Use supplements wisely
You can’t help but notice them — the endless bottles of supplements that line the shelves of grocery and discount stores and drugstores, all promising to improve your health in various ways. The question is, do they actually work? Some may. Some don’t. And for most, we simply don’t know.
Vitamin, mineral and herbal supplements are all considered dietary supplements by the Food and Drug Administration. Unlike prescription and over-the-counter medications, which are tested rigorously to prove their benefits and identify their risks, most dietary supplements aren’t. And the fact is, you’re far more likely to improve your diet and protect your health with good lifestyle habits than from dietary supplements — pills, capsules and other forms.
It may seem easier to take a few pills than to prepare a balanced meal. The trouble is, if you depend on supplements for nutrition, you miss out on the potential benefits of antioxidants, phytochemicals, fiber and other nutrients that only foods can provide. For example, you can get vitamin C from a pill or from an orange. Sure, the pill is easy. But the orange is a better choice because it also supplies carotene, calcium, fiber, flavonoids and simple sugars for energy — all important components of a healthy diet.
That said, this doesn’t mean vitamins, minerals and other supplements don’t play a role in good health. In some cases they’re highly recommended. Just remember that their purpose is to “supplement” a healthy lifestyle, not be a substitute for one.
Vitamin and mineral supplements
Having the right balance of vitamins and minerals in your body is essential. Deficiencies in certain vitamins or minerals can lead to specific diseases or conditions, such as pernicious anemia (vitamin B-12 deficiency) or anemia (iron deficiency).
However, too much of some vitamins and minerals isn’t good either.
Vitamins
You need vitamins for normal body functions, mental alertness and resistance to infection. They enable your body to process proteins, carbohydrates and fats. Certain vitamins also help you produce blood cells, hormones, genetic material and chemicals found in your nervous system.
There are 14 vitamins, which fall into two categories:
Minerals
Your body also needs minerals. Major minerals — those needed in larger amounts — include calcium, phosphorus, magnesium, sodium, potassium and chloride. Calcium, phosphorus and magnesium are important in the development and health of bones and teeth. Sodium, potassium and chloride, known as electrolytes, are important in regulating the water and chemical balance in your body.
In addition, your body needs smaller amounts of the minerals chromium, copper, fluoride, iodine, iron, manganese, molybdenum, selenium and zinc. These are all necessary for normal growth and good health.
The best way to get the vitamins and minerals you need is through a nutritionally balanced diet. However, even if you don’t have a vitamin or mineral deficiency, a vitamin or mineral supplement may be appropriate if:
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Daily Values for vitamins and minerals
If you decide to take a supplement, choose one that doesn’t exceed 100 percent of the Daily Value for each vitamin and mineral, unless your doctor advises otherwise. Daily Values are listed on supplement labels. They’re based on a daily intake of 2,000 calories and meet or exceed recommended vitamin and mineral needs for most people.
*For vitamin A, the Food and Nutrition Board of the Institute of Medicine recommends a lower amount: 3,000 IU a day for men and 2,330 IU a day for most women.
**For iron, it’s probably wise for men and postmenopausal women who take a multivitamin to use a pill with little (8 mg a day or less) or no iron. Too much iron can be toxic.
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Choosing and using supplements
If you wish to take a vitamin or mineral supplement, here are some recommendations to keep in mind:
An overview of 15 vitamins and minerals
Here’s what you need to know about 15 popular vitamins and minerals — how much you need, good food sources, what they do for your body, and cautions and side effects.
Vitamin A
Recommended Dietary Allowance (RDA) for Adults
Age 19 or older: 3,000 international units (IU), or 900 micrograms (mcg) a day
Women
Age 19 or older: 2,330 IU (700 mcg) a day
Maximum daily intake. Maximum intake from both food and supplements that’s unlikely to pose a risk of side effects for adults: 10,000 IU or 3,000 mcg a day.
Food sources. Animal sources include whole milk, fat-free milk fortified with vitamin A, whole eggs, liver, beef and poultry. Plant sources of beta carotene, which converts into vitamin A, include dark green leafy vegetables and orange and yellow fruits and vegetables, such as carrots, sweet potatoes, spinach, broccoli, cantaloupe, mangos and apricots. Vegetable soup and tomato juice also contain good amounts of beta carotene.
What it does. Vitamin A is a fat-soluble vitamin that plays a role in healthy vision, bone and tissue growth, and reproduction. It’s needed for the maintenance of your vital organs. It also helps to regulate your immune system, which prevents and fights infections.
What the research says. Two national surveys in the 1990s indicated that some Americans don’t eat enough foods rich in vitamin A. However, vitamin A deficiency is rare in the United States — it’s more often associated with malnutrition in developing countries. But people with certain diseases who have trouble absorbing vitamin A may take supplements recommended by their doctors. Surveys suggest a link between diets rich in vitamin A and beta carotene from food — not supplements — and a lower risk of some types of cancer.
Cautions. Too much vitamin A stored in the body may increase the risk of liver abnormalities as well as reduce bone mineral density, leading to osteoporosis. Long-term high vitamin A intake from supplements and fortified foods may increase the risk of hip fractures.
Side effects. Signs and symptoms of vitamin A toxicity may include nausea and vomiting, headache, dizziness, blurred vision, and problems with muscular coordination. Vitamin A toxicity usually results from excess use of supplements.
Vitamin B-6 (Pyridoxine)
Recommended Dietary Allowance (RDA) for Adults
Ages 19 to 50: 1.3 milligrams (mg) a day
Age 51 or older: 1.7 mg a day
Women
Ages 19 to 50: 1.3 mg a day
Age 51 or older: 1.5 mg a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 100 mg a day.
Food sources. Poultry, fish, pork, potatoes, soybeans, oats, whole-grain products, fortified cereals, nuts, seeds and bananas.
