Diet and Skin Barrier: The Role of Dietary Interventions on Skin Barrier Function

Facial Physiological Characteristics and Skin Microbiomes Changes are Associated with Body Mass Index (BMI)

Background

Overweight and obesity have become public health problems worldwide. An increasing number of research works are focusing on skin physiology and the manifestations of obesity-associated skin diseases, but little is known about the correlations between body mass index (BMI), facial skin physiological parameters, and the facial skin microbiome in healthy women.

Objective

To investigate the correlations between BMI, facial skin physiological parameters and facial bacteria and fungi in 198 women aged 18 to 35 years in Shanghai.

Methods

According to the international BMI standard and Chinese reference standard, subjects were divided into three groups, "lean" B1, "normal" B2 and "overweight" B3, and the physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiota was analyzed by 16S rRNA and ITS high-throughput sequencing.

Results

Compared with the skin physiological parameters of the normal group, those of the overweight group exhibited a significant increase in trans-epidermal water loss (TEWL), which indicated that the skin barrier was impaired. The skin haemoglobin content was significantly increased, and skin surface pH was significant decreased in those with a high BMI. Furthermore, α-diversity, analysed using the Shannon, Chao, Sobs, and Ace indexes, was increased in the overweight group, suggesting that the diversity and species abundance of facial bacterial and fungal microbiota were also increased. Moreover, the overweight group had higher abundances of Streptococcus, Corynebacterium, Malassezia, and Candida. Notably, skin surface pH was significantly and negatively correlated with the relative abundances of Malassezia, Candida, and Cladosporium. Besides, the abundance of Malassezia was positively associated with the abundances of Staphylococcus and Corynebacterium.

Conclusion

These results indicate that BMI is associated with differences in the biophysical properties and microbiome of the facial skin. A high BMI affects the integrity of skin barrier and changes the skin flora diversity and species composition.

Clinical Efficacy of Nutritional Supplements in Atopic Dermatitis: Systematic Review

BACKGROUND

Atopic dermatitis (AD), also known as eczema, is a chronic inflammatory skin condition that presents with symptoms of intense pruritus, dryness, and erythema. Dissatisfaction with first-line therapies for AD, the desire to avoid steroids, and the extreme cost of effective biologics have created a demand for alternative treatment options such as oral vitamins and nutritional supplements.

OBJECTIVE

The purpose of this review was to assess the effectiveness of oral nutritional supplements, pre- and probiotics, and vitamin deficiencies and supplements on AD symptomology and clinical course.

METHODS

We searched Scopus, PubMed, and MEDLINE (Ovid interface) for English-language articles published between 1993 and 2023. The final search was conducted on June 22, 2023. The search terms comprised the following: "(Atopic Dermatitis or Atopic Eczema) AND (supplement OR vitamin OR mineral OR micronutrients OR Fish Oil OR Omega Fatty Acid OR Probiotics OR Prebiotics OR apple cider vinegar OR collagen OR herbal OR fiber)."

RESULTS

A total of 18 studies-3 (17%) evaluating vitamins, 4 (22%) evaluating herbal medicine compounds, 2 (11%) evaluating single-ingredient nutritional supplements, and 9 (50%) evaluating pre- and probiotics-involving 881 patients were included in this review.

CONCLUSIONS

Overall, there is weak evidence to support any one nutritional supplement intervention for the alleviation of AD symptoms. Multiple trials (4/18, 22%) showed promise for supplements such as Zemaphyte, kefir, and freeze-dried whey with Cuscuta campestris Yuncker extract. The most evidence was found on the effectiveness of probiotics on the clinical course of AD. Lactiplantibacillus plantarum, Ligilactobacillus salivarius, and Lactobacillus acidophilus specifically showed evidence of efficacy and safety across multiple studies (6/18, 33%). However, larger, more extensive randomized controlled trials are needed to determine the true effectiveness of these supplements on the broader population.

TRIAL REGISTRATION

PROSPERO CRD42023470596; https://tinyurl.com/4a9477u7.

Effect of Lumenato a Tomato derived oral supplement on improving skin barrier strength

INTRODUCTION

Improvement of skin barrier strength could lead to healthy and youthful appearance. "Beauty inside-out" approach using nutraceuticals such as tomato derived carotenoids to support skin barrier strength could be of benefit to the ageing population.

METHOD

A panel of 60 female subjects were provided with the Lumenato capsules (containing carotenoids) or placebo capsules as nutritional supplements for 3 months. Skin health and barrier function were observed using evaporimeter which measures trans epidermal water loss (TEWL). Barrier strength was determined by study of the number of strippings required to disrupt skin barrier and barrier repair was observed in terms of TEWL a few hours after barrier disruption. Cutometer was used to observe skin firmness and elasticity. Measurements were obtained before treatment and after 4 and 12 weeks of use.

