Chapter 9

Foods Contribute to Water Intake

Current consumption patterns indicate that fluids provide about 80% of our total water intake, with plain water making up about 45% of those fluids and other beverages making up the rest. Food provides the remaining 20% of water toward meeting daily needs.

Sodium Outbreak

Currently, an estimated 90% of Americans exceed sodium recommendation and average about 3400 mg a day

Calcium and Bone Health

Peak bone mass is established at around age 30, so it is important, during the formative years of bone development, to consume adequate amounts of calcium and vitamin D.

Mineral Fact

The major minerals include sodium, potassium, chloride, calcium, magnesium, phosphorus, and sulfur; the essential trace minerals are iron, zinc, copper, iodine, selenium, molybdenum, and manganese. Two additional trace minerals, chromium and fluoride, have AIs, but there is little or no evidence (respectively) that they are essential nutrients

Fun Fact

The minerals sodium (Na), potassium (K), and chloride (Cl) maintain fluid balance in the body, transmit nerve impulses, and help muscles contract.

Electrolytes

electrically charged minerals (ions) dissolved in body fluids that balance the fluid outside the cells with the fluid inside the cells. With the help of the kidneys, electrolytes balance the fluid outside the cells with the fluid inside the cells.

Ions

elements that carry a positive or negative charge.

UL for Sodium

for adults 19 years and older is 2300 mg daily. No more than 1500 mg of sodium per day is advised for adults who would benefit from lower blood pressure, specifically those with prehypertension or hypertension.

Extracellular

found or occurring outside the cells of the body.

Intracellular

found within the body's cells.

Minerals

inorganic individual chemical elements obtained through foods that are essential in human nutrition

Calcium Homeostasis

the balance between the actions of parathyroid hormone, vitamin D, and the kidneys to tightly control blood calcium levels.X

Acid-Base Balance

the process by which the body maintains homeostasis of body pH; when this does not occur, the body cannot function normally, which can eventually lead to death.

Bone Remodeling

the process of continuous bone breakdown and rebuilding, which is required for bone maintenance and repair. Bone remodeling is necessary to maintain blood calcium levels; it is also required during bone growth in the young and in bone maintenance throughout life to allow bone to adapt to strain and to repair the microscopic damage that occurs daily.

Respiration

the process of transporting oxygen from the air to the cells within tissues (inhalation) and transporting carbon dioxide from cells to the air (exhalation).

Phosphorus

the second most abundant mineral in the body; it plays a critical role in bone health and energy metabolism and is an essential component of bone and cartilage, phospholipids, DNA, and RNA. In fact, there is some concern that Americans may be chronically over-consuming phosphorus, a potential problem considering that increased blood levels of the mineral have been associated with cardiovascular and other types of chronic diseases, particularly in people with kidney disease.

Dehydration

water deficiency resulting from fluid losses that exceed intake.

Phosphorus Deficiency/Excess

•Deficiency is rare -Readily found in protein-rich foods and food additives •Overconsumption is a concern -Increased levels are associated with cardiovascular and other chronic diseases, particularly in people with kidney disease

Dietary Approaches to Stop Hypertension (DASH) Diet

•Effective approach in helping lower blood pressure and reduce the risk of heart disease •Recommended by the American Heart Association and American College of Cardiology •Helps lower sodium intake and increases potassium, calcium, and magnesium intake •Emphasizes fruits, vegetables, whole grains, low-fat dairy products, poultry, fish and nuts The DASH eating plan shown above is based on a 2000 kcal/day diet. The DASH diet reduces sodium in the diet and encourages a variety of foods rich in nutrients, such as potassium, calcium, and magnesium.

Maintaining Fluid Balance in the Body

•Electrolytes - electrically charged minerals (ions) dissolved in bodily fluids -Sodium (Na+), potassium (K+), and chloride (Cl-) •Maintain fluid balance •Transmit nerve impulses •Muscle contraction •Transport nutrients The minerals sodium, potassium, and chloride maintain fluid balance in the body, transmit nerve impulses, and help muscles contract. When dissolved in bodily fluids, such as blood and urine and the fluids inside and outside our cells, these electrically charged minerals are known as electrolytes. Maintaining the right balance of electrolytes is necessary for the transport of nutrients, muscle contractions, and other processes.