What it does. Vitamin B-6 is a water-soluble vitamin that’s essential for protein metabolism, energy production and brain function. It’s also involved in immune function
What the research says. Vitamin B-6 works with vitamin B-12 and folic acid (folate) to reduce blood levels of homocysteine, an amino acid that builds and maintains tissues. Elevated homocysteine may increase your risk of heart attack or stroke or cause loss of circulation in your hands and feet. Studies evaluating vitamin B-6 as a remedy for premenstrual syndrome (PMS) show conflicting results.
Cautions. See your doctor before taking vitamin B-6 if you have intestinal problems, liver disease, an overactive thyroid, sickle cell disease, or if you’ve been under severe stress as a result of illness, burns, an accident or recent surgery.
Side effects. High daily doses of vitamin B-6, especially more than 250 mg a day, may cause nerve damage.
Vitamin B-12 (Cobalamin)
Recommended Dietary Allowance (RDA) for Adults
Men and women
Age 19 or older: 2.4 mcg a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects in adults: There’s no known toxicity in humans from vitamin B-12.
Food sources. Meat, fish, shellfish, poultry, eggs, dairy products and some fortified breakfast cereals.
What it does. This is a water-soluble vitamin that plays essential roles in red blood cell formation, cell metabolism and nerve function.
What the research says. Vitamin B-12 supplements containing 100 percent of the Daily Value (6 mcg a day) help prevent deficiency in vegetarians who eliminate all animal foods from their diets — plant foods don’t contain vitamin B-12. Injections of vitamin B-12 are used to prevent and treat deficiency in people whose digestive tracts can’t absorb this vitamin, because of surgery, bowel disease or a hereditary problem. In addition, with age, it can become harder to absorb vitamin B-12 from animal foods. If you’re older than age 50, you may need to get vitamin B-12 through supplements or fortified foods.
Cautions. Talk to your doctor before taking vitamin B-12 supplements if you have anemia with no known cause.
Side effects. Studies don’t indicate adverse health effects in healthy people from excess intake of supplements or food containing vitamin B-12.
Vitamin C (Ascorbic acid)
Recommended Dietary Allowance (RDA) for Adults
Men
Age 19 or older: 90 mg a day
Adult smokers: 125 mg a day
Women
Age 19 or older: 75 mg a day
Adult smokers: 110 mg a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 2,000 mg a day.
Food sources. Citrus juices and fruits, berries, tomatoes, potatoes, green and red peppers, broccoli, and spinach.
What it does. Vitamin C maintains skin integrity, heals wounds and is important in immune functions. It also has antioxidant properties, helping to prevent cell damage by neutralizing free radicals — molecules associated with aging and certain diseases.
What the research says. Studies indicate that people who eat foods high in vitamin C have lower rates of cancer and heart disease, though it’s unclear whether taking vitamin C supplements produces similar benefits. A 2001 study indicates that supplementation with vitamin C, other specific antioxidants and zinc may slow the progression of age-related macular degeneration. A doctor’s supervision is important to determine proper doses. The Institute of Medicine states there aren’t any established benefits for consuming more than the recommended amount of vitamin C. Other research has suggested that 200 mg/day may be the optimal daily dose.
Cautions. See your doctor before taking vitamin C if you have gout, kidney stones, sickle cell anemia or iron storage disease.
Side effects. Taking excessive amounts of vitamin C (more than 2,000 mg/day) may cause mild diarrhea and may interfere with blood sugar (glucose) testing, stool tests for blood and other laboratory tests.
Vitamin D (calciferol)
Recommended Dietary Allowance (RDA) for Adults
Men and women
Age 19 or older: 600 IU (15 mcg) a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 4,000 IU (100 mcg) a day.
Food sources. Vitamin D-fortified milk, vitamin D-fortified cereal, cod-liver oil, and fatty varieties of fish such as salmon, mackerel and sardines.
What it does. Vitamin D is necessary for effective absorption of dietary calcium and helps deposit calcium in your bones and teeth. It’s also important for muscle and nerve function and for the immune system to work effectively.
What the research says. Your body gets vitamin D from dietary sources, but it can also generate its own when sunlight converts a chemical in your skin into a usable form of the vitamin. Some people don’t get enough vitamin D naturally, due to lack of exposure to sunlight, less efficient conversion of the vitamin in their skin, or reduced liver or kidney function. If you don’t drink milk, have dark skin, are at risk of osteoporosis, live in a cloudy environment or rarely go outside, consider taking a vitamin D supplement. Studies show that people who supplement their diets with a combination of vitamin D and calcium slow bone loss and reduce the incidence of fractures.
Cautions. See your doctor before taking vitamin D if you have heart or blood vessel disease, disease of the kidney, liver or pancreas, intestinal problems, or the immune system disorder sarcoidosis.
Side effects. Prolonged intake of vitamin D above 4,000 IU/day poses the risk of toxic effects. Side effects can include nausea, headache, excessive urination, high blood pressure, deposits of calcium in soft tissues, kidney damage and other problems.
Vitamin E (Tocopherol)
Recommended Dietary Allowance (RDA) for Adults
Men and women
Age 19 or older: 15 mg (22.5 IU) a day
Maximum daily intake. Maximum intake from supplements and fortified foods that’s unlikely to pose a risk of side effects for adults: 1,500 IU or 1,000 mg a day. Important note: A recent review of multiple studies questions the safety of these upper limits. The analysis concludes that high daily intake — 400 IU or more — of vitamin E may pose health risks and should be avoided. It also found that harmful effects might occur at more than 150 IU daily for some people.
Food sources. Vegetable oils, wheat germ, whole-grain products, avocados and nuts, especially almonds.
