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Inside Special Report •Do You Need a Supplement? Supplement to Mayo Women’s HealthSource • D: Are You Getting Enough? •Choosing and Using Supplements • and Prevention Vitamins and •Vitamin-Rich What You Should Know About Essential

Vitamins and minerals are substances Nutrients Easy access your body needs to grow properly, / One small (5 inches) provides about function normally and stay healthy. It’s beta 6,000 international units (IU) of vitamin A. possible — and highly recommended — Vitamin B-3 Three ounces of (canned in ) that you get these substances from the () has 11 milligrams (mg) of niacin. foods you eat. However, it sometimes Vitamin B-6 One medium contains about 0.4 can be difficult to get the recommended mg of vitamin B-6. amount of some vitamins and minerals from alone. That’s why it’s not Vitamin B-9 Half a cup (4 ounces) of cooked unusual to hear that taking a multivita- (/folic ) contains 130 micrograms (mcg) of folate. min or other supplement on a daily Vitamin B-12 Three ounces of salmon contains about 5 basis can make good sense. mcg of vitamin B-12. Nevertheless, knowing when you One medium has about 70 mg of might need a supplement, what kind of vitamin C. vitamin and minerals are best, and how One cup (8 ounces) of fortified con- much your body needs can often be tains 100 IU of vitamin D. confusing. In this Special Report, you’ll One ounce of (about 23 nuts) has find out why vitamins and minerals are more than 7 mg of vitamin E. considered essential to good and what you should know about the latest One cup (8 ounces) of milk contains 300 mg of calcium. regarding their benefits. Three ounces of , , lamb or veal vs. supplements contains 2 to 3 mg of iron. You can get your entire daily require- One cup of cooked spinach has 150 to 160 ments of vitamin C by just popping a mg of magnesium. pill. You can get the same amount by One medium banana has 422 mg of potas- eating a large orange. So which is better? sium. One medium baked (with In most cases, the orange is better. skin) contains 926 mg of potassium. Whole foods — such as , vegeta- One slice of whole- contains bles, grains and dairy products — have 10 mcg of selenium. benefits you can’t find in a pill, including: Three ounces of lean sirloin contains 5 mg • Greater . Whole foods contain of zinc. a variety of nutrients your body needs — not just one. An orange, for example,

