Chapter 5Mineral Requirements of the Older

Adult

Minerals

• Inorganic• Essential• Regulatory processes• Structural functions

Minerals

• Major minerals– Electrolytes

• Calcium, phosphorus, magnesium, sodium, chloride, potassium

• Important for action potentials of cells, nerve conduction, and muscle excitation

• Part of metabolism• Body water and blood volume regulation, blood

pH, nerve conduction, and muscle contraction

Minerals

• Major Minerals– Calcium, phosphorus, magnesium, sodium,

chloride, and potassium– Recommended intakes expressed as

• DRIs, RDA, AI, ULs– Have antioxidant properties– Amounts in food varies– Cannot be destroyed with cooking or processing

Calcium

• Functions– Maintain structure of bone– Vasodilatation and vasoconstriction– Muscle contraction– Blood clotting– Nerve transmission

Calcium

• Absorption and Metabolism– Saturable

• Increases calcium uptake

– Nonsaturable

Calcium• Absorption

– Negative effect• Fiber, oxalic acid, Phytic acid, Caffeine, Fat, and

Phosphorus– Calcium balance

• Urinary loss–Sodium intake–Protein intake

• Calcium intake• Calcium in blood

Calcium

• Recommendations– 1,200 mg/day– Supplements may be required

• Typical Intakes of Older Adults– NHANES III findings below AI

• Food Sources– Dairy, fortified foods, dark green leafy vegetables,

shellfish, tofu

Nutrition Facts

• Calcium on Food Labels– Calcium as percent– 40% = 400 mg of

calcium

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Calcium

• Deficiency– Osteoporosis

• Toxicity– Adverse effects

• Kidney stones, kidney damage, and alteration in absorption or metabolism of other minerals

Calcium

• Special Considerations– Calcium absorption requires Vitamin D– Osteoclasts are stimulated by Vitamin D– Lactose intolerance considerations

• Lactase– Serum calcium maintained in narrow range

• Parathyroid hormone (PTH)

Phosphorus

• Hydroxyapatite• Phospholipids• Roles

– As acid-base buffer– In enzymatic reactions– In energy transfer

Phosphorus

• Absorption and Metabolism– From 55% to 70%– Can be reduced by aluminum-containing antacids

or medications, and by calcium carbonate– Hormone and kidney regulation

• Recommendations– RDA 700 mg/day

Phosphorus

• Typical Intakes of Older Adults– Generally meet the RDA

• Food Sources– Found in nearly all foods

• Meat, milk products, eggs, grains, legumes, soft drinks

Phosphorus

• Deficiency– Known only to occur with starvation– Refeeding– Very high intake of aluminum-containing antacids

• Toxicity– Not known to occur in persons with healthy

kidney function• Special Considerations

– Persons with renal disease

Magnesium

• Roles– Found in the bone– Cofactor for enzyme reactions– Needed for DNA and RNA synthesis– Required for muscle contractions– Maintain cellular ionic balance

Magnesium

• Absorption and Metabolism– Proportional to the amount ingested

• Recommendations– Men 51 or older – 420 mg/day– Women 51 or older – 320 mg/day

• Typical Intakes of Older Adults– Mean intake ~ 300 mg/day– Varies with calorie intake

Magnesium• Food sources

– Green leafy vegetables, fruits, grains, nuts– Milk, meat, eggs, shellfish

• Deficiency– Rare

• Toxicity– Occurs only with renal disease

• Special Considerations– Risk of toxicity in those with impaired renal

function

Sodium

• Roles– Extracellular cation– Required for maintaining extracellular fluid

volume and plasma volume– Membrane potential – Active transport of nutrients

Sodium

• Absorption and Metabolism– Renin-angiotensin hormonal system

• Recommendations– AI age 51 to 70 years is 1,300 mg/day– AI age older than 70 is 1,200 mg/day

• Typical Intakes of Older Adults– Generally higher than recommendations

Sodium

• Food Sources– Sodium chloride, or salt

• Processed meats, snack foods, canned soups, cheese, canned fish, salted nuts

• Deficiency and Toxicity– High sodium intake – hypertension– Low blood sodium – hyponatremia

• Special Considerations– Salt sensitivity

Chloride

• Roles– Anion in extracellular fluid– A main determinant of extracellular volume– Important in digestion

• Absorption and metabolism– Renin-angiotensin hormonal system

• Recommendations– AI for age 51 to 70 is 2.0 g/day– AI for age older than 70 is 1.8 g/day

Chloride

• Food Sources– Sodium chloride, or salt, salted foods, snack foods,

salted nuts, processed foods

• Deficiency and Toxicity– Attributable to sodium intake

• Special Considerations– Excess vomiting – Diuretics use

Potassium

• Roles– Main intracellular cation– Role in Cardiac function, neural transmission,

muscular contraction, vascular tone, acid-base metabolism, glucose metabolism

• Absorption and Metabolism– Kidney maintains potassium balance– Serum levels do not reflect potassium status– Large amount in the muscles

Potassium

• Recommendations– AI for age older than 50 is 4.7 g/day

• Typical Intakes of Older Adults– Generally less than the AI

• Food Sources– Fruits and vegetables, meat and dairy products,

and tea and coffee, can be added as a preservative

Potassium

• Deficiency and Toxicity– Hypokalemia results from increased potassium

excretion

• Special Considerations– Increased losses through sweat– Diuretics use can increase potassium losses

Iron

• Functions– Essential for oxygen transport

• Hemoglobin• Myoglobin

– Cellular respiration and metabolism• Cytochromes

– Energy metabolism– Immune function

Iron

• Absorption and Metabolism– Recycled– Absorbed

Iron

• Absorption and Metabolism– Stored as ferritin and as hemosiderin– Present in hemoglobin in RBC

