The dried fruit of the bilberry contains 5% to 10% tannins, which act as an as tringent; these tannins may help target the bowel and help treat diarrhea. The anthocyanidins in bilberry help prevent angina episodes, reduce capillary fragility, and stabilize tissues that have collagen-like tendons and ligaments. They also inhibit platelet aggregation and thrombus formation by interacting with vascular prostaglandins. The anthocyanidins also help regenerate rhodopsin, a light sensitive pigment found on the rods of the retina, so bilberry may help treat degenerative retinal conditions, macular degeneration, poor night vision, glaucoma, and cataracts.
The antioxidant effects of anthocyanidins may also give bilberry vasoprotective and hepatoprotective properties. The anthocyanidin pigment in the herb may increase the gastric mucosal release of prostaglandin E2, accounting for the antiulcerative and gastroprotective effects. Bilberry is available as a dried fruit, a 10% decoction for topical use, a dry extract (25% anthocyanosides) in 80 mg capsules, and a 1:1 fluid extract. It’s available in products such as Bilberry Power.
Benefits And Uses of Bilberry
Bilberry is used to treat acute diarrhea and mild inflammation of the mucous membranes of the mouth and throat. It’s also used to provide symptomatic relief from vascular disorders (including capillary weakness, venous insufficiency, and hemorrhoids), to prevent macular degeneration, and for its potential hepatoprotective properties.
Dried fruit: 4 to 8 g by mouth with water several times every day .
Fluid extract: 2 to 4 ml by mouth three times a day .
For eye disorders: 80 to 160 mg dry extract (25% anthocyanosides) by mouth three times a day .
For inflammation: 10% decoction prepared by adding 5 to 10 g of crushed dried fruit to 5 oz of cold water, boiling for 10 minutes, then straining while hot, applied topically as an astringent
For acute diarrhea: 20 to 60 g of dried fruit by mouth every day.
Side Effects of Bilberry
Because the herb may inhibit platelet aggregation, it may be unsuitable for those with a bleeding disorder. Bilberry may have additive effects when used with the drug warfarin.
Because bilberry may reduce a diabetic patient’s blood glucose level, dosage of his conventional antidiabetic may need to be adjusted.
Consistent dosing of bilberry is needed when using the herb to treat vascular or ocular conditions.
Advise patient who’s using the dried fruit to take each dose with a full glass of water.
If patient is using bilberry to treat diarrhea, advise him to consult his health care provider if it doesn’t improve in 3 to 4 days.
Tell patient to remind prescriber and pharmacist of any herbal or dietary supplement that he’s taking when obtaining a new prescription.
Advise patient to consult his health care provider before using an herbal preparation because a treatment with proven efficacy may be available.
A double-blind, placebo-controlled trial of bilberry extract in 14 people with damage to the retina caused by diabetes and/or hypertension found significant improvements observable by ophthalmoscopic examination and angiography. However, this was a very preliminary study.