M AYO C LINIC W OMEN’ S H EALTHS OURCE 1 S PECIAL R EPORT J ULY 2009 provides vitamin C as as beta carotene, calci- appropriate. For instance, if you don’t eat the rec- um and other nutrients. Vitamin C supplements ommended servings of fruits, and other lack these other nutrients. healthy foods, you may benefit from a that contains a variety of essential nutrients. Multi- • Essential fiber. Fiber is important for digestion. It vitamins can also be helpful if you are a strict vege- also helps prevent certain . For instance, tarian, eat a diet that’s limited because of food soluble fiber (found in , some grains, and allergies or intolerances, or have a disease or con- some fruits and vegetables) and insoluble fiber dition that doesn’t allow you to digest or absorb (found in whole grains and some fruits and veg- nutrients properly. Older age and certain lifestyle etables) may help prevent heart disease, habits, such as smoking and excessive con- and constipation. sumption, also can make it difficult to get all the • . Many foods — including some nutrients you need from food. fruits, vegetables, whole grains, and nuts As for boosting the amount of specific vitamins — contain naturally occurring food substances and minerals, there are times when this can make called phytochemicals. These substances may sense, especially for women. If you’re pregnant or help protect you against , heart disease, trying to become pregnant, certain nutrients — such osteoporosis and diabetes. as calcium, folic acid and iron — are needed more than ever to protect your health and the health of Do you need a supplement? your developing baby. In addition, supplementing Although supplements may not offer all the benefits your diet with additional calcium and vitamin D is that whole foods can provide, there are times when often considered crucial following to taking vitamins and minerals in pill form may be protect against osteoporosis and the risk of fractures. Having the right balance of vitamins and miner- Defining Terms als in your body is important for good health. How- ever, getting too much of some nutrients, usually When it comes to vitamins and minerals, it helps from high-dose supplements, can be dangerous. This to understand a few important terms, including: is especially true with some -soluble vitamins, which are absorbed and then stored in your body’s • Recommended Dietary Allowance (RDA). The fat for use as needed. Yet, it’s generally not recom- amount of each vitamin and needed mended that you take megadoses of water-soluble daily to meet the needs of nearly all healthy vitamins either. Even though these vitamins aren’t people, as determined by the Food and Nutrition stored in large amounts in your body, some can be Board of the Institute of Medicine. RDAs for toxic in large amounts. Here’s more of what you vitamins and minerals are based on your sex, should know about some key vitamins and minerals. age and physical condition, such as . Fat-soluble vitamins • Adequate Intake (AI). An AI is a recommended intake level of certain nutrients based on esti- Vitamin A/beta carotene mates of how much healthy people need. It’s Vitamin A plays a role in healthy vision, and used when there isn’t enough data to establish tissue growth, and reproduction. It also helps regu- an RDA. late your , which prevents and fights infections. • Daily Value (DV). This term, set by the Food Research findings: Although your body can con- and Administration, is used on food and vert sources of beta carotene into vitamin A, supplement labels. DVs are based on a 2,000- animal sources of vitamin A are better absorbed. calorie-a-day diet, but your DVs may be higher So, if you’re a vegetarian who relies on fruits and or lower, depending on your calorie needs. vegetables to meet your daily vitamin A require- • Percent Daily Value. What percentage of the DV ments, you need to eat at least five daily servings one serving of a food or supplement supplies. of these foods. Vitamin A deficiency is rare in the For instance, if the label on a multivitamin bot- , but people with certain diseases, tle shows that 30 percent of the DV for a vita- such as celiac disease, Crohn’s disease or pancreat- min is provided, you’ll need 70 percent from ic disorders, may have trouble absorbing the vita- other sources throughout the day to meet the min and need supplements. Dietary intake studies recommended goal. I suggest an association between diets rich in beta carotene and vitamin A and a lower risk of some

M AYO C LINIC W OMEN’ S H EALTHS OURCE 2 S PECIAL R EPORT J ULY 2009 types of cancer. However, if too much vitamin A is the sunshine vitamin because your skin produces it stored in the body, it may increase the risk of birth after being exposed to rays from the defects, abnormalities and reduced bone min- . eral — which could to osteoporosis. Research findings: Getting adequate amounts of Research has also found that beta carotene, taken vitamin D and calcium can prevent or slow osteo- in supplement form, can be dangerous. In several porosis and reduce bone fractures. A growing body recent studies, smokers and former smokers who of research also suggests that maintaining healthy took beta carotene had an increased risk of levels of vitamin D may reduce the risk of develop- cancer. It’s not possible, however, to get too much ing muscle pain and weakness, autoimmune dis- beta carotene from foods. eases (such as and multiple Recommended Dietary Allowance: 2,330 interna- sclerosis), and certain can- tional units (IU)/day (adult women), 3,000 IU/day cers. In addition, appears to (adult men). Although beta carotene from plant be a growing problem in the United States. (See sources is considered safe, beta carotene in supple- Vitamin D: Are You Getting Enough?, below). As a ment form is not recommended as a source of vita- result, supplemental vitamin D is commonly rec- min A. ommended for many people. Adequate Intake: 200 international units (IU)/day Vitamin D (calciferol) (adults ages 19 to 50), 400 IU/day (adults 51 to 70), Vitamin D helps your body absorb calcium, a min- and 600 IU/day (adults 71 or older). Despite cur- eral that’s responsible for the normal development rent recommendations, many experts now believe and maintenance of healthy teeth and . This that adults should get at least 800 to 1,000 IU/day vitamin also helps maintain proper levels of of vitamin D. Some even advise getting up to 2,000 calcium and . Vitamin D is often called IU/day.

