The participants’ skin response to UV light was measured before and after consuming grapes for two weeks by determining the threshold dose of UV radiation that induced visible reddening after 24 hours—the Minimal Erythema Dose (MED).
The results showed that grape consumption was protective as more UV exposure was required to cause sunburn following grape consumption, with MED increasing on average by 74.8 per cent.
Analysis of skin biopsies showed that the grape diet was associated with decreased DNA damage, fewer deaths of skin cells, and a reduction in inflammatory markers that if left unchecked, together can impair skin function and can potentially lead to skin cancer.
“We saw a significant photoprotective effect with grape consumption and we were able to identify molecular pathways by which that benefit occurs—through repair of DNA damage and downregulation of proinflammatory pathways,” said Elmets.
Most skin cancer cases are associated with exposure to UV radiation from the Sun—about 90 per cent of nonmelanoma skin cancers and 86 per cent of melanomas, respectively.
Additionally, an estimated 90 per cent of skin ageing is caused by the sun.