What is Bilberry?
Bilberry (Vaccinium myrtillus) is a small, dark blue-purple berry native to Europe, closely related to North American blueberries but distinct in composition and traditional use. Also known as European blueberry, whortleberry, or huckleberry, bilberry grows on low shrubs in northern and western Europe, particularly in shady, moist mountainous regions.
Active Compounds:
Anthocyanins/Anthocyanosides (15+ different types): Primary bioactive compounds responsible for most health benefits
Polyphenols: Powerful antioxidants
Tannins (5-10%): Astringent compounds with anti-inflammatory properties
Flavonoids: Additional antioxidant compounds
Vitamins & minerals: Including vitamin C, vitamin K, and manganese
Key Feature: Bilberries contain one of the highest concentrations of anthocyanins among all fruits, particularly in their skin, giving them exceptional antioxidant properties.
Primary Functions & Health Benefits
Evidence-Based Benefits:
1. Antioxidant & Anti-Inflammatory Effects
Exceptionally high antioxidant capacity due to anthocyanin content
Reduces markers of inflammation including C-reactive protein and IL-6
Protects cells from oxidative stress and free radical damage
May help prevent chronic diseases associated with inflammation
2. Eye Health (Most Famous Traditional Use)
Night vision: Historical claims (WWII British pilots) remain controversial; rigorous studies show mixed or minimal benefits for night vision in healthy individuals
Retinopathy: Shows promise for diabetic and hypertensive retinopathy
General eye health: May support retinal health and reduce eye strain
Age-related conditions: Potential protective effects against macular degeneration and cataracts
Dry eyes: Preliminary evidence shows improvement when combined with fish oil
3. Cardiovascular Health
Improves blood vessel health and elasticity
May lower blood pressure, particularly systolic pressure
Improves platelet function
May increase HDL (good) cholesterol
Reduces inflammatory markers associated with heart disease risk
Supports healthy circulation and venous insufficiency
4. Blood Sugar Regulation
May help lower blood glucose levels
Improves insulin sensitivity
Reduces HbA1c (long-term blood sugar marker)
Shows potential for type 2 diabetes management (both fruit and leaf extracts studied)
5. Digestive Health
Traditional use for diarrhea (tannin content provides astringent action)
Shows promise for ulcerative colitis and inflammatory bowel disease
May protect against gastric ulcers
Reduces inflammation in the gut
May help with irritable bowel syndrome
6. Cancer Prevention (Preliminary Research)
Anthocyanins show anti-cancer properties in laboratory studies
May induce detoxification enzymes
Early human studies show accumulation in tumor tissue
Reduces cancer cell proliferation markers
Requires more clinical research
7. Cognitive Function & Mood
May improve memory in older adults
Preliminary evidence for mood enhancement
Reduces depression, tension, and confusion scores in pilot studies
Neuroprotective effects against oxidative stress
Supports brain-derived neurotrophic factor (BDNF)
8. Additional Benefits
Oral health: Reduces bleeding and inflammation in gum disease
Liver protection: Guards against stress-induced liver damage
Weight management: May have anti-obesity effects
Antimicrobial properties
Improves recovery from exercise-induced muscle damage
Recommended Dosages
Fresh Bilberries:
Traditional: 100-300 g (3.5-10.5 oz) per day
For diarrhea: 20-60 g dried berries daily
Bilberry Extract Supplements:
Standardized extracts (typically 25% anthocyanosides or 36% anthocyanins):
General health maintenance: 40-160 mg daily
Therapeutic use: 80-500 mg daily, divided into 1-2 doses
Eye health: 80-160 mg twice daily
Cardiovascular support: 160-320 mg daily
Diabetes management: 160-500 mg daily
Ulcerative colitis: 95 g dry weight equivalent (160 g prepared bilberry) daily
Duration: Most studies range from 1-8 weeks, though up to 6 months has been studied safely
Important Notes on Dosing:
Fresh bilberries provide 300-700 mg anthocyanins per 100 g
Significant variation exists in commercial preparations
Start with lower doses and increase gradually
Higher doses (>500 mg) long-term may be problematic
Look for standardized extracts with verified anthocyanin content
Timing & Administration
Best Time to Take:
Morning or evening: No specific advantage to either
Consistency matters: Take at the same time daily for best results
Split doses: If taking higher amounts, divide into 2 doses (morning and evening)
With or Without Food:
Can be taken with or without food
Taking with food may reduce any potential mild gastrointestinal discomfort
Anthocyanins are water-soluble, so fat is not required for absorption (unlike fat-soluble vitamins)