Chloride (Cl)

•Found primarily in extracellular fluids •Involved in fluid balance •Half of hydrochloric acid (HCl) in gastric juices •Half of the mineral composition of table salt (NaCl) •Abundant in the diet along with sodium -Deficiency extremely rare •Overconsumption increases blood pressure Chloride is the third electrolyte involved in fluid balance. Like sodium, it is primarily found in extracellular fluids such as blood. Since chloride composes half of the mineral composition of table salt (NaCl), our chloride intake correlates directly to our sodium intake. In addition to its role in fluid balance, chloride forms half of hydrochloric acid (HCl), found in the stomach's gastric juices.

Potassium Toxicity

•Rare; likely only from supplement misuse •Symptoms -Low heart rate -Abnormal heart rhythm •Supplementation should be prescribed and monitored by a health care provider -FDA limits over-the-counter potassium supplements (including multivitamin/mineral pills) to less than 100 milligrams (2% of RDA of 4,700 milligrams) due to the risk of the side effects Potassium supplementation may sometimes be warranted, but should be prescribed and monitored by a health care provider because of the potential side effects.

Magnesium Toxicity

•Rare from food sources alone •High intake from supplements can result in -Diarrhea, nausea, and abdominal cramping •Toxicity reported with very large doses of magnesium-containing laxatives and antacids

Magnesium Deficiency

•~60% of American adults do not consume recommended amount of magnesium •Deficiency symptoms rare -Kidneys excrete less when intake is low and body may absorb more •May increase osteoporosis risk •May also increase risk of: -Atherosclerosis -Type 2 diabetes -Hypertension

Osmosis

A process by which water (but not solutes) passes through a selectively permeable membrane, from a less concentrated area into a more concentrated one.

Balance of Sodium and Potassium

A recently published study found that a 20% decrease in the ratio of the sodium-to-potassium intake decreased the risk of hypertension by about 15%. Researchers further estimate that a 20% decrease in sodium intake with a 20% increase in potassium intake would reduce the risk of cardiovascular disease by 20%. Recent dietary survey data indicate that only about 10% of American adults have sodium-to-potassium ratios that align with a reduced risk of overall mortality.

Too Much Sodium

Add to this the fact that we're all eating way too much sodium—on average, we ingest 50% more than the Tolerable Upper Intake Level (UL) set by the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine—it's no wonder that one in three Americans has hypertension. According to a 2011 study published by researchers at the U.S. Centers for Disease Control and Prevention, a high consumption of sodium and low consumption of potassium work in concert to threaten health, increasing the risk of death from any cause by 50% and doubling the risk of death from heart attacks.

Hypokalemia

decreased blood levels of potassium.

Water Intake Recommendations for Ages 19 to 30 Years Living in Moderate Climates

Because people vary so much in terms of how much water they need each day, there is not an established Recommended Daily Allowance (RDA) or Estimated Average Requirement (EAR) for water. However, in 2004, the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine set an AI value of 3.7 liters (about 15½ cups) of total water intake per day for men living in temperate climates and 2.7 liters (about 11½ cups) per day for women living in temperate climates. The AI totals include water from a combination of food, drinking water, and other beverages. The body also produces a small amount of water as a byproduct of metabolic reactions, which also helps meet our total water needs.

Bone Remodeling

Calcium plays an indispensable role in bone and tooth formation. In fact, bone is constantly being broken down and rebuilt in a process known as bone remodeling. Bone remodeling is necessary not only to maintain blood calcium levels, but also during bone growth in the young and in bone maintenance throughout life to allow bone to adapt to strain and to repair the microscopic damage that occurs daily.

DASH Diet

Dietary Approaches to Stop Hypertension; a food plan that moderates sodium intake while increasing the intake of foods rich in potassium, calcium, and magnesium to assist with blood pressure control.

Binders

Dietary elements such as phytates and oxalates that limit bioavailability of other nutrients by chemically binding to minerals. Binders, such as phytates, found in whole cereal grains; oxalates, found in spinach and some vegetables; and polyphenols, present in coffee and tea, can limit bioavailability by chemically binding to minerals. Minerals can also compete with one another for absorption. For example, excess iron consumption from supplements can interfere with zinc absorption. Finally, the presence of certain vitamins can also affect bioavailability. Vitamin D, for instance, actually boosts absorption of calcium and phosphorus.

