Bilberry contains anthocyanins and other naturally occurring compounds being studied for their potential effects on eye health, cardiovascular function and metabolism, although researchers say clinical evidence remains insufficient to confirm many traditional medicinal claims.
By yourNEWS Media Newsroom
Bilberry (Vaccinium myrtillus L.), a small, dark-blue fruit closely related to the blueberry, has a long history of use in traditional European herbal medicine. Researchers continue to investigate its potential health effects, particularly those associated with vision, circulation, inflammation and blood sugar regulation.
The fruit contains anthocyanins, flavonoids, tannins and other plant compounds with antioxidant properties. These naturally occurring substances have attracted scientific interest because of their biological activity in laboratory experiments and preliminary clinical studies.
However, a 2022 scientific review published in Frontiers in Pharmacology found that research into bilberry’s effects on vision disorders, diabetes and circulatory conditions has produced conflicting results.
The researchers concluded that additional well-designed clinical trials are necessary to determine whether bilberry extracts provide reliable therapeutic benefits and to establish appropriate dosages.
Bilberry’s Nutritional Composition and Traditional Uses
Bilberry grows naturally in parts of Europe, North America and northern Asia. It is known by several common names, including blaeberry, whortleberry, myrtle blueberry, winberry and huckleberry.
The berries can be eaten fresh or incorporated into juices, jams, pies, tarts and other foods. They are also sold in dried form and as concentrated extracts used in dietary supplements.
Bilberries are particularly rich in anthocyanins, the pigments responsible for the red, blue and purple coloring of many fruits and vegetables.
According to information published by Mercola.com, bilberries are among the notable natural dietary sources of these compounds.
Anthocyanins belong to the larger family of flavonoids, which have been studied for antioxidant activity and their potential influence on inflammation and blood vessel function.
The 2022 review identified numerous bioactive substances in bilberry fruit and leaves, including phenolic acids and other polyphenols.
Historically, bilberry preparations have been used for digestive complaints, circulation problems, elevated blood sugar and vision-related conditions.
The leaves have also been used in herbal preparations, although their safety profile differs from that of the edible fruit.
Eye Health and Night Vision
One of bilberry’s most widely publicized traditional applications involves improving eyesight, especially night vision.
Interest in this use grew during the 20th century, partly because of reports that British military pilots consumed bilberry jam during World War II to improve their ability to see in darkness.
The historical accounts helped popularize bilberry as a vision supplement, but subsequent scientific research has not consistently supported the claim.
A systematic review published in Survey of Ophthalmology examined 30 studies involving bilberry-derived anthocyanosides and vision under reduced-light conditions.
Twelve of the studies were placebo-controlled.
The four most recent randomized controlled trials reviewed found no significant improvement in night vision, while several earlier studies reported favorable results.
Researchers determined that the strongest available clinical evidence did not support using bilberry extracts to improve normal night vision in healthy individuals.
The National Center for Complementary and Integrative Health (NCCIH), part of the National Institutes of Health, similarly states that the most rigorous studies have not demonstrated a night-vision benefit in healthy people.
Nevertheless, investigators continue examining whether anthocyanins influence retinal function, oxidative stress and other biological processes associated with eye health.
Some laboratory research suggests that compounds found in bilberry and related plants may help protect retinal cells against certain forms of damage.
Research discussed by NaturalNews.com has also highlighted experimental studies involving bilberry polyphenols and retinal cells exposed to blue light.
Such findings are preliminary. Protective effects observed in isolated cells or animal experiments do not establish that consuming bilberry supplements prevents retinal disease or improves vision in humans.
Cardiovascular Health and Circulation
Bilberry anthocyanins have also been investigated for possible effects on blood vessel function and cardiovascular health.
Laboratory studies suggest these compounds may influence vascular relaxation, inflammation and oxidative stress.
The Textbook of Natural Medicine discusses experimental findings indicating that bilberry anthocyanosides can affect vascular smooth muscle, the tissue involved in regulating blood vessel diameter.
Researchers have also examined bilberry preparations in relation to capillary function and chronic venous insufficiency, a condition in which blood circulation through the veins becomes impaired.
The 2022 review identified some encouraging findings involving blood lipid levels and inflammatory conditions.
However, the researchers emphasized that many available clinical studies were small or lacked the rigorous controls needed to establish consistent results.
