Vitamins & Supplements Archive

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.

A recent study in The Journal of the American Medical Association found that seniors got no mental boost from taking daily omega-3 fatty acid supplements and antioxidant vitamins for four years. On the other hand, that doesn't mean eating a nutritious diet throughout life doesn't promote healthy aging.

The clinical trial involved more than 3,500 people, average age 73. Researchers were primarily testing the ability of daily nutritional supplements to prevent vision loss from age-related macular degeneration (AMD), which damages the light-sensing retina in the back of the eye. Participants also had tests of their mental function every other year in addition to annual eye exams.

Q. Are there any benefits to taking vitamin E supplements? Or any risks?

Ask the doctor

Q. My wife and I are planning a trip to Europe and we are dreading the jet lag, which hits both of us hard. Is there any evidence that melatonin really helps? Are there any prescription drugs we could ask our doctor about?

A. Jet lag refers to fatigue or a disturbed sleep pattern after travel across multiple time zones. Some small studies have suggested that melatonin is helpful for jet lag if taken a few days before and after travel. Melatonin is a natural substance released by our brain to help with our circadian (day/night) rhythm. This rhythm is disturbed with travel across three or more time zones.

The world moves at a hectic pace these days. If you feel like you're constantly running on empty, you're not alone. Many people say that they just don't have the energy they need to accomplish all they need to. Sometimes the cause of fatigue is obvious — for example, getting over the flu or falling short on sleep. Sometimes a vitamin deficiency is part of the problem. It might be worth asking your doctor to check a few vitamin levels, such as the three we've listed below.

• Iron. Anemia occurs when there aren't enough red blood cells to meet the body's need for oxygen, or when these cells don't carry enough of an important protein called hemoglobin. Fatigue is usually the first sign of anemia. A blood test to measure the number of red blood cells and amount of hemoglobin can tell if you have anemia. The first step in shoring up your body's iron supply is with iron-rich foods (such as red meat, eggs, rice, and beans) or, with your doctor's okay, over-the-counter supplements.
   
• Vitamin B₁₂. Your body needs sufficient vitamin B₁₂ in order to produce healthy red blood cells.  So a deficiency in this vitamin can also cause anemia. The main sources of B₁₂ are meat and dairy products, so many people get enough through diet alone. However, it becomes harder for the body to absorb B₁₂ as you get older, and some illnesses (for example, inflammatory bowel disease) can also impair absorption. Many vegetarians and vegans become deficient in B₁₂ because they don't eat meat or dairy. When B₁₂ deficiency is diet-related, oral supplements and dietary changes to increase B₁₂ intake usually do the trick. Other causes of B₁₂ deficiency are usually treated with regular injections of vitamin B₁₂.
   
• Vitamin D. A deficit of this vitamin can sap bone and muscle strength. This vitamin is unique in that your body can produce it when your skin is exposed to sunlight, but there also aren't many natural food sources of it. You can find it in some types of fish (such as tuna and salmon) and in fortified products such as milk, orange juice, and breakfast cereals. Supplements are another way to ensure you're getting enough vitamin D (note that the D₃ form is easier to absorb than other forms of vitamin D).

For more ways to combat fatigue, buy Boosting Your Energy, a Special Health Report from Harvard Medical School.