Bilberry (Vaccinium myrtillus)

 
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Bilberry
Bilberry

Background

Bilberry, a close relative of blueberry, has a long history of medicinal use. The dried fruit has been popular for the symptomatic treatment of diarrhea, for topical relief of minor mucus membrane inflammation, and for a variety of eye disorders, including poor night vision, eyestrain, and myopia.

 

Bilberry fruit and its extracts contain a number of biologically active components, including a class of compounds called anthocyanosides. These have been the focus of recent research in Europe.

 

Bilberry extract has been evaluated for efficacy as an antioxidant, mucostimulant, hypoglycemic, anti-inflammatory, "vasoprotectant," and lipid-lowering agent. Although pre-clinical studies have been promising, human data are limited and largely of poor quality. At this time, there is not sufficient evidence in support of (or against) the use of bilberry for most indications. Notably, the evidence suggests a lack of benefit of bilberry for the improvement of night vision.

 

Bilberry is commonly used to make jams, pies, cobblers, syrups, and alcoholic/non-alcoholic beverages. Fruit extracts are used as a coloring agent in wines.

 

Synonyms

Airelle, anthocyanins, black whortle, bleaberry, blueberry, burren myrtle, cranberry dwarf bilberry, dyeberry, European blueberry, heidelberry, huckleberry, hurtleberry, ligonberry, lowbush blueberry,  Myrtilli fructus , Optiberry, resveratrol, sambubiosides, trackleberry, vaccinium myrtillus anthocyanoside extract, VMA extract, VME, whortleberry, wineberry.

 

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence Grade*
Atherosclerosis ("hardening" of the arteries), peripheral vascular disease

Bilberry has sometimes been used traditionally to treat heart disease and atherosclerosis. There is some laboratory research in this area, but there is no clear information in humans.

C
Cataracts

Bilberry extract has been used for a number of eye problems, including the prevention of cataract worsening. At this time, there is limited scientific information in this area.

C
Chronic venous insufficiency

Chronic venous insufficiency is a condition that is more commonly diagnosed in Europe than in the United States, and may include leg swelling, varicose veins, leg pain, itching, and skin ulcers. A standardized extract of bilberry called Vaccinium myrtillius anthocyanoside (VMA) is popular in Europe for the treatment chronic venous insufficiency. However, there is only preliminary research in this area, and more studies are needed before a recommendation can be made.

C
Diabetes mellitus

Bilberry has been used traditionally in the treatment of diabetes, and animal research suggests that bilberry leaf extract can lower blood sugar levels. Human research is needed in this area before a recommendation can be made.

C
Diarrhea

Bilberry is used traditionally to treat diarrhea, but there is no reliable research in this area.

C
Fibrocystic breast disease

There is limited research suggesting a possible benefit of bilberry in the treatment of fibrocystic disease of the breast. More study is needed before a recommendation can be made.

C
Painful menstruation (dysmenorrhea)

Preliminary evidence suggests that bilberry may be helpful for relief of menstrual pain, although more research is necessary before a firm conclusion can be drawn.

C
Retinopathy

Based on animal research and several small human studies, bilberry may be useful in the treatment of retinopathy in patients with diabetes or high blood pressure. However, this research is early, and it is still unclear if bilberry is beneficial for this condition.

C
Stomach ulcers (peptic ulcer disease)

Bilberry extract has been suggested as a treatment to help stomach ulcer healing. There is some support for this use from laboratory and animal studies, but there is no reliable human evidence in this area.

C
Night vision

Traditional use and several unclear studies from the 1960s and 1970s suggest possible benefits of bilberry on night vision. However, more recent well-designed studies report no benefits. Based on this evidence, it does not appear that bilberry is helpful for improving night vision.

D

 

*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.

