Dietary macronutrients and total dietary energy are associated with skin microbiota, researchers reported in a study published in the British Journal of Dermatology.
The investigators conducted a cross-sectional survey of skin microbiota from participants of 2 population-based adult German cohorts, PopGen, and KORA FF4. The study authors assessed skin bacteria at the bacterial community level and bacterial marker gene variants (16S ribosomal RNA [rRNA] gene amplicon sequence variants [ASVs]). They collected microbiota profiles from 647 participants (294 from PopGen and 353 from KORA FF4), and collected 1794 skin samples.
The researchers obtained individual and lifestyle information for 86% of PopGen participants (n = 254; median age, 66 years; 56% men). Skin microenvironment was the major trait associated with skin microbiota beta diversity, accounting for about 9.2 ± 0.9% of the bacterial community variation. Age, body mass index (BMI), and sex were associated with community variation at all 4 sampling sites. The associations with microenvironment, sex, and BMI were also observed in the KORA FF4 cohort (n = 225; median age, 45 years; 59% women).
The study authors found 647 unique significant associations of age, BMI, sex, and lifestyle factors with bacterial marker gene variants, of which 209 associations were observed in at least 2 sampling sites and further evaluated. Age (maximum of 33 associated ASVs), sex (maximum 30 ASVs), smoking (maximum 15 ASVs), and BMI (14 ASVs) were associated with the highest numbers of variants per site, followed by dietary macronutrients (maximum 12 ASVs for carbohydrates).
Associated ASVs included members of the genera Propionibacterium, Corynebacterium, and Staphylococcus. Age, BMI, sex, and lifestyle factors were generally associated with ASVs from these genera. Other lifestyle factors were associated with as many as 5 ASVs from these 3 genera, including smoking, alcohol consumption, systemic use of antibiotics, washing, use of lotion/cream, and sporting activity.
Dietary intake of macronutrients was associated with 12 ASVs from Corynebacterium and Staphylococcus genera. Dietary energy, fat, and fiber were also associated in both directions with Corynebacterium and Staphylococcus variants.
The researchers noted that their findings are based on polymerase chain reaction amplification of the V1 and V2 variable regions of the 16S rRNA gene, which is subject to primer bias and has limited taxonomic classification resolution, particularly at the species level.
“We provide the first direct evidence of the association of diet with skin bacteria,” stated the investigators. “Although effect sizes were low, the amount of total energy and macronutrient intake was significantly associated with ASV abundances….” They also wrote,”Our results confirm that host factors and skin microenvironments are potential confounders for skin bacterial communities and should be acknowledged in future clinical studies.”
Moitinho-Silva L, Boraczynski N, Emmert H, et al. Host traits, lifestyle and environment are associated with human skin bacteria. Br J Dermatol. Published online March 18, 2021. doi:10.1111/bjd.20072