Bilberry Interactions Overview

Additional Details

Is Bilberry Safe? Are There Any Warnings?

Bilberry is generally safe to consume in the amounts commonly found in foods. It has been granted Generally Recognized As Safe (GRAS) status for use in foods in the US. When used medicinally, bilberry fruit extracts have been used safely in clinical trials at doses of up to 160 mg daily for up to 6 months. Higher doses of bilberry extract and prolonged use of bilberry leaves can be potentially unsafe. There is insufficient reliable information available about the safety of bilberry during pregnancy and lactation, so it is advised to avoid using it in medicinal amounts in these cases.

How Is Bilberry Thought To Work?

Bilberry contains various compounds that contribute to its biological activity. The main chemicals found in bilberry extract are anthocyanidins, anthocyanins, and anthocyanosides, as well as flavonoids, quercetin, epicatechin, hydroquinone, oleanolic acid, neomyrtillin, sodium, tannins, and ursolic acid. These compounds have demonstrated several biological properties, including antioxidant effects, inhibition of prostacyclin synthesis, reduction of capillary permeability and fragility, inhibition of enzymes, and anti-carcinogenicity. Bilberry also possesses antibacterial and anticancer effects in vitro.

Pharmacokinetics

Bilberry anthocyanosides, the active components of bilberry extract, are poorly absorbed in animals. The gastrointestinal absorption of these components ranges from 0.61% to 1.82%. After absorption, bilberry anthocyanosides are distributed to various tissues, with a preference for the skin and kidneys. Metabolism and degradation of bilberry anthocyanidins may be slowed by consuming encapsulated extracts. Bilberry anthocyanosides are eliminated through bile and urine.

Interaction Overview

Bilberry may interact with certain drugs and supplements, including anticoagulant/antiplatelet drugs, antidiabetes drugs, and drugs metabolized by the cytochrome P450 2E1 enzyme. It may also interact with the anticancer drug erlotinib. Additionally, bilberry may have interactions with certain herbs and supplements that have similar effects on blood clotting or blood sugar levels. It is important to exercise caution when combining bilberry with these medications and supplements.

Common Side Effects To Watch For

Orally, bilberry fruit, juice, and extracts are generally well tolerated. The most common side effects include dark-colored stools, flatulence, and gastrointestinal discomfort. These side effects are typically mild and transient.

Are Bilberry Supplements Standardized?

Bilberry supplements come in various formulations, including fresh bilberries, dried bilberries, bilberry juice, and bilberry extracts. The quality of commercially available dried bilberries and bilberry juice is generally good, but there are concerns about the quality of some bilberry extract supplements. Among the analyzed bilberry extract supplements, 45% were considered to be of unacceptable quality. It is recommended to follow specific dosing instructions for each formulation, as the strength and dosing may vary between preparations.

Drugs that interact with Bilberry