is consumed in a short time period or the kidneys have difficulty filtering water from blood. The excess water dilutes the sodium concentration of blood, disrupting water balance and resulting in hyponatremia (low blood sodium). As a result of the imbalance, too much water moves into cells, including brain cells. Signs and symptoms of water intoxication may include drowsiness, nausea and vomiting, confusion, inability to coordinate muscular movements, bizarre behavior, and seizures. If the condition is not detected early and treated effectively, coma and death can result.

Blood Pressure Values

When a person's blood pressure is tested, two measurements are taken. The first measurement is the systolic pressure, which is the maximum blood pressure within an artery. This value occurs when the ventricles, the heart's pumping chambers, contract. The second measurement is the diastolic pressure, which measures the pressure in an artery when the ventricles relax between contractions. The systolic value is always higher than the diastolic value. For adults, healthy blood pressure readings are less than 120/80 millimeters of mercury (mm Hg).

Sodium Deficiency

While engaging in endurance physical activities, athletes may need to consume sports drinks containing sodium and other electrolytes to avoid dehydration and sodium depletion. Hyponatremia can also result from severe diarrhea or vomiting, and infants are especially at risk. Symptoms of mild to moderate hyponatremia include weight loss, headache, nausea, vomiting, diarrhea, fatigue, and muscle cramping. Serious hyponatremia can result in seizures, coma, and death if untreated. In such cases, prompt medical care is required to replace lost fluids and electrolytes.

Zinc Deficiency

Worldwide, approximately 2 billion people have a zinc deficiency. Signs and symptoms of zinc deficiency include loss of appetite, diarrhea, hair loss, skin rash, poor wound healing, impaired sense of taste, and mental slowness. In severe cases, zinc deficiency stunts a child's growth, leading to dwarfism and failure of sexual maturation. Zinc deficiency during pregnancy can cause serious complications, including premature birth and delivery of a low-birth-weight baby. Breastfed babies may be at risk of developing zinc deficiency. Although breast milk contains zinc, the milk does not supply enough of the trace mineral for infants who are older than 6 months of age. To increase the likelihood that their diets contain enough zinc, breastfed babies who are between 6 and 12 months of age need to consume foods that contain the trace mineral, such as meat and zinc-fortified infant cereal.

Water

Your body obtains water from beverages and foods, especially fruits, vegetables, and meats. The body also makes some water as a result of metabolism. Depending on a person's age, sex, and body composition, 50 to 75% of his or her body is water weight. Lean muscle tissue contains more water (about 73%) than fat tissue (about 20%).

Zinc Functions

Zinc is important for the functioning of over 300 enzymes. The trace mineral is necessary for growth and development, wound healing, the sense of taste and smell, DNA synthesis, and proper functioning of the nervous and immune systems.