Click on any article with a headline like 9 sun-protective foods, 7 foods to eat for sun protection, or 6 food groups that will protect you from the sun, and you’ll get a grocery list of items that increase the skin’s natural defense against UV radiation. The same components that protect plants from the sun—carotenoids and flavonoids—can help humans ward off sun damage. When ingested, these micronutrients act as antioxidants that protect the skin. Molecules in foods containing carotenoids and flavonoids like tomatoes, carrots, and even dark chocolate, may also absorb UV light to protect skin cells from damage.
Now let’s get to the practical stuff. You must take in at least 10 milligrams of carotenoids per day over six to eight weeks to start reaping photoprotective benefits. (Here's a list of foods and their beta-carotene content. A medium sweet potato, for example, contains about six milligrams of beta-carotene.)
“With such a supplementation one can achieve a protection comparable to an SPF of 2-3,” wrote Dr. Wilhelm Stahl, a leading researcher of the biochemistry of oxidative stress, in an email. Those benefits disappear one to two weeks after you stop that daily dose of 10+ milligrams.
An SPF of two to three may not seem like much, but the idea is you’ll protect yourself against inadvertent sun exposure and its cumulative damaging effects. Maintaining your own natural level of UV resistance, Stahl writes, is an important part of life-long protection.