Effects of yacon syrup on postprandial blood glucose in women with polycystic ovary syndrome: A double-blind randomized clinical trial

Authors: FREITAS PEREIRA, FERNANDA - University Of São Paulo; VERGINIA LOURENCO, MIRIAM - Yacon-Br; VENDRUSCOLO PISO, GABRIEL - Santa Martha Agro; GOMES SIQUEIRA, BEATRIZ - University Of São Paulo; MORAES, RITA - Yacon-Br; Cantrell, Charles; Wang, Mei; MARIA DO REIS, ROSANA - University Of São Paulo; MARLIERE NAVARRO, ANDERSON - University Of São Paulo

Submitted to: Clinical Nutrition Open Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2025
Publication Date: 5/29/2025
Citation: Freitas Pereira, F., Verginia Lourenco, M., Vendruscolo Piso, G., Gomes Siqueira, B., Moraes, R.M., Cantrell, C.L., Wang, M., Maria Do Reis, R., Marliere Navarro, A. 2025. Effects of yacon syrup on postprandial blood glucose in women with polycystic ovary syndrome: A double-blind randomized clinical trial. Clinical Nutrition Open Science. 62 (2025): 79-88. https://doi.org/10.1016/j.nutos.2025.05.011.
DOI: https://doi.org/10.1016/j.nutos.2025.05.011

Interpretive Summary: Polycystic Ovary Syndrome (PCOS) is a highly prevalent endocrine disorder that affects women of reproductive age worldwide. Hyperglycemia is an aggravating factor for women with PCOS, especially if associated with overweight and obesity. Certain root vegetables, such as the tuberous root of yacon (Smallanthus sonchifolius), shows potential antidiabetic activity for improving human health. This study evaluates the effect of yacon syrup on overweight or obese women with PCOS as a means to maintain consistent postprandial blood glucose levels. This paper describes a randomized double-blind crossover clinical trial that lasted 15 days. We performed a biochemical and anthropometric evaluation of daily food consumption. Yacon syrup and placebo were administered randomly at breakfast, lunch, and dinner. There were no significant differences in food consumption (p < 0.05). However, blood glucose data revealed differences in immediate postprandial blood glucose at meals in general (p = 0.007) and in immediate postprandial blood glucose at breakfast and dinner (p= 0.03 and p = 0.034, respectively). Data suggests that overweight or obese women with PCOS that received yacon syrup as part of their meals showed a reduction in the speed of immediate postprandial blood glucose levels. Thus the findings suggest that the use of yacon syrup after meals lessens blood sugar fluctuations, avoiding peaks and valleys.

Technical Abstract: Background & Aims: Polycystic Ovary Syndrome (PCOS) is a highly prevalent endocrine disorder that affects women of reproductive age worldwide. Hyperglycemia is an aggravating factor for women with PCOS, especially if associated with overweight and obesity. Certain root vegetables, such as the tuberous root of yacon (Smallanthus sonchifolius), shows potential antidiabetic activity for improving human health. This study evaluates the effect of yacon syrup on overweight or obese women with PCOS as a means to maintain consistent postprandial blood glucose levels. Methods: This paper describes a randomized double-blind crossover clinical trial that lasted 15 days. We performed a biochemical and anthropometric evaluation of daily food consumption. Yacon syrup and placebo were administered randomly at breakfast, lunch, and dinner. We monitored blood glucose pre-meal, immediate post-meal, post-meal 1 hour and post-meal 2 hours. A total of 20 women with PCOS were evaluated: 60% (n=12) overweight and 40% (n=8) obese, mean age of 27.15 (±5.92) years. Results: There were no significant differences in food consumption (p < 0.05). However, blood glucose data revealed differences in immediate postprandial blood glucose at meals in general (p = 0.007) and in immediate postprandial blood glucose at breakfast and dinner (p= 0.03 and p = 0.034, respectively). Conclusion: Data suggests that overweight or obese women with PCOS that received yacon syrup as part of their meals showed a reduction in the speed of immediate postprandial blood glucose levels. Thus the findings suggest that the use of yacon syrup after meals lessens blood sugar fluctuations, avoiding peaks and valleys.