Fun Fact

Few American adults have usual intakes of potassium that meet or exceed the Adequate Intake (AI) levels set by the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine. Recent data reveals that less than 25% of males and less than 1% of females achieve AI levels

Where do humans absorb most minerals in?

Humans absorb most minerals in the small intestine, and both active and passive processes transport them into the blood for distribution and use throughout the body. Mineral absorption is influenced by their bioavailability, the ability of nutrients to be absorbed and utilized in the body, which is itself affected by various factors. When a person is deficient in a mineral or the needs for that mineral have increased, the absorption and bioavailability of that mineral tends to increase

Soft Water

Likewise, consuming 2 liters of "soft" tap water generally contributes rather insignificant amounts of sodium to overall intake, but in some areas, it can add up to almost half of the daily sodium recommendations.

Classification of Minerals

Major Minerals > 100 mg/day: •Sodium •Potassium •Chloride •Calcium •Magnesium •Phosphorus •Sulfur Trace Minerals < 100 mg/day •Iron •Zinc •Copper •Iodine •Selenium •Molybdenum •Manganese •Fluoride •Chromium Essential minerals are categorized according to how much we need each day. •Major minerals ("macro" minerals) have a daily requirement of 100 milligrams or more. •Trace minerals ("micro" minerals) have a daily requirement of less than 100 milligrams. Both major and trace minerals play critical roles in human health.

Structural Roles in the Body

Minerals make up approximately two-thirds of the mass of the skeletal system and are involved in growth and maintenance of cellular membranes and connective tissues. Three major minerals of particular importance for bone formation and maintenance are calcium, phosphorus, and magnesium; with crystals of primarily calcium and phosphorus laid down on a matrix of proteins (predominantly collagen, a structural protein found in connective tissue) during bone formation. Accounting for 98% of the body's mineral content by weight, calcium, phosphorus, and magnesium play key roles in the development and maintenance of bone and other calcified tissues.

Fun Fact

Minerals often function as parts of enzymes and hormones, participate in chemical reactions, transmit nerve impulses, maintain fluid balance, and support the immune system. They can also work with enzymes as cofactors, inorganic substances that facilitate and catalyze chemical reactions. Minerals play roles in energy metabolism, the chemical reactions that release energy from food. Minerals also help build and maintain structural components in the body, such as bones, teeth, cell membranes, and connective tissue. Minerals can't be synthesized by the body, so they must be ingested through diet.

Tap Water

Tap water may contribute as little as 6% of overall intake of calcium or magnesium but can add around 30% with consumption of approximately 2 liters a day in some areas.

Dietary Sources of Calcium

The Health and Medicine Division of the National Academy of Sciences, Engineering, and Medicine has set the AI for calcium at 1000 milligrams per day for men and women age 19 to 50 years; the Tolerable Upper Intake Level (UL) is set at 2500 milligrams. Calcium-rich foods include milk, yogurt, and cheese, as well as some legumes, and certain dark-green leafy vegetables, such as Chinese cabbage, kale, and broccoli. Because these vegetables are low in oxalates, the bioavailability of calcium is high: About 50% is absorbed. In contrast, though spinach is high in calcium, it is also high in oxalates that bind calcium and inhibit its absorption. Consequently, the bioavailability of calcium in spinach is low: Only about 5% is absorbed. Calcium is also added to some grains, juices, tofu, and cereals. Milk, an excellent natural source of calcium, is usually fortified with vitamin D, which works with calcium to promote bone health. Most studies indicate that calcium from food is better absorbed than calcium from supplements. This is likely due to improved absorption with meals and the tendency of people to consume smaller amounts of calcium more frequently, which likely improves absorption efficiency.

Mineral Fact

The best way to get essential minerals is to eat an adequate, varied, and balanced diet.

Water Consumption

The body of an adult man is approximately 60% water and an adult woman is about 55% water—with water composing about 75% of the mass of muscle and 15% of adipose tissue mass (fat). As people age, they typically lose muscle mass and gain fat, which will decrease the percent of body mass made up of water. The brain and heart are made of approximately 73% water, but bone is only 10% water. Because water can't be compressed, it helps to protect delicate tissues such as the brain, eyes, and spinal cord against injury and shock.

