Micronutrients are vitamins and minerals—nutrients required by the body in small
amounts—yet have powerful effects. They assist in energy-producing reactions,
growth and development, protect against free radical damage, and perform many
vital functions. Micronutrients are essential for health, and a defi ciency can lead to
health problems and disease.
In 2002 the US Food and Nutrition Board, the Institute of Medicine, and Health
Canada released a report providing reference values for nutrient intakes for healthy
North Americans, including:
• Recommended Dietary Allowance (RDA): The average daily dietary nutrient intake
level suffi cient to meet the nutrient requirement of nearly all (97–98 percent)
healthy individuals in a particular life stage and gender group.
• Adequate Intake (AI): The recommended average daily intake level based on observed
or experimentally determined estimates of nutrient intake of apparently
healthy people that are assumed to be adequate. The AI is given when an RDA
cannot be determined.
• Tolerable Upper Intake Level (UL): The highest average daily nutrient intake level
that is likely to pose no risk of adverse health effects for almost all individuals in the
general population. As intake increases above the UL, the potential risk of adverse
effects may increase.
In this chapter I have outlined the essential vitamins, minerals, and trace elements;
their functions in the body; their role in disease prevention and treatment; defi ciency
symptoms; drugs that deplete; and supplement guidelines.
The table at the end of this chapter summarizes food sources, recommended intake
levels, and possible side effects and toxicity for the various nutrients. For some
nutrients an RDA has not been established; however, an AI is provided. It is important
to note that the RDA is mainly based on information on short-term effects. The optimum
nutrient intake for health and disease prevention may be higher than the RDA,
and varies with age, state of health, diet, and other factors.WHO NEEDS SUPPLEMENTS?
There are many factors that cause nutrient depletion, such as poor diet, stress, exercise,
use of prescription drugs, environmental toxicity, and excessive alcohol intake. For
many micronutrients, defi ciency, inadequate intake or nutrient depletion is common
relative to the RDA. This is why supplements are so important in making up for shortcomings
in the diet and preventing defi ciencies.
VITAMINS
There are 13 essential vitamins that our bodies need for proper growth, function, and
maintenance of healthy tissues. The vitamins are either water-soluble or fat-soluble.
The B-vitamins and vitamin C dissolve in water and are easily eliminated from the
body. Adverse reactions, even with high-dose supplements, are rare with these vitamins.
Fat-soluble vitamins (A, D, and E) are not readily excreted from the body
and have the potential to accumulate in the tissues and cause adverse effects at high
doses.
Vitamin A
• Found in animal foods and converted from beta-carotene in plant foods.
• Required for vision, gene expression, reproduction, embryonic development, red
blood cell production, and immune function.
• Prescription vitamin A derivatives are used to treat skin conditions (acne) and retinitis
pigmentosa (genetic eye disease).
• Defi ciency is rare in Canada, but common in developing countries due to malnutrition.
It causes night blindness, dry eyes and skin, and impaired growth.
• Drugs that deplete vitamin A: cholestyramine, colestipol, mineral oil, and neomycin.
• Supplements should be avoided by those at risk of lung cancer (smokers) or liver
toxicity (alcoholics, liver disease).
• Doses greater than 10,000 IU daily should be avoided by pregnant women due to the
risk of birth defects. Most prenatal vitamins provide 5,000 IU.
• Doses greater than 5,000 IU may increase risk of osteoporosis.
• Supplements of vitamin A beyond what is provided in a multivitamin are not recommended
due to risk of toxicity. To avoid this risk, choose a multivitamin that
contains beta-carotene, which is converted to vitamin A in the liver, but is not associated
with health risks.
Vitamin B1 (Thiamine)
• Required for energy production, nerve and muscle function, enzyme reactions, and
fatty acid production.
• Defi ciency causes beriberi, a disease that affects cardiovascular, nervous, muscular,
and gastrointestinal systems.
• Defi ciency is common in developing countries; in North America it occurs in alcoholics,
those with kidney disease, malabsorption syndromes (celiac disease), and
in those with poor diets.
• Drugs that deplete vitamin B1: furosemide, antibiotics, oral contraceptives, and
phenytoin.
