The benefits of omega-3 on the skin

Consuming omega-3 may prove beneficial for our skin. Indeed, these fatty acids have interesting skin effects, particularly in the context of cancers. A study led by Yao-Ping LU aimed to explore the effects of a diet rich in omega-3 fatty acids compared to omega-6 on UVB-induced skin carcinogenesis. Mice were irradiated with 30 mJ/cm2 of UVB once a day, twice a week for 39 weeks. One group of mice received a diet based on fish oil rich in omega-3 fatty acids and the other group of mice received a diet based on lipid mixtures rich in omega-6 fatty acids.

The results demonstrated that, compared to the omega-6 regimen, the omega-3 treatment increased the latency for the development of UVB-induced skin tumours, decreased the formation of tumour lesions such as keratoacanthomas and carcinomas by 52% and 46% respectively, and reduced their size by 80% and 83% respectively.

In order to determine the mechanisms involved, mechanistic studies conducted using an antibody network have revealed that, compared to the omega-6 diet, the administration of omega-3 to mice significantly reduced the UVB-induced increases in levels of TIMP-1, LIX and sTNF R1, as well as other pro-inflammatory cytokines. These proteins promote the proliferation of tumour cells, their reduction therefore allows for the decrease in cancer development. Furthermore, it was observed that the omega-3 diet stimulated UVB-induced apoptosis in the epidermis. Thus, promoting apoptosis will induce the death of tumour cells.

Hadi ESMAILY and his colleagues sought to investigate the effects of dietary eicosapentaenoic acid (EPA), an omega-3 fatty acid, in children suffering from atopic dermatitis, an inflammatory skin disease. 48 children with atopic dermatitis were randomly assigned to receive either 250 mg of EPA twice a day, or a placebo for four weeks. The improvement of the SCORing Atopic Dermatitis (SCORAD, increasing with the severity of symptoms, ranging from 0 to 103) index and the need to use a corticosteroid were evaluated.

The scores decreased after two weeks from 50 to 30.5 in the EPA group, and from 47 to 38.34 in the placebo group. After four weeks, the results showed a reduction in scores to 18.01 in the EPA group and to 30.11 in the placebo group. After two weeks, a corticosteroid was required in 50% of patients in the EPA group and 58.3% of patients in the placebo group, and after four weeks, it was required in 33.3% of patients in the EPA group and 63.6% of patients in the placebo group.

Studies have shown that omega-3 fatty acids compete with arachidonic acid for incorporation into the phospholipids of cell membranes. This results in a reduction in the production of prostaglandin E2 metabolites, thromboxane A2, and leukotriene B4, potent inducers of inflammation, responsible for typical symptoms of inflammation such as redness and itching. Therefore, it is through these mechanisms that the ingestion of omega-3 can reduce symptoms associated with inflammatory skin diseases like atopic dermatitis, but also psoriasis for example.

A study led by Dae Hun SUH was undertaken to assess the clinical efficacy, safety, and histological changes induced by dietary omega-3 fatty acids in the acne. A 10-week parallel dietary intervention study was conducted among 45 participants suffering from mild to moderate acne, who were divided into an omega-3 fatty acid group (2,000 mg of eicosapentaenoic acid or EPA and docosahexaenoic acid or DHA), or a control group.

The severity score of acne was approximately 2.4 before treatment. After 10 weeks of supplementation with omega-3 fatty acids, both inflammatory and non-inflammatory acne lesions significantly decreased, dropping to a score of 1.9. The staining of acne lesions showed a reduction in inflammation and in the intensity of immunohistochemical staining for interleukin-8, a pro-inflammatory cytokine.

It has been demonstrated that supplementation with omega-3 fatty acids inhibits the secretion of IL-1, IL-6, IL-8, and TNF-α, which are the primary mediators of acne inflammation. Furthermore, omega-3 fatty acids may help to reduce inflammatory responses by altering the levels of TLR-2 and TLR-4. During the development of acne, P. acnes triggers the activation of TLR-4 and TLR-2, leading to the maintenance of inflammation by keratinocytes. Therefore, as inflammation is one of the most significant pathogenic factors of acne, omega-3 fatty acids could potentially improve acne in this regard.

Khaled EZZEDINE and his team have studied the associations between daily consumption of omega-3 fatty acids and the severity of skin ageing. A cross-sectional study was conducted on 2919 subjects. At the start of the study, investigators assessed the severity of photoageing of the facial skin using a six-level scale during a clinical examination. The intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were as follows: women consumed an average of 386 mg/day of omega-3, and men 467 mg/day of omega-3.

Severe photoaging has been found to be inversely associated with higher consumption of EPA in women, decreasing from 0.81 to 0.69 for women with the highest EPA intake. No significant difference was identified for men.

Matrix metalloproteinases (MMP) are a family of enzymes that degrade the matrix and play a significant role in various destructive processes, including skin ageing. Furthermore, the expression of various UV-induced MMP in dermal fibroblasts leads to the degradation of collagen and other extracellular matrix proteins, resulting in the appearance of wrinkles. A study has shown that pre-treating human fibroblasts with EPA inhibits the expression of UV-induced MMP-1, by inhibiting the MEK1/ERK/c-Fos and SEK1/JNK/c-Jun pathways. Therefore, the inhibition of matrix metalloproteinases could be the mechanism involved in the slowing down of skin ageing caused by the ingestion of omega-3.

• CHUNG J.H. & al. Eicosapentaenoic acid inhibits UV-induced MMP-1 expression in human dermal fibroblasts. Journal of Lipid Research (2005).

• LU Y.P. & al. Effects of high-fat diets rich in either omega-3 or omega-6 fatty acids on UVB-induced skin carcinogenesis in SKH-1 mice. Carcinogenesis (2011).

• EZZEDINE K. & al. Association between dietary intake of n-3 polyunsaturated fatty acids and severity of skin photoaging in a middle-aged Caucasian population. Journal of Dermatological Science (2013).

• SUH D.H. & al. Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: A randomised, double- blind, controlled trial. Acta Dermato-Venereologica (2014).

• MOKOS Z.B. & al. Omega-3 versus Omega-6 polyunsaturated fatty acids in the prevention and treatment of inflammatory skin diseases. International Journal of Molecular Sciences (2020).

• ESMAILY H. & al. Evaluating the effect of eicosapentaenoic acid in children with atopic dermatitis: A randomized triple-blind clinical rial. The Journal of Pediatric Pharmacology and Therapeutics (2023).