New research shows intermittent fasting improves symptoms in women with PCOS
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Polycystic ovary syndrome, or PCOS, affects 18% of all childbearing-age women. The condition causes an overproduction of a group of hormones called androgens, chiefly testosterone, which may result in menstrual irregularity, obesity and even infertility.
The first line of treatment is typically hormonal birth control, said KN professor Krista Varady. But there can be negative side effects to mood, libido and metabolism, plus an increased stroke risk in some people, Varady said.
“We’re looking for other ways of lowering testosterone levels in these women,” she said. “One way is through weight loss. If someone loses around 5% of their body weight, they can actually help lower testosterone levels and sidestep any kind of drug intervention.”
A new study led by Varady and published in Nature Medicine tested how one weight-loss method, intermittent fasting, affects hormones and symptoms in patients with PCOS.
The study was a team effort among KN faculty, including clinical assistant professor Sofia Cienfuegos, who designed and ran the study with Varady, assistant professor Kelsey Gabel, professor Lisa Tussing-Humphreys ’09 PhD NUT and assistant professor Vanessa Oddo. Other coauthors from AHS include Sarah Corapi, Mary-Claire Runchey, Jodie Lyons, Maria Alonso de Leon, Vasiliki Pavlou and Mark Ezpeleta.
The team studied a type of intermittent fasting called time-restricted eating, which limits eating to a set six- or eight-hour period each day. During the remaining 18 or 16 hours, you fast with calorie-free beverages and water.
Simply put, the strategy helps people eat less, Varady said. So does counting calories, a method Varady and her colleagues tested alongside intermittent fasting in the study.
A group of 76 premenopausal women with PCOS were split into two groups — one for time-restricted eating between 1 and 7 p.m. daily and another for calorie counting — and outcomes were compared after six months. Both diet schemes cut participants’ intake by about 200 calories per day, leading to average weight loss of about 10 pounds over the six months. Both groups also experienced a decrease in testosterone concentrations. But only time-restricted eating reduced free androgen index, a marker of how much active testosterone is reaching a body’s tissues. It also improved A1C levels, a risk marker for diabetes.
Though intermittent fasting did not lessen other PCOS symptoms, like menstrual period irregularity, Varady suggested those symptoms might improve with more time on the diet and greater weight loss.
About 80% of the participants in the time-restricted eating group said they were going to continue the diet, Varady said.
This article has been edited for length and clarity by Emily Parenti-Lopez.