What it does. Vitamin E is a fat-soluble vitamin that protects red blood cells and plays an important role in reproduction. It also has antioxidant properties, helping to prevent cell damage by neutralizing free radicals — molecules believed to be associated with aging and certain diseases.
What the research says. A 2001 study indicates that supplementation with vitamin E and certain other antioxidants may slow the progression of age-related macular degeneration, but a doctor’s supervision is important to determine proper doses. Although research results conflict, recent studies show no benefit for individuals with high-risk heart disease who took vitamin E supplements. Recent studies also found vitamin E supplements had no impact on preventing progression from mild to moderate memory impairment among people with Alzheimer’s disease.
Most important, a high daily intake of vitamin E supplements may harm your health. Researchers analyzed 19 studies that involved almost 136,000 people (most with chronic diseases) who took vitamin E alone or in a multivitamin. People who took about 400 IU a day or more of vitamin E for at least one year died at a higher rate than did those who didn’t take the supplements, but the reason why isn’t clear. Some studies involved individuals who were taking a number of other supplements in addition to vitamin E. This further complicates interpretation of the data.
Cautions. Check with your doctor first before taking vitamin E if you’re taking blood-thinning (anticoagulant) medications. Vitamin E can hinder the control of blood thinning. Also see your doctor before taking vitamin E if you have iron deficiency anemia, bleeding or clotting problems, cystic fibrosis, intestinal problems, or liver disease.
Side effects. In rare cases, people who take vitamin E may develop dizziness, fatigue, headache, weakness, abdominal pain, diarrhea, flu-like symptoms, nausea or blurred vision. In addition to the risks previously noted, high doses of vitamin E can cause side effects that can include bleeding — especially for people on blood-thinning medications — and gastrointestinal complaints.
Folic acid (folate, or vitamin B-9)
Recommended Dietary Allowance (RDA) for Adults
Men and women
Age 19 or older: 400 mcg a day
Maximum daily intake. Maximum intake from supplements and fortified foods that’s unlikely to pose a risk of side effects for adults: 1,000 mcg a day.
Food sources. Citrus juices and fruits, beans, nuts, seeds, liver, dark green leafy vegetables, and some fortified grain products.
What it does. Folate, also called vitamin B-9, occurs naturally in certain foods. Folic acid is the synthetic form of folate. Folic acid is found in supplements and in fortified breads and cereals. This water-soluble vitamin is important in red blood cell formation, protein metabolism, growth and cell division.
What the research says. Folic acid has been shown to work together with vitamin B-6 and vitamin B-12 to reduce blood levels of homocysteine, an amino acid that builds and maintains tissues. Elevated homocysteine levels may increase your risk of heart attack, stroke, or loss of circulation in your hands and feet. If you don’t get adequate folate in your diet, talk with your doctor about taking a folic acid supplement.
Cautions. See your doctor before taking folic acid if you have anemia. Intake of folic acid from supplements and fortified foods shouldn’t exceed 1,000 mcg a day, to prevent folic acid from covering up the symptoms of a vitamin B-12 deficiency. Follow your doctor’s recommendation if you’re taking folic acid for any medical reasons.
Side effects. People who take folic acid may develop bright yellow urine, fever, shortness of breath, a skin rash or, very rarely, diarrhea. Doses higher than 1,500 mcg a day can cause nausea, appetite loss, flatulence and abdominal distention.
Niacin (Vitamin B-3)
Recommended Dietary Allowance (RDA) for Adults
Men
Age 19 or older: 16 mg a day
Women
Age 19 or older: 14 mg a day
Maximum daily intake. Maximum intake from supplements and fortified foods that’s unlikely to pose a risk of side effects for adults: 35 mg/day.
Food sources. Lean meats, poultry, fish, organ meats, brewer’s yeast, peanuts and peanut butter.
What it does. Niacin is a water-soluble B vitamin that is important in converting food to energy.
Cautions. Don’t take niacin if you have impaired liver function or an active peptic ulcer. See your doctor before taking niacin if you have diabetes, gout, gallbladder or liver disease, or glaucoma.
Side effects. At doses higher than 2,000 mg a day, niacin has potentially serious side effects that can include liver damage, high blood sugar and irregular heartbeats. As little as 50 mg a a day can cause flushing, itching, headaches, cramps and nausea.
Beta carotene
Recommended Dietary Allowance (RDA) for Adults: None established at this time.
The Food and Nutrition Board of the Institute of Medicine states that beta carotene supplements are not advisable for the general population.
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: None established.
Food sources. Carrots, cantaloupe, pumpkin, winter squash, sweet potatoes and dark leafy vegetables, such as spinach, kale, turnip greens and collards.
What it does. Beta carotene is one of more than 600 carotenoid compounds found in animals, plants and microorganisms. Your body converts beta carotene into vitamin A.
What the research says. Some studies indicate that diets high in beta carotene and other carotenoids obtained from food are associated with a lower risk of chronic diseases such as heart disease and some cancers. However, this beneficial effect may be due to other substances found in carotenoid-rich foods, not only beta carotene.
Several well-designed studies have shown that beta carotene supplements offer no protection against heart disease. Three large clinical trials found the supplements didn’t protect against cancer. Two studies found an increased risk of lung cancer among smokers who took beta carotene supplements, and one found an increased risk of prostate cancer among men who took the supplements and also drank alcohol. A large Finnish study of male smokers found that daily beta carotene supplements had no effect on the incidence of cataract surgery.
Another study indicates that a small amount of beta carotene taken with certain other antioxidants and zinc may slow the progression of age-related macular degeneration. However, a doctor’s supervision is important to determine proper doses, to lower the risk of side effects.
Cautions. Avoid taking beta carotene supplements because of the potential risks, unless your doctor advises otherwise. If you’re seeking the potential benefits of beta carotene, eat more red, yellow and dark green leafy vegetables.