 

Grading rationale

Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Age-related macular degeneration, angina, angiogenesis, antifungal, antimicrobial, antioxidant, arthritis, bleeding gums, cancer, cardiovascular disease, chemoprotectant, chronic fatigue syndrome, common cold, cough, dermatitis, dysentery, eye disorders, fevers, glaucoma, gout, heart disease, hemorrhoids, high blood pressure, high cholesterol, kidney disease, leukemia, liver disease, oral ulcers, pharyngitis, poor circulation, prevention/stopping of lactation (breast milk flow), retinitis pigmentosa, scurvy, skin infections, stomach upset, tick-borne encephalitis, urine blood, urinary tract infection, vision improvement.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)
Fresh berries 55 to 115 grams three times daily, or 80 to 480 milligrams of aqueous extract three times daily by mouth (standardized to 25% anthocyanosides) has been used.

 

Dried fruit 4 to 8 grams by mouth with water two times per day has been used traditionally, or decoction of dried fruit by mouth three times per day (made by boiling 5 to10 grams of crushed dried fruit in 150 milliliters of water for 10 minutes and straining while hot), or cold macerate of dried fruit by mouth three times per day (made by soaking dried crushed fruit in 150 milliliters of water for several hours). Experts have warned that patients should use dried bilberry preparations, because the fresh fruit may actually worsen diarrhea.

 

Some experts recommend using a mouthwash gargle of 10% dried fruit decoction as needed.

 

Children (younger than 18 years)
There is not enough scientific evidence to recommend the use of bilberry in children.

 

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies
People with allergies to plants in the Ericaceae family or to anthocyanosides may have reactions to bilberry. However, there are no reliable published cases of serious allergic reactions to bilberry.

 

Side Effects and Warnings
Bilberry is generally believed to be safe in recommended doses for short periods of time, based on its history as a foodstuff. There are no known reports of serious toxicity or side effects, although if taken in large doses, there is an increased risk of bleeding, upset stomach, or hydroquinone poisoning.

 

Based on human use, bilberry fresh fruit may cause diarrhea or have a laxative effect. Based on animal studies, bilberry may cause low blood sugar levels. Caution is therefore advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary. In theory, bilberry may decrease blood pressure, based on laboratory studies. With the use of bilberry leaf extract, there is a theoretical increased bleeding risk, although there are no reliable published human reports of bleeding. Caution is advised in patients with bleeding disorders, taking drugs that may increase the risk of bleeding, or prior to some surgeries and dental procedures.

 

Pregnancy and Breastfeeding
There is not enough scientific evidence to recommend the safe use of bilberry in pregnancy or breastfeeding, although eating bilberry fruit is believed to be safe based on its history of use as a foodstuff. One study used bilberry extract to treat pregnancy-induced leg swelling (edema), and no adverse effects were reported.

 

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs
Based on animal research, bilberry may lower blood sugar levels. There are no reliable human studies in this area. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare provider. Medication adjustments may be necessary.

 

Based on human use, bilberry may increase diarrhea when taken with drugs that cause or worsen diarrhea, such as laxatives or some antibiotics. Bilberry theoretically may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®). There are no reliable published human reports of bleeding with the use of bilberry. Based on theory, bilberry may further lower blood pressure when taken with drugs that decrease blood pressure.

 

Based on early laboratory study, berry extracts have been shown to inhibit  H. pylori,  an ulcer producing bacteria and enhance the effects of the prescription drug clarithromycin (Biaxin ®).

 

Interactions with Herbs and Dietary Supplements
Based on animal research, bilberry may lower blood sugar levels. Although there is no reliable human study in this area, caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

 

Based on theory, bilberry may further lower blood pressure when taken with herbs or supplements that decrease blood pressure.

 

Based on theory, bilberry may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of  Ginkgo biloba , fewer cases with garlic, and two cases with saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

 

Based on traditional use, bilberry may increase diarrhea or laxative effects when taken with herbs and supplements that are also believed to have laxative effects.

 

Consuming bilberry with quercetin supplements may result in additive effects. Cooking bilberries with water and sugar to make soup may decrease the amount of quercetin by 40%. Berries contain resveratrol, which has been studied as an antioxidant, for cardiovascular disease and cancer and may have additive effects when taken with supplements like grapeseed.