Vitamins & Supplements Archive

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.

Ask the doctor

Q. Are vitamin supplements (like vitamin D) good for your health, and can you tell me who might benefit from taking the pills?

Q. Why can't doctors decide if vitamin supplements are good for your health, or not?

A. You might think that it would be simple for doctors to determine if vitamin supplements are good for your health. Alas, it's not. Here's why.

Q. Whatever happened to the idea that taking vitamin C could boost your immune system and prevent colds? Is there still a possibility it could work?

A. Vitamin C, also known as ascorbic acid, was promoted as a health supplement for decades, achieving its greatest renown in the 1970s through the writings of scientist Linus Pauling. Despite the excitement about its natural antioxidant function, vitamin C does not appear to prevent colds, and its ability to shorten the duration of colds is minimal. A recent summary of 29 studies involving more than 10,000 people confirmed the lack of benefit of regular vitamin C supplementation.

If you feel run-down, lack of iron is probably not the cause. You can easily get enough of this key mineral in your diet.

Decades ago, advertising for the liquid vitamin and mineral supplement Geritol warned against "iron-poor, tired blood." It's a reference to the fact that red blood cells need iron to make hemoglobin, the molecule that grabs oxygen and transports it around the body.