Side effects. People who take beta carotene may develop an orange color to their skin, which is reversible.
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Antioxidants are vitamins, minerals and enzymes that protect the body by neutralizing “free radicals.” Free radicals are byproducts of normal cell activity. The damage done to cells by free radicals is thought to contribute to aging and to disorders such as coronary artery disease and cancer.
Vitamins C and E are antioxidants. Some people take large amounts of these vitamins in the hope of slowing the aging process. Other antioxidants include beta carotene (a form of vitamin A), the mineral selenium and coenzyme Q10, an antioxidant produced by the body, which is also found in meat and seafood.
While the use of antioxidants to prevent aging makes sense, no studies have proved that they actually do. In addition, taking large doses of some antioxidants, such as vitamin E, may be harmful.
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Calcium
Recommended Dietary Allowance (RDA) for Adults
Men
Ages 19 to 70: 1,000 mg a day
Age 71 or older: 1,200 mg a day
Women
Ages 19 to 50: 1,000 mg a day
Age 51 or older: 1,200 mg a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 2,500 mg a day for adults ages 19 to 50; 2,000 mg a day for adults 51 or older.
Food sources. Milk and milk products, fish with bones that are eaten, calcium-fortified tofu, calcium-fortified orange juice, calcium-fortified cereals, greens (collards, spinach, turnips, kale), green soybeans (edamame), and broccoli.
What it does. Calcium is a mineral important for strong teeth and bones and for muscle and nerve function.
What the research says. Studies suggest that calcium supplements, if taken regularly, help prevent osteoporosis by reducing bone loss. The question is how much calcium you need to achieve this. Although the suggested intake for calcium is 1,200 mg a day for women age 51 or older and men age 71 or older, some people may need more, such as those with osteoporosis or osteopenia or postmenopausal women not taking estrogen. If you don’t get enough calcium in your diet, consider a supplement. In addition, a 14-year study of 86,000 women found that those who had a relatively high intake of calcium, whether through diet or use of supplements, had a reduced risk of stroke.
Cautions. Don’t take calcium if you have sarcoidosis or a high blood-calcium level. See your doctor before taking calcium if you have kidney disease, chronic constipation, colitis, diarrhea, stomach or intestinal bleeding, irregular heartbeat, or heart problems. Although studies conflict, the American Cancer Society (ACS) notes that a high calcium intake, primarily through supplements, may increase the risk of aggressive prostate cancer in some men. The ACS advises men at risk to get calcium through low-fat and fat-free food sources. Follow your doctor’s advice about using supplements, especially if you have osteoporosis or you don’t get enough calcium in your diet.
Avoid calcium supplements made from bone meal, dolomite or oyster shell, often advertised as “natural.” These may contain toxic substances, such as lead, mercury and arsenic. If you take an iron supplement, don’t take it at the same time as your calcium supplement. Calcium can interfere with the absorption of iron.
Side effects. People who take calcium supplements may experience constipation and headache. Potential serious side effects include confusion, muscle or bone pain, nausea, vomiting, and slow or irregular heartbeat.
Iron
Recommended Dietary Allowance (RDA) for Adults
Age 19 or older: 8 mg a day
Women
Ages 19 to 50: 18 mg a day**
Age 51 or older: 8 mg a day*
*For men and postmenopausal women who take a multivitamin, it’s probably wise to take a pill with little or no iron — 8 mg a day or less.
**Women who are menstruating.
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 45 mg a day.
Food sources. There are two types of dietary iron:
What it does. Iron is a mineral that is an essential constituent of blood and muscle and important for the transport of oxygen.
What the research says. When there isn’t enough iron in your diet, too few red blood cells are made to adequately carry oxygen. This condition is called iron deficiency anemia. It can affect women of childbearing age and people with conditions that cause internal bleeding, such as ulcers or intestinal diseases. For men who are healthy and postmenopausal women, iron deficiency is rare. If you want to make sure you’re getting enough iron, your best bet is to eat a balanced diet containing iron-rich foods.
Cautions. Don’t take iron if you have acute hepatitis, hemosiderosis or hemochromatosis (conditions involving excess iron in the body), hemolytic anemia or if you’ve had repeated blood transfusions. See your doctor before taking iron if you’ve had peptic ulcer disease, enteritis, colitis, pancreatitis or hepatitis. Also see your doctor if you have kidney disease, intestinal disease or you consume excessive alcohol. And if you’re older than age 55 and have a family history of heart disease, consult your doctor before taking iron.
Side effects. In some people, iron supplements can cause side effects such as nausea, vomiting, constipation, diarrhea, dark-colored stools or abdominal pain. Taking the supplement in divided doses and with food may help avoid or limit these signs and symptoms. Liquid iron can stain your teeth.
Magnesium
Recommended Dietary Allowance (RDA) for Adults
Men
Ages 19 to 30: 400 mg a day
Age 31 or older: 420 mg a day
Women
Ages 19 to 30: 310 mg a day
Age 31 or older: 320 mg a day
Maximum daily intake. Maximum intake from supplements only that’s unlikely to a pose risk of side effects for adults: 350 mg a day.
Food sources. Nuts, legumes, whole grains and dark green vegetables.
What it does. Magnesium is a mineral necessary in many enzyme processes. It helps your nerves and muscles function.
What the research says. Low magnesium levels are linked with a variety of diseases, including high blood pressure, heart disease, osteoporosis and poorly controlled diabetes, as well as alcohol abuse. Using certain diuretics and other medications can increase the loss of magnesium through urination and requires monitoring of magnesium levels by a doctor. Your doctor will likely recommend eating more foods that contain magnesium if your levels are mildly depleted. Supplements may be recommended when normal levels can’t be achieved through dietary changes.