For digestive issues, taking between meals may be more effective
Duration of Use:
Short-term use (up to 6 months) appears safe
Long-term safety beyond 6 months is not well-established
For acute conditions (diarrhea), use for 3-4 days maximum before consulting a doctor
Chronic use should be monitored by a healthcare provider
Synergistic Supplements
Take WITH Bilberry (Enhanced Benefits):
Vitamin C: Helps regenerate anthocyanins and enhances antioxidant effects
Vitamin E: Works synergistically with bilberry's antioxidants
Fish oil (Omega-3s): Particularly beneficial for eye health and anti-inflammatory effects
Lutein & Zeaxanthin: Complementary eye health support
Other berry extracts: May provide synergistic antioxidant benefits
Ginkgo biloba: May enhance circulation benefits
Grape seed extract: Additional proanthocyanidin support
Beneficial Combinations:
Eye health formulas (lutein, zeaxanthin, zinc, vitamin A)
Antioxidant complexes
Cardiovascular support formulas
Blood sugar management supplements (under supervision)
Drug & Supplement Interactions
AVOID or Use Extreme Caution With:
Blood Sugar Medications:
Bilberry may lower blood sugar levels, potentially causing hypoglycemia when combined with:
Insulin
Metformin
Glimepiride (Amaryl)
Glyburide (Diabeta, Micronase)
Glipizide (Glucotrol)
Pioglitazone (Actos)
Rosiglitazone (Avandia)
Other diabetes medications
Action: Monitor blood sugar closely; may need medication adjustment
Blood Thinning Medications:
Bilberry may slow blood clotting, increasing bleeding risk when combined with:
Warfarin (Coumadin)
Aspirin
Clopidogrel (Plavix)
Heparin
Enoxaparin (Lovenox)
Dalteparin (Fragmin)
Ibuprofen (Advil, Motrin)
Naproxen (Aleve, Naprosyn)
Diclofenac (Voltaren)
Action: Stop bilberry 2 weeks before surgery; monitor for unusual bleeding
Liver-Metabolized Medications:
Bilberry may affect how the liver processes certain medications, potentially altering their effectiveness or side effects. Consult your doctor if taking medications metabolized by liver enzymes.
Herbs/Supplements to Avoid Combining:
Blood sugar-lowering herbs: Devil's claw, fenugreek, garlic, guar gum, horse chestnut, Panax ginseng, psyllium, Siberian ginseng
Chromium-containing supplements: Brewer's yeast, cascara, horsetail
Anticoagulant/antiplatelet herbs: Ginger, ginkgo, garlic (in high doses), turmeric (in high doses)
Who Should Take Bilberry
Ideal Candidates:
Individuals seeking antioxidant and anti-inflammatory support
People with family history of cardiovascular disease
Those with type 2 diabetes or prediabetes (under medical supervision)
Individuals with retinopathy or age-related eye concerns
People with chronic venous insufficiency or varicose veins
Those with mild inflammatory bowel conditions (under supervision)
Individuals experiencing frequent infections
People seeking cognitive health support
Those with high oxidative stress or inflammatory markers
Individuals with gum disease or oral health issues
May Benefit From Bilberry:
Computer users experiencing eye strain
People with poor night vision (though evidence is weak)
Individuals with elevated blood pressure
Those with elevated cholesterol levels
People recovering from exercise-induced muscle damage
Individuals seeking natural anti-aging support
Who Should AVOID or Use Caution
Absolute Contraindications:
Allergy to bilberry or related berries (blueberries, cranberries)
Allergy to tannin-containing foods
Upcoming surgery: Stop at least 2 weeks prior
Use With Extreme Caution (Medical Supervision Required):
Pregnant women: Safety not established; stick to food amounts only
Breastfeeding mothers: Safety unknown; avoid medicinal doses
Children: Not recommended without medical supervision
Diabetes patients on medication: Risk of hypoglycemia
People taking blood thinners: Increased bleeding risk
Bleeding disorders: May exacerbate bleeding
Individuals with liver disease: Potential interaction concerns
Those scheduled for surgery: Risk of bleeding complications
People with low blood pressure: May lower it further
Special Populations:
Alcohol dependence: Some liquid formulations contain alcohol
Diabetics: Monitor blood sugar closely; formulations with sugar may be problematic
Deficiency Symptoms
Note: Bilberry is NOT an essential nutrient, so true "deficiency" does not exist. However, lack of dietary anthocyanins and polyphenols from berries may contribute to:
Increased oxidative stress
Higher inflammation markers
Reduced antioxidant protection
Potentially increased risk of chronic diseases
Poor vascular health
Suboptimal eye health (in combination with other factors)
Dietary Context: Bilberries are part of a healthy diet rich in fruits and vegetables. No specific deficiency state exists from lack of bilberry consumption alone.
