Bilberry (Vaccinium Myrtilus)
James Meschino DC, MS, ROHP
Bilberry extract is well recognized for its ability to support collagen tissue (especially in blood vessel supporting connective tissues) and provides antioxidant protection to the macula of the eye. As such, it is recommended for certain eye conditions, such as macular degeneration, diabetic retinopathy, and in cases of capillary fragility. During World War II British fighter pilots taking Bilberry reported an improved ability to adjust to glare and an increase in their visual acuity and nighttime vision.21,22,23
Research has focused primarily upon the anthocyanosides, which are flavonoid compounds, unique to Bilberry extract. They are formed by an anthocyanidin backbone bound to one of three sugars (arabinose, glucose or galactose).
The concentration of anthocyanosides in the fresh fruit is only 0.1 to 0.25 percent, whereas concentrated extracts of Bilberry taken as supplements yield an anthocyanidin content of 25 percent.1,2,3,21,22
Mechanism of Action
Stabilizing action – Bilberry preserves collagen and related ground substance by increasing the cross-linking of collagen fibers, acting as a free radical scavenger, inhibiting enzymatic cleavage of collagen by enzymes secreted by leukocytes during inflammation, reducing the release of histamine, serine proteases, prostaglandins and leukotrienes and by promoting the synthesis of glycosaminoglycans (see glucosamine in this document) and collagen by chondrocytes.4,5,6,7
- Anti-aggregation of platelets
Like many other flavonoids anthocyanosides heve been shown to decrease platelet aggregation in experimental studies.8,9,10
The anthocyanodins derived form Bilberry also demonstrate very potent antioxidant properties.4
- Macular Degeneration of the Eye
Macular degeneration is the most common cause of blindness in individuals over the age of 55 (see also Lutein and Zeaxanthin in this document) in North America. Bilberry anthocyanidins appear to be able to help defend against and manage macular degeneration and other eye conditions via several biological actions. The first is that these unique flavonoids have been shown to improve the delivery of oxygen and blood to the eye. The second is that they provide antioxidant protection against ultra-violet light induced free radical damage (from sunlight) to the macula of the eye, which has been shown to contribute to the development and progression of macular degeneration. Third, anthocyanidins from Bilberry have been shown to stabilize the blood vessel wall of small blood vessels in the macular region of the eye, helping to prevent leaking of blood (micro-hemorrhaging) into the macular region as often occurs in diabetic retinopathy and the wet form of macular degeneration. Like the antioxidant carotenoids lutein and zeaxanthin, Bilberry anthocyanosides are known to concentrate in the macula of the eye, where they have the opportunity to quench ultra-violet light induced free radicals.21,22
In one study, 31 patients with various retinopathies (20 diabetic, 5 retinitis pigmentosa, 4 macular degeneration, 2 hemorrhagic retinopathy) were treated with Bilberry extract.
There was a tendency toward reduced permeability and hemorrhage observed in all patients, especially in those with diabetic retinopathy.18
In the study by Bravetti G. (1989), Bilberry extract, plus vitamin E stopped progression of cataract formation in 97 percent of 50 patients with senile cortical cataracts. This effect is thought to be due to its powerful antioxidant properties, protecting the lens of the eye from oxidation and regenerating its collagen fibers.17
- Night Vision
Bilberry anthocyanosides have an affinity for the pigmented epithelium or visual purple of the retina, which is the portion of the retina responsible for night vision (rhodopson pigment formed from vitamin A on the rods).
The Royal Air Force pilots reported improved night vision during World War II with the use of Bilberry extract (also, quicker adjustment to darkness and faster recovery from glare). Even individuals with retinitis pigmentosa and hemeralopia (day blindness) have realized impressive improvement with Bilberry extract supplementation.11,12,13,14,15,16,17,18
Varicose Veins and Capillary Fragility
Via its effects on collagen and connective tissues, which include increased synthesis of glycosaminoglycans (cement substance between fibers), reduced permeability and impaired prostaglandin synthesis, Bilberry has been used in clinical trials with capillary fragility problems. In one study, 47 patients with varicose veins treated with Bilberry extract (480 mg per day) witnessed significant improvement with edema, heaviness feeling, parethesia, pain and skin dystrophy.19,20 ( see also Horse chestnut and Grape seed extract in this document).
Dosage and Standardized Grade
For most eye conditions and capillary fragility conditions, the following recommendations can be considered:
80 to 160 mgs of Bilberry extract, (standardized to 25 percent anthocyanidin content), three times per day.
Adverse Side Effects, Toxicity and Contraindications
Bilberry extract has been shown to be very non toxic and has not produced any significant side effects is studies to date. There are no well known health conditions that preclude the use of Bilberry extract.21,22
Anticoagulant Medications (e.g. warfarin, coumadin, aspirin) – as Bilberry extract has been shown in experimental studies to reduce the clotting action of blood platelets, it may potentiate the action of other anticoagulant drugs. In these cases, prothrombin time (INR) should be monitored closely to guard against a possible bleeding disorder, although no human reports of such an occurrence have yet been reported.24
|Pregnancy and Lactation
During pregnancy and lactation, the only supplements that are considered safe include standard prenatal vitamin and mineral supplements. All other supplements or dose alterations may pose a threat to the developing fetus and there is generally insufficient evidence at this time to determine an absolute level of safety for most dietary supplements other than a prenatal supplement. Any supplementation practices beyond a prenatal supplement should involve the cooperation of the attending physician (e.g., magnesium and the treatment of preeclampsia.)
