If you grew up among the heaths, moors, and woodlands of northern Europe or are a wild-foods enthusiast in the Rocky Mountain region, you might be familiar with bilberries, fruits of a member of the heath family (Ericaceae) that are much like blueberries. Most Americans, however, are more likely to encounter them in the form of purple gelatin capsules in health-food stores.
The genus Vaccinium includes nearly 450 species that occur in cool, temperate flatlands and mountains of the Northern and Southern Hemispheres. Many are deciduous or evergreen shrubs with edible fruits, including blueberry, huckleberry, cranberry, whortleberry, and lingonberry.
Bilberry (V. myrtillus) is a foot-tall deciduous shrub with ovate leaves that bears globular pinkish bell-like flowers in spring. It covers vast areas of high mountains in Europe, thriving in damp, acid soils, damp woods, and sandy and rocky soils. From Europe, it ranges eastward to western Mongolia, and in North America, it is found from British Columbia southward to Utah, Arizona, and New Mexico. In Europe, the sweet, plump blue-black fruits are harvested commercially from the wild in July through September.
Bilberry fruits have been valued for centuries as a nutritious food. In England and Scotland, they are eaten with milk and used in pies, tarts, syrups, jellies, and wine. They were also esteemed by Native Americans living in the Rockies.
The first record of bilberry fruits as an herbal medicine is Hildegard of Bingen’s recommendation in the twelfth century to use them to induce menstruation. In the sixteenth century, other German herbalists were prescribing bilberries for bladder stones and liver disorders and bilberry syrups for coughs and lung ailments.
By the eighteenth century, European herbalists and physicians had added intestinal disorders, typhoid fever, gout, rheumatism, and infections of the mouth, skin, and urinary tract to the list of ailments that they believed bilberry would cure. Two hundred years later, people were drinking a tea of the dried berries as a tonic and to stop diarrhea and bleeding, promote urination, and prevent scurvy (vitamin C deficiency); it was also used as an astringent and disinfectant mouthwash for mouth inflammations.
Interest in bilberry’s potential as an herbal medicine was renewed during World War II when British Royal Air Force pilots reported an improvement in night vision during night bombing missions after eating bilberry jam. These observations led to laboratory tests in the 1960s and later clinical studies on the effects of bilberry fruit extracts on the eyes and vascular system.
Among the constituents of the extracts are at least fifteen anthocyanosides, flavonoids that are derivatives of anthocyanins, the pigments responsible for the red, blue, or violet colors of flowers and fruits and the red in autumn leaves. Most studies have involved extracts that contain 25 to 36 percent anthocyanosides; most standardized bilberry extracts available to U.S. consumers contain 25 percent anthocyanosides.
Bilberry fruits contain up to 7 percent tannins as well as several alkaloids, including myrtine and epimyrtine. At least twelve different phenolic acids have been identified from the fruits as well as three glycosides of quercetin. All of these components could contribute to bilberry’s effectiveness as an herbal medicine.
The vascular system. Bilberry extracts have been shown to be effective in relieving disorders of the peripheral blood vessels, especially the capillary fragility associated with aging. Studies in the 1960s showed that extracts reduced bruising, blood in the stool, and tiny bleeding spots on the skin. Patients suffering from water retention in the lower limbs and varicose veins experienced relief from feelings of heaviness, pain in the legs and ankles, and sensations of burning, prickling, or numbness of the skin. One double-blind, placebo-controlled study of forty-seven patients with various peripheral vascular disorders reported improvement in the symptoms described above as well as a reduction in swelling due to water retention. Other clinical studies involving more than 47 patients with atherosclerosis, a tendency to bruising, hemorrhoids, and varicose veins—all conditions related to poor microcirculation—have shown that the extracts reduce damage from free radicals and promote healthy circulation to the extremities. In other studies, the tea has proven useful for relieving diarrhea and inflammation of the mucous membranes of the mouth and throat.
Bilberry anthocyanosides are believed to strengthen capillaries by protecting them from free-radical damage, stimulating the formation of healthy connective tissue, and promoting the formation of new capillaries. Bilberry fruit may reduce blood platelet stickiness, which can lead to heart attacks or stroke.
Eye disorders. When French researchers in the 1960s fed a mixture of bilberry anthocyanosides to rabbits, the animals’ ability to adapt to darkness increased, an effect attributed to an increase in the regeneration rate of the purple pigment rhodopsin in the retina. In laboratory and animal experiments, bilberry anthocyanosides have also been shown to deter enzyme reactions that damage the retina.
Researchers have examined the effect of bilberry fruit extracts (either alone or in combination with beta-carotene and vitamin E) on disorders related to impaired photosensitivity or poor microcirculation to the retina. Four Italian studies published during the 1960s showed that both healthy individuals and patients with visual disorders had significantly improved night vision and adapted more rapidly to both darkness and light after taking a bilberry extract. Additional studies on air-traffic controllers, airplane pilots, and truck drivers confirmed that a standardized extract of bilberry fruits improved their night vision and enhanced their adjustment to darkness.
In two clinical trials, Italian researchers found that 76 percent of nearsighted subjects showed a marked improvement in retinal sensitivity after taking 150 mg per day of a bilberry fruit extract for fifteen days, along with vitamin A.
Diabetic retinopathy (a noninflammatory degeneration of the retina) occurs in many people with diabetes mellitus. At least three double-blind, placebo- controlled studies during the 1980s, in which participants were given 320 to 480 mg per day of a high-anthocyanoside extract of bilberry for thirty days to twelve months, showed significant reduction or disappearance of hemorrhages in the retina.
Bilberry anthocyanosides are believed to strengthen capillaries by protecting them from free-radical damage, stimulating the formation of healthy connective tissue, and promoting the formation of new capillaries.
Most studies on bilberry were conducted by French or Italian researchers during the 1960s and 1970s and published in foreign scientific journals. That the results are dated, not widely publicized, and not available in English has made some scientists here slow to accept the generally positive results. Additional, and more rigorous, studies are needed if we are to accept the claims made for bilberry fruit extracts.
The safety of bilberry, however, is well established. One study of 2295 subjects taking a 36 percent anthocyanoside-standardized bilberry fruit extract showed positive results with no adverse effects, even after prolonged use. There are no reported contraindications, interactions with other drugs, or side effects.
In the United States, bilberry dietary supplements, including extracts standardized to 25 percent anthocyanosides and tablets and capsules of the dried fruits, are readily available. A tea made from 20 to 60 g of the dried ripe berries is taken daily in three doses. The usual dosage of standardized products is 340 mg per day, divided into two or three doses.
• Blumenthal, M., ed. German Bundesgesundheitsamt Commission E Therapeutic Monographs on Medicinal Products for Human Use. Translated by S. Klein. Austin, Texas: American Botanical Council, in press.
• Brown, D. Herbal Prescriptions for Better Health. Rocklin, California: Prima, 1996.
• Cunio, L. “Vaccinium myrtillus”. Australian Journal of Medical Herbalism 1993, 5(4):81–85.
• Morazzoni, P., and E. Bombardelli. “Vaccinium myrtillus”. Fitoterapia 1996, 67(1):3–29.
• Weiss, R. F. Herbal Medicine. Translated by A. R. Meuss. Beaconsfield, England: Beaconsfield, 1988.
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