Vitamins & Supplements Archive

Ask the doctor

Q: My eyesight is declining, but my eye doctor tells me I do not have any serious eye problems. Are there any vitamins or supplements I can take to protect my eyes?

A: Based on the most recent research, there is no proven vitamin cocktail to prevent vision loss. The most common causes of vision loss as you grow older are cataracts and age-related macular degeneration (AMD). Since cataracts can be treated with simple surgery, much of the attention for prevention of vision loss has focused on macular degeneration. Initially, there was excitement about antioxidant vitamins, since a combination of vitamins A, C, and E delayed progression of AMD in previously diagnosed individuals. However, the Age-Related Eye Disease Study showed no benefit from antioxidants in people who did not already have AMD. A single study in women (average age 64) reported that a combination of vitamins B₆, B₁₂, and folate reduced the development of AMD over a seven-year period. But this study has not been replicated, and it hasn't been done in men, which makes it hard to recommend these supplements.

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Ask the doctor

Q. I have difficulty falling asleep, and melatonin has not worked. I want to avoid medications and I have read magnesium supplements can help. Should I try them?

A. Magnesium is an important element in many biological functions, including nerve and muscle function, so it is often proposed as a natural treatment. It has gained some acceptance as a preventive treatment for migraine headaches, but there is not strong scientific evidence for its use with insomnia.

Ask the doctor

Q . I am 68 and in excellent health. I eat a healthy diet, exercise every day, and do not drink or smoke. I'm on no medicines. The only pill I take is vitamin D. But I'm wondering: is there any benefit in that?

A. In a nutshell, here's what we know. Our skin makes most of the vitamin D in our bodies after exposure to sunlight. Because most of us are indoors most of the 24 hour day, many of us have relatively low blood levels of vitamin D.

Fruits and vegetables contain vitamins, minerals, and other nutrients that are essential for good health. That's one reason why a plant-based diet that includes lots of fruits and vegetables can lower your risk of developing life-threatening diseases such as heart disease, diabetes, and some cancers. And when you pile on the produce, there's less room for the unhealthy foods, too.

Dinner is typically the largest (and latest) meal of the day, and it's a good opportunity to make sure that you meet your daily quota for fruits and vegetables. Here are five easy ways to work more produce into dinner.

In the Journals

A study in The New England Journal of Medicine casts light on a little-known hazard associated with America's multibillion-dollar dietary supplement habit: difficulty swallowing among older people who take vitamin and mineral supplements—particularly calcium supplements.

Using a decade of records from 63 hospitals, researchers with the CDC and FDA estimated that 23,000 Americans end up in the emergency room because of bad reactions to dietary supplements. This includes herbal supplements and those containing vitamins, minerals, and other nutrients (such as amino acids).

Q. What do you know about taking extra folic acid to boost the immune system?

A. Folic acid is the synthetic form of folate, a B vitamin that occurs naturally in some foods, including vegetables, fruits, and dried beans and peas — and is essential for health. Folate is vital for the production and maintenance of our bodies' cells, especially during rapid periods of growth, such as pregnancy and infancy. It's needed to make DNA and RNA, the genetic material that dictates cell functions, and it helps prevent changes to DNA that may lead to cancer.

In the journals

Dietary supplements containing the herbal ingredient yohimbe often contain prescription-strength active ingredients that are potentially dangerous, according to a study in Drug Testing and Analysis.

Scientists analyzed 49 popular brands of supplements with yohimbe. They found evidence that 39% of the products tested appeared to contain a pharmaceutical-grade extract of the herb.

Research we're watching

A national survey published Sept. 30, 2015, in Menopause indicates almost a third of women who take hormones at menopause are using compounded hormones—estrogen, progesterone, or testosterone prepared by a pharmacist according to a prescription. Such preparations aren't FDA-approved.

The survey, conducted by the North American Menopause Society, asked 3,700 women ages 40 to 84 about their hormone use at menopause. They were queried about the benefits they expected, the benefits they actually received, the side effects they experienced, and their health histories.

Although vitamin D is essential to bone health, a controlled clinical trial published online by JAMA Internal Medicine on Aug. 3, 2015, found that vitamin D supplements didn't build bone in postmenopausal women with blood levels of vitamin D below the 30-ng/mL threshold generally considered necessary for good health. Researchers at the University of Wisconsin randomly assigned 230 women to three groups: one got 800 IU of vitamin D daily and a placebo twice a month; one got a placebo daily and 50,000 IU of vitamin D twice a month; the third got placebos both daily and twice a month. The study lasted a year. The researchers found that neither dose of vitamin D had a significant effect on bone mass, falls, or fractures.

The Wisconsin study may not have used the right doses of vitamin D or lasted long enough to show an effect. One ongoing study, The Vitamin D and Omega-3 Trial (VITAL), is large enough to demonstrate even small-to-moderate benefits of vitamin D supplementation. VITAL is evaluating a 2,000-IU daily dose for five years in 26,000 women and men. The results are expected in 2017. Until then, it's still important to get the recommended daily dose of vitamin D: 600 IU for adults through age 70 and 800 IU for people ages 71 or older

Q. Some of my friends take saw palmetto supplements to reduce urinary problems caused by an overgrown prostate, which I was recently diagnosed with. My friends swear by it, but is there any good evidence this stuff helps? Is saw palmetto safe?

A. The short answer is that we don't have great scientific evidence that taking saw palmetto truly reduces male urinary problems. On the other hand, it doesn't appear to cause major side effects either.