Cautions. Don’t take magnesium supplements if you have kidney failure or heart block (unless you have a pacemaker) or have had an ileostomy. See your doctor before taking magnesium if you have stomach or intestinal bleeding, symptoms of appendicitis, or chronic constipation, colitis or diarrhea. Laxatives and antacids often contain magnesium, so check the label. Because older adults usually have decreased kidney function, those who routinely take large amounts of magnesium-containing laxatives may increase their risk of toxicity.
Side effects. People who take magnesium supplements may experience abdominal cramps, appetite loss, diarrhea, irregular heartbeat, mood changes, fatigue, nausea, vomiting or pain when urinating. When taken with food, magnesium supplements are less likely to cause diarrhea, nausea and abdominal cramps.
Potassium
Adequate Intake (AI) for Adults*
Men and women
Age 19 or older: 4,700 mg (4.7 grams) a day
*AI levels are used because the Recommended Dietary Allowance (RDA) has not been established.
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: None established.
Food sources. Citrus fruits (such as oranges), apples, bananas, apricots, cantaloupe, potatoes (especially with skin), tomatoes, spinach, Brussels sprouts, mushrooms, beans, peas and almonds.
What it does. Potassium is one of the minerals responsible for maintaining the electrical stability of the cells of your heart and nervous system. It’s also called an electrolyte. Potassium is important for cell and muscle growth and for maintaining normal fluid balance in the body.
What the research says. Most people in the U.S. get only about half the recommended amount of potassium daily. It’s important to eat adequate fruits and vegetables, which are naturally good sources of potassium. If you don’t get enough potassium because of a medical condition or certain medications, your doctor may recommend a potassium supplement. For example, chronic diarrhea may cause potassium deficiency. Some studies indicate that low potassium may contribute to high blood pressure and that increasing potassium intake through diet may help prevent or help treat high blood pressure. Some studies indicate that increased potassium intake is linked with a lower risk of stroke, but more research is needed.
Cautions. Don’t take potassium supplements unless your doctor specifically recommends them. Too much or too little potassium can lead to serious health effects. Your blood levels will likely be monitored if you’re taking potassium or a medication that affects blood potassium. Some high blood pressure medications (diuretics) increase urination, which could lead to potassium deficiency. However, potassium-sparing diuretics cause the kidneys to retain potassium. Follow your doctor’s recommendations. Too much potassium may be a concern.
Side effects. Side effects can include nausea, vomiting, upset stomach, diarrhea and gas. Confusion and an irregular heartbeat are less common.
Selenium
Recommended Dietary Allowance (RDA) for Adults
Men and women
Age 19 or older: 55 mcg a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 400 mcg a day.
Food sources. Milk, poultry, fish, seafood, organ meats, Brazil nuts and whole-grain products.
What it does. Selenium is a mineral that has antioxidant properties, helping to prevent cell damage by neutralizing free radicals — molecules believed to be associated with aging and certain diseases. Selenium also helps regulate thyroid function.
What the research says. Some studies suggest that selenium may help prevent cancer and, possibly, heart disease. One small study found that those taking 200 mcg of selenium a day had lower rates of prostate and colon cancers than did those taking an inactive pill (placebo). Another small study confirmed the prostate cancer finding. In 2001, a large study was launched to determine if selenium and vitamin E can help protect against prostate cancer. However, results released in 2011 showed no benefit in using this combination of supplements or in taking selenium alone. Participants in this study continue to be followed to see if results change over time.
Cautions. See your doctor before taking selenium in high doses.
Side effects. Excessive amounts of selenium may cause hair and nail loss, gastrointestinal disturbance, skin rash, fatigue, tooth decay, and nervous system abnormalities.
Zinc
Recommended Dietary Allowance (RDA) for Adults
Men
Age 19 or older: 11 mg a day
Women
Age 19 or older: 8 mg a day
Maximum daily intake. Maximum intake from all sources that’s unlikely to pose a risk of side effects for adults: 40 mg a day.
Food sources. Meat, fish, poultry, liver, milk, oysters, crab, lobster, beans, nuts, wheat germ, whole-grain products and fortified cereals.
What it does. Zinc is a mineral involved in wound healing, immune function, sense of taste and smell, growth, and sexual maturation. Zinc is also contained in enzymes that regulate metabolism.
What the research says. Studies have conflicted on the use of zinc to ease cold symptoms. Most-recent data suggest that zinc (as lozenges or syrup) is beneficial in reducing the duration and severity of the common cold in healthy people when taken within 24 hours of the onset of symptoms. However, because different dosages and preparations were used for different lengths of time, it’s not clear what the effective dose and treatment schedule would be.
In addition, a 2001 study indicates that supplementation with zinc and certain antioxidants may slow the progression of age-related macular degeneration, but a small percentage of participants had side effects. A doctor’s supervision is important.
Cautions. Don’t take zinc if you have stomach or duodenal ulcers. It’s better not to exceed the RDA, although vegetarians may need more because of lower absorption of zinc from plant sources. If you take zinc lozenges for a cold, stop taking them once your cold is gone. Be aware that lozenges may cause nausea or a bad taste in the mouth. See your doctor before taking zinc in higher doses or if you’re taking a calcium supplement or tetracycline drugs. Zinc may interfere with absorption of these medicines.
Side effects. Long-term, high doses of zinc (50 to 100 mg/day) can lower high-density lipoprotein (HDL, or “good”) cholesterol, suppress immune system function and interfere with the absorption of copper, which may result in microcytic anemia. Other side effects may include diarrhea, heartburn, nausea, vomiting and abdominal pain.
