Obesity, we know, can impact your heart, joints, liver, gut and blood sugar levels, among other things. Now, here's another reason to lose those extra pounds: obesity also has a direct impact on your hair density.
ANI reported that a new study had found why obesity can lead to hair thinning and hair loss. The study's findings, which was published in the journal 'Nature', shed light on the complicated link between obesity and organ dysfunction, said the report. The study, conducted by researchers from Tokyo Medical and Dental University (TMDU), used mouse model experiments to examine how a high-fat diet or genetically induced obesity can affect hair thinning and loss.
ANI reported that they found that stem cells within hair follicles in mice given a high-fat diet behaved differently from those with a standard diet. “Inflammatory signals in the stem cells led to these differences, ultimately resulting in hair thinning and loss. These fascinating data shed light on the complicated link between obesity and organ dysfunction," reported ANI.
In short, the authors proved that obesity could lead to depletion of hair follicle stem cells (HFSCs) through the induction of specific inflammatory signals, blocking hair follicle regeneration and ultimately resulting in loss of hair follicles. "Normally, HFSCs self-renew every hair follicle cycle. This is part of the process that allows our hair to grow back continuously. However, as humans age, HFSCs fail to replenish themselves, leading to fewer HFSCs and therefore hair thinning," reported ANI.
The report also pointed out that while overweight people have a higher risk of androgenic alopecia, whether obesity accelerates hair thinning, how and the molecular mechanisms have been largely unknown. "The TMDU group aimed to address those questions and identified some of the mechanisms," it said.
Hironobu Morinaga, the study's lead author, told ANI that a high-fat diet feeding accelerates hair thinning by depleting HFSCs that replenish mature cells that grow hair, especially in old mice. "We compared the gene expression in HFSCs between HFD-fed mice and standard diet-fed mice and traced the fate of those HFSCs after their activation," Morinaga said, adding that they found that those HFSCs in HFD-fed obese mice change their fate into the skin surface corneocytes or sebocytes that secrete sebum upon their activation. "Those mice show the faster hair loss and smaller hair follicles along with depletion of HFSCs. Even with HFD feeding in four consecutive days, HFSCs shows increased oxidative stress and the signs of epidermal differentiation," Morinaga added.
Emi K. Nishimura, a senior author, pointed out that the gene expression in HFSCs from the high-fat-fed mice indicated the activation of inflammatory cytokine signalling within HFSCs. "The inflammatory signals in HFSCs strikingly repress Sonic hedgehog signalling that plays a crucial role in hair follicle regeneration in HFSCs," he said.
ANI reported that the researchers confirmed the activation of the Sonic hedgehog signalling pathway in this process could rescue the depletion of HFSCs. "This could prevent the hair loss brought on by the high-fat diet," said Nishimura.
Since this study has provided interesting new insights into the specific cellular fate changes and tissue dysfunction that can occur following a high-fat diet or genetically induced obesity, it may open the door for future prevention and treatment of hair thinning and the understanding of obesity-related diseases concluded ANI.