• Most people get adequate thiamine from diet and/or a multivitamin.
Vitamin B2 (Ribofl avin)
• Required for energy metabolism, enzyme reactions, vision, and skin/hair/nail
health; functions as an antioxidant; activates vitamin B6, niacin, and folate.
• May play a role in preventing migraine headaches and cataracts.
• Defi ciency occurs in alcoholics, the elderly, and those with poor diets.
• Symptoms of defi ciency include sore throat; redness/swelling of the mouth, throat,
tongue, lips, and skin; decreased red blood cell count; and blood vessel growth over
the eyes. Defi ciency may impair iron absorption and increase risk of pre-eclampsia
in pregnant women.
• Drugs that deplete vitamin B2: antibiotics, chlorpromazine, amitriptyline, adriamycin,
and phenobarbitol.
• Most people get adequate ribofl avin from diet and/or a multivitamin.
Vitamin B3 (Niacin)
• Required for energy metabolism, enzyme reactions, skin and nerve health, and
digestion.
• High doses of nicotinic acid (3 g daily) can lower cholesterol (reduce LDL and triglycerides
and increase HDL) and reduce the risk of heart attack and stroke; high
dosages should be supervised by a physician.
• Defi ciency causes pellagra, the symptoms of which are skin rash, diarrhea, dementia,
and death.
• Defi ciency may be caused by poor diet, malabsorption diseases, dialysis, and HIV.
• Drugs that deplete vitamin B3: antibiotics, isoniazid, and 5-Fluorouracil (chemotherapy).
• High-dose niacin, taken along with statin drugs (i.e., lovastatin), may increase the
risk of rhabdomyolysis (muscle degeneration and kidney disease).
• Most people get adequate niacin from diet and/or a multivitamin; supplements may
be recommended for those with high cholesterol.
Vitamin B5 (Pantothenic Acid)
• Required for carbohydrate metabolism, adrenal function, enzyme reactions, and
production of fats, cholesterol, bile acids, hormones, neurotransmitters, and red
blood cells.
• Defi ciency is rare, except in malnutrition, and causes burning/tingling in hands and
feet, fatigue, and headache.
• Drugs that deplete vitamin B5: oral contraceptives, amitriptyline, imipramine, and
desipramine.
• Most people get adequate niacin from diet and/or a multivitamin.
Vitamin B6 (Pyridoxine)
• Necessary for protein and fat metabolism, hormone function (estrogen and testosterone),
and the production of red blood cells, niacin, and neurotransmitters
(serotonin, dopamine, and norepinephrine).
• Used therapeutically for PMS, depression, morning sickness, carpal tunnel syndrome,
and heart health (lowers homocysteine, an amino acid that, at high levels,
can cause arteriosclerosis and build up arterial plaque).
• Defi ciency is uncommon, except in alcoholics and the elderly, and causes seizures,
irritability, depression, confusion, mouth sores, and impaired immune function.
• Drugs that deplete vitamin B6: antibiotics, oral contraceptives, isoniazid, penicillamine,
and Parkinson’s drugs.
• Supplements are recommended for the elderly, alcoholics, and those with poor diets.
Vitamin B12 (Cobalamin)
• Required for nerve function, synthesis of DNA and RNA, metabolism of energy,
enzyme reactions, and production of red blood cells.
• Used therapeutically for heart health (lowers homocysteine), male infertility, prevention
of neural tube defects, asthma, and cancer prevention.
• Defi ciency is common among the elderly and those with poor diets, pernicious anemia,
depression, Alzheimer’s, or malabsorption conditions (celiac disease).
• Defi ciency symptoms: anemia, appetite loss, constipation, numbness and tingling
in the extremities, and confusion. Pregnant women with defi ciency have increased
risk of giving birth to a child with neural tube defects.
• Drugs that deplete B12: acid-lowering drugs (omeprazole, lansoprazole, ranitidine),
oral contraceptives, antibiotics, cholestyramine, and metformin.
• Supplements are recommended for those over age 50, vegetarians, women planning
to become pregnant, those with poor diets, and those at risk of heart disease.