Toxicity & Side Effects
Common Side Effects (Generally Mild):
Gastrointestinal upset (nausea, abdominal discomfort)
Diarrhea (ironic, given its traditional use for diarrhea)
Mild digestive disturbances
Rare Side Effects:
Allergic reactions: Rash, hives, itching, swelling (face, lips, tongue, throat)
Difficulty breathing: Seek immediate medical attention
Severe dizziness
Long-Term/High-Dose Concerns:
Bilberry LEAVES: Long-term use suspected to be hazardous (not approved therapeutically in many countries)
High doses: Safety of very high doses (>500 mg) over extended periods is unknown
Contamination risk: Some supplements may contain impurities or adulterants
Serious Warnings:
Hypoglycemia: Excessive blood sugar lowering when combined with diabetes medications
Bleeding: Increased risk when combined with anticoagulants or before surgery
Drug interactions: May alter effectiveness of liver-metabolized medications
No Evidence Of:
Liver toxicity (bilberry has not been implicated in liver injury)
Kidney damage
Cardiovascular toxicity
Significant mutagenic or carcinogenic effects
Important Considerations
Quality & Standardization:
Significant variation exists in commercial bilberry products
Look for standardized extracts with verified anthocyanin content (typically 25%)
Fresh berries have highest anthocyanin content; processing and storage degrades anthocyanins
Ripeness affects anthocyanin concentration
Skin damage during harvesting reduces anthocyanin content
Choose reputable brands with third-party testing
Clinical Evidence Limitations:
Many studies are small, short-term, or methodologically weak
Conflicting results exist for several claimed benefits (especially night vision)
Most rigorous studies show bilberry is NOT effective for improving night vision in healthy people
More high-quality, large-scale clinical trials needed
Evidence strongest for antioxidant, anti-inflammatory, and cardiovascular benefits
Historical Context:
The famous WWII claim about British RAF pilots eating bilberry jam to improve night vision may be a hoax or myth perpetuated through research literature without proper fact-checking
Traditional uses don't always align with modern scientific evidence
Food vs. Supplement:
Fresh bilberries provide whole-food nutrition with fiber, vitamins, and minerals
Supplements offer concentrated anthocyanins but may lack other beneficial compounds
Dietary inclusion of bilberries and other berries is generally preferred over supplementation
Forms Available
Fresh/Whole Berries:
Most traditional form
Highest quality when properly harvested and stored
Can be eaten raw (slightly acidic taste)
Used in jams, pies, juices, smoothies
Cooking releases juice; may need draining for baked goods
Supplements:
Capsules/Tablets: 40-1000 mg standardized extract
Liquid extracts/Tinctures: Various concentrations
Powdered supplements: Can be added to smoothies or drinks
Dried berries: For tea or direct consumption (20-60 g/day)
Combination Products:
Eye health formulas (with lutein, zeaxanthin, vitamins)
Antioxidant complexes (with other berry extracts)
Berry mixtures (may have synergistic effects)
Cardiovascular support formulas
Special Populations
Pregnancy & Breastfeeding:
Stick to food amounts only
Medicinal doses not recommended
Safety data insufficient
Discuss with healthcare provider
Children:
Not recommended without medical supervision
Whole berries in normal food amounts likely safe
No established pediatric dosing
Elderly:
May benefit from cognitive and cardiovascular support
Monitor for drug interactions (often on multiple medications)
Start with lower doses
Athletes:
May reduce exercise-induced muscle damage and inflammation
Supports recovery
Generally safe for athletic populations
Summary & Key Takeaways
Bilberry is a nutrient-dense berry with exceptionally high anthocyanin content, offering potent antioxidant and anti-inflammatory benefits. While traditional claims about night vision remain questionable based on rigorous research, substantial evidence supports its use for cardiovascular health, blood sugar management, digestive health, and general antioxidant support.
Bottom Line:
Food first: Incorporate fresh or frozen bilberries into your diet as part of a berry-rich eating pattern
Supplementation: Consider standardized extracts (80-320 mg daily) for specific health goals
Safety: Generally safe when consumed as food; medicinal doses require caution with certain medications
Drug interactions: Critical to monitor when taking blood sugar medications or blood thinners
Quality matters: Choose standardized, third-party tested products
Evidence varies: Strongest for cardiovascular and antioxidant benefits; weakest for night vision claims
Medical supervision: Recommended for therapeutic use, especially with existing conditions or medications
Bilberry represents a promising natural supplement with centuries of traditional use, but users should maintain realistic expectations based on current scientific evidence and prioritize food sources when possible.