Unit 4: Minerals
What if you don't consume enough phosphorus?
Deficiencies of phosphorus are rare
Mineral Balance
- Body maintains tight control over mineral balance - GI tract -- Regulates absorption from food based on the body's need -- Minerals in gastric juices and that slough-off intestinal cells are either excreted in the feces or reabsorbed through the large intestine - Kidneys -- Excretes excess and reabsorbs the minerals when the body needs them
Iron overload
- Body usually protects itself from over-absorption of iron - Hemochromatosis: iron overload -- Usually genetic disorder that enhances iron absorption -- Other causes: repeated blood transfusions, massive doses of supplementary iron, rare metabolic disorders - Symptoms—similar to those of iron deficiency - Apathy, Lethargy, Fatigue - Characteristics -- Tissue damage, Infection -- More severe symptoms in alcohol abusers - Symptoms appear earlier in men than women -Fortification of foods makes an iron-restricted diet difficult
Calcium in bone
- Calcium salts crystallize on protein collagen during formation of bones - Crystals become denser, adding strength & rigidity to mature bone - Continuously gain & lose minerals -- Active bone growth from birth until about 20 years: modifying width, length, shape -- Peak bone mass development between ages 12-30 -- Final phase of growth (starting around age 30-40 & continuing throughout life)—bone loss exceeds new bone formation -- Excessive loss of minerals leads to problems (i.e. osteoporosis)
Zinc deficiency
- Causes -- Observed in diets low in zinc & high in fiber & phytates (impair absorption) -- Blood loss due to parasitic infection -- Increased sweat loss -- Ingestion of clay -Symptoms & effects -- Dwarfism, severe growth retardation -- Arrested sexual maturation -- Impaired immune function -- Loss of appetite -- During pregnancy, growth & development disorders
Hypothyroidism
- Decreased production of T4 & T3 - Causes: -- autoimmune response -- stress hormones -- pregnancy -- hyperthyroidism treatment
Magnesium deficiency
- Deficiency: - Causes -- Vomiting, diarrhea -- Alcohol abuse -- Protein malnutrition -- After long-term infusion of incomplete IV fluids following surgery -- With diuretic use - Severe deficiency causes tetany - May be related to cardiovascular disease & hypertension - May be related to risk of colon cancer - May be cause of hallucinations during withdrawal from alcohol - Toxicity: -Most common through abuse of magnesium-containing laxatives, antacids, other medications - Consequences -- Lack of coordination -- Confusion -- Coma -- Death, in extreme cases
Fluoride Roles and actions
- Diets high in fluoride during growing years produce crystalline deposits in bones & teeth -- Fluorapatite: stabilized form of bone & tooth crystal -- Bones become stronger; teeth more resistant to decay - After eruption of teeth, topical application (through toothpaste or mouth rinse) exerts caries-reducing effect
Zinc Storage & release
- Extra stores maintained in intestinal cells—only amount needed released into bloodstream - Zinc status affects percentage absorbed from foods - Primarily transported in blood by albumin (serum concentrations decline in conditions that lower plasma albumin)
Potassium
- Fluid and electrolyte balance - Very important in muscle contractions and transmission of nerve impulses - High potassium intake helps to maintain a lower blood pressure - Recommended intake 4700 mg/day
Fluoride sources & recommendations
- Found in all normal diets, especially those containing fish & tea - Primary sources -- Fluoridated drinking water -- Processed soft drinks & juices made with fluoridated water -- Fluoride toothpastes, gels, oral rinses - Fluoride AI Men: 4 mg/day Women: 3 mg/
Sources of phosphorus
- Found widespread in many foods - Found in high amounts in foods that contain protein (such as meat, milk, eggs) - More readily absorbed from animal sources - Phytic acid prevents absorption of phosphorus from plant sources
Selenium: Roles & actions
- Functions as part of group of antioxidant enzymes (glutathione perioxidases) -- Prevents formation of free radicals—blocking damage before it starts -- Works in concert with vitamin E - Role in converting thyroid hormone to active form Selenium & cancer - Role in protection against development of some cancers under investigation
Chloride
- Functions of chloride -- Coupled with sodium in the extracellular fluid to maintain fluid balance -- Part of hydrochloric acid (HCl) in stomach aiding digestion -- Assists the immune system -- Assists in the transmission of nerve impulses - Recommended intake -- AI: 2300 mg/day
What if you consume too much phosphorus?
- High blood phosphorus can occur with kidney disease or when taking too many vitamin D supplements - Causes muscle spasms, convulsions
What if you consume too much potassium?