Biotin
• Part of the B-vitamin family; involved in the synthesis of fat, glycogen, and amino
acids and enzyme reactions; required for DNA replication; important for healthy
hair and nails.
• Used therapeutically to strengthen fi ngernails.
• Defi ciency is rare except in those with hereditary disorders of biotin metabolism,
liver disease, and during pregnancy (due to increased needs). It can also occur in
those who consume raw egg white for prolonged periods (weeks to years) because
a protein found in egg white (avidin) binds biotin and prevents its absorption or in
those given intravenous feeding without biotin supplementation.
• Defi ciency symptoms include hair loss; scaly red rash around the eyes, nose, mouth,
and genital area; depression; lethargy; hallucination; numbness and tingling of the
extremities; and impaired glucose utilization and immune system function.
• Drugs that deplete biotin: primidone, carbamazepine, phenobarbital, phentyoin,
valproic acid, and antibiotics.
• Most people get adequate biotin from diet and/or supplements.
Folate (Folic Acid)
• Part of the B-vitamin family; known as folate when it occurs in foods, or as folic
acid when present in supplements or added to foods.
• Required for cell division, growth, amino acid metabolism, enzyme reactions, and
production of RNA, DNA, and red blood cells.
• Used for heart health (lowers homocysteine) and prevention of cancer (colon and
cervical) and birth defects (neural tube).
• Defi ciency occurs in alcoholics and those with poor diets, and causes anemia,
fatigue, weakness, headache, hair loss, diarrhea, and poor immune function.
Pregnancy or cancer results in increased rates of cell division and metabolism, increasing
the need for folate.
• Drugs that deplete folate: non-steroidal anti-infl ammatory drugs (NSAIDs) such
as ibuprofen and aspirin, phenytoin, methotrexate phenobarbital, cholestyramine,
colestipol, trimethoprim, and sulfasalazine.
• Supplements are recommended for most adults for heart and cancer protection, and
especially for pregnant women; multivitamins typically provide the recommended
amount of 400 mcg per day.
Vitamin C (Ascorbic Acid)
• Required for synthesis of collagen (structural component of blood vessels, tendons,
and bone), norepinephrine (neurotransmitter), and carnitine (amino acid involved
in energy production); promotes wound healing; supports immune function and
gum health; and has antioxidant properties.
• Used to prevent cataracts, macular degeneration, heart disease, stroke, cancer, and
colds; improve wound healing and response to stress; reduce bronchial spasms in
asthmatics; and prevent lead toxicity.
• Severe defi ciency causes scurvy (bleeding, bruising, hair and tooth loss, joint pain,
and swelling), which is rare today.
• Marginal defi ciencies are common among the elderly, alcoholics, and those with
cancer, chronic illness, or stress. Symptoms include fatigue, easy bruising, poor
wound healing and appetite, anemia, and sore joints.
• Drugs that deplete vitamin C: oral contraceptives, aspirin, corticosteroids, and
furosemide.
• Large doses of vitamin C (greater than 1,000 mg/day) may reduce the effect of warfarin
(blood-thinning drug).
• The Linus Pauling Institute recommends 400 mg of vitamin C daily, which is higher
than the RDA, yet much lower than the UL. Most multivitamin supplements provide
60 mg of vitamin C.
• Natural and synthetic forms are chemically identical and have the same effects on
the body.
• Mineral salts of ascorbic acid (i.e., calcium ascorbate) are buffered and therefore
less acidic and less likely to cause upset stomach.
Vitamin D
• Regulates calcium and phosphorus levels and promotes absorption of these minerals
for growth of bones and teeth; involved in insulin secretion; supports immune
function; regulates blood pressure.
• Vitamin D can be produced in the skin upon exposure to sunlight or must be obtained
from the diet.
• Used to prevent and treat osteoporosis, psoriasis, autoimmune disease, and to reduce
the risk of cancer.
• Defi ciency occurs with inadequate dietary intake, limited sun exposure, kidney or
liver disease, and alcoholism. Elderly, dark-skinned, obese people, or those with
infl ammatory bowel disease and fat-malabsorption syndromes (celiac disease and
cystic fi brosis) are also at greater risk.
