Herbs & Supplements

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Uses

Currently, bilberry is probably best known for treating eye conditions. It has been shown in clinical studies to decrease some of the retinal damage caused by diabetes or high blood pressure in at least two ways. First, it contains chemicals known as anthocyanosides (or anthocyanins), which may increase retinal pigments (coloring agents) that allow the eye to tolerate light. Additionally, bilberry may help to make the walls of blood vessels in the eyes stronger by increasing collagen linkages. Collagen is a protein that supports and strengthens body structures such as skin and bones. As one result, retinopathy (the gradual break down of the retina in the eyes) may be slowed. Individuals with hardening of the arteries, diabetes, high blood pressure, or other conditions that increase the likelihood for damage to the small blood vessels in the eyes are more likely to have serious vision problems due to blood vessel damage. Note that bilberry is taken by mouth to treat eye problems. It is not used in eye drops.

Oral bilberry preparations are also used to prevent and treat weakened blood vessels. They are used extensively to relieve a condition known as chronic venous insufficiency, which occurs when valves in the veins that carry blood back to the heart are weak or damaged. Blood may collect in the veins of the legs and lead to varicose veins, spider veins, or sores on the legs. More serious results can include blood clots in the legs. Because bilberry may strengthen the walls of all blood vessels in the body, taking it may also relieve hemorrhoids. Some recent research may show that bilberry's effect on blood vessels may also protect the heart and the coronary arteries from damage.

Bilberries contain tannins, although the actual tannin content may fluctuate between as little as 1.5% and as much as 10%. Drying bilberry fruits concentrates the tannins, so dried bilberries generally contain a higher percentage than fresh bilberries. In the past, dried bilberries have been used to treat diarrhea because the tannins act as an astringent to the gastrointestinal tract. An astringent shrinks and tightens the top layers of skin or mucous membranes, thereby reducing secretions, relieving irritation, and improving tissue firmness. Due to the same astringent effect, tea brewed from dried bilberry fruits has also been used to soothe a sore throat or sore mouth tissue. Recent laboratory studies show that bilberries also have an antibacterial effect, which may contribute to their antidiarrheal properties.

In folk medicine, bilberry leaf has been used to treat a number of conditions including diabetes. Limited evidence from a few animal studies shows that it may have a decreasing effect on blood sugar. Additionally, in at least one study, an extract of bilberry leaves may also have lowered cholesterol levels in laboratory animals. Other laboratory and animal studies have tested potential anticancer effects of bilberry. In a laboratory study, bilberry stopped the growth of both leukemia and colon cancer cells. While preliminary results suggest that anthocyanosides obtained from bilberries may also block the effects of an enzyme and other chemicals that promote tumor growth, much more study is needed. To date, no human clinical studies have confirmed any of these results from bilberry.