Water Balance: Input Must Equal Output

To remain in water balance, fluid input must equal fluid output. This figure shows the approximate amounts of water sources and losses for an average 20-year-old man who is sedentary and does not have extensive water loss from sweating. One of the reasons we need to drink fluids is because we lose water throughout the day and our bodies cannot store extra to fill the void. But how much water we need to drink depends on many factors. We lose, on average, about 350 ml, or 1½ cups, of water each day through respiration, the process of transporting oxygen from the air to the cells within tissues (inhalation) and, conversely, transporting carbon dioxide to the air (exhalation). When we breathe, water evaporates from the lungs and the skin. How much water we lose while respiring depends on the air temperature and our body temperature, how active we are, how humid the air is, and how big our bodies are. The more we respire—for instance, when we exercise and breathe hard—the more water we lose.

Solvent

a liquid substance that is capable of dissolving another substance. Water acts as solvent.

Water Loss

We lose, on average, about 350 ml, or 1½ cups, of water each day through respiration, the process of transporting oxygen from the air to the cells within tissues (inhalation) and, conversely, transporting carbon dioxide to the air (exhalation). We lose 140 ml to 150 ml of water, or about two-thirds of a cup, through our bowel movements, too When we suffer diarrhea, we lose from 3300 ml to 7300 ml of water a day—as much as 70 times what we would lose through normal bowel movements. Our water needs can fluctuate because of other factors as well. We need more water when we are ill, because we respire more with a fever and our body perspires to cool itself. Vomiting also increases water loss. Furthermore, we need more water when we eat high-protein diets, in part because water is necessary to remove the byproducts of protein metabolism that accumulate in the blood. High-fiber diets increase our water needs, too, because fiber increases the water content of our stools, making it easier for us to pass them.

Antidiuretic Hormone and Water Balance

When the concentration of solutes in the blood increases, or when blood volume drops, the brain responds by stimulating the pituitary to release antidiuretic hormone (ADH). ADH tells the kidneys to conserve water to bring more water back into the bloodstream, which will also lower the concentration of solutes. When the brain detects that water volume has increased again, it decreases the production of ADH so that the kidneys stop conserving water. Without ADH, urine becomes very dilute. Thirst is typically a powerful and rapid barometer that tells us when we need to drink (and conversely, lack of thirst tells us when we don't need to drink). The same factors (an increase in solutes in the blood or a drop in blood volume) that stimulate the release of ADH also stimulate the brain to generate the sensation of thirst. Thus, ADH and thirst work in concert to increase body fluids and decrease the concentration of solutes in blood. However, in persons older than the age of 65, the thirst sensation is often diminished when they become dehydrated or experience increased solute concentrations in blood, which slows the restoration of fluid balance.

Osteoporosis and Bone Mass

With age, the balance of calcium release and deposition in bone changes. During years of growth, such as childhood, more calcium is added to bone in relation to the amount lost, but as we get older, bone breakdown often exceeds formation. Peak bone mass is established at around age 30, so it is important, during the formative years of bone development, to consume adequate amounts of calcium and vitamin D. If intake is low or absorption is impaired, bone loss occurs because the body uses the calcium in bone to maintain blood levels and support calcium-dependent bodily functions. A significant number of Americans have low bone mass. Although some bone loss is a normal consequence of aging, bone loss accelerates in postmenopausal women because of low levels of the hormone estrogen. This reduced bone mass, or bone density, along with reduced mineral content, can lead to a condition called osteopenia. When osteopenia becomes severe, and bone loss worsens to cause bones to become fragile and porous, a person develops osteoporosis, or "porous bones," and the risk of bone fractures is dramatically increased. Osteoporosis afflicts more than 10 million Americans; approximately one-half of all women and one-fourth of all men older than 50 years of age experience osteoporosis-related bone fracture.

Osteoporosis or "porous bones"

a bone disease in which the bone density and total mass are decreased, leading to porous bones, increased fragility, and susceptibility to fractures. Osteoporosis afflicts more than 10 million Americans; approximately one-half of all women and one-quarter of all men older than 50 years of age experience osteoporosis-related bone fracture.

Hyponatremia

a condition characterized by a low blood sodium concentration and clinical signs of confusion, nausea, vomiting, bloating, and swelling around the brain; may be seen in athletes who consume excess water with no sodium.

Osteopenia

a condition characterized by low bone mineral density.

Solutes

a dissolved substance.

