The effects of spinach-derived thylakoid supplementation in combination with calorie restriction on anthropometric parameters and metabolic profiles in obese women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled clinical trial

Randomized, double-blind, placebo-controlled clinical trial in obese women with polycystic ovary syndrome (PCOS) recruited from clinics in Tabriz, Iran. Participants were reproductive-age women, all on oral contraceptive therapy and non-smokers; in the active thylakoid group, 24 were randomized and 21 completed the trial.

Spinach-derived thylakoid-rich extract powder at 5 g/day, taken orally once daily as a sachet 30 minutes before lunch for 12 weeks, added to a calorie-restricted diet. The regimen was compared with placebo plus the same dietary restriction.

Adding 5 g/day spinach-derived thylakoids to calorie restriction for 12 weeks was associated with greater improvements in weight-related outcomes and metabolic status than calorie restriction alone. In the thylakoid group, weight decreased from 89.21 to 82.23 kg (MD -6.97, 95% CI -7.21 to -6.73; P<0.001), BMI from 35.13 to 32.38 kg/m^2 (MD -2.74; P<0.001), waist circumference from 108.09 to 100.31 cm (MD -7.78; P<0.001), and fat mass from 32.40 to 27.21 kg (MD -5.19; P<0.001). The authors also concluded that insulin sensitivity improved and total testosterone decreased, with no adverse effects reported.

The trial was small, with 24 randomized and 21 completed in the active arm, and lasted only 12 weeks. It was conducted in a specific population of obese women with PCOS who were all using oral contraceptives, which limits generalizability. Mechanistic insights and dose-response information were limited, and longer follow-up was not available.