Abstract
Objectives
Resistant starch (RS) is a non-digestible fermentable carbohydrate found naturally in food sources such as potatoes that can lower postprandial glucose and improve insulin sensitivity. Potato RS can be increased by baking then chilling the potato. The purpose of this study is to identify which body composition and dietary outcomes affect glucose and insulin response after female subjects consume a boiled hot Russet potato (∼6 g RS) compared to a baked then chilled Russet potato (∼12 g RS).
Methods
Subjects were randomized to consume 250 g of either a chilled or boiled potato with a one week wash-out between the two visits using crossover study design. Three days prior to each visit, dietary intake was obtained from food records. Mean three-day nutrient analysis prior to each visit was analyzed by Nutrition Data System for Research. Body composition (% lean mass (%LM) and fat mass (%FM)) was measured by air displacement plethysmograph at baseline. Fasting and postprandial blood following the intake of each potato were collected for area under the curve (AUC(0–120)) glucose and insulin determination. Spearman's rho examined the relationship among %FM, %LM, and each mean three-day dietary variables on AUC(0–120) glucose and insulin following each potato intervention.
Results
Healthy overweight (n = 25; mean BMI 31.8 ± 7.4 kg/m2) adult females (mean age 29.0 ± 5.9 years) completed the study. In both chilled and boiled potatoes, AUC(0–120) insulin was significantly positively related to %FM, but significantly inversely related to %LM. AUC(0–120) glucose was not related to body composition. Mean energy, macronutrients, added sugars, total sugars, soluble fiber, and glycemic index were significantly positively related to AUC(0–120) insulin in both chilled and boiled potato; energy and most macronutrients (except fat) were significantly positively related to AUC(0–120) glucose only after boiled potato.
Conclusions
A body composition higher in %FM and lower in %LM exhibits less insulin control following potato intake. Higher energy and nutrient intake patterns contribute to less favorable glucose concentrations following boiled potato consumption, but not after chilled potato consumption. The higher RS in the chilled potato may have contributed to glucose homeostasis.
Funding Sources
The Alliance for Potato Research and Education and the University's Small Grant Program.