Bilberry

Background

• The bilberry bush is native to northern areas of Europe and Asia, the northern United States, and Canada. Its dark berries resemble blueberries.
• Its name is derived from the Danish word bollebar, which means “dark berry.”
• Bilberry has been used for medicinal purposes since the Middle Ages. The berries and leaves are the parts of the plant that are used. Historically, bilberry has been used for a variety of conditions, including diarrhea, inflammation of the mouth, urinary problems, and diabetes. It’s also been used traditionally to prevent scurvy, due to its high vitamin C content. During World War II, British pilots ate bilberry jam, thinking it would improve their night vision.
• Today, bilberry is promoted as a dietary supplement for night vision, cataracts, varicose veins, and other conditions such as atherosclerosis (in which plaque builds up in arteries).

How Much Do We Know?

• There are few high-quality clinical trials (studies in people) of bilberry supplements.

What Have We Learned?

• There’s little scientific evidence to support the use of bilberry for many health conditions.
• A few recent studies have suggested possible beneficial effects of bilberry. However, these studies involved small numbers of people. More research would be needed to confirm these findings.
  • Results from a small clinical study (24 people) suggest that consuming bilberries may reduce gum inflammation and bleeding.
  • Data from a Japanese study with 88 office workers suggest that a bilberry extract helped with eye fatigue.
  • Data from a small study with 21 people suggest that consuming bilberry juice for 5 days before and 2 days after a half-marathon may lead to small to moderate transient increases in muscle soreness and inflammation in recreationally trained runners.
• The berries have a high concentration of polyphenols called anthocyanins, which some studies suggest may have health benefits.

What Do We Know About Safety?

• Bilberry fruit is considered safe when consumed in amounts typically found in foods, or as an extract for 6 months to a year.
• Bilberry leaves may be unsafe when taken orally (by mouth) in high doses or for long periods of time.
• Little is known about whether it’s safe to use bilberry during pregnancy or while breastfeeding. (Consuming amounts typically found in foods is considered safe.)
• Bilberry may interact with a cancer drug called erlotinib (Tarceval), antidiabetes drugs, or medications that slow blood clotting. If you’re taking medicine, talk with your health care provider before taking bilberry supplements.

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.

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