Intermittent Fasting May Slow Hair Growth, Study Finds
Intermittent fasting, a dietary trend known for its benefits in weight loss, metabolic health, and inflammation reduction, might have an unexpected downside: it could slow hair growth. A recent study published in the journal Cell has revealed that the popular eating pattern impacts hair follicle stem cells (HFSCs), potentially affecting hair regeneration in both mice and humans.
The Study
Researchers at Westlake University in Zhejiang, China, conducted experiments using mice and a small clinical trial on humans. Mice subjected to intermittent fasting regimens, such as the 16:8 pattern (16 hours fasting, 8 hours eating) or alternate-day fasting, exhibited slower hair regrowth compared to a control group with unrestricted food access.
In the control group, shaved mice regrew most of their hair within 30 days. In contrast, fasting mice displayed only partial regrowth even after 96 days. The researchers attributed this to oxidative stress caused by the body’s metabolic switch during fasting, which forces it to use fat as an energy source instead of glucose.
The released free fatty acids from adipose tissue enter HFSCs, causing damage through the accumulation of harmful reactive oxygen species (ROS). These effects triggered apoptosis, or programmed cell death, in the HFSCs, thereby impairing hair regrowth.
Human Findings
The researchers also conducted a small clinical trial with 49 healthy adults. Participants who fasted for 18 hours daily over 10 days experienced an average hair growth reduction of 18% compared to those on regular diets. However, the study found the effect was less severe in humans than in mice, likely due to humans’ slower metabolic rates and differences in hair growth cycles.
Bing Zhang, PhD, the senior author and stem cell biologist leading the study, noted that while intermittent fasting has undeniable benefits, its effects on hair growth might vary among individuals. “The human population is very heterogeneous,” Zhang explained. “Mice also have a much higher metabolic rate compared with humans, so fasting and metabolic switching have a more severe effect on mouse HFSCs. In humans, there are still apoptotic stem cells, but many survive. Hair regrows, just a little slower than usual.”
Antioxidants to the Rescue
Interestingly, researchers found that the negative impact of fasting on HFSCs could be mitigated by antioxidants like vitamin E. In their experiments, applying vitamin E topically to the shaved skin of mice reduced oxidative stress, helping HFSCs survive and promoting faster hair regrowth.
The study highlights a broader insight: fasting affects different types of stem cells in distinct ways. While HFSCs struggle with oxidative stress during fasting, epidermal stem cells in the skin appear unaffected, likely due to their higher antioxidant capacity.
Implications and Future Research
This study underscores the importance of understanding the potential trade-offs associated with intermittent fasting. While the diet’s metabolic benefits are well-documented, these findings add nuance to its overall impact on health.
The researchers plan further investigations into how fasting influences other types of stem cells and regenerative processes, including wound healing. They also aim to identify metabolites or treatments that could protect HFSCs and enhance hair growth during fasting.
For now, experts advise that individuals considering intermittent fasting remain informed about its potential effects. While it may not be a dealbreaker for most, those prioritizing rapid hair growth might need to weigh this possible side effect.
“Intermittent fasting offers numerous benefits,” Zhang emphasized. “But like any lifestyle choice, it’s important to consider how it might uniquely affect your body.”
References
- Intermittent fasting may slow hair growth, study finds – Medical News Today – (Accessed on Dec 14, 2024)
- This popular diet might be slowing your hair growth, says new study – New York Post _(Accessed on Dec 14, 2024)
- Intermittent Fasting Could Have a Downside For Those Wishing to Grow Their Hair – Science Alert – (Accessed on Dec 14, 2024)
- Hair Regeneration Slowed by Intermittent Fasting – Neuro Science – (Accessed on Dec 14, 2024)