Interstitial Fluid

a fluid that surrounds the cells of the body and creates an aqueous environment.

Hypercalcemia

a high level of calcium in the blood.

Parathyroid Hormone (PTH)

a hormone released from the parathyroid gland in response to low blood calcium levels.

Magnesium

a mineral that is a cofactor in more than 300 chemical reactions in the body; as an ion, it plays a role in muscle contraction, nerve impulse conduction, and heart rate maintenance. Most of it—about 50-60%—is found in the bones; the rest is in the cells and fluids of the body. Magnesium plays a role in the transport of ions across the cell membrane, a process that is important to muscle contraction, nerve impulse conduction, and maintenance of the rhythm of the heart. Magnesium is involved in extracting energy from carbohydrates, fats, and protein, as well as using that energy to perform work; it also plays a role in protein production. Magnesium is also necessary to convert vitamin D into its active form (calcitriol) to increase calcium absorption; thus, magnesium plays an important role in bone health. Approximately 60% of American adults do not consume the recommended intake level of magnesium

Chloride

a mineral that is an electrolyte involved in fluid balance; it is often found in table salt (NaCL). is the last of the three electrolytes involved in fluid balance Because chloride composes half of the mineral composition of table salt (NaCl), our chloride intake correlates directly to our sodium intake

Sodium

a mineral that is commonly consumed in table salt, it is also known as sodium chloride (NaCl); it is the primary electrolyte responsible for maintaining fluid balance between cells and throughout the body. Table salt contains 40% sodium and 60% chloride, so a teaspoon of salt that weighs about 6 grams contains about 2400 mg of sodium. An essential nutrient, sodium is the primary electrolyte responsible for maintaining fluid balance between cells and throughout the body. It plays a crucial role in regulating blood pressure and is the major positively charged ion in extracellular fluids such as blood. It is also required to transmit nerve impulses and contract muscles and is involved in the active transport of a number of nutrients. For instance, sodium is required to move glucose and amino acids into cells. For instance, sodium is required to move glucose and amino acids into cells. Its role in the active transport of a variety of compounds also means that it is needed indirectly to maintain the body's acid-base balance and a stable pH.

Sulfur

a mineral that is present in protein-rich foods; it is present in the vitamins thiamin and biotin as well as the amino acids cysteine and methionine. It is present in the B vitamins thiamin and biotin, and it is present in two of the amino acids (cysteine and methionine) that are found in our body's proteins as well as those we eat. Because sulfur is a component of all proteins, deficiency is virtually unknown. Toxicity is also rare because the body can excrete excess sulfur in the urine.

Potassium

a mineral that is the primary electrolyte in cells; it works with sodium and chloride to maintain fluid balance.

Antidiuretic Hormone (ADH)

a peptide hormone produced by the hypothalamus, with the primary function of decreasing the amount of water excreted by the kidneys; stored and released in the posterior pituitary gland. Without ADH, urine becomes very dilute.

Osmosis

a process by which water passes between intracellular and extracellular spaces (or compartments) through cellular membranes.

Water

an essential nutrient that has critical functions in the body.

AL level for sodium

at 1500 mg per day for men and women aged 19 to 50 years

Hypertension

blood pressure of at least 130/80 mmHg most of the time; a major risk factor for cardiovascular disease and stroke. 2017 guideline from the American Heart Association (AHA) as having a blood pressure of at least 130/80 mmHg most of the time. High blood pressure used to be defined as levels of 140/90 mmHg or above. According to the AHA, the change means 46% of U.S. adults are identified as having high blood pressure, compared with 32% under the previous definition. A blood pressure of less than 120/80 mmHg still will be considered normal, but levels at or above that, to 129, will be called "elevated." Hypertension is a major risk factor for cardiovascular disease and stroke.

RDA for calcium

is at 1000 mg per day for women aged 19 to 50 years and men aged 19 to 70 years

UL for Calcium

is set at 2500 mg

Calcium (Ca)

is the most abundant mineral in the body, with 99% found in bones and teeth, where it provides an essential structural component for their formation. The other 1% is located in the body cells and fluids, where it is necessary for many essential functions such as blood clotting, hormone secretion, muscle contraction, and nerve transmission.

Major Minerals

minerals with a daily requirement of 100 mg or more: sodium, potassium, chloride, calcium, magnesium, phosphorus, and sulfur.