Vitamin D: Are You Getting Enough?

A few years ago, vitamin D rarely made news. with vitamin D. Many experts also believe that Now, the so-called sunshine vitamin is regularly current government recommendations regarding in the headlines. adequate intakes of vitamin D are far too low. As One reason is that recent research has found a result, standard , which are influ- that this essential does much more than enced by these recommendations, may do little to help your body absorb the calcium it needs to guard against deficiency. The U.S. government build and maintain strong bones. It also appears recommends adults get anywhere from 200 to to play a role in reducing the risk of many illness- 600 international units (IU) of vitamin D a day, es — including common , autoimmune depending on their age. However, many experts diseases and cardiovascular disease. now say vitamin D intakes should be at least 800 The other reason for this vitamin’s increasing to 1,000 IU a day in all adults. Some even recom- notoriety: Studies show vitamin D deficiency is mend a higher daily intake. commonplace in nearly every segment of society. If you’re over age 50, live in a northern latitude In fact, vitamin D levels appear lower among (where sunlight is rare in certain months), have Americans today than 15 to 20 years ago, accord- darker skin or have a condition that makes it dif- ing to a recent report in The American Journal of ficult for you to absorb nutrients, your risk of vit- . amin D deficiency may be even higher than it is Researchers attribute vitamin D deficiency to for others. many factors, including more time spent indoors Although vitamin D deficiency is a potentially and the increasing use of sun protection, which serious problem, it can be avoided or corrected. blocks skin from absorbing the sunlight it needs The first step is to talk with your doctor. If he or to create vitamin D naturally. Still, most health she is concerned about your vitamin D status, a professionals continue to recommend limiting sun blood can be used to check for a deficiency. exposure and wearing sunscreen to protect Your doctor can also advise you on how much against other problems, such as . vitamin D you should be getting every day and Another problem may be that there are a limit- whether you should consider taking supplements ed number of foods that provide or are fortified to boost your daily intake. I

M AYO C LINIC W OMEN’ S H EALTHS OURCE 3 S PECIAL R EPORT J ULY 2009 Vitamin E (tocopheral) Choosing and Using Supplements Vitamin E is an that protects red blood cells and may play a role in immune function, Supplements are not substitutes for the nutrients DNA repair and other metabolic functions. and healthy compounds in whole foods. How- Research findings: It’s long been thought that ever, if you do decide to take a vitamin or miner- diets rich in , such as vitamin E, could al supplement, here are some guidelines you help lower the risk of some cancers and other con- should follow: ditions, such as heart disease. However, recent • Avoid megadoses. High-dose supplements can studies suggest that vitamin E supplements don’t cause toxic levels of nutrients to build up in provide the same health benefits as dietary sources your body. Therefore, it’s better to choose a do, and may even be harmful to your health. In multivitamin-mineral supplement that pro- fact, some research indicates that vitamin E supple- vides about 100 percent of the Daily Value mentation in high doses may increase the risk of (DV) of all vitamins and minerals — unless heart failure or death. If vitamin E is taken with your doctor advises otherwise. One notable certain other supplements, it may slow the pro- exception to this guideline is calcium. You may gression of early age-related . notice that calcium-containing supplements But it’s best not to use vitamin E for this purpose don’t provide 100 percent DV. Instead they until you’ve discussed the pros and cons, and safe may contain 50 percent and need to be taken dosages, with your doctor. twice a day. That’s because calcium is best Recommended Dietary Allowance: 15 milligrams/ absorbed in smaller doses. day (adults). Dosages of vitamin E may also be list- • Look for “USP Verified”on the label. The initials ed in international units (IU). In this case, the rec- “USP” ensure that the supplement meets the ommended amounts are 22 IU for natural sources standards for strength, quality and purity of vitamin E and 33 IU for synthetic sources for established by the testing organization U.S. adults. Recent research has found that taking 400 Pharmacopeia. Other third party verification IU/day or more of vitamin E may pose health risks services also are becoming increasingly recog- and should be avoided. Before taking any vitamin nized. Importantly, the Food and Drug E supplement, talk with your doctor. Administration (FDA) Good Manufacturing Water-soluble vitamins Practices regulation is intended to ensure the quality and purity of all dietary supplements Vitamin C (ascorbic acid) in the United States by 2010. Vitamin C is an antioxidant that maintains healthy tissue and helps the body absorb iron. It also plays • Beware of extras. Don’t give in to the temptation a role in . of added herbs, , amino or Research findings: Studies have shown that eat- unusual “special” ingredients. These additions ing foods high in vitamin C can lower rates of can- usually add nothing but cost. In some instances, they may adversely interfere with Fortified and Enriched Foods or medical conditions. • Check the expiration date. Supplements can lose These days, you may notice that a number of the potency over time, especially in hot and humid products you buy at the grocery store have been climates. If a supplement doesn’t have an expi- “fortified” or “enriched” with certain vitamins ration date, don’t buy it. or minerals. What does this mean? • Get medical advice. Check with your doctor If a food or beverage is said to be fortified, or pharmacist before taking even a standard it means that one or more nutrients have been multivitamin-mineral supplement. This is added that weren’t originally there. Enriched, especially important if you have a health prob- on the other hand, means that the nutrients lost lem or are taking any . At your next during processing have been added back. The checkup, take all of your supplements along Nutrition Facts list on the product label will so that your doctor can review and discuss tell you which nutrients have been added. It whether you’re taking the right types and will also show what percentage of the Daily amounts. I Value (DV) for each nutrient is met with one serving of the product. I

