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Supplements can be downright confusing: One week, a particular vitamin prevents one disease; the next, it actually causes another. "Research is always evolving, and as we refine our understanding, guidelines change," says Jeffrey Blumberg, PhD, director of the Antioxidants Research Laboratory at Tufts University in Boston. That's why one news report shouldn't cause panic. To help you (calmly) figure out which supplements are worth taking, we investigated the following claims.The Claim: If you're chronically tired, you're low in B-vitamin complex.
The Big Picture: Vitamin B complex, which includes B12, B6, and others, is necessary for your body's cells to produce energy, explains Heidi Becker, RD, who specializes in supplements. "But taking B vitamins doesn't have the same effect as, say, drinking a cup of coffee and feeling instantly awake; it's more like regularly putting oil in your car and having it run smoothly," says Becker. Plus, women are prone to other energy stealers, including stress and insomnia. Several medical conditions common in women, including iron-deficiency anemia and hypothyroidism, also cause fatigue.
Bottom Line: Before chalking your fatigue up to low B, talk to your doctor about whether any of the above-mentioned culprits could be the cause, and ask for a blood test. Also include vitamin B?rich foods in your diet, such as oatmeal, broccoli, yogurt, bananas, and lean red meats. Becker recommends taking a daily multi and if you're a vegetarian, a B12 supplement. (B12 is found naturally only in animal products, but you can also find it in fortified cereals.)
The Big Picture: These claims came mostly from years of studies in which researchers looked at people who took vitamin E without any medical supervision, explains Harvard Medical School assistant professor Helen Delichatsios, MD. "The problem is that it's difficult to factor in other positive behaviors that might have contributed to the vitamin's protective effects," says Dr. Delichatsios. "People who take vitamins are more likely to exercise, eat well, and lead a healthy lifestyle."
On the contrary, an analysis of clinical trials published in the Annals of Internal Medicine showed that high daily doses of supplemented E (400 International Units or more) raised the risk of stroke. Plus, there was no heart-disease protection; and, in fact, there was an increased overall risk of death. Further studies have also shown no cardiac or cancer-protective benefit.
Bottom Line: Experts like Dr. Delichatsios are advising patients to limit total daily E intake from food and supplements to 400 IU.
The Big Picture: Most women lose around 35 milliliters of blood (about two tablespoons) during a four- to six-day period. It's when you start losing more than 80 ml that you may be at risk for anemia. However, vegetarians (or those who rarely eat meat) and women who have heavy periods should talk to their doctor about taking a supplement that contains iron, says Roberta Anding, RD, a spokeswoman for the American Dietetic Association. Everyone needs different amounts, and you can easily get too much, says Anding. High doses can hinder the absorption of other minerals, plus have unpleasant side effects such as constipation. The RDA for iron is 18 mg, and the upper limit is 45 mg a day. A quick way to tell if you may be lacking: Pull down your lower eyelid; if the color of the inner rim is pale pink or whitish, you may be anemic.
Bottom Line: If you think you're iron-deficient, see your doctor, who will do a blood test to determine if and how you should supplement. In the meantime, eat more iron-rich foods, including dark, leafy green vegetables and lean ground beef.
The Big Picture: This concern was raised by the stir surrounding The UV Advantage (ibooks, Inc., 2005) a book by Michael Holick, PhD, MD, and Mark Jenkins, which claims that fear of skin cancer prevents us from getting the sun exposure we need to naturally produce vitamin D. Sunlight is essential for vitamin D production in our bodies. However, several minutes a few times weekly is all you need, explains Darrell Rigel, MD, a clinical professor of dermatology at New York University Medical Center and past president of the American Academy of Dermatology. "You can get this walking to and from your car or taking out the trash," Dr. Rigel says. "Plus, there's no data that show wearing sunscreen daily puts you at risk for D deficiency."
Also fueling this fear is a recent study that suggests taking D supplements may help prevent colon, breast, and other cancers. The researchers recommend high doses of D: 1,000 mg daily. However, cancer experts aren't rushing to advocate this. "These findings need to be confirmed by more studies before there's a major shift in guidelines," says B. Jay Brooks, MD, chairman of the hematology/oncology department at the Ochsner Clinic Foundation in Baton Rouge, Louisiana. The upper limit is 2,000 mg; high levels can put you at risk for heart arrhythmias and kidney problems.
Bottom Line: Spending five minutes in the sun daily (even with sunscreen) can ensure that you get enough to produce vitamin D. To supplement, the amount found in a multivitamin (the RDA of 400 IU) is sufficient.
The Big Picture: Women on strict low-carb diets may benefit from formulas with added B vitamins (found in whole grains) and vitamin C, lutein, lycopene, and beta-carotene (for those limiting fruits and certain vegetables), says Andrew Shao, PhD, vice president of Scientific and Regulatory Affairs for the Council for Responsible Nutrition in Washington, D.C. A supplement that contains zinc, iron, and calcium, often found in dairy and whole grains, may also prevent the loss of nutrients, because those food groups tend to be shunned by low-carbers.
Bottom Line: If you're on a diet, talk to your doctor about whether you need to take a supplement.
The Big Picture: If only! Save the money you'd spend on vitamins for a pretty ponytail holder instead. "How you treat your hair -- the shampoos you use and limiting blow-drying and coloring -- is what affects how it looks," says Karen Burke, MD, a dermatologist in New York City.
However, some data does show that antioxidants such as C, E, and A (topically and internally) can protect the skin from sun damage, says Shao.
Bottom Line: Get the nutrients you need for healthy skin and hair from a diet high in fruits, vegetables, and whole grains. Certain deficiencies can cause brittle nails or pale skin, but talk to your doctor before taking specific supplements to treat these conditions.
Originally published in Fitness magazine, April 2006.