Trace Minerals

minerals with a daily requirement of less than 100 mg: iron, zinc, copper, iodine, selenium, molybdenum, fluoride, manganese, and chromium

Magnesium (Mg)

•50% to 60% is found in bones •Functions: -Cofactor in more than 300 chemical reactions -Role in the transport of ions across cell membranes for muscle contraction, nerve impulse conduction, and maintaining heart rhythm -Involved in extracting energy from carbohydrates, proteins, and fats -Role in protein production -Necessary in activating vitamin D -Bone health An adult body contains about 25 grams of magnesium, most of which—about 50% to 60%—is found in the bones; the rest is in the cells and fluids of the body. Magnesium plays a role in the transport of ions across the cell membrane, a process that is important to muscle contraction, nerve impulse conduction, and maintaining the rhythm of the heart. Magnesium is involved in extracting energy from carbohydrates, fats, and protein, as well as using that energy to perform work; and it plays a role in protein production. Magnesium is also necessary to convert vitamin D into its active form (calcitriol) to increase calcium absorption, so it plays an important role in bone health.

Sodium Intake and Sources

•AI (19-50 years) = 1500 mg/day •UL (age 19 and over) = 2300 mg/day •1 teaspoon table salt (NaCl) = 2400 mg sodium Currently, an estimated 90% of Americans exceed sodium recommendation and average about 3400 mg a day, but that number varies by age and sex. We get most of our sodium from packaged processed and restaurant foods, with only about 10% coming from salt added at the table and another 10% coming from "fresh" unprocessed foods.

Water Makes Up 60% to 70% of Our Bodies

•Adult male has more total body water than an adult female •Ratio of water in body's organs varies -Muscle 75% water -Heart and brain 73% water -Adipose tissue 15% water -Bone 10% water Approximately 60% to 70% of our bodies are made up of water, but the ratio of water to other substances in our tissues varies, depending primarily on the ratio of fat mass to lean body mass (body composition), which is strongly influenced by age and sex. The body of an adult man is approximately 60% water and an adult woman is about 55% water—with water composing about 75% of the mass of muscle and 15% of adipose tissue mass (fat). As people age, they typically lose muscle mass and gain fat, which will decrease the percent of body mass that is water. Organs have different water percentages, too: The brain and heart are made of approximately 73% water, but bone is only 10% water.

Mineral Absorption and Bioavailability

•Bioavailability affected by nutritional status -Deficiency in a mineral -Increased need -Presence of binders in foods •Phytates •Oxalates •Polyphenols -Competition with other minerals -Presence of vitamins Humans absorb most minerals in the small intestine, and both active and passive processes transport minerals into the blood for distribution and use throughout the body. Mineral absorption is influenced by their bioavailability, the ability of nutrients to be absorbed and utilized in the body, which is affected by various factors. One such factor is nutritional status. When a person is deficient in a mineral or the needs for that mineral have increased, the absorption and bioavailability of that mineral tends to increase. For instance, during pregnancy, a woman's body absorbs calcium more efficiently than usual. Likewise, people absorb less of minerals if they already have enough. Note that although absorption of minerals slows during overconsumption, it doesn't stop—so it is still possible to consume excess, or even toxic, amounts of minerals.

Calcium Toxicity

•Combined with dietary sources, calcium supplements may push intake over recommended levels •Upper tolerable intake level (UL) = 2500 mg •Can cause: -Constipation -Interfere with iron absorption -Hypercalcemia Studies show that more than 60% of women older than 60 years take calcium supplements, which could push their intake close to the UL. High dietary intakes may cause constipation and potentially interfere with iron absorption. Although rare in healthy people, excess intake may contribute to hypercalcemia, or excess calcium in the blood

Sulfur (S)

•Component of proteins -in amino acids: cysteine and methionine •Present in B vitamins thiamin and biotin •Deficiency unknown •Toxicity rare -Excess is excreted in the urine Sulfur is a mineral that occurs in our diet as a component of other compounds. It is present in the vitamins thiamin and biotin; it is also present in two of the amino acids (cysteine and methionine) that are found in our body's proteins, as well as proteins that we eat. When we need to synthesize sulfur-containing compounds, the ultimate source of that sulfur is almost invariantly one of those amino acids. Because sulfur is a component of all proteins, deficiency is virtually unknown. Toxicity is also rare because the body can excrete excess sulfur in the urine.

