More and more is being known about intermittent fasting, a type of diet that restricts food intake. A new study by researchers at the University of Illionis (USA) has found that it could have a negative impact on reproductive hormones in women.
Specifically, the work published in the journal Obesity has analyzed a specific type of fast, which is known as the warrior diet. In it, people who practice it are restricted from eating in a window of four hours a day, in which they can eat without counting calories, the rest can only drink water.
The study measured the differences in hormone levels in blood samples from a group of premenopausal and postmenopausal women who followed an intermittent fasting diet of four and six hours of intake, compared to a part of them who did not have any type of fasting. of food restriction.
Lower levels of the hormone DHEA
As a result, the researchers found that levels of the hormone globulin, a protein that transports reproductive hormones throughout the body, were not altered in the women who followed the diets for eight weeks. Likewise, no changes were observed in the levels of testosterone and androstenedione, a steroid hormone that serves to generate testosterone and estrogen.
Women who intermittently fasted for four and six hours lost between 3% and 4% of their initial weight during the study
However, dehydroepiandrosterone or DHEA levels were found to be 14% lower in premenopausal and postmenopausal women at the end of the trial. This DHEA hormone is one of the prescriptions by clinics to improve ovarian function and egg quality in fertility treatments.
“This suggests that in premenopausal women, the smaller drop in DHEA levels should be weighed against the proven fertility benefits of lower body mass. The drop in DHEA levels in postmenopausal women could be of concern because menopause already causes a dramatic drop in estrogen, and DHEA is a major component of estrogen. However, a survey of participants reported no negative side effects associated with low estrogen levels after menopause, such as sexual dysfunction or skin changes,” explains Krista Varady, lead researcher on the study.
Doing intermittent fasting reduced up to 4% the weight
High levels of DHEA have been linked to an increased risk of breast cancer, so Varady believes that a moderate drop in its levels could be a useful tool for reducing risk before and after menopause. In addition, other hormones such as estrone, estradiol and progesterone, which are vital for pregnancy, were also measured in the study.
However, these measurements could only be made in postmenopausal women, because those who have not gone through that stage have many changes in these hormones throughout the menstrual cycle. In the postmenopausal group no significant changes in hormones were found in the eight weeks of analysis.
On the other hand, women in the four-hour and six-hour intermittent fasting diet groups lost between 3% and 4% of their starting weight during the study, compared to the control group, which had almost no weight. weight changes. The women who dieted also saw a drop in insulin resistance and biomarkers of oxidative stress.
“I think this is a great first step. We have observed thousands of pre- and postmenopausal women through different strategies of alternate day fasting and time-restricted eating. All you are doing is making people eat less. By shortening that eating window, you’re naturally cutting calories. Much of the reported negative information about intermittent fasting comes from studies in mice or rats. We need more studies to look at the effects of intermittent fasting in humans”, concludes Krista Varady.
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