Acute human consumption of crystalline short‐chain amylose

Abstract

The glycemic index (GI) is used to rank foods based on postprandial blood glucose response. Physiologically, starch escaping small intestinal digestion is termed resistant starch (RS). Available carbohydrate for the GI test is often calculated as total carbohydrate minus dietary fiber; yet, AOAC fiber methods do not always include RS. The objective of this study was to examine the effects of a starch product with high RS content but no total dietary fiber (TDF) content on glycemic response, GI, and fermentation. Using standard GI methods, 50 g available carbohydrate was compared in 10 adults to waxy maize starch (TDF: 0%; RS: 1.6%) and crystalline short‐chain amylose (CSCA) (TDF 0%; 75% RS); alone and in mixed formulation. All volunteers had low postprandial glucose curves after CSCA consumption. The rise in mmol/L glucose for CSCA in mixed formulation was similar to the rise observed with glucose, yet the mixed formulation had reduced (P < 0.05) extension, and 100% of subjects returned to basal blood glucose levels at 2 h. CSCA was considered available carbohydrate in the GI test, but was not fully available in vivo. Breath hydrogen testing showed CSCA did not elevate H2 production more than other trial samples and all 0% TDF samples were as likely to ferment. This study shows that RS content affects glycemic response and GI values and addresses functions of RS in the colon with noninvasive measures for carbohydrate metabolism.