- Hyperkalemia is a high blood potassium level - Can occur in patients with kidney disease - Can alter normal heart rhythm resulting in a heart attack and death - Must avoid consuming potassium-containing salt substitutes
What if you consume too much sodium?
- Hypernatremia is abnormally high blood sodium concentration - Can happen to patients with congestive heart failure or kidney disease - Results in high blood volume, edema, and high blood pressure
What if you don't consume enough potassium?
- Hypokalemia is low blood potassium levels - Can be seen in patients with kidney disease or diabetic ketoacidosis - Can occur when taking certain diuretic medications
What if you don't consume enough sodium?
- Hyponatremia is an abnormally low blood sodium level - Can result from prolonged vomiting, diarrhea, or sweating - Has been seen in marathon athletes who consume too much water
Roles of major minerals
- Influence on fluid balance (especially sodium, chloride, potassium) - Transmission of nerve impulses & muscle contractions (sodium, potassium, calcium, magnesium) - Energy metabolism (phosphorus, magnesium) - Contribution to bone structure (calcium, phosphorus, magnesium) - Intakes: consuming too much of one mineral may suppress the absorption of another mineral. Ex: consuming too much Phosphorus will decrease Calcium absorption.
Iodine
- Integral part of thyroid hormones, which regulate... -- Body temperature -- Metabolic rate -- Reproduction -- Growth --Manufacture of blood cells --Muscle & nerve function -- Other roles
Sodium
- Involved in fluid and electrolyte balance - Main electrolyte in the extracellular compartment - Associated with blood pressure and pH balance in the body - Required for nerve impulse transmission - Assists in the transport of certain nutrients (e.g., glucose) into body cells - AI: 1500 mg, most recommend ~2500 mg/day - Processed foods are high in sodium - High blood pressure from high sodium diets
Thyroid system
- Iodine + Amino acid Tyrosine → ( used to form) T3 and T4 - TSH circulating in the bloodstream tells the thyroid to make T3 and - - T4 thyroid hormones - and release them into the bloodstream - T4 is a pro-hormone that is converted into T3 (mainly by the liver); T3 is the active hormone
Iron - Recommendations
- Iron RDA for adults -- Men (>19 years): 8 mg/day -- Women (19-50 years): 18 mg/day -- Women (>50 years): 8 mg/day - Average diet provides about 6-7 mg in 1000 kcalories -- Men usually do not have problem reaching RDA (based on 2000 kcalorie/day diet) -- Women generally receive about 12-13 mg/day -- Premenopausal women need to select iron-rich foods at every meal
Magnesium: Roles & actions
- Majority (about 50%) found in bone - Also in muscles, heart, liver, other soft tissues - Only about 1% in body fluids - Critical to operation of hundreds of enzymes - Part of protein-making action in cells of soft tissue - Necessary for release of energy - Helps muscles to relax after contraction
Calcium & obesity
- May play role in maintaining healthy body weight -- Inverse relationship between calcium intake & body fatness -- Calcium from dairy foods (not supplements) seems to influence weight -- More research needed to determine effects of dietary calcium on body weight
Calcium Food Sources
- Most abundant in milk & milk products - Daily consumption of low-fat or fat-free milk products recommended - Other foods fortified, offering large amounts -- Juices -- Cereals -- Some mineral waters EX: sardines, milk, turnip greens, waffle, broccoli, tofu, cheddar cheese
Fluorosis
- Mottling of tooth enamel - Caused by ingestion of excess amounts of fluoride during tooth development - Irreversible - Tolerable Upper Intake Level: 10 mg/day (adults) - Prevention -- Monitor fluoride content in water supply -- Supervise children during tooth brushing (to prevent swallowing) -- Use supplements only as prescribed
Major minerals
- Need to consume > 100 milligrams per day - At least 5 grams of the mineral in the body these include: - calcium -chloride -magnesium -phosphorus -potassium -sodium -sulfur
Trace minerals
- Need to consume > 20 milligrams per day - The body contains less than 5 grams total these include: -arsenic -boron -chromium -cobalt -copper -fluoride -iodine -iron -manganese -molybdenum -nickel -selenium -silicon -vanadium -zinc
Risk factors for zinc deficiency
- Not widespread in developed countries - Most vulnerable groups in US: pregnant women, young children, elderly, poor - Pregnant teenagers require zinc for their own growth, as well as that of fetus -Vegetarians may also be at risk -- Those who emphasize whole grains, legumes, other plants: foods are rich in zinc, but contain phytate (potent inhibitor of zinc absorption) -- Those who exclude all animal-derived foods may require greater intake --Those who include cheese, eggs, other animal protein absorb more zinc than those who exclude these foods
Calcium in body fluids
- Only 1% of body's calcium circulates in body fluids - Still, is vital to life - Assists with... -- Regulation of muscle contractions -- Transmission of nerve impulses -- Clotting of blood -- Secretion of hormones, digestive enzymes, neuro-transmitters - Conveys impulses received at cellular surface to the inside of cell; activates proteins involved in action - Cofactor for several enzymes
Sources of potassium
- Processed foods are usually low in potassium - Good sources: fresh fruits, vegetables, and whole grains - Most salt substitutes are made from potassium chloride
Copper deficiency, etc.
