Study suggests high BMI adversely impacts facial characteristics and skin microbiome

05 Apr 2024 --- A new study suggests physiological characteristics of the face, as well as skin microbiome changes, are associated with body mass index (BMI).

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

In the experiment, a group of overweight individuals exhibited a significant increase in trans-epidermal water loss, which indicated impairments to their skin barrier. 

Skin hemoglobin content for this group was also significantly elevated, while pH levels of the skin surface were significantly decreased.

“Overweight and obesity have become public health problems worldwide,” stress the study authors.

“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 BMI, facial skin physiological parameters and the facial skin microbiome in healthy women.”

Obesity correlated with skin barrier damage
Benchmarked against the international BMI standard and Chinese reference standard, subjects were divided into three groups, “lean” B1, “normal” B2 and “overweight” B3. 

Researchers used painless instruments to measure skin health and analyzed the microscopic communities of bacteria living on participants’ faces through DNA sequencing.

Overweight individuals exhibited a significant increase in trans-epidermal water loss.Compared with the skin physiological parameters of the “normal” group, those of the “overweight” group exhibited a significant increase in trans-epidermal water loss, which indicated that the skin barrier was impaired.

“The skin hemoglobin content was significantly increased and skin surface pH was significantly decreased in those with a high BMI,” highlight the study authors.

“Hemoglobin levels reflect vascular activity, and an increase in skin hemoglobin content often manifests as skin inflammation, which affects the appearance of the skin. Obesity is known to be a major risk factor for inflammatory skin diseases, including atopic dermatitis and psoriasis,” they note.

“The inflammatory cytokines produced by adipose tissue and the activation of innate immunity are considered important factors in obesity-induced inflammation.”

Skin microflora and BMI
The study’s authors highlight that the skin is colonized by an assemblage of commensal microorganisms, including bacteria, fungi and viruses that compose the skin microbiota. 

Expanding research efforts demonstrate that the skin microbiota plays a crucial role in maintaining skin homeostasis. In consumer goods applications, microbiome-balancing innovations have come into the spotlight, including bamboo-based intimate care solutions and functional botanicals like dragon fruit extract.

In the study, a closer look at the skin bacteria of the overweight group showed a greater variety and abundance of different microbes.

“Moreover, the overweight group had higher abundances of Streptococcus, Corynebacterium, Malassezia and Candida,” note the authors. “Notably, skin surface pH was significantly and negatively correlated with the relative abundances of Malassezia, Candida and Cladosporium.”

Furthermore, the abundance of Malassezia was “positively associated” with an abundance of Staphylococcus and Corynebacterium.

“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,” conclude the study authors.

By Benjamin Ferrer