Bilberry

Precautions

Running: in 19 half-marathon runners, 2 × 200 mL of juice per day slightly increased muscle soreness and CRP instead of reducing them. Inflammation: in the 4-week juice trial, TNF-α, an inflammation marker, rose unexpectedly. Tolerance: no serious side effects over 8 weeks in office workers taking 480 mg of extract per day, nor with the placebo. Limitations: night vision: out of 12 placebo-controlled trials, the 4 most recent randomized trials are negative; the review concludes that bilberries do not improve normal night vision. Cholesterol and pressure: across 8 trials, no clear effect on total cholesterol, HDL, blood pressure, or weight, and an LDL that rises slightly (0.07 mmol/L) with prolonged intake. Blood sugar: the drop in HbA1c remains borderline significant across 3 trials; in 20 type 2 diabetics, 1.4 g of extract per day for 4 weeks did no better than placebo. Isolated anthocyanins: in 52 adults with high cholesterol, 320 mg per day for 28 days changed neither LDL nor blood sugar. Overweight women: in 30 women, 8 weeks of bilberry juice or fiber lowered LDL but raised total cholesterol, with no placebo group. Post-infarction: neither CRP nor LDL differed from the control group, and the trial was open-label. Sport: across 13 studies on berries of the same family (bilberry, American blueberry, cranberry), no effect on performance and a single benefit for recovery. Small trials: eye studies involve 21 to 109 people, and none compare extracts against each other.