Inadequate or Excess Water Intake has Adverse Effects

•Deficiency = dehydration -Nausea -Dizziness -Elevated temperature -Concentrated urine •Water intoxication = hyponatremia -Confusion -Nausea -Vomiting -Bloating -Swelling around the brain Athletes who consume excess water without sodium may develop hyponatremia, a condition characterized by a low blood sodium concentration and clinical signs of confusion, nausea, vomiting, bloating, and swelling around the brain. The symptoms of hyponatremia sometimes mimic the symptoms of dehydration, or deficiency of water. Dehydration is typically caused by excessive sweating, excessive urine output (because of diuretic use or uncontrolled diabetes), fever, vomiting, or diarrhea. It is also a widespread problem in developing countries, where safe, drinkable water can be hard to find. Although 70% of Earth is composed of water, only 3% of it is fresh and drinkable.

Sodium Overconsumption

•Increases risk of hypertension •Studies show blood pressure rises progressively with sodium intake > 2,300 mg/day •American Heart Association: -Now defines high blood pressure > 130/80 mmHG -~46% adults have high blood pressure •Major risk factor for cardiovascular disease and stroke High blood pressure previously defined as levels of 140/90mmHg or above. AHA redefined in 2017 to 130/80 - the new guideline is in part intended to help people take steps to reduce risk by identifying and controlling their blood pressure earlier.

Potassium Power

•Lewis K. Dahl, MD -Pioneering research on the relationship between sodium and hypertension •Sodium increased risk of hypertension •Potassium protected against hypertension

Sodium (Na+)

•Major positively-charged ion in extracellular fluid •Functions: -Maintaining fluid balance -Regulating blood pressure -Transmitting nerve impulses -Contracting muscles -Involved in nutrient transport -Indirectly needed to maintain the body's acid-base balance and a stable pH An essential nutrient, sodium is the primary electrolyte responsible for maintaining fluid balance between cells and throughout the body.

Potassium Deficiency

•Mild forms (common in the U.S.) -Increase risk of hypertension, stroke, and heart attacks •Severe depletion causes hypokalemia -Usually from excessive fluid loss through vomiting, diarrhea, use of diuretics, or kidney disorders -Fatigue -Muscle weakness -Abnormal heart rhythms -Increased calcium excretion -Reduced insulin production Milder forms of potassium deficiency—which are common in the United States, as most Americans get only about half the potassium they should—can increase the risk of hypertension, stroke, heart attacks, and other health problems.

Calcium (Ca)

•Most abundant mineral in the body •99% in bone and teeth -Structural component -Reservoir of calcium •1% in body cells and tissues -Blood clotting -Hormone secretion -Muscle contraction -Nerve transmission Calcium is the most abundant mineral in the body, with 99% found in bones and teeth, where it provides an essential structural component for their formation. Bones provide a reservoir of calcium that can be tapped to supply calcium to body fluids when its concentration in blood decreases

Phosphorus (P)

•Present in every cell of the body •Functions: -Component of bone and cartilage, phospholipids, DNA, and RNA -Involved in energy metabolism -Regulates many enzymes and other proteins -Helps maintain acid-base balance Phosphorus is the second most abundant mineral in the body. It plays a critical role in bone health and is an essential component of bone and cartilage, phospholipids, DNA, and RNA. It is also involved in energy metabolism, and a multitude of enzymes and other proteins depend upon phosphorus to regulate their activity. Phosphorus is important in the maintenance of proper acid-base balance in the body.

Potassium (K)

•Primary electrolyte within cells •Functions: -Maintains fluid balance (along with sodium and chloride) -Acts as a cofactor for certain enzymes -Plays a role in nutrient transport -Helps nerves transmit and muscles contract -Helps maintain electrical activity of the heart to sustain a steady heartbeat •May counter the effects of excess sodium on blood pressure Potassium may also help relax blood vessel walls, which can lower blood pressure. Potassium is found in a wide range of minimally processed foods, particularly fruits and vegetables.