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Hormones are chemicals made by your body to regulate the activities of vital organs. Because hormone levels decline with age, some scientists speculate that hormones play a role in the aging process. According to proponents of hormone products, you can set back your body’s clock by restoring your hormone levels to those of your youth. Studies generally don’t support such thinking. Hormone supplements include:
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An overview of other popular supplements
In addition to vitamins and minerals, many people look to other supplements to improve their health. Research on herbal and other dietary supplements is ongoing. The best approach here is a cautious one. Use such supplements with care — if you use them at all. Do your homework and don’t be afraid to ask questions.
Following are some of the more popular products. Some additional supplements are discussed in Part 4 of this book.
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Anti-aging therapies: Beware of the hype
Ponce de León never did find the fountain of youth. But the lure of an ultimate elixir of life continues to beckon. These days, however, people are more likely to search on the shelves of a drugstore for a magic potion than in the swamps of Florida. Who wouldn’t want to look and feel years younger simply by taking a pill?
Anti-aging products range from dietary supplements to wrinkle creams. Can they really slow down or even stop the aging process? When evaluating claims made about such remedies, some old advice is good advice — if it sounds too good to be true, it probably is.
Aging is an intricate, complex process that involves many areas of your body. It’s unlikely that a product, pill or potion could cure all of the changes age brings. One technique that does seem to increase life span — in lab animals, anyway — is to radically cut daily calories, by nearly half. But how many people want to go through life in a constant state of hunger? The strategies that do help are the sensible ones outlined in this book.
Despite tempting claims, there’s no product out there that’s scientifically proved to prevent or reverse aging. Even worse, many have potentially dangerous side effects. The safety of anti-aging supplements also isn’t guaranteed. As you take steps to stay active and vibrant in your later years, stick with good health practices proved by time — not quick fixes with a lot of glitz but no real results.
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DHEA
Dehydroepiandrosterone (DHEA) is a steroid hormone produced by the adrenal glands that’s converted into sex hormones, such as estrogen and testosterone.
Other names. Prasterone Popular uses. DHEA is taken to improve memory, mood, energy and a sense of well-being. Many athletes claim DHEA supplements build muscle, and there are also claims that DHEA may reverse the effects of aging, stimulate the immune system, treat depression, lupus and a variety of other conditions, and improve functioning in people with Parkinson’s disease or Alzheimer’s disease.
What the research says. A two-year Mayo Clinic study published in 2006 found that DHEA has no effect on anti-aging indicators such as endurance, muscle mass, fat mass and insulin sensitivity and no effect on quality of life. DHEA may be useful for treating depression and lupus, but strictly under the guidance of a specialist.
Cautions. When DHEA is used for a long time or in large amounts, it may stimulate the growth of some prostate, breast, ovarian and other hormone-sensitive cancers. The supplements may also reduce the level of high-density lipoprotein (HDL, or “good”) cholesterol in blood in people with diabetes and liver problems. However, none of these potential negative effects has been confirmed.
Generally, individuals with a history of abnormal heart rhythms (arrythmias), blood clots and liver disease should avoid DHEA supplements.
Side effects. The most common complaints are fatigue, nasal congestion and headache. The supplements may result in breast enlargement in men and excess hair growth in women. The supplements may also lead to hair loss. Other potential side effects include insomnia, agitation, delusions, nervousness and mania.
Echinacea
You may know echinacea by its common name, the coneflower. The roots and herbs from three echinacea species are prepared for medicinal use as pills, applications and teas.
Popular uses. Echinacea is taken to stimulate the immune system and is typically used for colds and influenza. It’s also used to help heal wounds.
What the research shows. Despite all of the claims, latest study results suggest echinacea isn’t an effective method for cold prevention or treatment. If you have a cold, it won’t hurt you to try echinacea for a few days, but there’s no guarantee that it will help. Some studies have found that taking echinacea orally in combination with a topical antifungal cream seems to help prevent recurrent vaginal yeast infection.
Cautions. It’s best to use echinacea for eight weeks or less because some studies have suggested that chronic use actually leads to diminished immune function. You shouldn’t take echinacea if you have diabetes, multiple sclerosis, leukemia, HIV or autoimmune diseases, such as rheumatoid arthritis or lupus, because it can stimulate your immune system. Avoid taking echinacea if you’re allergic to the daisy family, including ragweed, chamomile and chrysanthemum.
Side effects. Side effects can include intestinal upset, diarrhea, skin rash (if used topically) and a suppressed immune system (with habitual use).
Fish oil
Fish oil contains both docosahexaenoic acid (DHA) and eico-sapentaenoic acid (EPA). Supple-ments vary in the amounts and ratios of DHA and EPA. A common amount of omega-3 fatty acids in fish oil capsules is .18 grams (180 mg) of EPA and .12 grams (120 mg) of DHA.
Popular uses. Fish oil supplements are typically taken to protect against heart and blood vessel (cardiovascular) disease. They may also ease symptoms of depression in some people.
What the research shows. Fish oil has been shown to reduce triglycerides (a type of blood fat) as well as deaths from heart attack. Omega-3 fatty acids found in fish also have been shown to reduce heart disease and other problems related to blood vessel disease. Some evidence also suggests fish oil may help lower blood pressure slightly, reduce the risk of artery re-blockage following angioplasty, increase exercise capacity in people with clogged arteries, reduce strokes in people with cardiovascular disease and may possibly reduce the risk of irregular heartbeats.
The American Heart Association recommends getting omega-3 fatty acids in your diet, mainly from fish and plant sources. However, some people with high triglycerides or known cardiovascular disease may benefit from taking fish oil supplements to get more omega-3 fatty acids than they can get from diet alone.
Cautions. High doses of fish oil may have harmful effects, such as increased risk of bleeding. Don’t take more than the recommended amount.
Side effects. Fish oil supplements can cause gastrointestinal upset, nausea and vomiting, or bleeding in some people. But for most people they’re considered safe.