M AYO C LINIC W OMEN’ S H EALTHS OURCE 4 S PECIAL R EPORT J ULY 2009 Vitamins and Disease Prevention

Vitamin pills offer an easy way to get the nutri- benefits when it comes to warding off chronic ill- ents your body needs but may not always get from nesses. This appears to be particularly true of vita- diet alone. But if you regularly take a multivita- min C, vitamin E and beta carotene — a compound min or other to guard against your body converts into vitamin A. When these cancer or heart disease, you may be disappointed. vitamins are obtained through foods, they can Recent research has found that most supple- protect against damage caused by free radicals — mental vitamins and minerals fail to provide substances that can harm cells, tissues and organs. women with any added protection from these ill- In pill form, however, these vitamins don’t appear nesses. In one study, published earlier this year to have the same benefit. And, in some cases, they in the Archives of Internal Medicine, researchers may even be dangerous, especially when taken at tracked more than 161,000 older women partici- levels that exceed recommended dosages. pating in the Women’s Health Study. More than So does this mean you should stop taking your 40 percent of these women used multivitamins. vitamins? Not necessarily. If you want to reduce However, after eight years of follow-up there your risk of heart disease, cancer or other illness- wasn’t any evidence that these supplements had es, health experts still say it’s best to focus on eat- any impact on the risk of cancer, heart disease ing a balanced diet that’s high in vitamin-rich or death. fruits and vegetables. Yet if your diet is lacking, Another study, published in the Journal of the or you have trouble digesting or absorbing vita- National Cancer Institute, had no better news. It mins because of your age or certain health condi- involved more than 8,000 women over age 40, tions, a multivitamin can help you avoid develop- who were randomly assigned to take a ; a ing any deficiencies that might affect your health. supplement containing beta carotene, vitamin C Other supplemental nutrients, such as calcium and or vitamin E; or a combination of these antioxi- vitamin D, also may be recommended, especially dant supplements. Researchers found the women as you age. (See Vitamin D: Are You Getting who took the supplements either individually or Enough?, page 3) in combination developed cancer at the same rate When in doubt, it’s always best to talk with as did the women who took the placebo. your doctor about what supplements might be These studies follow closely on the heels of best for you and to avoid taking excessive doses other research that has shown that antioxidant of any one vitamin or mineral without your doc- vitamins, in supplement form, offer few, if any tor’s knowledge. I cer and heart disease. It’s unclear whether vitamin convert food to energy. Niacin also helps improve C supplements can provide the same benefits. In blood circulation and levels. fact, taking megadoses of vitamin C in supplement Research findings: In high doses, niacin can form is discouraged because there aren’t any estab- reduce low-density lipoprotein (LDL, or “bad”) lished benefits. For instance, there’s still little evi- cholesterol and triglycerides and raise high-density dence that vitamin C can prevent colds or lessen lipoprotein (HDL, or “good”) cholesterol. Studies cold symptoms. On a brighter note: Vitamin C show niacin may also slow the development of supplements, taken with some other antioxidants when used with other cholesterol- and zinc, may slow the progression of age-related lowering , diet and exercise. However, in the macular degeneration. However, this treatment doses needed for these effects (usually greater than should only be used under a doctor’s supervision 1,000 mg/day), niacin can cause liver damage. to ensure proper dosages. Therefore, high-dose intakes should be considered Recommended Dietary Allowance: 75 milligrams a prescribed medication, not a vitamin, and taken (mg)/day (adult women), 110 mg/day (women under a doctor’s supervision. who smoke), 90 mg/day (adult men), 125 mg/day Recommended Dietary Allowance: 14 milligrams (men who smoke). (mg)/day (adult women), 16 mg/day (adult men).