• Recommendations– RDA for adults older than 50 is 8 mg/day

• Typical Intakes of Older Adults– Mean intake 14.9 + 36.9 mg/day

Iron

• Food Sources– Heme iron

• Animal products– Nonheme iron

• Cereal and vegetables

Iron

• Deficiency and Toxicity– Three stages of deficiency

• Depleted iron stores• Early functional iron deficiency• Iron deficiency anemia

• Special Considerations– Chemotherapy medication– Dialysis patients– Inflammation/infection

Zinc

• Roles– Catalyst for about 100 enzymes– Structural component in many proteins– Regulator of gene expression– Essential for immune function and growth– Required for normal smell and taste– Required for skin integrity

Zinc

• Absorption and Metabolism– Higher absorption from meat products– Phytic acid (in vegetables) reduces absorption

• Recommendations– RDA for men older than 51 is 11 mg/day– RDA for women older than 51 is 8 mg/day

• Typical Intakes of Older Adults– Generally meets RDA

Zinc• Food Sources

– Meat, seafood, whole grains, legumes

• Deficiency– May result in alopecia, dermatitis, and impaired

immune function

• Toxicity– Possible from supplementation

• Special Considerations– Vegetarianism and alcohol may impair absorption

Copper

• Role– Co-factor in a number of enzymes

• Absorption and Metabolism– Varies with intake– Circulates in blood

• Recommendations– RDA for age 51 and older is 900 mg/day

• Typical Intakes of Older Adults– Generally meets RDA

Copper• Food Sources

– Organ meats, seafood, nuts, seeds, liver, mixed nuts, peanut butter

• Deficiency– May result in anemia and reduced WBC

• Toxicity– May result from contamination of food or

beverages• Special Considerations

– Supplemental zinc intake or penicillamine decrease copper absorption

Chromium

• Absorption and Metabolism– Poor absorption– Trivalent chromium is most common form

• Recommendations– AI for men 51 years or older is 30 mcg/day– AI for women 51 years or older is 20 mcg/day

• Typical Intakes of Older Adults– Amount in foods not quantified

Chromium

• Food Sources– Contamination by stainless steel containers– Food sources: bran cereals, beer, wine, fruits and

vegetables, eggs, meat

• Deficiency and Toxicity– Rare

• Special Considerations– Increased losses in type 2 diabetes

Selenium

• Roles– As an antioxidant– Role in detoxification

• Absorption and Metabolism– Most that is ingested is absorbed

• Recommendations– RDA for persons over 55 years is 55 mcg/day

• Typical Intakes of Older Adults– Generally meets RDA

Selenium

• Food Sources– Variable in plants– Found in garlic, broccoli, meat, and seafood

• Deficiency– Not common in the U.S.

• Toxicity– Can result from food sources or supplements

• Special Considerations– Can be linked to Vitamin E

Aluminum

• Role– No physiologic role– Possible role in Alzheimer’s disease

• Absorption and Metabolism– Small amount is absorbed

• Recommendations– No recommended intake levels

• Food Sources– Water, foods cooked in aluminum cookware

Aluminum

• Deficiency and Toxicity– Has negative effects on several other minerals– Hypothesized to interfere with normal brain

function

Molybdenum

• Role– Involved in oxidation and detoxification reactions

• Absorption and Metabolism– Rates from 50% to 93% absorption

• Recommendations– RDA for older than 51 years is 45 mcg/day

• Typical Intake of Older Adults– Unknown

Molybdenum

• Food Sources– Leafy vegetables, grains, legumes, kidneys, liver,

and milk

• Deficiency and Toxicity– None reported

Manganese• Role in

– Protein, fat, and carbohydrate metabolism– Enzyme reactions– Bone formation– Normal immune function, reproduction, digestion,

blood clotting• Absorption and Metabolism

– Small amount is absorbed• Recommendations

– AI for men older than 51 is 2.3 mg/day; women 1.8 mg/day

Manganese

• Typical Intakes of Older Adults– Generally meets AI

• Food Sources– Unrefined grain products, tea, nuts, leafy

vegetables• Deficiency

– Due to poor intake has not been reported• Toxicity

– Due to inhaled manganese dust

Nickel

• Role– No biochemical role in humans

• Absorption and Metabolism– Typically less than 10%

• Recommendations– No recommendations

• Typical Intakes of Older Adults– Median intake of 80-97 mcg/day

Nickel

• Food Sources– Mixed dishes and soups, grain products,

vegetables, legumes, desserts, meat

• Deficiency and Toxicity– Not been found in humans

• Special Considerations– Those who are nickel sensitive, or with renal

disease

Iodine

• Role– Part of thyroid hormones

• Absorption and Metabolism– Almost completely absorbed

• Recommendations– RDA for older than 50 years is 150 mcg/day

• Typical Intakes of Older Adults– Generally higher than RDA

Iodine

• Food Sources– Dairy products, marine fish, foods grown in

iodine-rich soils, seaweed, some salt

• Deficiency and Toxicity– Early symptoms show as enlarged thyroid

• Special Considerations– Rare in U.S.

Fluoride

• Role– Bone and teeth structure

• Absorption and Metabolism– About ½ of ingested is absorbed

• Recommendations– AI for men 4 mg/day; women 3 mg/day

• Typical Intakes of Older Adults– Not reported

Fluoride

• Food Sources– Water and foods or beverages made with

fluoridated water

• Deficiency and Toxicity– Toxicity is called fluorosis in tooth enamel and

bone

Conclusion

• Major Minerals• Trace Minerals• Mineral requirements for older healthy people• Chronic conditions associated with aging that

alter several mineral intake needs– Osteoporosis– Hypertension– Diminished renal function