References: Pregnancy and Lactation
1. Encyclopedia of Nutritional Supplements. Murray M. Prima Publishing 1998.
2. Reavley NM. The New Encyclopedia of Vitamins, Minerals, Supplements, and Herbs. Evans and Company Inc. 1998.
3. The Healing Power of Herbs (2nd edition). Murray M. Prima Publishing 1995.
4. Boon H and Smith M. Health Care Professional Training Program in Complementary Medicine. Institute of Applied Complementary Medicine Inc. 1997.
- Kuhnau J, The flavonoids, A Class of Semi-essential Food Components: Their Role in Human Nutrition, World Rev Nutr Diet 1976;24:117-91.
- Gabor M, Pharmacologic Effects of Flavonoids on Blood Vessels, Angiologica 1972;9:355-74.
- Havsteen B, Flavonoids, A Class of Natural Products of High Pharmacological Potency, Biochem Pharmacol 1983;32:1141-8.
- Monboisse JC, et. al. Non-enzymatic Degradation of Acid Soluble Calf Skin Collagen by Superoxide Ion: Protective Effect of Flavonoids, Biochem Pharmacol 1983;32:53-8.
- Monboisse JC, Braquet P, Borel JP. Oxygen-free Radicals as Mediators of Collagen Breakage. Agents Actions 1984;15:49-50.
- Rao CN, Rai VH, And Steinman B, Influence of Bioflavonoids on the Collagen Metabolism in Rats with Adjuvant Induced Arthritis. Ital J Biochem 1981;30:54-62.
- Ronziere MC, et. al., Influence of Some Flavonoids on Reticulation of Collagen Fibrils in Vitro. Biochem Pharmacol 1981;30:771-6.
- Middleton E, The Flavonoids, Trends Pharm Sci 1984;5:335-8.
- Amella M, et. al., Inhibition of Mass Cell Histamine Release by Flavonoids and Bioflavonoids. Planta Medica 1985;51:16-20. Jonadet M, et. al., Anthocyanosides Extracted from Vitis Vinifera, Vaccinium Myrtillus and Pinus Maritimus, I. Elastese-inhibiting Activities in Vitro, II. Compared Angioprotective Activities in Vivo, J Pharm Belg 1983;38:41-6.
- Detre A, et. al., Studies on Vascular Permeability in Hypertension: Action of Anthocyanosides. Clin Physiol Biochem 1986;4:143-9.
- Jayle GE and Aubert L, Action des Glucosides D’Anthocyanes sur la Vision Scotopique et Mesopique du Sujet Normal Therapie 1964;19:171-85.
- Terrasse J and Moinade S, Premiers Resultats Obtenus Avec un Nouveau Facteur Vitaminique P “les Anthocyanosides” Extraits du Vaccinium Myrtillus, Presse Med 1964;72:397-400.
- Sala D, Rolando M, Rossi PL and Pissarello L, Effects of Anthocyanosides on Visual Performances at Low Illumination. Minerva Oftalmol 21, 283-285, 1979. Gloria E and Peria A, Effect of Anthocyanosides on the Absolute Visual Threshold, Ann Ottalmol Clin Ocul 1966;92:595-607.
- Junemann G, On the Effect of Anthocyanosides on Hemeralopia Following Quinine Poisoning. Klin Monatsbl Augenheilkd 1967;151:891-6.
- Caselli L, Clinical and Electroretinographic Study on Activity of Anthocyanosides. Arch Med Int 1985;37:29-35.
- Wegman R, Maeda K, Troche P, and Bastide P. Effects of Anthocyanosides on Photoreceptors, Cytoenzymatic Aspects. Ann Histochim 1969;14:237-56.
- Bravetti G, Preventive Medical Treatment of Senile Cataract with Vitamin E and Anthocyanosides: Clinical Evaluation. Ann Ottalmol Clin Ocul 1989;115:109.
- Scharrer A and Ober M, Anthocyanosides in the Treatment of Retinopathies. Klin Monatbsl Augenheilkd 1981;178:386-9.
- Mian E, et.al., Anthocyanosides and the Walls of Microvessels, Further Aspects of the Mechanism in the Action of their Protective Effect in Syndromes due to Abnormal Capillary Fragility. Minerva Med 1977;68:3565-81.
- Ghiringhelli G, Gregoratti F, and Marastoni F, Capillarotropic Activity of the Anthocyanosides in High Doses in Phlebopathis Stasis. Min Cardioangiol 1978;26:255-76.
- Murray MT, The Healing Power of Herbs (2nd edition), Prima Publishing, 1995.
- Dietary Supplement Information Bureau. content.intramedicine.com: Bilberry
- Jayle GE, et al. Study concerning the action of athocyanoside extracts of Vaccinium myrtillus on night vision. Ann Occul Paris. 1965; 198 (6): 556-62.
- Moranzonni P, et al. Vaccinium myrtillus. Fitoterapia. 1996; vol LXVII (1): 3-29