Intermittent fasting has been shown to be an effective way to lose weight, but critics worry that the practice may have a negative impact on women’s reproductive hormones. Now, a team of University of Illinois Chicago researchers has published a study in Obesity that brings new evidence to the table.
Researchers led by UIC nutrition professor Krista Varady followed a group of pre- and post-menopausal obese women with the “warrior diet” method of intermittent fasting for eight weeks.
The warrior diet envisions a four-hour-a-day time-restricted diet that dieters can eat without counting calories before continuing the water fast until the next day.
They measured the differences in hormone levels obtained by analyzing blood sample data in groups of dieters who stuck to four- and six-hour feeding predictions versus a control group with no dietary restrictions.
Varady and his team found that after eight weeks, dieters had unchanged levels of the hormone sex-binding globulin, a protein that carries reproductive hormones throughout the body. The same was true for both testosterone and androstenedione, a steroid hormone that the body uses to produce both testosterone and estrogen.
However, dehydroepiandrosterone, or DHEA, a hormone that fertility clinics prescribe to improve ovarian function and egg quality, was significantly lower in both premenopausal and postmenopausal women at the end of the trial, dropping by about 14%.
While the decline in DHEA levels was the study’s most important finding, DHEA levels remained within the normal range at the end of the eight-week period in both premenopausal and postmenopausal women.
“This suggests that the small decrease in DHEA levels in pre-pregnant women needs to be weighed against the proven fertility benefits of lower body mass,” Varady said. Said. “The decline in DHEA levels in postmenopausal women can be alarming as menopause already causes a dramatic drop in estrogen and DHEA is the primary component of estrogen. However, a survey of participants reported no adverse side effects associated with low estrogen post-abortion-sexual dysfunction. or skin changes.”
As an added benefit, since it’s been linked to a higher risk of DHEA, a moderate decrease in levels can help reduce this risk for both premenopausal and postmenopausal women, Varady said.
The study also measured levels of estradiol, estrone, and all hormones vital to pregnancy, but only in postmenopausal women because of the varying levels of these hormones throughout premenopausal women’s menstrual cycles. There were no changes in these hormones at the end of eight weeks in postmenopausal women.
Women in both the four-hour and six-hour groups lost 3% to 4% of their baseline weight over the course of the study, compared with the control group who lost almost no weight. The dieters also saw a decrease in insulin resistance and biomarkers of oxidative stress.
Perimenopausal women, typically in their 40s, were excluded.
Still, Varady says, “I think it’s a great first step. We’ve observed thousands of pre- and post-menopausal women with different days of fasting and time-restricted eating strategies. All it does is make people eat less. By shortening this eating interval, you naturally reduce calories. “Most of the negative information comes from studies in mice or rats. We need more studies to examine the effects of intermittent fasting on humans.”
Story Source: materials provided by. Originally written by Laura Fletcher.