RESULTS

Results indicated a statistically significant improvement (p < 0.05) in skin barrier strength; a higher number of strippings were required to disrupt skin barrier after 12 weeks of supplement use. There was also a significant improvement in skin firmness and elasticity as observed with a cutometer.

CONCLUSION

Based on the confines and conditions of this study, oral supplementation with Lumenato resulted in significant improvement in skin barrier as well as skin firmness and elasticity.

Unveiling Skin Manifestations: Exploring Cutaneous Signs of Malnutrition in Eating Disorders

The intricate interplay between eating disorders, malnutrition, and their cutaneous manifestations is the focal point of this comprehensive review. The review delves into the clinical significance of recognising and understanding these visible signs in the context of eating disorders. It highlights the vital role of nutrition in maintaining healthy skin and addresses the challenges associated with relying solely on cutaneous signs for diagnosis. Emphasising a multidisciplinary approach involving dermatologists, psychiatrists, and nutritionists, the review underscores the holistic nature of the treatment. Addressing psychological aspects alongside nutritional rehabilitation is underscored with a forward-looking perspective on future research avenues. This review is valuable for healthcare professionals by synthesising existing knowledge and identifying research gaps. It aims to improve the diagnosis, treatment, and preventative strategies for individuals dealing with the complex challenges of eating disorders and malnutrition.

Particulate matter 2.5 induces the skin barrier dysfunction and cutaneous inflammation via AhR- and T helper 17 cell-related genes in human skin tissue as identified via transcriptome analysis

Particulate matter (PM2.5) is an environmental pollutant causing skin inflammatory diseases via epidermal barrier damage. However, the mechanism and related gene expression induced by PM2.5 remains unclear. Our aim was to determine the effect of PM2.5 on human skin tissue ex vivo, and elucidate the mechanism of T helper 17 cell-related inflammatory cytokine and skin barrier function. We verified the expression levels of gene in PM2.5-treated human skin tissue using Quantseq (3' mRNA-Seq), and Gene Ontology (GO) terms and protein-protein interaction (PPI) networks were performed. The PM2.5 treatment significantly enhanced the expression of Th 1, 2, 17 and 22 cell-related genes (cut-off value: │1.2 │ > fold change and p < 0.05). Most of all, Th17 cell-related genes are upregulated and those genes are associated with skin epidermal barrier function and Aryl hydrocarbon receptor (AhR), a xenobiotic receptor, pathway. In human keratinocyte cell lines, AhR-regulated genes (e.g. AhRR, CYP1A1, IL6 and IL36G), Th17 cell-related genes (e.g. IL17C) and epidermal barrier-related genes (e.g. SPRR2A and KRT71) are significantly increased after PM2.5. In the protein level, the secretion of IL-6 and IL-36G was increased in human skin tissue following PM2.5 treatment, and the expression of SPRR2A and KRT71 was significantly increased. PM2.5 exposure could ruin the skin epidermal barrier function via AhR- and Th17 cell-related inflammatory pathway.

Effects of a mildly cooked human-grade dog diet on gene expression, skin and coat health measures, and fecal microbiota of healthy adult dogs

