Can bilberry improve vision?

Q: I'm sending you information on bilberry, which helped the World War II airmen flying their planes at night. I've been taking these pills since I read about them in an article in Woman's World magazine. (I don't remember the date.) It was about how the berry can help eyesight and night vision. I can now drive at night with no problem. Bilberries are inexpensive, and I purchase mine at Wal-Mart. Please let your readers know about this wonderful product.

A: Bilberries, also known as whortleberries, huckleberries or European blueberries, are commonly used in syrups, pies, cobblers and jams. The fruit extract is also used in wines as a coloring agent. According to the National Center for Complementary and Alternative Medicine (www.nccam.nih.gov), both the fruit and the leaves have been used for almost 1,000 years in traditional European medicine.

Historically, the fruit (dried, fresh or extract) has been used to treat diarrhea, scurvy (vitamin C deficiency) and more. Today, it is popular for the treatment of diarrhea, eye problems, some circulatory problems and menstrual cramps. The leaves (extract or tea) are sometimes used to treat diabetes.

There is not enough evidence that bilberry provides benefits for medical conditions. At the same time, there is not enough evidence proving that it won't help, either. Although the fruit is considered safe, owing to its long history as a food source, high doses may be toxic.

In theory, the plant may lower blood pressure and blood sugar, and may increase the risk of bleeding. However, until more reliable scientific studies are done, what this plant may be beneficial for remains unclear. For example, some studies done in the 1960s and 1970s suggested that bilberry may help preserve or improve vision and night vision, yet more current studies have not found any benefit. Part of the problem is that most of the testing was not done on humans, and the reported results were unclear.

If you have had positive results from the product, then stick with it. Be sure to tell your doctor that you are taking it and at what dose. In theory, bilberry may interact with certain medications, such as those to lower blood pressure or blood sugar. It is necessary that anyone interested in taking the medicine speak to his or her physician first to ensure that the risk of interaction is reduced. Ask Dr. Gott