Latin name Vaccinium myrtillus
Other names; European blueberry, huckleberry, whortleberry, or blueberry.
About Bilberry
Bilberry is a shrubby perennial plant one to two feet in height and can be found in the mountains and forests of Europe and the northern United States. The fruit of the bilberry plant is blue-black or purple and is harvested July through September. Bilberry has been used as food for centuries due to its high nutritive value, and whilst it’s history of medicinal use dates back to the Middle Ages, it did not become widely known to herbalists until the 16th century when its use was documented for treating bladder stones, biliary disorders, scurvy, coughs, and lung tuberculosis.
More recently, bilberry fruit extracts have been used for the treatment of diarrhoea, dysentery, and mouth and throat inflammations. Bilberry leaf decoctions have been used to lower blood sugar in diabetes. Currently, bilberry research is focused on the treatment of ocular disorders, vascular disorders, and diabetes mellitus.
Several active constituents have been isolated from the berries and leaves of the bilberry plant, including anthocyanoside flavonoids (anthocyanins), vitamins, sugars, and pectins, which are found in the berries,
Extracts containing anthocyanosides have been shown to possess strong antioxidant properties,(1) stabilize collagen fibers and promote collagen biosynthesis,(2-4) decrease capillary permeability and fragility, (5) and inhibit platelet aggregation (6)
Anthocyanosides and other bilberry leaf constituents prevent the release and synthesis of pro-inflammatory compounds such as histamine, prostaglandins, and leukotrienes.(2,4,7). In addition, bilberry leaf decoctions administered orally have been shown to lower blood glucose levels (8).
Uses
Eye Health
The mechanisms of action behind bilberry’s beneficial effect on the eye have not been completely elucidated but include the ability to improve oxygen and blood delivery to the eye and to scavenge free radicals that can disrupt collagen structures and contribute to conditions such as cataracts and macular degeneration. In addition, the anthocyanosides have an affinity for the pigmented epithelium (visual purple) area of the retina, the portion of the retina responsible for vision and adjustments to light and dark (9,10).
Bilberry extract’s visual enhancement properties were first studied by French researchers on Royal Air Force pilots during World War II. Administration of bilberry extract resulted in improved nighttime visual acuity, faster adjustment to darkness, and faster restoration of visual acuity after exposure to glare (11,12) Later studies confirmed this effect (13,14).
Studies of bilberry extract on individuals with retinitis pigmentosa and hemeralopia (inability to see distinctly in bright light) demonstrated a significant improvement in visual performance (14,15) It may be the most significant effects will be observed in those with impaired visual acuity.
Glaucoma
Consumption of bilberry extracts may offer significant protection against the development of glaucoma due to its collagen-enhancing and antioxidant properties. The reduced tensile strength and integrity of aging eye tissue may result in the increased intraocular pressure and loss of peripheral vision seen in glaucoma. In one study, patients with glaucoma given a single oral dose of Vaccinium myrtillus anthocyanosides demonstrated improvement based on electroretinography (9) A collagen-stabilizing effect on the trabecular meshwork, facilitating aqueous outflow, may provide a potential mechanism.
Cataracts
Animal studies show diets high in anthocyanoside flavonoids retard the development of cataracts (16,17). A clinical study, in which bilberry extract was given with vitamin E, demonstrated arrested cataract formation in 48 of 50 patients with senile cortical cataracts (18).
Diabetic Retinopathy
Several clinical studies are reported in the literature supporting its use in this indication (19-23). In a double-blind study, 14 patients with diabetic and/or hypertensive retinopathy were supplemented with bilberry extract or placebo for one month. Significant improvements were observed in the ophthalmoscopic parameters of 11 subjects receiving bilberry, and 12 patients showed improvement in angiographic parameters (22).
Vascular Disorders
Bilberry extracts improve microcirculation. Animal studies have shown it to be of benefit in decreasing vascular permeability and improving vascular tone and blood flow (23,24). Fifteen patients with polyneuritis due to peripheral vascular insufficiency were given bilberry extract and significant improvement was noted in microcirculation (25). In another study, the same dosage of bilberry extract given to 47 patients with various venous diseases resulted in reduced capillary flow as well as an elimination of microstagnation and blood stasis of the foot (26). A review of uncontrolled trials from 1979 to 1985 on a total of 568 patients with venous insufficiency of the lower limbs showed bilberry extract was effective in rapidly decreasing symptomology and improving both venous microcirculation and lymph drainage (27).
