Bilberry is a small shrub that has a long history of medicinal use. Extracts from its edible berries and leaves are sold as dietary supplements that are used to treat and prevent a variety of medical conditions. Much of bilberry's therapeutic value stems from its concentration of chemicals called ellagitannins and their metabolites. Bilberries are considered safe for most people, while supplements made from the leaves are linked with health risks. To avoid side effects, consult your health care provider before taking bilberry and only acquire it from reputable manufacturers.
Bilberry
Bilberry, also known as Vaccinium myrtillus, European bilberry and wineberry, is a small shrub related to blueberry and huckleberry. It produces small purple-black berries that you can harvest in late summer. In addition to being used in pastries and wine, bilberries and their leaves have a history of use in medicine. Depending on your ailment, you can eat the fresh or dried berries whole, drink them as a tea or take the dried powder as a dietary supplement. Because most commercial extracts are manufactured to contain a 25 percent concentration of therapeutic chemicals called anthocyanidins, they are the most potent medicinal form.
Ellagitannins
Chemically, ellagitannins are made of long chains of compounds called phenols. They are the most widespread form of tannins and have been found in over 500 plants, such as berries, nuts and seeds. When you eat certain foods, such as bilberries, the ellagitannins are metabolized by the microflora in your colon and are transformed into various metabolites with bioactive properties. Both the undigested ellagitannins in bilberries and their metabolites provide antioxidant, antimicrobial and anti-inflammatory activities.
Benefits
Bilberry is marketed for its medicinal use in treating ailments such as chronic venous insufficiency, diabetes, atherosclerosis, diarrhea and retinal problems. The underlying therapeutic value comes from bilberry's potential to increase blood circulation, repair blood vessels, regulate blood glucose levels, reduce bad cholesterol, reduce inflammation and act as an astringent. Most of bilberry's medicinal claims are based on its long history of use in Europe and animal studies. Its use to treat diarrhea is the area where it has been applied the longest: Bilberry tannins help constrict intestinal tissues, reduce inflammation and ward off pathogenic bacteria.
Risks
Whole bilberries and authentic extracts are edible and safe when eaten in reasonable portions, but there are risks associated with the high tannin content in bilberry leaves. Taking large doses or taking the leaves for too long can cause you to lose weight, suffer from muscle spasms or die. Consult your health care provider before taking bilberry as a dietary supplement because it can interact with certain medications, such as anticoagulants and diabetes treatments. Because some bilberry supplements are adulterated with drugs or metals, you should only purchase them from a reliable manufacturer.
References
- Medline Plus: Bilberry
- Drugs.com: Bilberry
- NYU Langone Medical Center: Bilberry
- "Food Research International"; Ellagitannins, Ellagic Acid and Their Derived Metabolites: A Review About Source, Metabolism, Functions and Health; J.M. Landete; June 2011
- University of Maryland Medical Center: Bilberry
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