Protocol for a randomized comparative effectiveness trial comparing a very low-carbohydrate diet to DASH diet for polycystic ovary syndrome: the SUPER (Supporting Understanding of PCOS Education and Research) trial.

Background: Polycystic ovary syndrome (PCOS), the most common endocrine disorder for women of reproductive age, is associated with increased risk for insulin resistance and type 2 diabetes. Current PCOS treatments insufficiently address the spectrum and severity of the disorder, and there is little evidence-based guidance available for lifestyle management of PCOS, especially through nutritional approaches. Some evidence shows that a very low-carbohydrate diet can improve glucose control compared to low-fat or moderate-carbohydrate diets, leading to improved glucose control and insulin levels that may help to treat symptoms of PCOS. This research investigates whether a very low-carbohydrate diet is more effective in improving glucose control and decreasing symptoms of PCOS in comparison to a DASH diet.

Methods: The SUPER study aims to address the gap in knowledge about nutritional advice for people with PCOS through a randomized, comparative effectiveness trial comparing two approaches to glucose control: the dietary approaches to stopping hypertension (DASH) diet, and a very low-carbohydrate (VLC) diet. We will randomize 184 women with PCOS with body mass indexes (BMIs) between 25 and 50 kg/m to a VLC or DASH diet. All participants will follow a 24-session, 12-month, online diet, and lifestyle intervention that teaches their assigned diet. Participants will receive nutritional education, support from diet coaches, and education about behavioral strategies to improve dietary adherence. The primary outcome measure is HbA1c, and secondary outcomes include glucose variance, lipid and hormone levels (including total and free testosterone), PCOS symptoms, inflammation (measured by high-sensitivity C-reactive protein), body composition and weight, psychological well-being, and intervention feasibility and acceptability.

Discussion: The SUPER study is a randomized comparative effectiveness trial that compares two promising approaches to glucose control in people with PCOS. The study also aims to assess the effects of each diet on PCOS symptoms. The research addresses an important gap in knowledge regarding nutritional advice for people with PCOS.

Trial Registration: ClinicalTrials.gov NCT05452642. Registered 6 July 2022.