Vitamin B-3 (niacin) Vitamin B-6 () Vitamin B-3, commonly known as niacin, is one of Vitamin B-6 is needed to help your body use , the eight B complex vitamins that help your body form red blood cells and maintain function.

M AYO C LINIC W OMEN’ S H EALTHS OURCE 5 S PECIAL R EPORT J ULY 2009 Research findings: Serious deficiencies of vitamin Vitamin B-9 (folate/folic acid) B-6 are rare, but they can increase your level of Vitamin B-9, also called folate, is important in red , and potentially boost your risk of blood cell formation and for healthy cell growth heart disease and . High doses of vitamin B-6 and function. It’s also important for the developing have been touted as a treatment for carpal tunnel fetus during pregnancy. Folic acid is the synthetic syndrome and premenstrual syndrome. But studies form of folate. have generally not supported the effectiveness of Research findings: Folic acid has been shown to this treatment in relieving these conditions. In work together with vitamins B-6 and B-12 to con- addition, large daily doses of the vitamin have trol elevated blood levels of homocysteine, which been associated with neurological problems, such is associated with an increased risk of heart dis- as numbness in the hands and feet (peripheral neu- ease. However, there’s no clear evidence that folic ropathy), and skin lesions. acid can prevent or treat heart disease. Studies do Recommended Dietary Allowance: 1.3 milligrams indicate that folate or folic acid can help prevent (mg)/day (women and men ages 19 to 50), 1.5 during pregnancy and reduce the risk of mg/day (women 51 or older), 1.7 mg/day (men 51 neural tube defects, such as spina bifida. Some or older). research also suggests that folate may reduce the

Vitamin-Rich Foods

Vitamins and minerals Food sources Vitamin A/beta carotene , sweet potatoes, , spinach, , , liver, egg and fortified milk Vitamin B-3 (niacin) Lean , poultry, fish, organ meats, brewer’s , and Vitamin B-6 Fortified and enriched grains, whole-grain products, poultry, fish, , nuts, ,s and Vitamin B-9 and fruits, beans, nuts, , liver, dark leafy (folate/folic acid) vegetables, and fortified and Vitamin B-12 , fish, shellfish, poultry, eggs, dairy products and fortified cereals Vitamin C Citrus juices and fruits, berries, tomatoes, potatoes, green and red peppers, broccoli, and spinach Vitamin D Fatty fish (such as salmon and ), -liver oil, and fortified milk and cereals Vitamin E oils, wheat germ, whole-grain products, and nuts (especially almonds) Calcium Dairy products, calcium-fortified cereals and , (spinach, , collards, , ), broccoli, green soybeans (), and fish eaten with their bones (salmon, sardines) Iron Meat, , poultry, whole-grain products, beans, and dark green leafy vegetables Magnesium Nuts, legumes, whole-grain products and dark green vegetables Potassium Citrus fruits, , bananas, apricots, cantaloupe, potatoes (especial- ly with skin), tomatoes, spinach, Brussels sprouts, , beans, peas and almonds Selenium Milk, poultry, fish, seafood, organ meats, Brazil nuts and whole-grain products Zinc Meat, fish, poultry, liver, milk, , wheat germ, whole-grain products and fortified cereals I

