SPF: Sun Protection Foods
Limiting exposure, applying sunscreen and wearing protective clothing have long been the go-to recommendations for protection from the sun’s invisible yet harmful ultraviolet radiation. Now, research suggests there may be another way to help protect your skin — and it isn’t found in the sunscreen aisle. Studies have shown certain compounds in foods and beverages such as carotenoids, polyphenols and some vitamins may improve the skin’s ability to fight off UV damage and sunburn or speed up the recovery process from damage caused by UV rays.
The importance of skin protection
Spending time outside might boost your mood, but without proper skin protection, time outside can have unfavorable consequences, such as sunburn, increased risk of skin cancer and premature skin aging, all caused by ultraviolet radiation from the sun.
Sunlight produces three types of UV rays: UVA, UVB and UVC. UVA rays penetrate the skin deepest and contribute to premature aging, such as sunspots, wrinkles and sagging. There are two forms of UVA: UVA1 and UVA2; UVA1 rays penetrate the skin deeper than UVA2. Of the three main types of UV rays, UVA accounts for 95% of UV exposure, of which UVA1 accounts for 75%. UVB rays produce sunburns and are largely responsible for skin cancer. The most dangerous type, UVC, is blocked by the earth’s ozone layer but also is present in some artificial light sources, such as mercury lamps or lasers.
And while many people think sun protection is only relevant on sunny days, UV rays can penetrate through clouds and be reflected off snow, sand, concrete and water, and UVA rays specifically can penetrate through glass, making sun protection essential year-round.
Unprotected skin can be damaged in as little as 15 minutes outside. Because of this, the American Academy of Dermatology recommends getting vitamin D from foods, including natural sources, such as salmon, eggs and mushrooms exposed to UV light, and those fortified with vitamin D, such as orange juice, dairy products and cereals.
Skin tone and susceptibility
The Centers for Disease Control and Prevention reported 46.3% of non-Hispanic white adults experienced a sunburn in 2015. In contrast, 22.4% of Hispanic people and 9.9% of Black people experienced a sunburn the same year. A lower incidence of sunburn among people with darker skin tones is largely due to melanin, a skin pigment that helps block harmful UV rays. The darker a person’s skin tone, the more melanin it contains, whereas lighter skin tones have less melanin.
While melanin helps protect against UV rays, protecting skin from the sun through other measures is important for people of all skin tones. Some studies have shown that despite having lower incidences of melanoma, a form of skin cancer, Black people have a lower five-year melanoma survival rate compared to white people (67% and 92%, respectively) and Black people and Hispanic people are more likely to have a late-stage melanoma diagnosis compared to white people. Some dermatologists speculate medical bias may play a role, in addition to a public misconception that only white people develop skin cancers and sun damage. People with darker skin tones may not burn as easily, but skin cancer and sun damage affect people of all races, ethnicities and skin tones.
Although research is still early and ongoing, some studies suggest certain compounds in foods and beverages may help boost the skin’s defenses against UV rays. Carotenoids, vitamin C and vitamin E, omega-3 fatty acids and some polyphenols are a few notable compounds showing potential benefits, such as delaying or preventing sunburns and redness and helping prevent or reduce signs of aging.
Studies suggest lycopene may have photoprotective benefits, meaning it offers skin protection against UV light. Lycopene, a pigment found in red, yellow and orange fruits and vegetables, can be obtained through tomatoes, watermelon, pink guava, red oranges, pink grapefruit, rosehips, carrots, bell peppers and papaya. Lycopene is easier for the body to use when the source has been heated, meaning pasta sauce and tomato juice offer more lycopene than raw tomatoes.
Several studies have shown that consuming 10 to 16 milligrams of lycopene per day in the form of supplements or tomato paste with olive oil may offer photoprotective benefits. Compared to placebo groups, skin redness from exposure to UV light was significantly lower after consuming 10 to 16 milligrams each day for 10 to 12 weeks. Some of these studies included only participants with fair skin tones, while others did not list skin tone as an inclusion or exclusion criteria.
A delay in skin reddening after UV exposure suggests lycopene may help boost skin’s defenses against UVB rays, which are most responsible for an increased risk of skin cancer. However, one study sought to find if lycopene offered protection against UVA1 rays and discovered certain biomarkers associated with oxidative damage, collagen breakdown and inflammation from UVA1 were reduced after supplementing with 10 grams of lycopene soft gels daily for 12 weeks.
