Sunscreen is not only applied to your skin, your body also makes its own. It’s called melanin.
But that’s not all. Growing evidence indicates that carotenoids, the antioxidants responsible for the vivid colors of many fruits and vegetables, may provide added protection from the sun.
A recent study investigated the effects of taking carotenoid supplements — lycopene and lutein — on skin protection at the molecular level. Here is a detailed summary of its findings.
Carotenoids are a diverse group of antioxidant plant compounds that are responsible for the red, orange and yellow colors of many fruits and vegetables.
Several studies show that they may protect the skin against harmful sunlight.
Beta-carotene, which can be converted to vitamin A, is the most extensively studied carotenoid. A meta-analysis of seven controlled trials concluded that taking beta-carotene supplements may protect against sunburns and reduce their severity (1).
Carotenoids other than beta-carotene may also act in a similar way.
One study showed that taking 24 grams of a mixed carotenoid supplement containing equal amounts of beta-carotene, lycopene and lutein protected the skin as much as 24 grams of beta-carotene alone (2).
Another 10-week trial found that consuming tomato paste, providing 16 mg per day of lycopene, significantly reduced sunburns, compared to a placebo (3).
However, lycopene may not be the only plant compound in tomatoes providing benefits. Taking a supplement containing a combination of plant compounds from tomatoes led to better protection against sunburns than lycopene alone (4).
This was a randomized controlled trial investigating the effects of lycopene and lutein supplements on genes associated with sunburns.
This randomized, double-blind crossover trial examined the capacity of the carotenoids lycopene and lutein to protect the skin against harmful sun radiation.
It was divided into two parts:
Part 1: Lycopene
A total of 29 people (25 men and 4 women) completed part 1. They were assigned to two 3-month treatment periods in a random order.
- Lycopene: Every day the participants took four capsules containing a lycopene-rich tomato extract providing 5 mg of lycopene, as well as other plant compounds, such as phytoene, phytofluene, tocopherols and phytosterols.
- Placebo: Capsules containing soy bean oil were taken instead of lycopene.
Part 2: Lutein
A total of 30 people (23 men and 7 women) completed the lutein arm of the study. They were assigned to two 3-month treatment periods in a random order.
- Lutein: Every day the participants took two capsules containing 10 grams of lutein stabilized by 10% carnosic acid.
- Placebo: Capsules containing soy bean oil were taken instead of lutein.
Before each study period, there was a 2-week washout period to reduce any possible carry-over effects from the previous period or the participants’ regular diets.
To investigate the carotenoids’ effects on the skin’s ability to protect itself against harmful light, the following procedure was conducted at the start and end of each treatment period.
- The researchers started by irradiating a patch of each participant’s skin with two types of ultraviolet light — ultraviolet B (UVB/A-) and ultraviolet A (UVA1) — using a solar simulator.
- 24 hours later, they took a skin biopsy from the irradiated area. For comparison, they also took a biopsy from a skin area that was not exposed to ultraviolet light.
- Finally, they analyzed the skin samples for the expression of genes that are associated with oxidative stress and sunburns.
- These genes were heme oxygenase-1 (HO-1), intercellular adhesion molecule-1 (ICAM-1) and matrix metalloproteinase-1 (MMP-1).
In addition, the researchers measured the carotenoid levels in the participants’ blood.
Bottom Line: This was a randomized controlled trial examining the effects of supplements containing a lycopene-rich tomato paste or lutein on the expression of genes associated with sunburns.
Finding: Lycopene and Lutein May Protect Against Sun-Induced Skin Damage
Supplementing with lycopene or lutein significantly increased blood levels of these carotenoids.
Additionally, exposure to ultraviolet light increased the activity of genes linked to oxidative stress and sunburns (HO-1, ICAM-1 and MMP-1).
However, the researchers discovered that taking lycopene or lutein supplements reduced the activity of these genes, compared to placebo.
The findings indicate that these carotenoids may protect the skin against damage and premature aging caused by sun exposure. The protective effect was similar after both types of ultraviolet light (UVB/A-and UVA1).
It also didn’t matter if the lycopene was given in the first or second phase of each study arm.
However, the protective effect of lutein was significantly weaker, compared to lycopene, if it was given in the second phase. That is, after a placebo period.
On the other hand, there were no differences between lycopene and lutein when they were given in the first phase.
Why carotenoids work in this way is currently unknown, but some scientists believe it may have something to do with their antioxidant properties.
Bottom Line: The study found that the carotenoids lycopene and lutein may protect the skin against harmful ultraviolet sunlight.
This study had an excellent design. However, it had one fault — the short washout periods between treatments.
The purpose of washout periods is to prevent carry-over effects from a previous treatment or the participants’ habitual diets. Their insufficient length is often a weakness of crossover trials.
However, the protective effects of lutein were significantly weaker when it was given after 16 weeks of a lutein-restricted diet, indicating that the washout periods might not have been long enough.
Summary and Real-Life Application
In short, this study showed that dietary intake of lutein and lycopene may protect the skin against harmful sunlight, possibly slowing skin aging and reducing the risk of skin cancer.
Although the findings are very promising, further studies are needed before any definite health claims can be made.
Nevertheless, eating tomatoes, watermelons, bell peppers, kale or other carotenoid-rich fruits and vegetables is definitely a good idea if you spend a lot of time in the sun.