M AYO C LINIC W OMEN’ S H EALTHS OURCE 6 S PECIAL R EPORT J ULY 2009 risk of breast, cervical, pancreatic and colon can- early signs of bone thinning, your doctor may rec- cers — particularly among people who consume ommend you get more calcium than what’s typi- alcohol. However, folic acid supplementation cally recommended. currently isn’t specifically recommended for the prevention or treatment of cancer. Iron Recommended Dietary Allowance: 400 micrograms Iron plays an essential role in delivering to (mcg)/day (adults). Women who are pregnant or the body via the bloodstream. It also has many breast-feeding should get more — 600 mcg/day muscular and metabolic functions. and 500 mcg/day, respectively. Research findings: A lack of iron can lead to ane- mia and reduce your resistance to infection. Studies Vitamin B-12 show that iron supplements can prevent or treat Vitamin B-12 plays essential roles in anemia. Research also has demon- formation, cell and function. strated that iron supplements may benefit women Research findings: If you’re over age 50 or don’t during or pregnancy. Iron deficiency eat any animal foods, you’re likely to need supple- is uncommon in postmenopausal women. ments containing B-12 to prevent a deficiency in Recommended Dietary Allowance: 18 milligrams this vitamin. (Many older adults are at risk of defi- (mg)/day (women ages 19 to 50), 8 mg/day (women ciency because, with age, it can be harder to absorb 51 or older), 8 mg/day (adult men). Postmenopausal B-12 from animal foods.) A vitamin B-12 deficiency women and healthy men rarely need supplemental can cause permanent nerve damage, resulting in iron. If you’re taking a multivitamin and are no numbness and tingling in the hands and feet, and longer menstruating, choose a pill with little or no balance problems. Deficiency can also cause anemia, iron (8 mg/day or less) unless your doctor advises depression, confusion, poor memory and . otherwise. Concerns have also been raised about the apparent link between low levels of B-12 and an increase in Magnesium homocysteine, an that can cause prob- Magnesium is involved in many biochemical reac- lems within your coronary arteries. tions in the body, helping maintain normal heart Recommended Dietary Allowance: 2.4 micrograms/ rhythm, immune system and muscle function. day (adults). If you have vitamin B-12 deficiency or Research findings: Low magnesium levels are have had a portion of your linked with a variety of conditions, including removed, your body can’t absorb enough of an oral hypertension, heart disease, osteoporosis and poor- vitamin. In such cases, your doctor will likely rec- ommend getting this vitamin through injections. Upper Limits

Minerals More is not necessarily better when it comes vitamins and minerals. In fact, taking too much Calcium of some nutrients — usually in supplement form Calcium is important for strong teeth and bones. — could cause health problems. High doses of It’s also needed for your heart, muscles and niacin, for instance, can result in liver problems. to function properly. That’s why a Tolerable Upper Intake Level Research findings: Many Americans don’t get (UL) has been established for some vitamins and enough calcium in their diets. However, calcium minerals. A UL is defined as the highest level supplements can help prevent deficiencies that can of daily intake that is likely to pose no risk of lead to bone loss and the brittle bone disease osteo- adverse health effects. This amount includes porosis — especially when taken regularly and how much of a nutrient you get from both food combined with vitamin D. Calcium and vitamin D, and supplements. taken in combination with prescribed medications, Therefore, to be safe, you should try to stay can also be used to help treat osteoporosis or low under the UL for any nutrient — unless your bone mineral density (osteopenia). doctor has recommended otherwise. If you have Adequate Intake: 1,000 milligrams (mg)/day a chronic health condition, or are taking pre- (adults ages 19 to 50); 1,200 mg/day (adults 51 and scription medication, it’s also a good idea to older and postmenopausal women of all ages). For check with your doctor before taking supple- the best absorption, limit supplemental doses to ments. Many have possible drug interactions 500 to 600 mg at one time and space doses evenly and side effects. I throughout the day. If you have osteoporosis or