Astaxanthin is a red pigment responsible for the color of many marine animals, such as salmon, lobster and shrimp, plus some bacteria and algae. A 2019 review and a 2020 systematic review of 11 clinical trials found taking 3 to 6 milligrams of astaxanthin supplements per day for four to 16 weeks helped protect skin against UV-induced damage. Studies also showed astaxanthin minimizes effects of aging, such as wrinkles and sunspots. However, most of the studies conducted so far have had small sample sizes with primarily female Japanese participants. Therefore, more research and a more diverse study population is needed to further substantiate astaxanthin’s role in sun protection.
The pigment beta-carotene is found in yellow and orange fruits and vegetables including carrots, sweet potatoes and winter squash, and in leafy green vegetables such as spinach and lettuce.Research investigating potential sun-protective benefits of beta-carotene date back to the 1970s.
A 2020 review found that beta-carotene had sun-protective benefits at doses ranging from 12 to 180 milligrams a day. A seemingly more important factor was how long participants took the doses — not necessarily how much.
Beta-carotene may provide some sun protection at a minimum dose of 12 milligrams per day when taken for at least seven weeks. Studies show participants who followed this regimen could be exposed to UV rays longer before getting sunburned compared to those who weren’t taking beta-carotene. However, some of these studies had only participants with fair skin tones, while others did not mention if all participants had a similar skin tone.
A few animal studies found that beta-carotene reduced the risk of skin cancer, but human studies have not been able to reproduce the same results. For instance, one large human study had participants supplement with 50 milligrams daily and saw no significant reductions in skin cancer risk after five years.
Anyone considering beta-carotene supplements should take caution — when it comes to dose, more may not be better.
Two studies found that higher doses of beta-carotene (20 to 30 milligrams) taken over several years increased the risk of lung cancer in some people.
Ingesting a mixture of lycopene, beta-carotene and lutein also has shown to help protect skin against UV rays. One study found that 8 milligrams of the mixture taken daily for 12 weeks was as effective at protecting skin from UV rays as taking 24 milligrams of beta-carotene alone. Another study found that a mixture of beta-carotene (6 milligrams), lycopene (6 milligrams), vitamin E (10 milligrams) and selenium (75 micrograms) helped prevent sunburn and skin damage after seven weeks.
Lutein and Zeaxanthin
These orange and yellow pigments are found in foods such as cantaloupe, corn, carrots, peppers and eggs. Other sources include kale, spinach, broccoli and peas. Although lutein and zeaxanthin may be better known for supporting eye health, early research suggests they may help protect skin against UV rays. When supplementing with lutein and zeaxanthin, skin took longer to turn red under UV light. While results are promising, they are primarily from animal studies. Therefore, more research is needed.
Vitamins C and E
Most Americans get vitamin C from citrus fruits, tomatoes and tomato juice, but other sources include red and green bell peppers, kiwifruit, broccoli, Brussels sprouts and strawberries. Sources of vitamin E include vegetable oils, nuts and seeds, spinach, broccoli and kiwifruit.
While there is limited evidence (mostly from animal studies) suggesting topical vitamin C can help limit skin damage from UV exposure, there is not much evidence suggesting oral vitamin C supplementation can do the same. Likewise, while many studies have tested the potential photoprotective benefits of oral vitamin E supplementation, the results so far suggest it may not offer much protection. However, when vitamin C is combined with vitamin E, studies show it may reduce the rate at which skin burns and reduce the amount of DNA damage after UV exposure.
In one double-blind placebo-controlled study, participants took 2 grams of vitamin C with 1,000 international units of vitamin E. After eight days, researchers found it took longer for participants to get a sunburn than it did before they took the supplements. Another study had participants take 1 gram of vitamin C and 500 IU of vitamin E for three months and found similar results. For perspective, the current recommended daily dietary allowance of vitamin C is 90 milligrams for males 19 and older and 75 milligrams for females 19 and older (85 milligrams for pregnant women and 120 milligrams for those who are lactating). The current recommended daily dietary allowance of vitamin E is 15 milligrams for males and females 14 and older, plus those who are pregnant, and 19 milligrams for people who are lactating.
