Bilberry (Vaccinium myrtillus), also called European blueberry, is a dark-skinned berry native to northern Europe. Unlike North American blueberries, bilberry has purple flesh and contains a distinct mixture of polyphenols called anthocyanosides (anthocyanins). These compounds have attracted interest for retinal health, blood vessel integrity, and anti-inflammatory effects, though the overall clinical evidence remains limited.
Table of Contents
- Overview
- Forms and Bioavailability
- Evidence for Benefits
- Recommended Dosing
- Safety and Side Effects
- Drug Interactions
- Dietary Sources
- References
Overview
Bilberry (Vaccinium myrtillus), also called European blueberry, is native to northern Europe, the northern United States, and Canada. Its dark skin is similar to blueberries, but its flesh is purple rather than light green, and it contains a different mixture of anthocyanosides (anthocyanins). The NCCIH states bilberry "has not been clearly shown to be helpful for any health condition," though some preliminary research on retinal health exists [1].
The famous claim that British RAF pilots ate bilberry jam before night missions to improve vision may have been a deliberate hoax to conceal radar technology from the Germans [2].
Forms and Bioavailability
- Standardized extract (36% anthocyanosides): Used in most clinical trials (Myrtocyan, MirtoSelect). Concentrated 76:1 to 153:1 from raw material [3].
- 25% anthocyanidins: Equivalent to 36% anthocyanosides (excludes sugar moieties).
- Low-concentration extracts: Ratios as low as 4:1 provide only a few mg of anthocyanosides — unlikely to be clinically relevant.
How Is Your Eye Health?
Bilberry anthocyanins show preliminary promise for retinal health. Get a personalized health plan to identify which supplements may benefit your specific situation.
Get Your Personalized Health PlanEnsure labels specify Vaccinium myrtillus. Fresh bilberry contains only 0.3-0.7% anthocyanosides [4].
Evidence for Benefits
Retinopathy
A small double-blind, placebo-controlled trial found bilberry extract significantly improved retinal lesions in diabetic and hypertensive retinopathy [5]. The dose providing 115 mg anthocyanosides daily was effective. Other supporting studies were not double-blind.
Night Vision
Clinical studies have not definitively confirmed bilberry's effect on night vision. The most rigorous studies found no benefit for healthy people [6][1]. At best, there may be a short-term (~2-hour) improvement with at least 60 mg anthocyanosides per day [6].
Blood Vessel Health
Anthocyanosides may strengthen blood vessel walls, reduce inflammation, and stabilize collagen-containing tissues [7][8]. This has prompted suggestions for varicose veins and easy bruising, but clinical evidence is insufficient.
Blood Sugar
Bilberry extract may lower blood sugar and increase insulin sensitivity in type 2 diabetes [9][10]. Animal studies suggest bilberry leaves may also help blood sugar control.
Recommended Dosing
- Retinopathy: 115 mg anthocyanosides daily (standardized 36% extract)
- Night vision: At least 60 mg anthocyanosides/day, though evidence is weak
Bilberry extracts have been used at doses up to 160 mg/day for up to 6 months and appear well tolerated [1].
Safety and Side Effects
Bilberry fruit is a food and considered safe at dietary amounts. As a supplement:
- Mild digestive distress, skin rashes, or drowsiness in a small percentage [11]
- May lower blood sugar — caution with diabetes [9][10]
- Inhibits platelet aggregation at 173 mg anthocyanins/day — theoretical bleeding risk [12]
- Bilberry leaves may be unsafe in high doses or long-term [1]
- Stop two weeks before surgery
Drug Interactions
- Blood sugar medications: Additive hypoglycemic effect
- Blood thinners: Theoretical interaction due to platelet inhibition (no published clinical bleeding reports)
Dietary Sources
Fresh bilberries are available in northern Europe but less common in North America. Blueberries (Vaccinium corymbosum) are a related species with different anthocyanin profiles and are not interchangeable in clinical contexts. Bilberry jam and preserves are the traditional food form.
How Is Your Eye Health?
Bilberry anthocyanins show preliminary promise for retinal health. Get a personalized health plan to identify which supplements may benefit your specific situation.
Get Your Personalized Health PlanReferences
1. National Center for Complementary and Integrative Health (NCCIH). Bilberry fact sheet. NIH.
2. Tasman W et al. The bilberry RAF legend. Am J Ophthalmol. 2007.
3. United States Pharmacopeia (USP 36). Bilberry extract monograph.
4. Prior RL et al. Anthocyanin content of bilberry. JANA. 1999.
5. Perossini M et al. Bilberry extract in retinopathy. Ann Ottalmol Clin Ocul. 1987.
6. Canter PH et al. Anthocyanosides for night vision. Surv Ophthalmol. 2004.
7. Jonadet M et al. Bilberry anthocyanosides and vascular permeability. J Pharm Belg. 1983.
8. Chu WK et al. Bilberry. In: Herbal Medicine: Biomolecular and Clinical Aspects. CRC Press. 2011.
9. Stull AJ et al. Bilberry and type 2 diabetes. Antioxidants (Basel). 2016.
10. Hoggard N et al. Bilberry and insulin sensitivity. J Nutr Sci. 2013.
11. Eandi M et al. Bilberry tolerability study. Fitoterapia. 1996.
12. Pulliero G et al. Bilberry anthocyanins and platelet aggregation. Fitoterapia. 1989.