Purported benefits of human-grade pet foods include reduced inflammation, enhanced coat quality, and improved gut health, but research is scarce. Therefore, we compared gene expression, skin and coat health measures, and the fecal microbiome of dogs consuming a mildly cooked human-grade or extruded kibble diet. Twenty beagles (BW = 10.25 ± 0.82 kg; age = 3.85 ± 1.84 yr) were used in a completely randomized design. Test diets included: 1) chicken and brown rice recipe [feed-grade; extruded; blue buffalo (BB)]; and 2) chicken and white rice [human-grade; mildly cooked; Just Food for Dogs (JFFD)]. The study consisted of a 4-week baseline when all dogs ate BB, and a 12-week treatment phase when dogs were randomized to either diet (n = 10/group). After the baseline and treatment phases, fresh fecal samples were scored and collected for pH, dry matter (DM), and microbiome analysis; blood samples were collected for gene expression analysis; hair samples were microscopically imaged; and skin was analyzed for delayed-type hypersensitivity (DTH), sebum concentration, hydration status, and transepidermal water loss (TEWL). Data were analyzed as a change from baseline (CFB) using the Mixed Models procedure of SAS (version 9.4). At baseline, fecal pH was higher (P < 0.05) and hair surface score, superoxide dismutase (SOD) expression, and tumor necrosis factor-α (TNF-α) expression was lower (P < 0.05) in dogs allotted to JFFD. The decrease in CFB fecal pH and DM was greater (P < 0.05) in dogs fed JFFD, but fecal scores were not different. The increase in CFB hair surface score was higher (P < 0.05) in dogs fed JFFD. The decrease in CFB TEWL (back region) was greater (P < 0.05) in dogs fed JFFD, but TEWL (inguinal and ear regions), hydration status, and sebum concentrations in all regions were not different. Hair cortex scores and DTH responses were not affected by diet. The increase in CFB gene expression of SOD, COX-2, and TNF-α was greater (P < 0.05) in dogs fed JFFD. PCoA plots based on Bray-Curtis distances of bacterial genera and species showed small shifts over time in dogs fed BB, but dramatic shifts in those fed JFFD. JFFD increased (adj. P < 0.05) relative abundances of 4 bacterial genera, 11 bacterial species, 68 KEGG pathways, and 167 MetaCyc pathways, and decreased (adj. P < 0.05) 16 genera, 25 species, 98 KEGG pathways, and 87 MetaCyc pathways. In conclusion, the JFFD diet dramatically shifted the fecal microbiome but had minor effects on skin and coat measures and gene expression.

Koji amazake Maintains Water Content in the Left Cheek Skin of Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group, Comparative Trial

Purpose

Improvement in water content and skin barrier function on human skin is believed to be induced by koji amazake, a non-alcoholic beverage derived from rice fermented by Aspergillus oryzae (A. oryzae). In order to scientifically identify the effects of koji amazake on human skin, we performed a randomized, double-blind, placebo-controlled, parallel-group comparative trial and quantified the content of glucosylceramide (GlcCer) which would be responsible for the effects.

Participants and Methods

Healthy adults concerned with their skin dryness were divided into koji amazake (N = 30) or placebo group (N = 30). During this test, the test beverages were ingested at 118 g/day. Their water content and trans-epidermal water loss (TEWL) were measured at 0 week (baseline) and 8 weeks. The content of GlcCer in test beverages was quantified by HPLC-ELSD.

Results

In comparison with the placebo group, the water content in the left cheek of individuals in the koji amazake group was maintained for 8 weeks. In addition, changes in water content from the baseline to 8 weeks differed significantly between the koji amazake (0.19) and placebo groups (-3.98). Unexpectedly, there was no significant difference in the TEWL between koji amazake and placebo group. We analyzed GlcCer in both koji amazake and placebo beverages, which were found to contain 1.35 ± 0.11 and 0.30 ± 0.07 mg/118 g, respectively. The amount of GlcCer in koji amazake was approximately equal to the dosage of plant-derived GlcCer which has the ability to improve water content and TEWL in humans.

Conclusion

Present study has shown that intake of koji amazake contributes to maintain the water content only on the left cheek. The content of GlcCer derived from koji amazake was adequate for maintenance of the water content compared to previous reports. Therefore, it was concluded that GlcCer in koji amazake acts as a functional ingredient.

Effects of Sphingomyelin-Containing Milk Phospholipids on Skin Hydration in UVB-Exposed Hairless Mice

Reactive oxygen species (ROS) generated by ultraviolet (UV) exposure cause skin barrier dysfunction, which leads to dry skin. In this study, the skin moisturizing effect of sphingomyelin-containing milk phospholipids in UV-induced hairless mice was evaluated. Hairless mice were irradiated with UVB for eight weeks, and milk phospholipids (50, 100, and 150 mg/kg) were administered daily. Milk phospholipids suppressed UV-induced increase in erythema and skin thickness, decreased transepidermal water loss, and increased skin moisture. Milk phospholipids increased the expression of filaggrin, involucrin, and aquaporin3 (AQP3), which are skin moisture-related factors. Additionally, hyaluronic acid (HA) content in the skin tissue was maintained by regulating the expression of HA synthesis- and degradation-related enzymes. Milk phospholipids alleviated UV-induced decrease in the expression of the antioxidant enzymes superoxidase dismutase1 and 2, catalase, and glutathione peroxidase1. Moreover, ROS levels were reduced by regulating heme oxygenase-1 (HO-1), an ROS regulator, through milk phospholipid-mediated activation of nuclear factor erythroid-2-related factor 2 (Nrf2). Collectively, sphingomyelin-containing milk phospholipids contributed to moisturizing the skin by maintaining HA content and reducing ROS levels in UVB-irradiated hairless mice, thereby, minimizing damage to the skin barrier caused by photoaging.