Consumption of Fermented Foods: Do They Impact Our Skin?

Eating fermented foods offers numerous benefits for the skin.

Consuming fermented foods reduces the risk of developing inflammatory skin diseases.

Indeed, Ji-Hyun BAE and Sunmin PARK hypothesized that the prevalence of atopic dermatitis is associated with the consumption of fermented foods among the adult Korean population. They examined this hypothesis by surveying 9,763 adults. A high consumption (> 92 times/month) of fermented foods such as kimchi (Korean fermented vegetables), fermented seafood, and beer was associated with a lower prevalence of atopic dermatitis (with an odds ratio of 0.56). Conversely, a high consumption of meat and processed foods was strongly associated with the prevalence of atopic dermatitis (with an odds ratio of 2.42).

Studies have suggested that fermented foods might act against inflammation. During fermentation, vitamin K and vitamin B12 can be synthesized by microbes; they play an important role in host health, including the prevention of atopic diseases. For example, vitamin K2 or menaquinone, which can be found in fermented foods, has been reported to reduce the expression of tumor necrosis factor-alpha and interleukin-6, pro-inflammatory cytokines. Vitamin B12, which is only found in foods fermented by B12-producing probiotic lactic acid bacteria, has also been shown to exert a protective effect against atopic dermatitis, although the mechanisms involved have not yet been elucidated.

Oral intake of fermented foods could potentially reduce the risk of developing atopic dermatitis, as well as other topical inflammatory diseases such as psoriasis.

Consuming fermented foods improves skin hydration.

Ki Won LEE and his team aimed to evaluate the effect of fermented foods on skin hydration. To do this, the researchers developed a blend of barley and soy by incorporating yeast fermentation and assessed its effects on skin hydration as a dietary supplement. Participants ingested the blend or a placebo (3 g per day) for eight weeks. A significant increase in hydration was observed in the group that ingested the blend compared to the placebo group after four weeks. A reduction in the thickness of the stratum corneum was also observed.

This effect is believed to be associated withhyaluronic acid. This molecule is known for its ability to maintain skin hydration due to its water-binding properties. Indeed, the study showed that the formula increased the production of hyaluronic acid and the function of the skin barrier in vitro, but it also reduced the expression of hyaluronidase 2 (Hyal2), which is responsible for the degradation of hyaluronic acid in human dermal fibroblasts. These mechanisms are what enable this hydrating action.

Consuming fermented foods prevents skin aging.

Chia-Hua LIANG and colleagues evaluated the effects of orally consumed fermented pomegranate on skin aging. Forty subjects were divided into fermented or placebo groups, and were given 50 ml of a fermented pomegranate/placebo drink per day for eight weeks. The free radical scavenging activity in the fermented group was higher than in the placebo group. Thus, fermented pomegranate appears to be antioxidant. Additionally, the hydration, brightness, and elasticity levels of the subjects in the fermented group increased by 7.7%, 2.6%, and 7.8%, respectively, compared to baseline values. Finally, the consumption of the drink increased collagen density by at least 14.5% at eight weeks and 41.6% at four weeks, respectively, compared to the baseline value.

Skin aging can be accelerated by oxidative stress (tobacco, pollution, UV rays), which leads to the production of free radicals. These free radicals cause significant damage to DNA and dermal fibers (collagen, elastin), which can result in the appearance of signs of aging such as wrinkles and fine lines. Thus, it can be hypothesized that fermented foods, due to their antioxidant action that can neutralize free radicals and their promotion of collagen synthesis, can delay premature skin aging.

Nevertheless, the precise mechanisms have not yet been identified. Further studies are necessary.