Diet Digest
If you grew up among the heaths, moors, and woodlands of northern Europe, or for that matter are a wild foods enthusiast in the Rocky Mountains of the United States, you would probably be familiar with bilberry as the stuff of which jam or pies are made. Now, however, the average consumer is most likely to find bilberries in the form of purple-colored gelatin capsules in dietary supplement products.
Bilberry, Vaccinum myrtillus, is a relative of blueberry in the heath family. The genus Vaccinum includes upwards of 450 species which occur in cool temperate regions and mountains of both the northern and southern hemispheres. Many are deciduous or evergreen shrubs with edible fruits including blueberries, buckberries, huckleberries, farkleberry, cranberry, whortleberry, crowberry, and bilberry.
Bilberry is small shrub to about a foot in height with sweet, plump blue-black berries. It grows in heaths and woods of northern Europe, western Asia, and the Rockies of western North America. Bilberry is common in northern Europe, as well as mountains of southern Europe, absent only from southern Italy and the Iberian Peninsula.
It thrives in damp acid soils, damp woods and sandy and rocky soils, covering vast areas, and is a scrub shrub of high mountains. Its range extends to Western Mongolia, then jumps the Pacific to Western North America, occurring from British Columbia, southward from Utah to Arizona and New Mexico. Commercial harvest of the fruits is from wild regions of Europe when ripe from July through September.The genus name Vaccinum derives from the old Latin name used in the works of Virgil and Pliny. The species name "myrtillus" refers to the resemblance of the leaves to those of myrtle. In England the plant is known as bilberry, bleaberry, blueberry, as well as common whortleberry.
Bilberry Leaves
The leaves have been used as a tea substitute. In Edible Native Plants of the Rocky Mountains (The University of New Mexico Press, 1967), H. D. Harrington notes that of the leaves of all Rocky Mountain Vaccinum species, his favorite was bilberry leaf tea, which he stated was available at one of the local grocery stores in Fort Collins, Colorado.
Traditionally the leaves have been used for astringent, tonic, anti-inflammatory, and antiseptic qualities. Studies have shown that the leaves have weak anti-diabetic activity and have been used in various herbal combinations as a treatment for diabetes. The leaves contain a component (glucoquinine) which experimentally has been shown to lower blood sugar levels. The leaves are primarily used in the form of a tea. Leaf preparations have also been suggested by modern researchers in Germany as a potential treatment for rheumatism and gout, given the presence of quinic acid in the tea of the dried, heated leaves.
The leaves, however, are primarily used as a folk remedy, and are not nearly as important as the fruits. The German Commission E monographs, the basis of herb regulation in Germany, has a negative monograph on bilberry leaves. According to the monograph the leaves and their preparations are traditionally recommended for use in diabetes mellitus, and the prevention and treatment of gastrointestinal tract conditions, arthritis, gout, skin ailments, hemorrhoids, poor circulation, heart problems, blood purification, and to stimulate metabolic processes. While there are a few older laboratory studies supporting a theoretical basis for potential antiinflammatory and blood-sugar lowering potential, there is not sufficient scientific data to support the traditional use of the leaves. Therefore, because the claimed applications are not well-documented, bilberry leaves are not approved for their traditional uses. Safety issues are also a question. Animal studies have shown that the leaves can cause anemia, disturb tone of the gastrointestinal system, and adversely effect absorption of nutrients. Safety problems probably relate to high tannin content of the leaves.
Bilberry Fruits-Food and Medicine
Bilberry has been valued for centuries as a nutritious food and a wild edible delicacy.
The berries, best known as an edible fruit, are an ancient food in northern Europe. In an 1862 work, The Useful Plants for Great Britain, C. P. Johnson noted that the berries have a sweetish, but slightly acid taste and are best eaten cooked rather than. They have long been sold in English markets. In Scotland the berries are eaten with milk, and used for pies, tarts, syrups, and jellies. The berries have also been used for wine-making. In the 1870s, a USDA report noted that the fruits were a favorite food of various Indian groups of the Rocky Mountain region.
The use of bilberry fruits as an herbal medicine emerges in the Middle Ages. Saint Hildegard of Bingen (1098-1179), the first women to write an herbal, recommended the plant for inducing menstruation. In the 16th century German herbalists, such as Hieronymus Bock, recommended the berries for treatment of bladders stones, liver disorders, and in syrups for coughs and lung ailments.
In the eighteenth century, use of bilberry fruits became widespread among herbalists and physicians, particularly in Germany. Berry preparations were used for various intestinal conditions, as well as typhoid fever, infections of the mouth, skin, and urinary tract infections, and in gout and rheumatism. By the early part of this century, the dried berry tea was used as an astringent for diarrhea and dysentery, a diuretic, cooling nutritive tonic, to prevent scurvy (vitamin C deficiency), and to stop bleeding. It is also used as an astringent and disinfectant mouthwash for mouth inflammations.
