A recent study published in Cell has revealed that fasting may impair hair follicle stem cells (HFSCs), potentially slowing down the natural hair growth process.
Published Dec 17, 2024 | 7:00 AM ⚊ Updated Dec 17, 2024 | 8:04 AM
Doctors feel more study on humans is necessary to establish the link between intermittent fasting and alopecia. (Wikimedia Commons)
Intermittent fasting, a strategy embraced by millions worldwide for its health and weight loss benefits, has now revealed a surprising side effect: reduced hair growth.
A recent study published in Cell has revealed that fasting may impair hair follicle stem cells (HFSCs), potentially slowing down the natural hair growth process.
Though researchers at Westlake University in Zhejiang, China, who were part of this study, agreed that an intermittent fasting regimen improves metabolic health, they found that the effect of this mechanism on tissues was not studied. Hence, the researchers decided to check its potential side effects in mice.
While mice following an intermittent fasting regimen displayed improved metabolic health, they also experienced slower hair regeneration, raising questions about how the diet may affect hair growth in humans. Researchers observed that fasting alters regenerative activity by altering hair follicle stem cells (HFSCs).
“Fasting has been a longstanding tradition among many religious groups for centuries. In recent years, various intermittent fasting regimens incorporating periodic fasting or time-restricted eating schedules have become increasingly popular worldwide,” the study noted.
“Growing evidence suggests that these fasting paradigms not only benefit metabolic health and weight control but also exert profound effects on tissue health, although the mechanisms of such impacts are not well understood,” it added.
The findings revealed that mice subjected to intermittent fasting exhibited slower hair regrowth compared to those with unrestricted diets, suggesting oxidative stress from fasting hampers HFSC function.
Dr Bing Zhang, a stem cell biologist at Westlake University in China, explained the findings: “We found that fasting induces oxidative stress, which negatively affects hair follicle stem cell function, leading to slower regeneration.”
While fasting has been linked to several health benefits, including improved blood supply, muscle tissue regeneration, and metabolic health, its impact on hair has remained largely unexplored.
Dr Zhang and his team examined hair regrowth in mice that were shaved and subjected to different fasting regimens. One group maintained a normal diet, while another followed an eight-hour eating window with alternate days of fasting.
The results were striking. Mice on a normal diet regrew their hair within 30 days, while those on intermittent fasting showed only partial hair growth even after 96 days.
The researchers attributed this to stress on HFSCs, which struggled to adapt to switching from glucose to fat metabolism. This stress disrupted the hair follicles’ active phases, causing them to die off prematurely in the fasting group.
To explore whether these findings apply to humans, researchers conducted a preliminary trial involving 49 healthy adults practicing intermittent fasting.
Participants who fasted for 18 hours daily experienced an 18 percent reduction in hair growth speed compared to those who maintained a regular eating pattern. While the effects were milder in humans, the results hinted that fasting could have similar implications for human hair health.
However, the small sample size and short duration of the study warranted more extensive research.
“Mice have a much higher metabolic rate than humans, so the effects of fasting are more pronounced in them,” explained Dr Zhang. “In humans, the results may vary depending on individual metabolic differences,”
The researchers plan to collaborate with hospitals to explore how fasting impacts other types of stem cells in the skin and body, including its potential effects on wound healing.
Dr Abhiram Rayapatti, consultant dermatologist at Vasavi Hospital, agreed that people observing different fasting regimens have been seeing acute hair loss, and subsequently warranting visits to dermatologists.
“Generally, any form of prolonged fasting causes sudden and heavy hair loss called Telogen effluvium. Intermittent fasting, the most trending form of fasting said to impact weight loss, reversal of diabetes, lowering cholesterol, etc., can show impact on hair growth and hair fall,” Dr Rayapatti said.
He explained that fasting impacted the hair cycle which prolonged the Telogen (falling) phase of the hair cycle by impacting the stem cells in the hair follicle. He said that fasting induced stress on the body, thereby suppressing the stem cells causing hair fall and stopping hair regeneration.
However, he added that ” a few studies suggested that after some time the body gets adjusted to these fasting regimens and thereby slow down the negative impact on the hair follicles”.
Meanwhile, Dr Divya Sharma, a dermatologist at Dr Divya’s Skin and Hair Clinic, said in clinical practice there was rapid shedding of the hair two to three months after intermittent fasting.
However, “even viral fever, dengue or typhoid, etc., can also cause shedding of hair,” she said.
Dr Sharma added that overall intermittent fasting has metabolic benefits and also reduces oxidated stress on the body. “I would believe that intermittent fasting has long-term benefits on the health of the hair,” she opined.
She argued that the loss of hair could be transitory as the study spanned only 90 days and hence would not extrapolate or label intermittent fasting as bad for hair.
Doctors in India emphasised the need for further research and argued that hair loss was influenced by a variety of factors, including genetics, stress, and nutrition. They recommended more studies involving humans.
Interestingly Dr Zhang, the senior author of the study, cautioned that, “We don’t want to discourage people from intermittent fasting but rather stress the importance of understanding its broader effects on the body, including hair follicle health.”
Experts recommended a nutrient-rich diet during eating windows to mitigate any potential impact on hair health.
Dr Ramya S, nutritionist and health coach in Bengaluru said, “Intermittent fasting may lead to nutrient deficiencies if not done properly. A lack of essential vitamins like biotin, iron, and zinc can exacerbate hair loss. Individuals practicing IF must prioritize nutrient-rich foods during eating windows.”
For those who practice intermittent fasting, experts recommend the following:
Balanced diet: Include foods rich in biotin, zinc, protein, and iron to support hair health during eating periods.
Hydration: Drink plenty of water, as dehydration can worsen hair loss.
Moderation: Avoid extreme fasting protocols to prevent nutrient deficiencies.
Stress management: Practice yoga or meditation to reduce stress, which can contribute to hair thinning.
(Edited by Majnu Babu).
