By John Salak –
Intermittent fasting is moving along at lightning speed thanks to a purported menu of benefits that include reducing inflammation and aiding related conditions involving Alzheimer’s disease, arthritis, asthma, multiple sclerosis and strokes. However, the practice does come with potential drawbacks.
The Mayo Clinic, for example, warns that skipping meals may not be a great idea for those who are pregnant or breastfeeding. The practice can also lead to fatigue, insomnia, nausea, headaches and, of course, hunger.
The lure of potential weight loss and other benefits, however, has largely muted resistance to intermittent fasting. Between 10 and 13 percent of Americans, for example, embrace the idea at least periodically, the International Food Information Council reports. The market for related fasting apps is consequently expected to grow by almost 16 percent annually through the end of the decade.
Obviously, the diet has received a lot of backing. But now another somewhat hairy concern has been raised by Chinese scientists. They warn that intermittent fasting may speed up hair loss.
The researchers fully acknowledge the metabolic health benefits that intermittent fasting brings, but their study using mice as a test group found the practice thwarted hair regeneration compared to those who had complete access to food. Humans might suffer the same fate, although it’s possible the impact could be less severe because humans have a much slower metabolic rate and different hair growth patterns than mice.
“We don’t want to scare people away from practicing intermittent fasting because it is associated with a lot of beneficial effects, it’s just important to be aware that it might have some unintended effects,” reported senior author and stem cell biologist Bing Zhang of Westlake University in Zhejiang, China.
While fasting’s benefits may be well recognized, little is known about how it impacts peripheral tissues such as skin and hair. The Chinese team consequently wanted to explore whether fasting might also be beneficial for skin tissue regeneration, which is the process by which old and damaged cells are replaced.
This led to their examination of hair regrowth in mice. They focused on mice that were shaved and then subjected to different intermittent fasting regimes. Some mice were fed on a time-restricted feeding schedule that involved eighty hours of food access and 16 hours of fasting each day. Other mice were subjected to alternate-day feeding.
The results surprisingly showed that fasting inhibited hair regeneration. While control mice that had unlimited access to food had regrown most of their hair after 30 days, mice on both intermittent fasting regimes showed only partial hair regrowth after 96 days.
The team specifically showed that this inhibited hair growth occurs because hair follicle stem cells (HFSC) are unable to cope with the oxidative stress associated with switching from using glucose to fat.
“The human population is very heterogeneous, so the effects might be different for different people,” Zhang added. “Mice also have a very high metabolic rate compared with humans, so fasting and metabolic switching have a more severe effect on mouse HFSCs. We see a milder effect in humans. There are still apoptotic stem cells, but many HFSCs survive. So, there is still hair regrowth; it’s just a little bit slower than usual.”
Hair issues aside, this initial research has set the team up to collaborate with local hospitals to investigate how fasting impacts other types of stem cells in the skin and other body systems.
“We plan to examine how this process affects the regeneration activities in other tissues,” Zhang explained. “We also want to figure out how fasting impacts skin wound healing and identify metabolites that could help the survival of HFSCs and promote hair growth during fasting.”