Garlic
In addition to the fresh garlic found in grocery stores, garlic is also available as an oil and in the form of a tablet or capsule.
Other names. Allium sativum
Popular uses. Garlic is used to lower blood cholesterol and to reduce blood clot formation in narrowed arteries. It’s also used to relieve symptoms of upper respiratory infection because of its anti-biotic effect.
What the research shows. Several studies suggest garlic may modestly lower cholesterol and reduce blood clot formation. However, long-term effects remain unknown. Some studies suggest consuming garlic as a regular part of your diet may lower the risk of certain cancers, including gastric and colon cancers. However, no clinical trials have examined this. Research also suggests garlic may slow hardening of the arteries (atherosclerosis), a condition that can lead to heart disease, as well as reduce blood pressure.
Cautions. You shouldn’t use garlic supplements if you’re taking anti-clotting medications. This includes taking aspirin regularly. If you take garlic tablets, make sure they contain allicin, the active ingredient in garlic.
Side effects. Side effects can include stomach upset, heartburn, intestinal problems, and bad breath or body odor.
Ginger
The ginger plant has played a significant role in Chinese, Japanese and Indian medicine since the 1500s.
Other names. Zingiber officinale; Amomum zingiber; African ginger
Popular uses. Ginger is taken to reduce nausea, motion sickness and seasickness, and may help with nausea from chemotherapy when combined with standard anti-nausea medications. Ginger may also be used to treat pain associated with arthritis. The medicinal part of the plant is the root.
What the research shows. There’s mixed evidence regarding ginger’s effect on nausea associated with motion sickness, seasickness, chemotherapy and anesthesia. Some small studies found it had no effect, while other research found it reduced vomiting, but not nausea. It’s unclear whether ginger is effective in treating osteoarthritis, rheumatoid arthritis, or joint or muscle pain — results of a few small studies have been mixed.
Cautions. Ginger supplements shouldn’t be taken by individuals who are allergic to ginger. Individuals who’ve had ulcers, inflammatory bowel disease, blocked intestines and gallstones should use caution when taking ginger supplements and should avoid large quantities of fresh-cut ginger. Ginger increases the production of digestive juices and bile.
Side effects. There are few side effects when ginger supplements are taken at low doses. The most common side effects include a bad taste in the mouth, heartburn, bloating and gas, especially with the powdered forms. Fresh ginger that’s swallowed without enough chewing can cause blockage of the intestines.
Ginkgo
Ginkgo comes mainly from the fan-shaped leaves of the Ginkgo biloba (maidenhair) tree.
Other names. Ginkgo biloba
Popular uses. Ginkgo is used to treat symptoms connected with decreased blood flow to the brain, particularly in older adults. These include short-term memory loss, dizziness, ringing in the ears, headache, depression and anxiety. Ginkgo is also used to relieve circulation problems in the legs.
What the research shows. Numerous studies suggest ginkgo improves circulation to the brain, arms and legs. More studies are needed on the effect of its long-term use. Recent large studies indicate that ginkgo doesn’t reduce the risk of Alzheimer’s disease or other dementias, nor does it seem to improve memory or brain function. A 2009 study of 3,000 people found no difference in attention, memory or other cognitive functions between those who took ginkgo and those who didn’t. This was true for both those who had mild cognitive impairment at the start of the study and for those that didn’t.
Cautions. You shouldn’t take ginkgo if you’re taking an anti-clotting medication. Mayo Clinic doctors also recommend that you avoid ginkgo if taking a thiazide diuretic. If used with this drug, ginkgo may raise blood pressure.
Side effects. Possible side effects can include muscle spasms, mild digestive problems, allergic skin reactions and bleeding.
Ginseng
Ginseng is made from the root of the ginseng plant. Look for products that contain ginsenosides, the active chemical found in ginseng. Some so-called ginseng products don’t contain ginseng at all.
Other names. Panax ginseng, Panax quinquefolius, Panax japonicus and Panax notoginseng
Popular uses. Ginseng is used to increase energy and sexual stamina, reduce stress and improve mental performance. It may also be used for people with diabetes.
What the research shows. It’s unclear how much benefit ginseng provides with exercise performance — study results have been mixed. Studies report that gingeng can modestly improve the performance of thinking and learning tasks. It may also improve mood and enhance sleep. Several studies report that ginseng may lower blood sugar levels in people with type 2 diabetes.However, more studies are needed, and ginseng shouldn’t be substituted for proven therapies.
Cautions. It’s best not to take ginseng for more than three months or exceed the recommended maximum dosage. Some studies suggest ginseng may raise estrogen levels in women. Don’t take it if you have an estrogen-related disease, such as breast cancer. You also shouldn’t take ginseng if you have uncontrolled high blood pressure because ginseng may raise blood pressure.
Side effects. With proper use, ginseng typically doesn’t cause side effects. If you experience any adverse reactions, see your doctor.
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Herbal supplements contain ingredients that may not mix safely with prescription or over-the-counter medications. Here are two examples, but many other herbs also can interact with medications.
Herbal supplements can also be dangerous when used with anesthesia and surgery. Some herbs can increase your risk of bleeding or affect your heart rate or blood pressure. Be certain to stop taking an herbal supplement at least two to three weeks before surgery, to clear it from your body. If this isn’t possible, let medical professionals know what you’re taking.
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Glucosamine
Glucosamine is a natural compound found in healthy cartilage. Glucosa-mine sulfate is the most studied form of glucosamine.
Popular uses. Glucosamine is commonly combined with chondroitin sulfate, another naturally occurring substance that gives cartilage its elasticity. These two substances are typically taken in combination as tablets or capsules to decrease pain and inflammation in arthritic joints — primarily the knee joint. Together, the substances appear to strengthen cartilage and improve lubrication in the knee joint.
