What Is Bilberry?

Bilberries are a fruit closely related to blueberries, native to northern Europe, Asia, the northern United States, and Canada. Its uses for health purposes dates back to the Middle Ages.

Also known as whortleberry, huckleberry, or European blueberries, bilberries are often eaten fresh or made into jam, juices, or pies. Bilberries are also available in powder, juice, or supplement form.

Historically, bilberry has been used to treat diabetes, inflammation, and diarrhea. Today, bilberry supplements are marketed for numerous conditions, including night vision, cataracts (clouding of the lens of the eye), varicose veins (twisted, enlarged veins caused by weakened vein walls and valves), and atherosclerosis (a buildup of plaque in the arteries). However, there is not enough research to support its use for any health condition.

This article reviews the research around bilberry, its side effects, interactions, and more.

Uses of Bilberry

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Rich in antioxidants known as anthocyanins and polyphenols, bilberries have been used for medicinal purposes ranging from eye conditions to diabetes. Bilberry is often touted as a remedy for eye conditions such as glaucoma, cataracts, dry eyes, age-related macular degeneration, and retinitis pigmentosa (rare diseases of the light-sensitive area of the eye).

As a source of antioxidants, bilberries are also thought to curb inflammation and protect against diseases associated with oxidative stress, such as inflammatory bowel disease(IBD), cardiovascular disease, diabetes, gingivitis, and age-related cognitive decline.

So far, very few studies have tested the health effects of bilberry. There is not enough research to recommend its use. Preliminary research has looked at reducing risk factors for heart disease, reducing inflammation of the gums, and helping with eye fatigue associated with high use of video display terminals, all with mixed results or limited evidence.

What Are the Side Effects of Bilberry?

Bilberry fruit is generally considered safe when consumed in amounts typically found in food. However, allergic reactions can occur.

Side effects such as nausea or abdominal discomfort have been reported with bilberry use. Bilberry fruit and bilberry leaf extracts can also affect blood sugar levels. If you have diabetes, speak with your healthcare provider before adding bilberry to your regimen.

It's important to remember that supplements aren't routinely tested for safety, adverse reactions are often not reported, and dietary supplements are largely unregulated.

Precautions

Bilberry consumed as food is safe in most instances.

Bilberries naturally contain substances known as tannins (found in many foods such as coffee, tea, red wine, blueberries, cranberries, chocolate, and some nuts and beans). If you have an allergy or sensitivity to foods containing tannins, you should avoid bilberry.

Pregnant or nursing people should avoid bilberry extracts, as safety isn't known.

The safety of long-term use or high doses of bilberry supplements is also uncertain. Although, consuming bilberry leaves may be unsafe in high amounts or when taken long-term.

If you're considering trying bilberry supplements, talk with your healthcare provider first to weigh the pros and cons and to discuss whether it's appropriate for you.

Dosage: How Much Bilberry Should I Take?

There is not enough scientific data to provide a recommended dose of bilberry.

A typical dose of the dried, ripe berries is 20 to 60 grams (g) daily. Some consumers also drink a type of bilberry tea.

Bilberry extract in capsule and tables come in dosage ranges of 40 to 100 milligrams (mg).

Different amounts have been studied in research. The appropriate dose for you may depend on your age, gender, weight, and medical history. Speak to your healthcare provider to get personalized advice.

What Happens If I Take Too Much Bilberry?

There is not enough data to know what would happen if someone took too much bilberry. To be safe, only take the recommended amount as directed on the product packaging. Consult your healthcare provider before consuming bilberry supplements.

Interactions

Anthocyanins may inhibit drugs such as anticancer medications, antibiotics, beta-blockers, and arthritis medication.

Bilberry supplements also may help to thin blood which, when used in combination with blood thinners (e.g., warfarin), could lead to easily bruising or greater bleeding.

Bilberry supplements may interact with diabetes medications. Since bilberry may have glucose lowering effects, combining it with medications used to lower glucose levels could lead to hypogylcemia (low blood sugar). Additionally, since bilberry may interfere with blood sugar control, stop taking it two weeks before any planned surgery.

How to Store Bilberry

Follow manufacturer directions for proper storage of supplements. Always store supplements out of reach of children.

Sources of Bilberry & What to Look For

You can find bilberries fresh, frozen, dried, powdered, or in packaged foods like jam. In addition to eating them fresh, you can try adding frozen or powdered bilberries to a smoothie or use them to make a sauce or preserves.

Bilberry supplements and bilberry extract are sold in tablets, capsules, and drops. The berries are also sold dried and as a powder. Bilberry leaves are made into teas.

If you choose to buy a bilberry supplement, the National Institutes of Health (NIH) recommends that you look for a Supplement Facts label on the product that you buy. This label will contain vital information, including the amount of active ingredients per serving and other added ingredients (like fillers, binders, and flavorings).

You should also make sure the supplement contains the intended berry. Bilberry should be listed on the supplement facts label as Vaccinium myrtillus. Some supplements may have "bilberry" advertised on the front but contain "American bilberry," which is not the same. American bilberry is also known as huckleberry.

Bilberry supplements should also be concentrated and standardized. If possible, look for a supplement with 36% anthocyanosides or 25% anthocyanidins.

Lastly, you should look for a product with a seal of approval from a third party organization that provides quality testing. These organizations include USP, ConsumerLab, and NSF. A seal of approval from one of these organizations does not guarantee the product's safety or effectiveness. Still, it does assure that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants.

Summary

Bilberry is a berry native to northern Europe, the northern U.S. states, Asia, and Canada. It can be eaten as a food, and it can be found in supplement form. Bilberry supplements are marketed to help manage several different health conditions. However, there is not enough research evidence to support any of these uses.

While bilberry shouldn't be used as a substitute for standard treatment or preventive measures for any medical condition, in some cases, eating more bilberries (or other anthocyanin-rich fruit) may have some protective benefits.

If you think bilberry would be good for you, talk with your healthcare provider to evaluate the benefits and risks of taking such a supplement.