Modern interest in bilberry arose through serendipity after the Second World War. During night bombing missions, British Royal Air Force pilots reportedly experienced an improvement in night vision after eating bilberry jam. In the mid 1960s, reference to these observations eventually led to the first laboratory and later clinical studies on the effects of bilberry fruit extracts on the eyes and vascular system.
The use of bilberry fruits as an herbal medicine emerges in the Middle Ages. Saint Hildegard of Bingen (1098-1179), the first women to write an herbal, recommended the plant for inducing menstruation. In the 16th century German herbalists, such as Hieronymus Bock, recommended the berries for treatment of bladders stones, liver disorders, and in syrups for coughs and lung ailments.
In the eighteenth century, use of bilberry fruits became widespread among herbalists and physicians, particularly in Germany. Berry preparations were used for various intestinal conditions, as well as typhoid fever, infections of the mouth, skin, and urinary tract infections, and in gout and rheumatism. By the early part of this century, the dried berry tea was used as an astringent for diarrhea and dysentery, a diuretic, cooling nutritive tonic, to prevent scurvy (vitamin C deficiency), and to stop bleeding. It is also used as an astringent and disinfectant mouthwash for mouth inflammations.
Modern interest in bilberry arose through serendipity after the Second World War. During night bombing missions, British Royal Air Force pilots reportedly experienced an improvement in night vision after eating bilberry jam. In the mid 1960s, reference to these observations eventually led to the first laboratory and later clinical studies on the effects of bilberry fruit extracts on the eyes and vascular system.
What's in the fruits?
The effectiveness of the fruit extracts was linked to a group of compounds called "anthocyanosides." These compounds are derivatives of anthocyans - the pigments responsible for the red, blue or violet colors in flowers and fruits. The majority of studies on bilberry have involved extracts purified to contain from 25 to 36 percent anthocyanosides. At least fifteen different anthocyanoside compounds have been identified in bilberry extracts. Most standardized bilberry extracts available as dietary supplements on the American market contain 25 percent anthocyanosides.
Like most herbal medicines, positive effects obtained from the plant are not necessarily attributed to only one chemical component. In addition to anthocyanocides, bilberry fruits contain tannins (up to 7 percent) as well as several alkaloids including myrtine and epimyrtine. At least twelve different phenolic acids have been identified from the fruits along with three glycosides of quercetin, including quercitrin, isoquercitrin, and hyperoside. All of these components, in one way or another, could help to contribute to bilberry's beneficial effects.
Modern Use
In European herbal medicine, bilberry fruit preparations are now used to enhance poor micro-circulation, including eye conditions such as night-blindness and diabetic retinopathy. The German Commission E has produced a positive monograph on bilberry fruits, which are allowed in that country for the treatment of acute diarrhea, and for treatment of mild inflammations of the mucous membranes of the mouth and throat.
Modern laboratory studies on bilberry fruit extracts have confirmed a number of activities including antioxidant effects, an ability to inhibit aggregation of blood platelets (reduce stickiness, hence a tendency to clotting of blood cells), produce a slight relaxation effect on vascular smooth muscles, and a possible role in reducing factors associated with chronic inflammatory diseases. Extracts of the fruit have also been shown in laboratory experiments to inhibit enzymes such as elastase, which can cause the degradation of collagen. This can lead to a reduction in factors associated with inflammatory conditions such as atherosclerosis, pulmonary emphysema, and rheumatoid arthritis.
Bilberry and the Vascular System
Among the most credible uses of bilberry relate to conditions of peripheral vascular disorders, especially those involving capillary fragility. Tiny blood vessels (capillaries) can become fragile, common in aging populations, producing capillary fragility. This can lead to more frequent bruising. Weak capillaries are associated with poor blood circulation to connective tissues, and have been related to inflammatory conditions such as arthritis. Bilberry anthocyanosides serve to strengthen capillaries by protecting them from free radical damage. They also stimulate the formation of healthy connective tissue, and aid in the formation of new capillaries. Bilberry may reduce blood platelet stickiness (platelet aggregation), a risk factor associated with atherosclerosis. Given its proven ability to help reduce the fragility of blood capillaries, bilberry fruit products have been studied in clinical trials involving patients suffering from a wide range of diseases including diabetes, arteriosclerosis, hypertension, varicose veins, liver disorders, peptic ulcers, and other conditions in which capillary fragility may play a role in causing symptoms secondary to the disease itself. Most studies have been by French or Italian researchers and published in those languages.
Studies in the mid to late 1960s showed that bilberry extracts produced a reduction in symptoms associated with decrease resistance in the blood capillaries such as bruising, blood in the stool, and minute, pin-head sized bleeding spots on the skin. In various clinical studies with patients suffering from water retention in the lower limbs with varicose vein symptoms, the bilberry extracts helped to reduce subjective symptoms such as a feeling of heaviness, pain in the legs and ankles, and sensations of burning, pricking or numbness of the skin. One double blind placebo-controlled study on 47 patients with various peripheral vascular disorders also reported subjective improvement in the symptoms enumerated above, as well as an improvement in swelling (due to water retention) and movement of finger joints in patients suffering from Raynaud's syndrome, a condition involving spasms of the digits with blue coloration, probably relating to poor micro-circulation to the extremities. The syndrome is named after a Paris physician, Maurice Raynaud (1834-1881).