Diabetes Mellitus
Bilberry leaf decoctions have a long history of folk use as a hypoglycemic agent (28,29). This effect is attributed to the myrtillin anthocyanoside, apparently the most active hypoglycemic component (29). In addition, bilberry anthocyanosides enhance collagen integrity, stabilize capillary permeability, and inhibit sorbitol accumulation, thus providing protection against vascular and neurological sequelae of diabetes.
Anti-inflammatory
Bilberry extracts have demonstrated anti-inflammatory properties in animals, and thus may be useful in the treatment of conditions such as rheumatoid arthritis (30).
Additionally, women with dysmenorrhea were given bilberry extract for three days before and during menstruation. A significant improvement in pelvic/lumbosacral pain, mammary tension, nausea, and lower-limb heaviness was noted (31).
Bilberry extracts have also been shown to have strong antiplatelet aggregating activity in humans when given at doses of 480 mg daily for 30-60 days (32).
Safety
As might be expected with a food, bilberry consumption is very safe.. A review of studies comprising over 2,000 subjects taking bilberry extract reported only mild side effects affecting the gastrointestinal, cutaneous, or nervous system (33).
There is currently no EMEA monograph for bilberry.
References
1. Kuhnau J. Wld Rev Nutr Diet 1976;24:117-191.
2. Harvsteen B. Biochem Pharmacol 1983;32:1141-1148.
3. Gabor M. Pharmacologic effects of flavonoids on blood vessels. Angiologica 1972;9:355-374.
4. Mian E, Curri SB, Lietti A, Bombardelli E. Minerva Med 1977:68:3565-3581.
5. Bottecchia D, et al. Fitoterapia 1987;48:3-8.
6. Amella M, Bronner C, Briancon F, et al. Planta Medica 1985;51:16-20.
7. Bever B, Zahnd G. Plants with oral hypoglycemic action. Quart J Crude Drug Res 1979;17:13996.
8. Caselli L. Arch Med Int 1985;37:29-35.
9. Wegmann R, Maeda K, Tronch P, Bastide P. Ann Histochim 1969;14:237-256.
10. Jayle GE, Aubert L. Therapie 1964:19:171-185.
11. Terrasse J, Moinade S. Vaccinium myrtillus. Presse Med 1964;72:397-400.
12. Sala D, Rolando M, Rossi P Minerva Oftalmol 1979;21:283-285.
13. Gloria E, Peria A. Ann Ottalmol Clin Ocul 1966;92:595-607.
14. Junemann G. Klin Monatsbl Augenheilkd 1967;151:891-896.
15. Pautler EL, Ennis SR. Curr Eye Res 1984;3:1221-1224.
16. Hess H, Knapka JJ, Newsome DA, et al. Lag Anim Sci 1985;35:47-53.
17. Bravetti G. Ann Ottalmol Clin Ocul 1989;115:109.
18. Scharrer A, Ober M. Klin Monatabl Augenheilkd 1981;178:386-389.
19. Chaundry PS, Cambera J, Juliana HR, Varma SD. Biochem Pharmacol 1983;32:1995-1998.
20. Varma SD, Mizuno A, Kinoshita JH. Diabetic cataracts and flavonoids. Science 1977;195:87-89.
21. Perossini M, et al. Ann Ottalmol Clin Ocul 1987;113:1173.
22. Lietti A, Cristoni A, Picci M. Arzneim Forsch 1976;26:829-832.
23. Colantuoni A, Bertuglia S, Magistretti MJ, Donato L. Arzneim Forsch 1991;41:905-909.
24. Pennarola R, et al. Gazz Med Ital 1980;139:485-491.
25. Ghiringhelli C, Gregoratti L, Marastoni F. Minerva Cardioangiol 1978;25:255-276.
26. Bratman S, Kroll D. The Natural Pharmacist: Clinical Evaluation of Medicinal Herbs and Other Therapeutic Natural Products. Roseville, CA: Prima Publishing 1999:Bilberry 1-5.
27. Allen FM. BJAMA 1927;89:1577-1581.
28. Bever B, Zahnd G. Quart J Crude Drug Res 1979;17:139-196.
29. Rao CN, Rao VH, Steinman B. Ital J Biochem 1981;30:54-62.
30. Colombo D, Vescovini R. G Ital Ost Ginecol 1985;7:1033-1038l.
31. Puilleiro G, et al. Fitoterapia 1989;60:69-75.
32. Eandi M. Cited in Morazzoni P, Bombardelli E. Vaccinium myrtillus I. Fitoterapia 1996;67:3-29.