• Defi ciency causes rickets (weak, deformed bones) in children, osteomalacia (soft
bones) and osteoporosis in adults, dental problems, muscle weakness, and tooth
decay.
• Drugs that deplete vitamin D: carbamazepine, phenytoin, phenobarbital, cimetidine,
ranitidine, cholestyramine, colestipol, orlistat, and mineral oil.
• Since vitamin D is found in few foods and at low amounts, a supplement is recommended
for most people. Most multivitamins provide 400 IU (10 mcg). Those with
limited sun exposure, osteoporosis, multiple sclerosis, psoriasis, and those over age
65 should consider additional vitamin D.
Vitamin E
• Is an antioxidant (protects cell membranes against oxidative damage; prevents LDL
oxidation) that supports immune function, prevents blood clotting, and dilates
blood vessels.
• Used to prevent and treat heart disease, cancer, macular degeneration, and cataracts,
enhance immune response, reduce oxidative stress, and improve cognitive
function.
• Defi ciency is rare, except in those who are malnourished or who have fat-malabsorption
conditions (celiac disease, cystic fi brosis); however, suboptimal intake is
common and associated with increased risk of heart disease.
• Symptoms of defi ciency include impaired balance and coordination, damage to sensory
nerves (peripheral neuropathy), muscle weakness (myopathy), and damage to
the retina of the eye (pigmented retinopathy).
• Drugs that deplete vitamin E: cholestyramine, colestipol, isoniazid, mineral oil,
orlistat, sucralfate, phenobarbitol, phenytoin, and carbamazepine.
• Vitamin E may enhance the blood-thinning effects of warfarin.
• It is diffi cult to achieve the RDA from diet alone; supplements are particularly necessary
to achieve amounts needed for disease prevention.
• Look for natural vitamin E (alpha-tocopherol); the synthetic form (dl-alphatocopherol)
is less bioavailable (i.e., less absorbable) and only half as potent.
Vitamin D
• Regulates calcium and phosphorus levels and promotes absorption of these minerals
for growth of bones and teeth; involved in insulin secretion; supports immune
function; regulates blood pressure.
• Vitamin D can be produced in the skin upon exposure to sunlight or must be obtained
from the diet.
• Used to prevent and treat osteoporosis, psoriasis, autoimmune disease, and to reduce
the risk of cancer.
• Defi ciency occurs with inadequate dietary intake, limited sun exposure, kidney or
liver disease, and alcoholism. Elderly, dark-skinned, obese people, or those with
infl ammatory bowel disease and fat-malabsorption syndromes (celiac disease and
cystic fi brosis) are also at greater risk.
• Defi ciency causes rickets (weak, deformed bones) in children, osteomalacia (soft
bones) and osteoporosis in adults, dental problems, muscle weakness, and tooth
decay.
• Drugs that deplete vitamin D: carbamazepine, phenytoin, phenobarbital, cimetidine,
ranitidine, cholestyramine, colestipol, orlistat, and mineral oil.
• Since vitamin D is found in few foods and at low amounts, a supplement is recommended
for most people. Most multivitamins provide 400 IU (10 mcg). Those with
limited sun exposure, osteoporosis, multiple sclerosis, psoriasis, and those over age
65 should consider additional vitamin D.
Vitamin E
• Is an antioxidant (protects cell membranes against oxidative damage; prevents LDL
oxidation) that supports immune function, prevents blood clotting, and dilates
blood vessels.
• Used to prevent and treat heart disease, cancer, macular degeneration, and cataracts,
enhance immune response, reduce oxidative stress, and improve cognitive
function.
• Defi ciency is rare, except in those who are malnourished or who have fat-malabsorption
conditions (celiac disease, cystic fi brosis); however, suboptimal intake is
common and associated with increased risk of heart disease.
• Symptoms of defi ciency include impaired balance and coordination, damage to sensory
nerves (peripheral neuropathy), muscle weakness (myopathy), and damage to
the retina of the eye (pigmented retinopathy).
• Drugs that deplete vitamin E: cholestyramine, colestipol, isoniazid, mineral oil,
orlistat, sucralfate, phenobarbitol, phenytoin, and carbamazepine.
• Vitamin E may enhance the blood-thinning effects of warfarin.
