Photoaging is the process of aging of the skin due primarily to regular and long-term exposure to ultra-violet radiation. The long-chain omega-3 fatty acids (EPA and DHA) have been implicated in modulating inflammatory processes associated with the skin, and supplementation with 3 g EPA+DHA for 6 months has been shown to reduce both UVB-erythemal sensitivity (i.e. sun induced skin reddening) , sunburn and sun induced itchy rash.
A recently published study in Journal of Dermatological Science  investigated the associations between daily omega-3 fat intake and the severity of skin photoaging...
2919 subjects (both genders) ages 35-60 were assessed for their intakes of omega-3 fatty acids from various food sources, including EPA/DHA from fish and seafood, by dietary records and nutrient compositions of the foods consumed. Furthermore, the severity of facial skin photoaging was assessed (pigmentation anomalies, wrinkling, slackening) using a 6-grade scale of photodamage as depicted by reference photographs during medical examination by physicians.
After adjusting for possible confounding variables, severe photoaging was found to be inversely associated with higher intakes of EPA (eicosapentaenoic acid) in women and ALA (alpha-linolenic acid) in men. In other words, as the EPA intakes of the women (as % of total energy) and ALA intakes in men increased, a significantly lower severity of photoaging was noticed.
Assuming an average energy intake of 2100 kcal/day, the women who ingested most EPA (at least 200 mg /day) had a 31% lower severity of skin photoaging as compared to women who ingested the least EPA (less than 61 mg/day).
This study suggest a possible benefit effect of omega-3 fat intake in prevention of skin aging. While the exact mechanisms are unknown, it has been suggested that omega-3 fatty acids may act as an oxidizable buffer, protecting more vital structures from free radical damage , and also reduce UV-induced inflammation by lowering prostaglandin E2 levels.
1. Rhodes, L.E., et al., Dietary fish-oil supplementation in humans reduces UVB-erythemal sensitivity but increases epidermal lipid peroxidation. J Invest Dermatol, 1994. 103(2): p. 151-4.
2. Rhodes, L.E., et al., Dietary fish oil reduces basal and ultraviolet B-generated PGE2 levels in skin and increases the threshold to provocation of polymorphic light eruption. J Invest Dermatol, 1995. 105(4): p. 532-5.
3. Latreille, J., et al., Association between dietary intake of n-3 polyunsaturated fatty acids and severity of skin photoaging in a middle-aged Caucasian population. J Dermatol Sci, 2013. 72(3): p. 233-9.