Intermittent fasting & hair thinning?

Undesirable Side Effect

However, observational studies have provided evidence that the medically called “intermittent fasting” nutritional strategy could have an undesirable side effect: thinning hair. A Chinese research group has got to the bottom of this, initially in experiments with mice.

The team led by Bing Zhang from the private Westlake University in Hangzhou first shaved the animals’ back fur. One group of rodents then only received food within a time window of eight hours. For the remaining 16 hours, they had only access to water.

Such a rhythm is particularly popular with human intermittent fasters, as it can be integrated comparatively well into everyday social life.

A second group of mice was given unrestricted access to food alternately on one day, and the next they were prescribed a zero diet. A control group was able to help themselves at any time during the entire trial period.

Bald Spots in the fur

The result: While the continuously eating animals had grown dense fur again after 30 days, the fur of the conspecifics in both fasting groups still showed bald patches after 96 days.

It could not be due to a lack of nutrient supply: The mice quickly got used to the limited feeding times and ate as much in a shorter time as the animals that had food available all the time.

The role of stem cells

Instead, the stem cells of the hair follicles apparently play a key role in slowing down hair growth. These cells are responsible for the regeneration of the follicles and thus control the growth cycle. When activated, the hair begins to sprout. However, not all hair follicle stem cells are active at the same time, some are always in a dormant phase.

Hungry hair grows poorly

Examinations of cell samples showed that some of the hair stem cells apparently do not cope well with the fasting phases. Normally, they draw their energy from glucose, but during Lent they were dependent on energy from fatty acids. But that doesn’t seem to suit them.

“The number of hair follicle stem cells decreased dramatically in fasting mice. The regeneration of the hair follicles and hair growth were significantly delayed,” the Chinese research team’s publication says. However, only the activated hair follicle stem cells perished, the dormant ones remained intact.

During long-term fasting, the hair follicles degenerate

But what are the long-term effects of intermittent fasting? To investigate this, the team had the mice fasted intermittently over a period of eight months. The result: While short-term fasting only delayed hair growth, the consequences were now more serious: “Permanent intermittent fasting causes degeneration of the hair follicles,” the authors write.

The researchers cannot say whether the hair recovers from these longer periods of fasting.

How the body adapts to times of hunger

The researchers also found out who the conductors of these processes are thanks to an almost detective search for clues: they are the adrenal glands. They regulate the body’s response to stress. This also includes periods without food. The glandular organs, which sit on the kidneys like little caps, react to this, among other things, by switching from energy production from glucose to fat burning in large parts.

This response is a central part of the evolutionary adaptation to times of hunger that was once part of people’s everyday lives – and still is in many parts of the world. Less important organs and regenerative processes are then downregulated. “In this way, the body conserves resources for more important organs to ensure survival,” the authors write.

The skin is more important than the hair

And this also applies to the skin, for example: While full hair plays a subordinate role in times of hunger, the barrier function of the skin must be maintained at all costs. This is because it protects the body from harmful external influences and prevents excessive water loss. In fact, skin stem cells that regenerate them remain intact even during periods of starvation, the Chinese team found.

The throttled hair growth therefore does not only seem to be an unpleasant side effect of fasting but is a targeted physical measure.

Does all this also apply to fasting people?

But can the results be transferred to humans at all? In fact, there are many parallels in hair growth between mice and humans – but also differences. The rhythm of active and inactive phases of the hair stem cells is different, and the metabolism of the animals is faster overall, which could accelerate problematic changes.

To get to the bottom of this question, the team recruited 40 young adults. They shaved a small piece of scalp of 1 × 1 cm. Afterwards, the men and women completed a ten-day fasting program. The result: the hair follicle stem cells were also damaged in these patients.

Fasting without hair loss

So do people have to choose between the undisputed positive effects of intermittent fasting on the one hand and full hair on the other? Not necessarily.

At least in the context of the mouse tests, the team found that the length of the fasting phases is decisive: While the effects became more and more severe with only eight, five and finally three hours of access to food, a 12-hour fasting window did little to affect the hair follicle stem cells.

A strategy for intermittent fasters could therefore be to keep an eye on personal hair growth and, if necessary, to make the fasting phases a little shorter.

Vitamin E could protect hair follicies

And the researchers found something else: The death of stem cells in fasting mice could be stopped by the external application of vitamin E. This suggests that oxidative stress caused by aggressive oxygen molecules damages stem cells. Vitamin E, which has an antioxidant effect, was apparently able to successfully counteract this.

However, the researchers have not yet investigated whether the administration of vitamin E can also protect intermittent fasting people from thinning hair.

In the UAE

Intermittent fasting is well known concept among residents in the UAE & with the fast-paced lifestyle here, it is researched and followed quite religiously. However, people are not knowledgeable about its side effects and only focus on its benefits. Other reasons also contribute towards hair loss which makes intermittent fasting an option which causes the least impact and the most benefits for residents here.