Study proves that tomatoes can protect the skin from UV radiation
By Evelin Maza, MBBS
Molecular evidence that oral supplementation with lycopene or lutein protects human skin against ultraviolet radiation: results from a double-blinded, placebo-controlled, crossover study (1).
Many studies have confirmed that excessive exposure to the sun and its ultraviolet radiation (UVR) is detrimental to healthy skin. It has been confirmed to cause skin damage, wrinkling, and even cancer (2).
But, is the use of sunscreen and avoiding too much direct sunlight our only means of protection? Not anymore.
For years, studies have analyzed the efficacy of dietary supplements as a source of skin health. Carotenoids are of particular interest (3). Carotenoids are organic pigments produced by plants, algae, some bacteria, and even certain fungi. And the most vastly studied carotenoid is beta-carotene, which is found in yellow, orange, or red fruits and vegetables, such as carrots and apricots.
Alas, negative long-term side effects have been linked to the chronic use of big amounts of beta-carotene (4).
Therefore, other substances have been tested, such as lycopene, lutein, and carotenoid mixtures. Some of these studies have shown that tomatoes, rich in lycopene, offer great protection from the sun when mixed with beta-carotene, as well as on its own (5, 6).
A randomized, double-blind, placebo-controlled, crossover trial which took place in Germany studied the standalone effects of lutein and lycopene-rich tomato supplements; and the findings were quite promising!
This study divided volunteers with no previous history of skin-related illnesses into 4 groups: lycopene active treatment, lycopene placebo treatment, lutein active treatment, and lutein placebo treatment.
Treatment was administered via softgel capsules. 2 capsules daily of 10 mg free lutein stabilized by 10% carnosic acid in the case of lutein and 4 capsules daily of 5 mg lycopene, as well as other tomato phytonutrients, such as phytoene and phytofluene, tocopherols and phytosterols, in the case of lycopene. With soybean oil capsules being used as placebo, as it offers the skin no protective effects against UVR.
The study consisted in 2 periods of 12-week treatments of either placebo or one of the two active agents. Each treatment period was preceded by a 2-week washout period. If a volunteer began with placebo, they were switched to an active lutein or lycopene supplement in the following treatment period, and vice versa.
Blood samples were taken at the beginning and end of each period to measure the rise in carotenoid levels.
Also, the participants were exposed to UVA/B and UVA1 and had 3 biopsies extracted. One from skin that wasn’t exposed to radiation, one from UVA/B-irradiated skin, and one from UVA1-irradiated skin. This was done at the beginning and end of each 12-week treatment period, 24 hours after the exposure to radiation.
With the biopsies, the researchers were able to measure the amount of certain proteins which are linked to oxidative stress, collagen breakdown, and skin inflammation caused by UV exposure. The genes analyzed were an enzyme that produces carbon monoxide (HO-1), intercellular adhesion molecule-1 (ICAM-1) and matrix metalloproteinase-1 (MMP-1).
This particular trial is unique for two important reasons.
For one, most of the studies about the effects of UVR on healthy skin and the protection dietary supplements may offer use UV-induced sunburn reactions or the reddening of the skin as a sign of damage caused by sunlight (7).
But this study used biopsies and proteins linked to oxidative stress as a new way to measure the sun’s harmful effects.
And secondly, most studies about UV damage use UVA and/or UVB radiation emitted by a solar simulator. This only covers the shortwave types of ultraviolet radiation. Thus, this study set out to also cover and analyze longwave UV radiation, or UVA1. To document its effect on the skin via he measurement of proteins and the inhibition of said effects via carotenoid supplements.
Findings: Tomatoes have protective qualities against solar skin damage
Throughout all of the volunteers, it was found that the plasmatic levels of carotenoids increased significantly. Results which were confirmed by the low levels found in the blood samples during periods of placebo intake.
Yet, they found that lycopene levels weren’t affected by the order of the treatments. But lutein levels were notably lower when administered after a 12-week period of treatment with the soybean oil capsules.
Also, the biopsies showed that exposure to UVR in all of its forms increased the expressions of the genes linked to oxidative stress.
However, the biopsies taken after periods of active lycopene or lutein supplement treatment showed a much lower activity of these genes. And both supplements show the same efficacy of protection if taken during the first period of treatment.
Also, the protective qualities of these carotenoids applied to the three different types of radiation used equally.
Although the researchers still don’t know exactly how lycopene and lutein achieve these effects, it is thought that they balance out oxidative stress (8).
In conclusion, these German scientists proved that lycopene and lutein protect the skin against UV-induced damage.
How can I apply these results?
To sum up, you must avoid the damage and skin ageing which excessive exposure to the sun may cause, including loss of elasticity, drying, and wrinkling. This can be achieved by modifications in your diet.
By including dietary supplements rich in lycopene, lutein, and beta-carotene, you can prevent UVR-induced skin damage and even lower your risk of cancer.
An easy way to incorporate more carotenoids into your diet is by consuming more brightly colored fruits and vegetables, such as tomatoes, bell peppers, corn, and bananas, among others.
The researchers state that “To ingest 20 mg lutein and 20 mg lycopene, a cup of chopped kale (130 g) and a serving (242 g) of tomato juice would be enough.”
Br J Dermatol. 2017 May;176(5):1231-1240. doi: 10.1111/bjd.15080. Epub 2017 Mar 15.
Molecular evidence that oral supplementation with lycopene or lutein protects human skin against ultraviolet radiation: results from a double-blinded, placebo-controlled, crossover study.
IUF - Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany.
Institute of Biochemistry and Molecular Biology I, Faculty of Medicine, Heinrich Heine University, Düsseldorf, Germany.