Bilberry

Background

• The bilberry bush is native to northern areas in Europe, the northern United States, and Canada. Its dark berries resemble blueberries. The berries and leaves of the bilberry plant have been used as medicine.
• Extracts from bilberry fruits and leaves have traditionally been used for conditions related to vision, elevated blood sugar levels, and several cardiovascular disorders. It has been reported that during World War II, British pilots ate bilberry jam, thinking it would improve their night vision. Although this may have been superstition or a deliberate hoax to help conceal improvements in radar, it prompted research on bilberry and night vision.
• Today, bilberry is promoted as a dietary supplement for eye conditions, circulatory problems, and other conditions.

How Much Do We Know?

• Some research has been done in people on the effect of bilberry on various conditions, but many of the studies did not use rigorous methods and did not include enough study participants to allow definite conclusions to be reached.

What Have We Learned?

• Bilberry has not been clearly shown to be helpful for any health condition.
• Bilberries contain some substances that may be of interest for further research, including anthocyanins, anthocyanosides, tannins, and flavonoids.
• Studies of the effects of bilberry on night vision have had conflicting results. Much of the research was of poor quality. The most rigorous studies have not found bilberry to be effective in improving night vision in healthy people.

What Do We Know About Safety?

• Bilberry fruit is considered safe when consumed in amounts typically found in foods. Bilberry fruit extracts have been used safely in research studies at doses of up to 160 mg/day for up to 6 months and appear to be well tolerated.
• Bilberry leaves may be unsafe when consumed in high doses or for long periods of time.
• If you take any type of medicine, talk with your health care provider before using bilberry or other herbal products; some herbs and medicines interact in harmful ways.
• Little is known about whether it is safe to use bilberry in amounts greater than those found in foods during pregnancy or while breastfeeding. 

Keep in Mind

• Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.
• Federal Regulation of Herbal Products
  • Depending on what’s in them, how they’re intended to be used, and how they’re administered (orally or topically), herbal products are regulated in a variety of ways. Many herbal products intended for oral use are marketed as dietary supplements. The rules for making and distributing dietary supplements are less strict than those for drugs.
  • Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public. When public health concerns arise about the safety of a dietary supplement or an ingredient including an herb, the FDA can take action to protect the public. Manufacturers and distributors of supplements are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all regulatory requirements. 

For More Information

• Using Dietary Supplements Wisely
• Know the Science: How Medications and Supplements Can Interact
• Know the Science: How To Make Sense of a Scientific Journal Article

Key References