• It is diffi cult to achieve the RDA from diet alone; supplements are particularly necessary
to achieve amounts needed for disease prevention.
• Look for natural vitamin E (alpha-tocopherol); the synthetic form (dl-alphatocopherol)
is less bioavailable (i.e., less absorbable) and only half as potent.
• A high intake of sodium (salt), protein, phosphorus (soft drinks and food additives),
or caffeine (more than 2 cups of coffee or 300 mg caffeine per day) can
promote calcium losses.
• Calcium supplements may reduce the effi cacy of calcium channel blockers (drugs
used to lower blood pressure); use with thiazide diuretics increases the risk of
hypercalcemia (high blood calcium levels); calcium supplements may reduce absorption
of antibiotics (tetracycline, quinolones), bisphosphonates (osteoprosis
drugs), and levothyroxine (thyroid hormone).
• It is diffi cult to meet the RDA through diet alone unless dairy intake is high. Most
multivitamin/mineral supplements provide a small amount of calcium because it is
quite bulky. Therefore, a separate calcium supplement may be necessary, especially
for those at risk of osteoporosis and those with high blood pressure.
• There are several forms of calcium: Carbonate provides the highest amount of calcium
(40 percent) and is inexpensive; citrate provides 21 percent calcium, but may
be better absorbed in the elderly and those taking acid-lowering drugs.
• To maximize absorption, take no more than 500 mg of elemental calcium at one
time, take with meals, and ensure adequate vitamin D intake (as this is required for
calcium absorption).
• Separate calcium-rich foods and supplements by two hours from iron supplements
(calcium reduces iron absorption); avoid drinking tea with meals, as the tannins in
tea reduce calcium absorption.
• Some vegetables contain chemicals that inhibit the absorption of calcium, such as
oxalic acid, which is found in raw spinach, rhubarb, sweet potato, and dried beans.
Cooking these foods releases calcium that is bound to oxalic acid, thus improving
the amount you can absorb. Phytic acid, which is found in wheat bran or dried
beans, also reduces calcium absorption.
Magnesium
• Required for nerve and muscle function, formation of bones and teeth, synthesis
of the antioxidant glutathione, cell membranes, and body temperature regulation;
involved in energy production, numerous enzyme reactions, and synthesis of DNA
and RNA.
• Used to prevent heart disease and in the treatment of high blood pressure, pre-eclampsia,
heart disease, diabetes, osteoporosis, migraine headaches, and asthma.
• Defi ciency is uncommon, but may occur in those with poor diets, malabsorption
syndromes (celiac disease), Crohn’s disease, intestinal surgery or infl ammation,
kidney disease, diabetes, alcoholism, and in the elderly due to reduced absorption.
• Marginal defi ciency (consuming less than the RDA) is common and is estimated to
affect 75 percent of people.
• Symptoms of defi ciency: muscle cramps and spasms, weakness, insomnia, poor
appetite, kidney stones, osteoporosis, nervousness, irritability, anxiety, depression,
and high blood pressure.
• Drugs that deplete magnesium: furosemide, hydrochlorothiazine, cholestyramine,
and oral contraceptives.
• Other interactions: Magnesium reduces absorption of digoxin, nitrofurantoin, antimalarial
drugs, quinolone antibiotics, tetracycline, chlorpromazine, alendronate,
and etidronate, so separate intake of magnesium from these foods by two hours.
• High doses of zinc (greater than140 mg/day) reduce magnesium absorption.
• It is diffi cult to meet the RDA through diet alone; therefore, a multivitamin/mineral
supplement is recommended. Certain individuals may require an additional magnesium
supplement.
Phosphorus
• Required for structure of bones, teeth, soft tissue, and cell membranes (phospholipids);
energy production and storage; enzyme reactions; hormones; formation of
DNA and RNA; and maintaining acid-base balance.
• Defi ciency is rare except among alcoholics and those with kidney disease, malabsorption
syndromes (celiac or Crohn’s disease), or poor diets.
• Symptoms of defi ciency: poor appetite, anemia, muscle weakness, bone pain, rickets
in children, osteomalacia in adults, increased risk of infection, and numbness
and tingling of extremities.