Results of clinical studies involving more than 700 patients with various conditions related to poor micro-circulation in cases of atherosclerosis, a tendency to bruising, hemorrhoids and varicose veins have shown the extracts help reduce damage from free radicals (antioxidant effects) and promote healthy circulation to the extremities. These studies involve extracts of the fruits standardized to contain 25 to 36 percent anthocyanosides. The tea has also been shown useful, mostly through clinical experiences (rather than controlled studies) for diarrhea, and inflammation of the mucous membranes of the mouth and throat.
Bilberry and Eye Conditions
Based on anecdotal reports from British air force pilots of increased night vision after eating bilberry jam, in the 1960s French researchers set out to discover if bilberry had any potential for the treatment of eye diseases. In experiments with rabbits, a mixture of the anthocyanosides from bilberry was found to increase the animals' ability to adapt to darkness. The improvement in visual function was related to an increase in the regeneration rate of rhodopsin, a purple pigment essential for helping the rods in the eye adapt to light and dark. The retina located at the back of the eye is a specialized structure that responds to light. Special cells called rods and cones in the retina are what makes it work. The cones are adapted to sense details and distinguish colors. They are like the color and tint adjustment dials on a television. The rods detect lightness and darkness. They are like a television's contrast and brightness adjustments. Bilberry's ability to speed up the regeneration of rhodopsin in the rods helps the retina to improve adaptation to light and dark. Studies on anthocyanosides from bilberry both in laboratory and animals experiments have also been shown to modify enzyme processes that are involved in producing damage to the retina.
A number of clinical studies have been carried out with bilberry fruit extracts either alone or in combination with beta-carotene and vitamin E for disorders related to impaired photo-sensitivity or poor micro-circulation to the retina. Four studies were published in the late 1960s by Italian researchers in Italian scientific periodicals that showed that both healthy individuals and patients with visual disorders had a significant improvement in night vision, more rapidly adapted to darkness, and had faster restoration of visual acuity following exposure to bright flashes of light after taking a bilberry extract.
Additional studies on air-traffic controllers, airplane pilots and truck drivers also showed that a standardized extract of bilberry fruits helped to improve night vision and enhanced adjustment to darkness. In two clinical trials, Italian researchers found that 76 percent of patients with myopia (short or near sightedness) had a marked improvement in retinal sensibility. The patients were given 150 mg per day of a bilberry fruit extract for 15 days, along with vitamin A.
Diabetic retinopathy is a condition secondary to diabetes mellitus, in which there is non-inflammatory degeneration of the retina. At least three double-blind placebo-controlled studies, in which patients were given 320 to 480 mg per day of a high-anthocyanoside-containing extract for 30 days to twelve months showed positive improvements. A significant reduction or disappearance of hemorrhages in the retina was observed. These studies were conducted by Italian researchers from 1982 to 1987.
Bilberry - The Future
Most studies on bilberry, as previously stated were conducted by French or Italian researchers, mostly in the 1960s and 70s. Much of the research is published in relatively obscure French or Italian scientific journals in the languages of the authors. The fact that the results are dated, and difficult to assess due to language barriers and lack of availability, makes some scientists slow to accept the results. A number of pharmacological and clinical studies have involved the isolated anthocyanosides used in injectable forms. Clearly more studies, involving a great number of patients using oral dosage forms are needed if we are to accept the claims made for bilberry fruit extracts.
While more studies are needed to prove effectiveness, safety is well-established. A post-marketing retrospective study followed 2,295 patients who had been prescribed a 36% anthocyanoside standardized bilberry fruit extract. Researchers showed positive results for improvement of symptoms associated with lower limb venous insufficiency, conditions of capillary fragility and altered permeability of blood capillaries, disease-related changes in microcirculation of the retina, and to reduce itching, inflammation and swelling following surgical removal of hemorrhoids. No adverse effects were reported even for prolonged use of the extract. The German Commission E monograph on bilberry fruits lists no known contraindication, interactions with other drugs, or side effects. Given its long history of food use, and clinical experience with extracts over a thirty year period, safety is not at issue.
In the United States, bilberry dietary supplement products including tablets and capsules of the dried fruits are available, as well as products standardized to 25% anthocyanosides. Standardized products will give more predictable results. The dried ripe berries are used in a dose of 20 to 60 g daily, prepared as a tea, divided into three doses. Standardized products are taken at a dose of 120 to 480 mg per day, (usually 340 mg) divided into two or three doses.
Whether you consider it a wild edible delicacy or a dietary supplement, bilberry is an herb that's here to stay.
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