Abstract:
New research reveals that intermittent fasting, despite its metabolic benefits, may impair hair growth by impacting hair follicle stem cells (HFSCs). Studies in mice show that prolonged fasting induces apoptosis in HFSCs due to oxidative stress and accumulation of free fatty acids. In humans, clinical trials suggest a moderate 18% reduction in hair growth rate associated with fasting, an effect that may be mitigated by antioxidants such as vitamin E.
Key facts:
- Stem cell stress: Fasting promotes the accumulation of free fatty acids around hair follicles, triggering apoptosis in HFSCs.
- Human impact: 18% reduction in hair growth rate in humans placed on time-restricted diets.
- Antioxidant function: Vitamin E and other antioxidants may protect HFSCs from fasting-induced damage.
Study Details:
Researchers led by Bing Zhang of Westlake University in Zhejiang, China, investigated the effects of intermittent fasting in mice and humans. In mice, fasting regimens such as fixed-time food restriction (16 hours of fasting and 8 hours of eating) and alternate-day feeding resulted in slower hair regeneration compared to animals with unrestricted access to food. After 96 days, fasting mice showed only partial hair growth, while the control group completed hair regeneration within 30 days.
The researchers observed that fasting causes HFSCs to undergo apoptosis due to oxidative stress, caused by the accumulation of free fatty acids released by dermal adipocytes during fasting. HFSCs, unable to metabolize these fatty acids efficiently, accumulate reactive oxygen species, leading to cell death. In contrast, epidermal stem cells showed greater resilience due to their antioxidant capacity.
Human Testing:
A clinical trial involving 49 healthy adults found that average hair growth rates were reduced by 18% in participants who fasted for 18 hours a day for 10 days. Although the impact was less severe in humans, given their slower metabolism, the results highlight potential implications for hair regeneration.
Potential Solutions:
The researchers demonstrated that topical application of vitamin E or genetic regulation of antioxidant capacity can protect HFSCs from the negative impact of fasting. In the future, they plan to investigate the effect of fasting on other types of stem cells and on regenerative processes in human tissues.
Final Considerations:
Although intermittent fasting offers broad metabolic benefits, the results suggest that caution should be exercised when applying it over a long period of time, especially for individuals concerned about hair regeneration. Antioxidant strategies may be a promising solution to minimize the undesirable effects.
Source:
Zhang, Bing et al. “Intermittent fasting triggers inter-organ communication to suppress hair follicle regeneration.” Cell Press, December 13, 2024. DOI: access full study .