• Drugs that deplete phosphorus: aluminum and magnesium (antacids and supplements),
cholestyramine, and digoxin.
• Most people get adequate phosphorus through diet; supplements are rarely
necessary.
TRACE MINERALS
Chromium
• Involved in glucose metabolism (enhances effect of insulin) and enzyme reactions.
• Used for diabetes and for those with impaired glucose tolerance and to lower cholesterol
and triglycerides.
• Severe defi ciency is rare, but marginal defi ciency is common; it is estimated that 90
percent of adults consume less than the RDA.
• The main cause of defi ciency is poor dietary intake (high-sugar diets increase urinary
excretion of chromium).
• Defi ciency results in impaired glucose utilization and may be a contributing factor
to the development of type 2 diabetes; symptoms include elevated blood sugar,
numbness, and tingling in the extremities and nerve problems.
• Drugs that deplete chromium: corticosteroids (prednisone).
• Other interactions: Chromium may enhance the blood sugar-lowering effects of insulin
and oral drugs (glyburide and metformin), thus requiring a dosage adjustment.
• Since marginal defi ciencies are common, a multivitamin/mineral complex containing
chromium is recommended. Chromium is available in several forms. Most
studies involving chromium were done with the picolinate form, which is readily
absorbed and utilized by the body. Certain individuals (diabetics and those at risk
for diabetes) may require an additional supplement.
Copper
• A component of enzymes, which are required for energy production, connective
tissue formation, iron metabolism, brain and nervous system, synthesis of neurotransmitters,
melanin, myelin, hemoglobin, and the antioxidant superoxide
dismutase; involved in regulating gene expression.
• Severe defi ciency is rare, but marginal defi ciencies are common. The typical diet
provides about 50 percent of the RDA. Others at risk: Premature and low birthweight
infants with diarrhea; infants fed only cow’s milk formula, which is low in
copper; those with malnutrition, malabsorption syndromes (celiac disease), cystic
fi brosis, and those receiving intravenous feeding.
• Defi ciency leads to iron defi ciency and anemia, low white blood cell count (increased
risk of infection), osteoporosis, loss of skin pigment, and impaired growth
in children.
• Drugs that deplete copper: penicillamine, ethambutol, and zidovudine.
• Other interactions: Prolonged high doses of zinc (50 mg daily or more) may result
in copper defi ciency.
• A varied diet provides adequate copper for most individuals. In addition, taking a
multivitamin/mineral complex will provide the RDA.
Fluoride
• Essential for formation of healthy bones and teeth.
• Used to prevent cavities, harden tooth enamel, and strengthen bones (prevent
osteoporosis).
• Defi ciency causes tooth decay and dental caries (cavities).
• Drugs that deplete fl uoride: Calcium supplements and calcium- and aluminum-containing
antacids reduce fl uoride absorption (separate intake of fl uoride from these
by two hours).
• Supplements are available by prescription and are recommended only for children
living in areas with low water fl uoride concentrations; rarely required for adults.
• People who consume well water should have the fl uoride content of their water
tested.
Iodine
• Required to make thyroid hormones, which regulate metabolism, energy production,
and body temperature, and are essential for growth and reproduction.
• Used for prevention of radiation-induced thyroid cancer in those with iodine defi -
ciency and to treat fi brocystic breast disease.
• Defi ciency may occur in those who do not consume salt, fi sh, or sea vegetables
and is becoming more common in the general population due to restrictions on salt
intake for blood pressure.
• Defi ciency reduces thyroid hormone production, causing hypothyroidism, fatigue,
weight gain, goiter, miscarriage, birth defects, and stunted growth. It is also the
most common cause of brain damage worldwide.
• Drugs that deplete iodine: potassium iodide, possibly resulting in hypothyroidism.
Other interactions: Amiodarone (heart drug) contains high levels of iodine and may
affect thyroid function; potassium iodide may decrease the anticoagulant effect of
warfarin.
• A defi ciency of selenium, vitamin A, or iron can worsen iodine defi ciency.
• Foods containing goitrogens—such as cabbage, broccoli, caulifl ower, Brussels
sprouts, and soybeans—inhibit the synthesis of thyroid hormone. These foods are
a concern only for those who are iodine defi cient and consume high amounts of
them. Cooking deactivates the goitrogens.