What the research shows. Results of more than 30 studies have produced enough mixed results that researchers aren’t able to conclude that glucosamine and chondroitin improve pain and function in people with osteoarthritis of the knee. Glucosamine, though, has shown benefits for osteoarthritis in other joints. In some instances, it appeared to reduce joint pain and tenderness as effectively as did conventional medications and slow progression of the disease. Whether people taking glucosamine for longer periods have less joint damage compared with those taking a placebo is uncertain and requires further study. Early evidence suggests glucosamine may also be beneficial in the treatment of rheumatoid arthritis; however, more study is needed before a conclusion can be drawn.
Cautions. Glucosamine can be made from the shells of shrimp, crab and other shellfish. Therefore, people with shellfish allergies or iodine hypersensitivity should avoid the supplement or be very cautious in its use. There’s also some evidence suggesting a possible link between glucosamine and chondroitin products and asthma attacks. Until more reliable data exists, it’s suggested individuals with a history of asthma avoid these supplements.
Side effects. When taken at recommended doses, the supplement is generally well-tolerated. Possible side effects may include upset stomach, insomnia, headache, skin reactions, sun sensitivity and nail toughening.
Lycopene
Lycopene is an antioxidant found in colorful fruit, such as the tomato. (Tomatoes are technically fruits, although they’re generally used as vegetables.) Lycopene is what gives tomatoes their red color.
Popular uses. Lycopene supplements are taken to reduce the risk of cardiovascular disease, macular degeneration and cancer, especially prostate cancer.
What the research shows. A number of studies have suggested a link between high intake of foods containing lycopene and reduced risk of cancer, cardiovascular disease and macular degeneration. However, many of these studies have been based on tomato intake, not on the use of lycopene supplements. In addition, since tomatoes are sources of other nutrients, it’s not clear that lycopene itself is beneficial, and not one of the other nutrients or a combination of nutrients. Because there hasn’t been a well-designed study involving lycopene supplements, whether they’re of any benefit is unclear.
Cautions. Lycopene supplements shouldn’t be taken by individuals who are allergic to tomatoes. The safety of these supplements has not been thoroughly studied.
Side effects. A review of available scientific literature finds no reports of serious side effects from use of lycopene supplements.
Mint plants such as peppermint have a long history of medicinal use, dating back to ancient Egypt, Greece and Rome.
Other names. Mentha piperita
Popular uses. Peppermint supplements (oils and capsules) are taken to relieve indigestion, abdominal cramps, headache and nasal congestion.
What the research shows. Studies on the effects of peppermint oil to relieve indigestion haven’t been well designed, and it’s unclear if the oil is beneficial for this condition. For the treatment of abdominal pain and bloating associated with irritable bowel syndrome, results have been mixed. These trials have been small and more study is needed. For the treatment of headache and nasal congestion, good-quality studies are lacking.
Cautions. People with allergies to peppermint should avoid these products. Peppermint oil should be used cautiously by people with gastroesophageal reflux disease (GERD) or gallbladder disease, including gallstones.
Side effects. When used on the skin, peppermint oil has been associated with skin rash and hives and with eye irritation. Peppermint products taken by mouth may cause headache, dizziness, heartburn and anal burning. In animals, very large doses of peppermint oil taken by mouth have resulted in muscle weakness, brain damage and seizure.
St. John’s wort
Extracts of Hypericum perforatum, the botanical name of the plant, have been used in folk medicine since Hippocrates’ time.
Other names. Hypericum perforatum
Popular uses. It’s taken to treat depression, anxiety and sleep disorders.
What the research shows. Several studies support the therapeutic benefit of St. John’s wort in treating mild to moderate depression. It’s been proved as effective as some prescription antidepressants and with fewer side effects. Potential benefits in the treatment of other disorders are less clear. A major concern is that studies show St. John’s wort may not mix well with various types of prescription drugs, significantly affecting the concentration of the medication in your blood. Results from studies examining its effectiveness on symptoms of anxiety have been mixed.
Cautions. If you think you’re experiencing depression, talk with your doctor. Depression is a serious illness, and you shouldn’t treat it yourself. And don’t mix St. John’s wort with other antidepressant medications. A good rule of thumb is not to mix St. John’s wort with any medication until you’ve talked with your doctor first.
Side effects. Possible side effects include sun sensitivity, itching, fatigue, headache, weight gain, bloating and constipation.
Soy
Soybeans are legumes, but their popularity and health effects puts them in a category of their own. The protein in soy is unique and has been the source of numerous studies.
Other names. Edamame
Popular uses. Soy is taken to reduce cholesterol, reduce menopausal hot flashes, prevent some cancers and for a variety of other reasons.
What the research shows. The thinking used to be that adding soy to your diet produced a moderate decrease in cholesterol levels. This view changed after the American Heart Association, following an extensive review of research, concluded that soy-based foods don’t significantly lower cholesterol.
Components of soy called isoflavones also appear to inhibit the effects of sex hormones, so they may offer some protection from cancers that feed on these hormones, such as some breast cancers. Consuming 20 to 60 grams of soy protein daily seems to modestly decrease the frequency and severity of hot flashes in some women.
Cautions. Soy can act as a food allergen similar to milk, eggs, peanuts, fish and wheat. Use of soy is discouraged in people with hormone-sensitive cancers, such as breast or ovarian cancer because of concerns soy’s estrogen-like effects could stimulate cancer growth.
Side effects. Limited side effects have been reported. When side effects do occur, they generally include bloating, nausea and constipation. It’s not known if soy or soy isoflavones share the same side effects as estrogens, such as increased risk of blood clots.
Be supplement savvy
If you take herbal or other types of supplements — or you’re considering doing so — keep these four points in mind: