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Mixed Carotenoids Protect Human Skin Against UVA-Induced Skin Pigmentation & UVB-Induced Erythema

7 May 2021

A randomized, double-blind, placebo-controlled study has shown that daily supplementation with mixed-carotenoids protects human skin.

A randomized, double-blind, placebo-controlled study has shown that daily supplementation with mixed-carotenoids protects human skin against both UVB-induced erythema and UVA-induced pigmentation. The study was conducted at the Leibniz Research Institute for Environmental Medicine, Germany, in collaboration with Amway Corporation and published in the journal of Photodermatology, Photoimmunology & Photomedicine.

Sixty volunteers were randomized into 2 groups; (i) multi-carotenoids supplement containing 4.25 mg β-carotene and 1.10 mg α-carotene (from EVTene™), 1.12 mg lutein, 0.053 mg zeaxanthin, per softgel, or (ii) placebo. The supplements were taken three times a day with meal.

After 12 weeks of supplementation, the minimal persistent pigmentation dose (MPPD) of each volunteer was assessed (Note: the increase in MPPD reading indicates increased protection against UVA-induced skin pigmentation). MPPD was determined by visual grading 20-24 hours after irradiation with a Dermalight 80 MPD test and the minimum PPD dose is defined as the smallest UVA dose required to produce brown pigmentation. It was found that daily oral intake of such carotenoids-complex, but not of placebo, increases UVA-induced MPPD values and hence protects human skin against UVA-induced pigmentation and UVA radiation. This is the first clinical evidence that oral intake of such carotenoids complex can protect human skin against UVA radiation.

Besides measuring the UVA (320-400 nm) radiation, this study also measures photoprotective effect of carotenoids against UVB (290-320 nm) radiation by measuring minimal erythema dose (MED). MED is the minimal amount of energy required to induce visible erythema (redness of the skin), which can be defined as a uniform, clearly demarcated redness at 16-24 hours after UV exposure. Significant differences were observed between the placebo and intervention group at 4, 8, and 12 weeks. In the intervention group – a significant increase was observed in UVB-induced MED. Thereby indicating that supplementation with carotenoids complex protects human skin against UVB-induced erythema.

In addition to that, the study conclusively demonstrated that nutritional supplementation with carotenoids complex, is associated with a significant increase in carotenoids levels in human skin. The carotenoids level in the skin was measured by Biozoom® Scanner that uses Multiple Spatially Resolved Reflection Spectroscopy (MSRRS) to precisely measure carotenoid level on the thenar eminence (a group of muscles at the base of the thumb) of the palm of the hand, before and after the supplementation.

The researchers propose that these photoprotective effects (against UVA and UVB) is due to the enhanced synergistic antioxidant activity of the carotenoids complex. Hence, supplementation of such carotenoids complex increases both carotenoids level and antioxidant capacity in our skin, thereby reducing the oxidative stress exerted by both UVA and UVB radiation.

This group of researchers further indicates that future clinical work is warranted to address the extent of nutritional supplementation with carotenoids in mitigating or preventing clinical consequences of UVA irradiation beyond skin pigmentation such as photoaging and photocarcinogenesis. 

Reference

Baswan, S. M., Marini, A., Klosner, A. E., Jaenicke, T., Leverett, J., Murray, M., ... & Krutmann, J. (2020). Orally administered mixed carotenoids protect human skin against Ultraviolet A‐induced skin pigmentation: A double blind, placebo controlled, randomized clinical trial. Photodermatology, Photoimmunology & Photomedicine.

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