Some studies suggest supplementing with omega-3 polyunsaturated fats, particularly eicosapentaenoic acid, or EPA, may help protect the skin against UV damage. Common food sources of omega-3 fatty acids include fatty fish such as salmon, mackerel, herring and sardines.
During one randomized controlled-trial, participants took 4 grams of either purified (95%) EPA supplements or oleic acid supplements (a monounsaturated omega-9 fatty acid) for three months. At the end of the trial, the EPA group saw a significant reduction in UVB-induced redness and DNA damage. Another trial involved participants taking fish oil capsules (2.8 grams of DHA and 1.2 gram of EPA) every day for four weeks and found those who supplemented could be exposed to UV light for longer before experiencing skin redness. Another trial found taking 5 grams of fish oil twice a day for six months significantly increased the amount of UV exposure participants could handle before being burned, but the benefits seemed to disappear once they stopped supplementing. Plus, the safety of this high of a dose may be a concern. Some scientists believe supplementing with omega-3s may help suppress the inflammatory response that happens after exposure to ultraviolet radiation, but more research is needed.
Research suggests omega-3s also may help reduce signs of aging. A few cross-sectional studies found people with higher intakes of omega-3 fatty acids had less skin wrinkling on sun-exposed areas and were less likely to have dry skin and skin thinning.
Some studies have found sun-protective benefits in both topically applied and ingested polyphenols. Polyphenols are powerful antioxidants found in plants, such as fruits and vegetables, whole grains and flowers. Many well-known sources include black and green tea, red wine and foods such as cocoa and dark chocolate, beans, soy, berries and artichokes.
In vitro and animal studies suggest polyphenols in green tea might have photoprotective benefits when ingested or applied topically. More human studies have been done on the benefits of topical green tea extract application, but some have tested the sun-protective benefits from ingesting green tea.
One study had participants (all females) drink a liter of green tea (containing 1,402 milligrams of green tea catechins) daily for 12 weeks and found it had skin-protective benefits after six weeks. Participants who drank the tea could be exposed to UV light longer before experiencing skin reddening. After 12 weeks, the benefits were even greater and included better skin elasticity and structure, reduced water loss from the skin, increased blood flow in the skin and higher serum flavonoid concentration. However, a separate study in which participants took capsules of 1,080 milligrams of green tea catechins per day for 12 weeks found no benefit.
In one study on cocoa powder, participants (all female) drank either a high (326 milligrams) or low (27 milligrams) flavanol-containing cocoa beverage every day for 12 weeks. At the end of the study, participants who consumed the high-flavanol drink saw less skin reddening when exposed to UV and had improved skin structure and circulation. Another study found consuming 6 milliliters of high-polyphenol wine per kilogram of body weight over 40 minutes helped protect skin against UVB. However, the study size was small with only 15 male participants, and the amount of wine needed to reproduce these benefits may not be practical. For instance, a 120-pound person would need to drink 11 ounces of wine in 40 minutes. For individuals who are of legal age and choose to drink, the 2020-2025 Dietary Guidelines for Americans suggests limiting alcohol intake and, for wine, this amounts to one, five-ounce glass or less a day for women and two, five-ounce glasses a day or less for men.
Coffee also may have sun-protective benefits. Researchers of one study examined food-frequency questionnaires of 447,357 non-Hispanic white people and found those who consumed four or more cups per day had a 20% lower risk of developing malignant melanoma after a 10-year follow-up compared to those who drank one or fewer cups. Interestingly, the benefits were not applicable to decaffeinated coffee. The Food and Drug Administration has stated that 400 milligrams of caffeine a day (or about four or five cups of coffee) is not generally associated with dangerous, negative effects for healthy adults who are not pregnant or breastfeeding.
For registered dietitian nutritionists
While more research is needed — especially research including a wider range of skin tones — current findings suggest some carotenoids, polyphenols and vitamins may help protect the skin from ultraviolet radiation from the inside out. For registered dietitian nutritionists seeing patients or clients with a heightened risk of skin cancer or who have patients or clients asking questions about overall skin health, it may be worthwhile to discuss the potential benefits of these compounds and encourage greater consumption from dietary sources or possibly supplementation. If supplementation is considered, other factors will need to be taken into account, since the doses of supplements described were high in some cases and/or may interact with medications. However, it is important to reiterate that the more certain ways to protect skin are by limiting exposure to sunlight and wearing sunscreen and sun-protective clothing.