M AYO C LINIC W OMEN’ S H EALTHS OURCE 7 S PECIAL R EPORT J ULY 2009 ly controlled diabetes. Use of certain medications, studies indicate that taking a daily multivitamin- such as and some , also may mineral supplement may increase the immune affect magnesium levels. response in older adults, while other studies sug- Recommended Dietary Allowance: 310 milligrams gest supplementation may weaken the immune (mg)/day (women ages 19 to 30), 320 mg/day response. Supplementation with zinc and certain (women 31 or older), 400 mg/day (men 19 to 30), antioxidants may slow the progression of age-relat- 420 mg/day (men 31 or older). In large doses, ed macular degeneration. But, a doctor’s supervi- magnesium supplements can cause abdominal sion is considered crucial to ensure proper dosages. , and . However, taking Recommended Dietary Allowance: 8 milligrams supplements with food may reduce the risk of (mg)/day (adult women), 11 mg/day (adult men). these potential side effects. Playing it safe Potassium In general, vitamins have proved to be safe. How- Potassium is an that is critical to the ever, it’s best to think twice before chasing the latest function of nerve and muscle cells, including those headlines. Sound health advice regarding vitamins in your heart. and minerals, especially when taken as supplements, Research findings: Some studies indicate that is generally based on research over time. That’s why low potassium may contribute to hypertension, you should be wary of any scientific “evidence” that and that increasing potassium intake through diet claims a certain product or formulation can offer a may help prevent or help treat this problem. Other quick fix or a miracle cure — especially if that evi- studies indicate that increased potassium intake dence departs from accepted research findings and is linked with a lower risk of stroke, but more established dietary guidelines. Supplemental vita- research is needed. mins can be a part of your overall wellness plan. Adequate Intake: 4,700 milligrams/day (adults). But it’s important to use them wisely, and remember Don’t take potassium supplements unless your that they can’t replace a nutritious diet. I doctor recommends them.

Selenium A DDITIONAL R ESOURCES Selenium has antioxidant properties, which may Department of Health and Human Services help your body fight off illnesses. It also helps Dietary Guidelines for Americans maintain the immune system and regulate thyroid www.health.gov/dietaryguidelines function. Research findings: Some studies suggest that sele- National Institutes of Health nium may help prevent certain types of cancer. Office of Dietary Supplements However, research on supplementation hasn’t http://dietary-supplements.info.nih.gov demonstrated that selenium, in pill form, can aid in cancer prevention. Preliminary studies have also Department of looked at the relationship between selenium and National Agricultural Library arthritis. So far, selenium supplements haven’t been www.nal.usda.gov recommended for any type of disease prevention. (Click “Food and Nutrition”) Recommended Dietary Allowance: 55 micrograms/ day (adults). MayoClinic.com Zinc Nutrition and Healthy Eating Zinc is needed for normal growth, development www.MayoClinic.com and sexual maturation, and helps regulate appetite, (Search on “vitamins”) stress level, and sense of taste and smell. It also has antioxidant properties and plays an essential role Mayo Clinic in the immune system. Mayo Clinic Book of I Research findings: Studies have produced con- http://bookstore.mayoclinic.com/home.cfm flicting evidence on whether zinc lozenges reduce the duration and severity of cold symptoms. Some

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M AYO C LINIC W OMEN’ S H EALTHS OURCE 8 S PECIAL R EPORT J ULY 2009