Roles of Water in the Body

•Regulates body temperature •Transports nutrients and oxygen •Lubricates joints •Present in mucus and salivary juices •Helps delicate tissues •Acts as a solvent •Removes waste Water has many important roles in the body. It helps regulate body temperature within a very narrow range, which is important because even slight variations can affect body functions and damage organs. Water transports nutrients and oxygen to tissues in the body. It is also present in the mucus and salivary juices of the digestive system, which help to move food through the digestive tract. Water lubricates joints and the mucous membranes in our noses, eyes, and gastrointestinal tract. Since water cannot be compressed, it helps to protect delicate tissues like the brain, eyes, and spinal cord against injury and shock.

Diverse Functions of Minerals

•Regulatory and structural functions: -Work in partnership with other minerals -Part of hormones and enzymes -Transmit nerve impulses -Maintain fluid balance -Support immune system -Act with enzymes as cofactors to facilitate chemical reactions Minerals have diverse regulatory and structural functions. Many work in partnership with other minerals. They often function as parts of enzymes and hormones, participate in chemical reactions, transmit nerve impulses, maintain fluid balance, and support the immune system. They can also work with enzymes as cofactors—that is, as inorganic substances that facilitate and catalyze chemical reactions. Like many of the B vitamins, minerals also play roles in energy metabolism, the chemical reactions that release energy from food. In addition, minerals help build and maintain structural components in the body such as bones, teeth, cell membranes, and connective tissue.

Overview of Minerals

•Solid, stable, inorganic elements that are essential with diverse regulatory and structural functions •Cannot be broken down into smaller constituents •Cannot be destroyed by heat, light, cooking, or digestion •Minerals are ions -Elements with positive or negative charge •Unequal number of protons and electrons •Allow minerals to participate in chemical reactions and bond with other molecules minerals make up about 4% of our body weight, with major minerals composing more of that weight and trace minerals composing less. There are 14 minerals for human health and nutrition. Minerals are solid, stable inorganic elements. Unlike vitamins, minerals cannot be broken down into smaller constituents or destroyed by heat, light, cooking, or digestion.

Minerals in Food

•Tap water -Hard water contains calcium and magnesium -Soft water contains sodium •Plants -Reflect mineral content of the soil •Animal foods -Better source of minerals •Whole, unprocessed foods -To maximize mineral intake Minerals in plants reflect the mineral content of the soil in which they are grown. As a result, mineral content can vary drastically depending on the region in which the plants are grown and the farming practices used to grow them. Animal foods are typically a better source of minerals, in part because animals eat plants and concentrate their nutrients. Processing can boost, but tends to reduce mineral content. The best way to get essential minerals is to eat whole, unprocessed foods. Tap water, too, can be a source of some essential minerals.

Water Balance in the Body

•Two-thirds of water is intracellular •One-third of water is extracellular •Direction of movement depends on the concentration of solutes -Sodium, potassium, chloride are most important solutes -Water moves toward areas with greater concentration of solutes and lower concertation of water molecules Approximately two-thirds of the water in our bodies is intracellular, or found inside cells. The rest is extracellular, found outside cells, primarily in the blood and the fluid that surrounds our cells (interstitial fluid). Water may move from the outside to the inside of cells, and vice versa, in a process called osmosis. The direction of water movement depends on the concentration of solutes, dissolved substances in the intracellular and extracellular fluids. Some of the most important solutes are the electrolytes sodium, potassium, and chloride. Water moves across a membrane toward areas where there is a greater concentration of solutes and therefore a lower concentration of water molecules.

Calcium Homeostasis

•When calcium levels fall -The parathyroid gland releases parathyroid hormone (PTH) -PTH stimulates production of active vitamin D •Increases calcium absorption in the intestine -PTH and activated vitamin D mobilize calcium from the bone and decrease calcium excretion from the kidneys When calcium in blood falls even slightly, it is released from bone to maintain steady blood calcium levels. The process by which the body maintains calcium levels in the blood is known as calcium homeostasis. When blood calcium levels fall, the parathyroid gland releases parathyroid hormone (PTH), which stimulates the production of the active form of vitamin D (calcitriol) and thereby increases calcium absorption from the intestine.

3 in 10 People Worldwide Lack Access to Safe, Drinkable Water

•Without sustainable access to sufficient, safe supply of water -Dehydration -Increased bacterial and viral diseases impacting children most •Growing concerns about water supply and safety globally: -Increases in population -Declining sources -Impact of changing food preferences -Poor water management -Violations of safety regulations -Aging infrastructure of water sources Although 70% of Earth is composed of water, less than 3% is fresh and potentially drinkable.