Bilberries are harvested from a perennial shrub that grows approximately 12 inches in height. There are several hundred species, but the one most commonly studied for its medicinal value is Vaccinium myrtillus. It is part of the Ericaceae plant family and is native to the northern regions of North America and Europe. This fruit was commonly used to make jams and pies in Europe, and the nutritional benefits of bilberries were scrutinized for use in traditional medicines. Eventually, the chemical compounds in bilberry extract were identified and tested for medicinal value.
Beneficial Compounds in Bilberries
There are several compounds in bilberries that give this fruit significant nutritional and medicinal value. Most of them are classed in a large group of molecules called flavonoids. They are responsible for color and pigmentation in plants and have potent antioxidant activity. Hyperoside, quercitrin, isoquercitrin, and astragaline are flavonoid derivatives found in bilberries.
Another group of flavonoid derivatives present in the bilberry is the anthocyanosides. This group of molecules is responsible for many of the beneficial properties of bilberry. Anthocyanosides are plant pigments with a significant capacity for antioxidant activity. Some of the anthocyanosides isolated from bilberries include myrtillin, cyanidin, malvidin, and delphinidin.
The third group of molecules found in bilberries that have medicinal benefits are the tannins. These molecules are characterized as astringents, meaning they shrink or constrict tissue. The concentration of tannins in bilberries is small and most of the compounds are grouped with the catechins.
Conditions Which May Improve With Bilberry Extract
Bilberry extract has been used for centuries to treat several conditions. The flavonoids in bilberry extract are effective at increasing the integrity of capillary walls and reducing the clumping of platelets. This could benefit several circulatory conditions, including chronic venous insufficiency, but there haven’t been any conclusive scientific studies to prove it.
In laboratory tests, anthocyanosides enhance collagen cross-linkages and promote collagen production. In combination with its antioxidant effects, anthocyanosides may reduce the risk of atherosclerosis, which is the build up of plaque in blood vessels. The antioxidant activity of anthocyanosides is particularly effective at reducing the oxidation of LDL, which is considered a necessary type of cholesterol.
Diarrhea is another condition that was treated with bilberry extract in traditional medicine. The astringent compounds, particularly the tannins, give bilberry extract properties that constrict tissue and reduce inflammation in the GI tract. However, a high concentration of tannins ( greater than 10%) can lead to GI discomfort. This property is also useful in treating ulcers of the mouth and sore throats. Wound healing is another potential benefit of the tannins in bilberries.
There have been some indications that bilberry extract can improve certain ailments affecting vision. Specifically, the anthocyanosides have been studied to see if they can repair damage to the retina and prevent cataracts. Nothing conclusive has been established yet. Anthocyanosides also increase the production of rhodopsin, which is a pigment molecule that helps the eye adapt to changes in light.
Eat fresh or dried bilberries as part of a balanced diet to receive its benefits. Concentrated versions of the fruit are available as extracts, which are prepared from the fruit and leaves of the bilberry shrub. Teas prepared from the bilberry shrub also have nutritional value.
Bilberry extract contains 25 percent anthocyanosides, significantly more potent than a single serving of bilberries. For a preventive course, it is recommended to take 80 to120 mg of 25 percent standardized bilberry extract two times per day. To treat eye conditions or circulatory problems, the suggested dosage is 80 to 480 mg per day in two or three divided doses of the capsule form of standardized bilberry extract.
To treat diarrhea, prepare a solution from dried bilberries by soaking 5 to 10 g of dried bilberries in 2/3 cup of cold water. Then boil the solution for about 10 minutes and strain. Do not use the solution for more than four days.
If more than the recommended dosage is taken, the level of tannins in your body may increase. This will lead to several problems including weight loss and muscle spasms. Children over the age of two may be given bilberry, but only under the care of a doctor.
The benefits of bilberry extract may interact with the effects of other drugs. The main concern is with medications that thin the blood. Since compounds in bilberries reduce the accumulation of platelets, clotting is reduced. This could lead to more bleeding when combined with a blood-thinning drug. Another potential interaction is with diabetic medications. In some studies, bilberries lower blood sugar levels. When combined with drugs designed to lower blood sugar, hypoglycemia may occur.
1. “Bilberry.” University of Maryland Medical Center. https://www.umm.edu/altmed/articles/bilberry-000225.htm
2. Kemper, Kathi J. “Bilberry (Vaccinium myrtillus).” Longwood Herbal Task Force. https://www.longwoodherbal.org/bilberry/bilberry.pdf