Posted by: Glow-worm PJ14 AUG 2008
A lover of poor, acid soil, the bilberry is a provider to a variety of animal species. In spring its nodding, lantern-like, green and pink flowers are an important source of early season nectar for bumble bees, and one species has been named the bilberry bumble bee because of its affinity for the plant’s flowers.
Various species of moth larvae feed on the leaves, and in autumn its sweet, black berries offer a rich harvest for a variety of birds, most notably the red grouse.
Man, too, has long appreciated the special qualities of the fruit (which has a plethora of local names, including whortleberry, whimberry and blaeberry), making them into pies or jellies or eating them raw with cream.
The berries are rich in vitamins C and D. In medieval times the juice was used as a remedy for diarrhoea. In Scotland and Ireland it was used as a dye for paper, linen and wool.
Although bilberry constituents have many pharmacological actions, recent research has focused on the anthocyanoside flavonoids, which are present in both the berry and leaf. The content in the berries increases as they ripen and, at the same time, the reverse happens in the leaves.
Anthocyanoside extracts have been shown to possess strong antioxidant properties, to stabilise collagen fibres, to promote collagen biosynthesis, to decrease capillary permeability and fragility and to inhibit platelet aggregation.
In addition, bilberry leaf decoctions administered orally to dogs have been shown to lower blood glucose levels. Indeed, bilberry leaf teas have been used for centuries to produce this effect.
During the 1939–45 war, British pilots reported improved night vision after a nightly dose of bilberry jam before bombing missions. Subsequent research suggested that bilberry extract may improve microcirculation within the eye, with the most significant effects on those with impaired visual acuity.
Other research, often inconclusive, has been looked into the reported beneficial effects of bilberry upon the eye. The mechanisms behind these effects are not well understood but they include the ability to improve oxygen and blood delivery to the eye and to scavenge free radicals that can disrupt collagen structures, leading to macular degeneration and cataract formation.
They also affect the trabicular network, which has an influence on aqueous outflow, a factor in the development of glaucoma.