Bilberry

Scientific Name(s): Vaccinum myrtillus L. Family: Ericaceae (heaths)

Common Name(s): Bilberries , bog bilberries , 1 blueberries (variety of) , 2 whortleberries

Uses

Dried bilberry tea is used internally to treat nonspecific diarrhea and topically to treat inflamed mouth and throat mucosa. Bilberry extracts may improve visual acuity and ability to adjust to changing light. Derivatives demonstrate vasoprotective, antiedema, and gastroprotective effects.

Dosing

Typical bilberry products are standardized to 25% anthocyanoside content. One recent study administered 160 mg of the extract tid to improve night vision.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Generally recognized as safe or used as food. Avoid dosages above those found in food because safety and efficacy are unproven.

Interactions

None well documented.

Adverse Reactions

No data.

Toxicology

The effects of ingesting large doses of bilberry are not known.

Botany

Bilberry fruit originates from Northern and Central Europe and has been imported from parts of southeastern Europe. These black, coarsely wrinkled berries contain many small, shiny brownish-red seeds. They have a somewhat caustic and sweet taste. 1

History

The historical uses of dried bilberry fruit include being a supportive treatment of acute, non-specific diarrhea when administered as a tea and serving as a topical decoction for the inflammation of the mucous membranes of the mouth and throat. 1

During World War II, British Royal Air Force pilots ate bilberry preserves before night missions in order to improve their vision. After the war, studies confirmed the folk beliefs that bilberry extracts could improve visual acuity and lead to faster visual adjustments between light (eg, glare) and darkness. 2 Some European physicians went on to recommend bilberry extracts for other eye complaints (eg, retinitis pigmentosa, diabetic retinopathy). Clinical studies, however, have not confirmed these therapeutic applications.

Chemistry

According to older studies, bilberry consists of up to 10% tannins, most of which are catechol tannins. In addition to tannins, bilberry contains anthocyanins, flavonoids, plant acids, invert sugars and pectins. The fresh fruit does not have the antidiarrhetic effects; therefore, it must be dried to obtain the tannins which come about by the condensation of the monomeric tannin precursors during the drying process. 1

Uses and Pharmacology

Dried bilberry fruit is used as an antidiarrhetic drug, especially in mild cases of enteritis. It is also used as a topical treatment for mild inflammation of the mucous membranes of the mouth and throat. 1

Most clinical studies have concentrated on the fruit's anthocyanoside content.

Vasoprotection/antiedema effects
Animal data

An experiment using a preparation of anthocyanosides from bilberry (equal to 25% of anthocyanidins) indicated vasoprotective and antiedema effects in experimental animals. Oral doses of 25 to 100 mg/kg increased the permeability of the skin capillary. Antiedema activity was discovered after intravenous or topical use. 3

When vascular permeability is increased in rabbits by cholesterol-induced atheroma, a treatment of anthocyanosides from bilberry decreases vascular permeability. This is acheived when the drug interacts with collagen to increase its cross-links. 4 The administration of anthocyanosides before the induction of hypertension in rats maintains normal blood-barrier permeability and limits the increase in vascular permeability. This may also result from the interaction of the drug with collagens of the blood vessel walls to protect against the permeability-increasing action of hypertension. 5

Vaccinium myrtillus anthocyanosides are effective in promoting and intensifying arteriolar rhythmic diameter changes which aid in the redistribution of microvascular blood flow and interstitial fluid formation. 6

An investigation using an anthocyanidin pigment (IdB 1027) found in bilberries showed protective gastric effects without influencing acid secretion. The pigment was administered orally using 600 mg b.i.d. for 10 days in 10 laboratory animals. The results showed an increase in the gastric mucosal release of prostaglandin E2 which may explain the antiulcer and gastroprotective effects of IdB 1027. 7

Anthocyans and vitamin E are natural antioxidants which produce a protective effect on liver cells damaged by injury. 8

Clinical data

Research reveals no clinical data regarding the use of bilberry fruit for its vasoprotective or antiedema effects.

Dosage

Typical bilberry products are standardized to 25% anthocyanoside content. One recent study administered 160 mg of the extract t.i.d. to improve night vision. 9

Pregnancy/Lactation

Generally recognized as safe or used as food. Avoid dosages above those found in food because safety and efficacy are unproven.

Interactions

None well documented.

Adverse Reactions

Research reveals little or no information regarding adverse reactions with the use of this product.

Toxicology

The effects of ingesting large doses of bilberry are not known.

It is important that the fruit has not been attacked by insects and that it is free of mold. The berries should be as soft as possible or the long-stored drug will become hard and brittle. 1

Bibliography

1. Bissett NG, ed. Herbal Drugs and Phytopharmaceuticals . Stuttgart: Medpharm Scientific Publishers, 1994.
2. Murray MT. The Healing Power of Foods . Rocklin, CA: Prima Publishing, 1993.
3. Lietti A. et al. Studies on Vaccinium myrtillus anthocyanosides. I. Vasoprotective and antiinflammatory activity. Arzneimittel-Forschung . 1976;26(5):829.
4. Kadar A, et al. Influence of anthocyanoside treatment on the cholesterol-induced atherosclerosis in the rabbit. Paroi Arterielle . 1979;5(4):187.
5. Detre Z, et al. Studies on vascular permeability in hypertension: action of anthocyanosides. Clin Physiol Biochem . 1986;4(2):143.
6. Colantuoni A, et al. Effects of Vaccinium Myrtillus anthocyanosides on arterial vasomotion. Arzneimittel-Forschung . 1991;41(9):905.
7. Mertz-Nielsen A, et al. A natural flavonoid, IdB 1027, increases gastric luminal release of prostaglandin E2 in healthy subjects. Ital J Gastroenterol . 1990;22(5):288.
8. Mitcheva M, et al. Biochemical and morphological studies on the effects of anthocyans and vitamin E on carbon tetrachloride induced liver injury. Cell Microbiol . 1993;39(4):443.
9. Muth ER, Laurent JM, Jasper P. The effect of bilberry nutritional supplementation on night visual acuity and contrast sensitivity. Altern Med Rev . 2000 Apr;5(2):164-73.

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