According to Memorial Sloan Kettering Cancer Center, laboratory evidence suggests bilberry compounds may influence blood vessels and clotting mechanisms, but more human research is needed to determine whether those effects translate into meaningful clinical benefits.
Bilberry supplements should therefore not be considered established treatments for cardiovascular or circulatory disorders.
Blood Sugar and Metabolic Research
Bilberry fruit and leaf extracts have historically been used in preparations intended to support blood sugar regulation.
Researchers have investigated whether anthocyanins and other polyphenols influence glucose metabolism, insulin sensitivity and inflammatory pathways associated with metabolic disease.
Some preliminary studies have reported changes in metabolic markers, but the evidence remains inconsistent.
The 2022 review found no clear conclusion supporting bilberry as a treatment for type 2 diabetes.
The researchers also noted that some traditional claims about bilberry and blood sugar regulation have been repeated for decades without sufficient clinical verification.
Individuals taking medication to lower blood sugar should discuss concentrated bilberry preparations with a health care professional because of potential interactions and uncertainty about their metabolic effects.
Bilberry is not a substitute for prescribed diabetes treatment.
Inflammation and Other Potential Uses
Bilberry’s polyphenol content has also prompted research into inflammatory conditions and other health concerns.
Experimental studies have examined whether bilberry compounds influence inflammatory signaling, oxidative damage and cellular responses associated with chronic disease.
The Textbook of Natural Medicine describes preliminary investigations into bilberry anthocyanosides and dysmenorrhea, or painful menstrual cramps.
Other researchers have studied bilberry preparations in connection with digestive disorders and inflammatory conditions.
Although some findings have been encouraging, evidence from isolated laboratory experiments and small clinical studies is insufficient to establish bilberry as an effective treatment for these conditions.
Safety, Side Effects and Drug Interactions
Bilberry fruit is generally considered safe when consumed in ordinary food quantities.
The NCCIH reports that bilberry fruit extracts have appeared well tolerated in research involving doses of up to 160 milligrams daily for periods of up to six months.
However, concentrated supplements can present different risks than eating the fruit.
Memorial Sloan Kettering warns that bilberry may increase bleeding risk when combined with blood-thinning medications, including warfarin, aspirin and certain nonsteroidal anti-inflammatory drugs.
A case of excessive bleeding associated with bilberry consumption and anticoagulant medication has been reported.
Bilberry preparations may also produce mild gastrointestinal symptoms, including nausea or abdominal discomfort.
The plant’s leaves require additional caution.
Although traditional preparations sometimes use bilberry leaves, the NCCIH warns that consuming them in high doses or over extended periods may be unsafe.
Some herbal sources have raised concerns about liver-related effects from bilberry leaves. However, the National Institutes of Health’s LiverTox database reports that bilberry has not been clearly linked to clinically apparent liver injury.
That distinction is important because potential toxicity from prolonged leaf consumption should not be confused with established evidence of liver damage from eating bilberry fruit.
People who are pregnant, breastfeeding, taking prescription medications or managing chronic health conditions should consult a qualified health care professional before using concentrated bilberry supplements.
Choosing Bilberry Products
Fresh and frozen bilberries are generally consumed as food, while dried berries, capsules, teas and extracts are sold through grocery stores, natural food retailers and online suppliers.
Supplement formulations differ considerably in their concentrations of anthocyanins and other compounds.
The 2022 review also identified concerns about supplement quality, including products containing anthocyanins from other botanical sources or failing to provide the ingredients indicated on their labels.
Consumers considering bilberry supplements should look for clearly identified ingredients, appropriate labeling and independent quality testing where available.
What the Research Shows
Bilberry remains of scientific interest because of its concentration of anthocyanins, flavonoids and other biologically active plant compounds.
Laboratory findings and some preliminary human studies suggest potential applications involving eye health, inflammation, circulation and metabolic function.
However, the NCCIH states that bilberry has not been clearly demonstrated to benefit any specific health condition.
The existing evidence does not establish bilberry supplements as effective treatments for impaired night vision, diabetes, cardiovascular disease or other medical disorders.
For most consumers, bilberry’s established role is as an edible fruit containing naturally occurring plant compounds. Its potential medicinal applications require further research through larger, well-controlled clinical trials.
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