- Rare, but not unknown - Seen in premature and malnourished infants - High intakes of zinc interfere with absorption -Toxicity --Some genetic disorders can result in toxicity --Toxicity from food intake is unlikely --Tolerable Upper Intake Level: 10,000 g/day -Recommendations & food sources --Best sources include legumes, whole grains, seafood, nuts, seeds --Copper RDA for Adults: 900 g/day
Minerals
- Remain intact during digestion - Generally do not change shape or structure when performing biological functions - Most minerals absorbed from the diet are in the form of water-soluble salts - Are not destroyed by heat, acid, oxygen, or ultraviolet light - Mineral bioavailability: Degree to which a nutrient from food is absorbed and utilized in the body
Zinc: Roles and actions
- Required as cofactor by more than 200 enzymes -- Performing tasks in eyes, liver, kidneys, muscles, skin, bones, male reproductive organs -- Assists in manufacture of genetic material & heme -- Assists in digestion & metabolism of nutrients - Interacts with platelets in blood clotting - Affects thyroid function, immune function - Affects behavior & learning
Chromium
- Roles & actions -- Participates in carbohydrate & lipid metabolism -- Enhances activity of insulin, requiring less insulin to control blood glucose Deficiency: diabetes-like condition -- Elevated blood glucose --Impaired glucose --tolerance, insulin response, glucagon response -- Deficiency unlikely to occur Recommendations & sources - Unrefined foods best source -- Liver -- Brewer's yeast -- Whole grains, nuts -- Cheeses
Copper roles and actions
- Serves as constituent of enzymes - Diverse metabolic roles -- Catalyze formation of hemoglobin -- Help manufacture of collagen -- Assist in healing of wounds -- Maintain sheaths around nerve fibers -- Required in reactions related to respiration & energy metabolism - Vital role: assist cells to utilize iron
Calcium & hypertension
- Some evidence that calcium protects against hypertension - DASH diet -- Effective in lowering BP -- Rich in calcium, potassium, magnesium -- Combined with reduced sodium intake, diet is even more effective in lowering BP
Calcium-binding proteins
- Some foods contain calcium-binders that prevent calcium absorption -- Some dark green, leafy vegetables, fibers in plant foods -- Phytate & oxalate - Vitamin D assists body to regulate absorption of calcium -- Alters production of calcium-binding protein -- Infants & children absorb about 60% of calcium ingested -- Pregnant women absorb about 50% -- Other, non-growing adults absorb about 25%
Assessment of iron deficiency
- Stages -- Iron stores diminish -- Transport of iron decreases -- Hemoglobin production declines
Iron poisoning
- Sudden death can result from rapid ingestion of large amounts of iron - Accidental poisoning in children usually result of ingestion of iron supplements—as few as 6-12 tablets can be lethal - Improved labeling & packaging urged by American Academy of Pediatrics
Functions of phosphorus
- The major intracellular negatively charged electrolyte - Required for fluid balance - Critical role in bone formation - Regulates biochemical reactions by activating or deactivating enzymes (phosphorylation) - Found in ATP, DNA, RNA, cell membranes (phospholipids), and lipoproteins - Recommended intake -- RDA for phosphorus is 700 mg/day
Iodine Toxicity and recommendations
- Toxicity -- Excessive intakes also result in enlargement of thyroid gland -- Tolerable Upper Intake Level: 1100 g/day (adult) -Recommendations & sources -- Iodine RDA: 150 g/day -- Oceans provide major source ---Seafood, water, sea mist in coastal areas ---Inland, sources are variable, depending on soil content ---In US & Canada, use of iodized salt meets requirements
Iron deficiency
- Usually caused by inadequate intake -- Poor food choices -- Overall lack of food -- High consumption of iron-poor foods -- High sugar & fat intakes often associated with low iron intake - Blood loss is primary non-nutritional cause
Factors that reduce bioavailiability
- binders, such as oxalates found in some vegetables - phytates found in grains - polyphenols in tea and coffee - supplementation of competing minerals
Factors that increase Bioavailability
-deficiency in a mineral increases absorption - cooking increases the bioavailiability of minerals in legumes - vitamin C increases the absorption of some minerals such as iron - vitamin D increases the absorption of calcium, phosphorus, & magnesium
What if you don't consume enough chloride?