• Supplements are rarely necessary, but should be considered in pregnant and lactating
women if dietary iodine is insuffi cient to meet the RDA.
• A daily prenatal supplement providing 150 mcg of iodine will help to ensure that
pregnant and breast-feeding women consume suffi cient iodine during these critical
periods.
Iron
• Required to produce hemoglobin and myoglobin (proteins involved in the transport
and storage of oxygen) and amino acids (carnitine); required for cellular energy
production; produces enzymes that have antioxidant effects; supports DNA synthesis
and immune function.
• Used for prevention of anemia in pregnancy and in others at risk, and in the treatment
of restless legs syndrome.
• Defi ciency is common, especially in women with heavy menstrual bleeding and
during pregnancy (increased needs for baby), vegetarians, and those with malabsorption
syndromes (celiac disease), bleeding ulcers, copper defi ciency, and in
surgery.
• Defi ciency leads to depleted iron stores, impaired red blood cell formation, and
anemia. Symptoms include fatigue, paleness, headache, hair loss, brittle nails, rapid
heart rate, increased risk of infections, and rapid breathing on exertion.
• Drugs that deplete iron: antacids, cimetidine, ranitidine, omeprazole, lansoprazole,
aspirin, anti-infl ammatory drugs, and cholestyramine.
• Iron supplements can bind to and reduce absorption and effi cacy of levodopa, levothyroxine,
methyldopa, quinolones, tetracyclines, bisphosphonates, and zinc and
calcium supplements. To avoid this, separate intake of iron supplements from these
products by two hours.
• Vitamin C-rich foods and supplements enhance the absorption of nonheme iron
(form of iron found primarily in plants).
• A multivitamin/mineral complex providing the RDA is recommended for most premenopausal
and pregnant women and those at risk of defi ciency.
• Men and post-menopausal women should choose iron-free multivitamin/mineral
supplements to avoid iron excess.
Manganese
• Required for the production and activation of enzymes that are involved in energy metabolism;
bone, cartilage, and collagen formation; and the production of antioxidants.
• Defi ciency is uncommon, but may occur in those with epilepsy, hypoglycemia, diabetes,
schizophrenia, and osteoporosis.
• Defi ciency symptoms: impaired growth and reproductive function, skeletal abnormalities,
impaired glucose tolerance, and altered carbohydrate and fat metabolism.
• Drugs that deplete: magnesium-containing antacids and laxatives and tetracycline.
• Absorption is reduced by calcium, phosphate, and iron.
• Supplements beyond the amount provided by diet and/or a multivitamin and mineral
complex are not necessary.
Molybdenum
• Required for the production of enzymes that are cofactors in amino acid metabolism,
formation of uric acid, and the metabolism of drugs and toxins.
• Defi ciency is extremely rare and may occur in those with a rare genetic condition;
defi ciency causes seizures, developmental delays in neonates, tachycardia, brain
damage, and coma.
• Drugs that deplete: high intakes of copper or sulphate.
• Supplements beyond the amount provided by diet and/or a multivitamin and mineral
complex are not necessary.
Selenium
• Component of enzymes that function as antioxidants; involved in detoxifi cation;
converts thyroid hormone to its active form; supports immune function; enhances
the antioxidant activity of vitamin E.
• Used to strengthen immune function and prevent infection, to protect against colon
and prostate cancer, and to prevent oxidative stress and support immune system
function in those with HIV/AIDS.
• Defi ciency is uncommon, but may occur in those with poor diets, those who live
in areas where the soil is depleted in selenium, Crohn’s disease, and malabsorption
syndromes (celiac disease).
• Symptoms of defi ciency: muscular weakness and wasting, cardiomyopathy (infl ammation
of the heart), pancreatic damage, and impaired immune function.
• Drugs that deplete: valproic acid and corticosteroids (prednisone).
• Supplements beyond the amount provided by diet and/or a multivitamin and mineral
complex may be necessary for some individuals.
Zinc
• Involved in numerous enzyme reactions; required for growth and development, immune
and neurological function, reproduction and regulation of gene expression;
stabilizes the structure of proteins and cell membranes.
