In World War II British pilots noticed that eating bilberries or bilberry preserves before flying nightly bombing raids improved their vision. Since then, studies have shown that bilberry contains more than 15 different anthocyanosides, flavonoid compounds that not only improve visual acuity, but are important for the treatment of many eye disorders, including cataracts, macular degeneration, diabetic retinopathy, and night blindness. A botanical relative of blueberry, cranberry, and huckleberry, the anthocyanosides in bilberry are also known for their ability to stabilize collagen, rebuild capillaries, inhibit platelet aggregation, reduce hyperglycemia, relax smooth muscle, and increase gastric mucus. Dried bilberry fruit is rich in tannins and pectin, making it an effective treatment for diarrhea, both historically and in modern day European usage.

Bilberry extract contains the highest percentage of anthocyanidin content (25% compared to 0.1% to 0.25% in fresh fruit), making it the most effective means of treatment. This extract improves the delivery of oxygen and blood to the eyes, the maintenance of which is necessary to prevent cataracts and macular degeneration. The extract is also a powerful antioxidant, preventing free radical damage that can cause cataracts and macular degeneration and lead to cancer and heart disease. Bilberry extract's ability to stabilize and strengthen collagen protects the integrity of the eye tissue against glaucoma. The anthocyanosides also strengthen the area of the retina that controls vision and the adaptation between dark and light, improving poor night vision and poor day vision in particular.

The ability of bilberry extract to strengthen capillaries not only protects the eye from the hemorrhaging associated with diabetic retinopathy, but also makes it an important aid for other vascular disorders as well. Because this strengthening power is combined with the ability to reduce platelet aggregation, the extract may help prevent ischemic stroke without risking hemorrhagic stroke. It is also very effective for varicose veins and hemorrhoids and helps reduce the risk of atherosclerosis. As an antioxidant, bilberry is able to raise the levels of intracellular vitamin C, which increases the protection to the capillary walls, improving circulation. The collagen stabilizing, antioxidant, and anti-inflammatory properties of the extract make it very helpful for treatment of arthritis.

Bilberry leaves have been used historically to treat diabetes mellitus by lowering blood glucose levels, an ability that may be related to their chromium content. Use of bilberry extract to prevent and improve diabetic retinopathy is documented. These uses are not approved, however, by the German Commission E, which refers to a lack of documented evidence for bilberry leaves' efficacy.

Anthocyanosides help protect against ulcers by stimulating mucus flow that protects the stomach lining from digestive acids. Their ability to relax smooth muscle is thought to relieve dysmenorrhea as well.

Deciduous shrub grows to 16 inches. Stems are multibranched and erect; leaves are pointed and oval; flowers are small, pink, and white; berries are round and purple-black when ripe. Native to Europe, Asia, and North America. Flowers from April through June. Fruit collected July through September.

• Fruit

Catechins, invertose, flavonone glycosides, and anthocyanosides (particularly glycosides of malvidin, cyanidin, and delphinidin).

Fresh or dried berries; tea made from dried leaves or dried berries; bilberry extract (standardized for 25% anthocyanidin)

Traditional herbal actions: antioxidant, stimulates gastric mucus, breaks down plaque deposits on arterial walls, strengthens capillary walls and causes new capillary formation, vasodilator, reduces platelet aggregation, astringent, antidiarrheal, muscle relaxant, membrane and collagen stabilizing, anti-inflammatory, vascular tonic

Clinical applications: eye disorders (poor night and day vision, cataracts, glaucoma, diabetic retinopathy, macular degeneration), ulcers, ischemic stroke, angina, diarrhea, dysmenorrhea, circulation, rheumatoid arthritis, varicose veins, hemorrhoids, circulation problems, vascular disorders, diabetes, capillary fragility

Research on the pharmacology of the bilberry has focused primarily on its anthocyanoside content. Anthocyanosides strengthen and protect collagen by reinforcing its natural matrix, preventing free radical damage, and inhibiting cleavage caused by inflammation and the release of compounds that cause inflammation (e.g., histamine). This protects tissue from secondary damage from inflammation and aids the regeneration of new tissue after injury.

Anthocyanosides build and strengthen capillaries by increasing intracellular vitamin C levels and decreasing capillary permeability. This aids the circulation of blood to connective tissue in the body, promoting healing after injury or damage from inflammation. Stronger capillaries prevent hemorrhage, such as the eye damage caused by diabetic retinopathy. Anthocyanosides also improve circulation in the larger arteries and veins, reducing platelet aggregation, which aids in the treatment of vascular disorders, such as varicose veins, hemorrhoids, and atherosclerosis. As well as improving circulation and blood flow in the eyes, anthocyanosides also increase the regeneration of rhodopsin in the retina. This purple pigment is crucial to the optimal functioning of the rods, cells that are important for night vision and light adaptation.

The tannins in dried bilberry are effective for treating nonspecific, acute diarrhea. Tannins act as astringents, reducing intestinal inflammation by thickening the surface protein layer of the mucous membrane. This slows the secretion process and protects against resorption of toxins. Germany's Commission E has officially recognized and positively evaluated bilberry fruit, but not bilberry leaf, for nonprescription and clinical applications.

• For eye conditions and circulation: standardized bilberry extract (with 25% anthocyanidin) in encapsulated form, dose of 480 mg/day in two to three divided dosages. After improvement, maintenance dose of 240 mg/day for prevention.
• For dysmenorrhea or ulcer prevention: 20 to 40 mg extract tid, ¹/2 cup of fresh bilberries (difficult to acquire in the U.S.), or tincture (1: 5) 2 to 4 ml tid.
• For diarrhea: 5 to 10 g crushed dried bilberry in cold water, brought to a boil for 10 minutes, then strained.
• For diabetes mellitus: Pour boiling water over 1 g (approximately 1¹/2 tsp.) bilberry leaf, and strain after 10 to 15 minutes. Do not continue use for long duration.

There are no side effects or toxicity associated with bilberry fruit or extract. Prolonged overuse of bilberry leaf may result in severe hydroquinone poisoning, which, with continued chronic use, could be fatal.

There are no known contraindications for bilberry fruit or extract. Its use is not contraindicated during pregnancy or lactation. Prolonged overuse of bilberry leaves could result in chronic intoxication or death.

No clinically significant interactions between bilberry and conventional medications are known to have been reported in the literature to date, including the German Commission E monograph (Blumenthal 1998).

In Germany, Commission E has approved the use of bilberry fruit and extract for treatment of diarrhea and inflammation of the mouth. Commission E has not approved therapeutic use of bilberry leaves, because efficacy has not been documented.

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