This is rare but can occur in people with eating disorders
Magnesium: Food sources
- "Hard" water contains calcium & magnesium -- Contributes significantly to magnesium intakes - Food sources include -- Dark green, leafy vegetables -- Nuts & legumes -- Whole-grain breads & cereals -- Seafood --Chocolate & cocoa Easily lost from foods during processing
Iron food sources
- 2 forms - Heme iron: most absorbable form -- Bound into iron-carrying proteins in meat, poultry, fish -- Contributes small portion of iron consumed—absorbed at rate of about 23% - Non-heme iron: less absorbable form -- Found in meats & plant foods -- Absorbed at lower rate (about 2-20%) -- Absorption depends on dietary factors & iron stores - Iron absorption enhanced by MFP factor & vitamin C -- Meat, fish, poultry contain MFP factor that promotes iron absorption -- Vitamin C eaten at same meal doubles or triples non-heme absorption -Absorption impaired by tannins & phytates EX: clams, beef steak, navy beans, black beans, enriched cereal, spinach, swiss chard, beef liver
goiter
- A deficiency of iodine leads to decreased production of T3 and T4, enlarges the thyroid tissue and will cause the disease known as
Zinc Food sources
- Abundant in foods high in protein content -- Shellfish (especially oysters) -- Meats & liver - Other proteins also provide good source if eaten in large quantities -- Milk, eggs -- Whole-grain products -- Breast milk for infants, zinc-fortified infant formulas - 2 ordinary servings of animal protein per day provide most of zinc requirements for healthy individuals - Supplements not recommended unless accurate diagnosis of zinc deficiency or other unusual medical conditions EX: oysters, shrimp, beef steak, enriched cereal, yogurt, pork chop
Calcium: Roles & actions
- Adequate intake early in life helps growth of skeleton & prevention of bone disease later -- Body's most abundant mineral -- 98% stored in bone --- Integral part of bone structure --- Serves as calcium bank, supplying body fluids when blood calcium levels drop
Symptoms of iron deficiency
- Affects on behavior - Impaired energy metabolism - Impaired temperature regulation - Fatigue and reduced work capacity & productivity
What if you consume too much chloride?
- All dietary chloride come from salt - May lead to hypertension in salt-sensitive patients
Iron: Roles and actions
- All living cells contain iron -- Most is component of hemoglobin in red blood cells (RBC) & myoglobin in muscle cells -- Assists with carrying & release of oxygen - Recycled as RBCs die -- Liver saves iron -- Returned to bone marrow for building new RBCs -- Only small amounts of iron are lost - 10-15% of dietary iron absorbed -- Diminished supplies, or increased need (i.e. during pregnancy) results in increased absorption - Transferrin: blood protein that carries iron to tissues throughout body - Ferritin & hemosiderin: storage proteins
Selenium - Deficiency
- Associated with heart disease in children & young women in regions of China - Soil & foods lack selenium Toxicity -High doses become toxic -Symptoms --Vomiting, diarrhea --Loss of hair & nails --Lesions of skin & nervous system Recommendations & intakes - Normal diet composed of mostly unprocessed foods provides adequate intake -Sources include meats & shellfish, vegetables & grains grown in selenium-rich soil -Selenium RDA for adults 55 g/day
Calcium Recommendations
- Blood calcium concentration does not reflect calcium status -- Optimal intake reflects amount needed to retain the most calcium -- The more calcium retained, the greater the bone density, reducing risk of osteoporosis - Calcium AI -- Adolescents: 1300 mg/day -- Adults 19-50 years: 1000 mg/day -- Adults 51 & older: 1200 mg/day
Calcium balance
- Blood concentrations tightly controlled -- Increase in blood levels: hormones & vitamin D promote deposit of calcium into bone -- Decrease in blood levels: regulatory actions occur in 3 locations to increase levels --- Increased absorption by small intestine ---Increased release from bone --- Decreased excretion by kidneys - Bone stores of calcium provide nearly inexhaustible source for blood -- Chronic dietary deficiency or deficiency due to poor absorption does not change blood levels -- Bone storage supplies are depleted to maintain blood level - Blood levels change only in response to regulatory control—not to diet
Iron deficiency
refers to depleted body stores— not degree of depletion or presence of anemia
Iron-deficiency anemia
refers to severe depletion of iron stores, resulting in low hemoglobin concentration
Foods rich in iodine
seaweeds, sea salt, strawberries, fennel, Himalayan crystal salt, broccoli, coconut oil, spinach, cranberries, watercress