• Used to support immune function, reduce severity and duration of the common
cold, and delay the progression of macular degeneration.
• Severe defi ciency is rare, except in those with a genetic disorder, severe malnutrition
or malabsorption, severe burns, or chronic diarrhea.
• Marginal defi ciencies are common in malnourished people, vegetarians, pregnant
women, the elderly, and those with celiac disease, Crohn’s disease, colitis, and
sickle cell anemia.
• Symptoms of defi ciency include impaired growth and development, skin rashes, severe
diarrhea, immune system defi ciencies, impaired wound healing, poor appetite,
impaired taste sensation, night blindness, clouding of the corneas, and behavioural
disturbances.
• Drugs that deplete: diuretics, anticonvulsants, iron supplements, penicillamine,
ACE-inhibitor drugs, acid-reducing drugs, and oral contraceptives.
• Zinc supplements can reduce copper levels, so look for a multivitamin that contains
copper as well as zinc.
• Zinc supplements can reduce absorption of antibiotics (tetracycline and quinolones),
so separate intake of zinc supplements from these products by two hours.
• Since the average zinc intake is below the RDA and many conditions and drugs
deplete zinc levels, a supplement should be considered. Most multivitamin and
mineral complexes provide at least the RDA for zinc.
ELECTROLYTES
Potassium
• Required to maintain fl uid balance; required for nerve conduction and muscle
function; cofactor for enzymes involved in energy production and carbohydrate
metabolism.
• Used for prevention of stroke, osteoporosis, kidney stones, and in the treatment of
high blood pressure.
• Defi ciency (hypokalemia) is common and caused by prolonged diarrhea or vomiting,
alcoholism, kidney failure, laxative abuse, anorexia, or magnesium defi ciency.
• Defi ciency symptoms include fatigue, muscle weakness and cramps, bloating, constipation,
and abdominal pain. Severe hypokalemia may result in muscular paralysis
or abnormal heart rhythms.
• Drugs that deplete: furosemide, hydrochlorothiazide, corticosteroids, pseudoephedrine,
caffeine, and high-dose penicillin.
• Drugs that enhance potassium (may cause hyperkalemia): Spironolactone, triamterene,
amiloride, ACE-inhibitors, anti-infl ammatory drugs (ibuprofen), heaparin,
digoxin, and beta-blockers.
• The average dietary potassium intake is about 2,300 mg/day for women and 3,100
mg/day for men. Evidence suggests that diets supplying at least 4,700 mg per day
are associated with a decreased risk of stroke, hypertension, osteoporosis, and kidney
stones, and this is the AI level set by the Institute of Medicine.
• Multivitamin/mineral complexes typically provide 99 mg of potassium per serving.
Depending on dietary intake and personal risk factors, additional potassium supplements
may be necessary for some people.
• Take supplements with meals or choose a microencapsulated form to reduce the
risk of upset stomach.
Sodium
• Regulates fl uid balance along with potassium; required for nerve conduction and
muscle function; assists absorption of chloride, amino acids, glucose, and water;
regulates blood volume and blood pressure.
• Excess sodium intake is linked to gastric cancer, osteoporosis, high blood pressure,
and kidney stones. Reducing sodium intake may help to reduce the risk of these
conditions.
• Defi ciency is rare; low blood levels of sodium (hyponatremia) may be caused by
fl uid retention or excess sodium loss (excessive sweating, prolonged exercise, severe
and prolonged vomiting and diarrhea, and kidney disease).
• Symptoms of hyponatremia include headache, nausea, muscle cramps, fatigue, confusion,
and fainting. Severe cases may lead to swelling of the brain, seizures, coma,
and brain damage.
• Drugs that deplete sodium: diuretics, anti-infl ammatory drugs, carbamazepine, codeine,
morphine, and some antidepressants.
• Supplements are rarely necessary, except in the above-mentioned conditions.
• The AI level for sodium and sodium chloride (salt) is based on the amount needed
to replace losses through sweat in moderately active people and to achieve a diet
that provides suffi cient amounts of other essential nutrients. Most adults consume
an amount much greater than the AI.
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