Blackcurrant juice doesn't provide photoprotection

(HealthDay)—Blackcurrant juice consumption with low or high vitamin C content is not associated with photoprotection against ultraviolet (UV) radiation, according to a study published online Nov. 19 in the British Journal of Dermatology.

Sumantra Ray, M.D., from the University of Dundee in the United Kingdom, and colleagues examined the possible photoprotective effects of two blackcurrant juice drinks, with high and low content of vitamin C and polyphenols. Participants were randomized to drink 250 ml of either blackcurrant juice or placebo four times a day. Group A received colored, flavored water as a control, group B received 6.4 percent blackcurrant juice (low concentration), and Group C received 20 percent blackcurrant juice (high concentration). Thirty-two volunteers completed phototesting at baseline and after six weeks of intervention (12, 11, and nine participants in groups A, B, and C, respectively).

The researchers found that the minimal irradiation dose required to produce just perceptible erythema (minimal erythema dose [MED]) at each waveband did not differ significantly between the groups at baseline. Post-intervention, the MEDs at each waveband were not significantly different from baseline in any of the groups.

"We detected no photoprotection across UVB and UVA wavebands over six weeks of intervention with either high or low vitamin C concentration (total daily intake of 102 mg and 11 mg respectively) drinks," the authors write.

The study was funded by GlaxoSmithKline.

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