Bruce R. Hamaker
Slow digestion property of African traditional millet and sorghum foods
Bruce R. Hamaker, Fatimata Cisse, Mohamed Diarra, Anna M.R. Hayes. Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN USA
Beyond anecdotal evidence of slow digestion of various millet and sorghum foods in Africa, as well as Asia, recent studies in our group and others are providing some validation and mechanistic basis for this property. Slow digestion refers principally to the carbohydrates of these grains to result in moderated glycemic response profiles and an extended energy and fullness quality to millet and sorghum foods. A human study conducted in Bamako, Mali showed West African millet and sorghum viscous thick porridges and non-viscous millet couscous to have approximately twice the gastric half-emptying time (4-5 hours) as introduced non-traditional white rice, boiled white potato, and wheat pasta (macaroni, well-cooked). A validation study conducted one-year later replicated these findings. Another study in Mali showed that consumers make less thick porridges when they move to the city, and that these are less satiating. A gastric simulator showed that millet couscous breaks down much more to small particles due to shearing action than comparable size wheat couscous. These small particles could form a paste-like substance in the stomach that may slow emptying, but they also showed slower digestion property compared to wheat couscous. We reported recently that ileal digesting starch triggers the ileal break mechanism in the body that, through a physiological pathway, also slows gastric emptying. Overall, at least some traditional African millet and sorghum foods appear to have an inherently slower digestion property than many starchy foods eaten in urban areas, and are proposed to provide a potentially important health-related effect in the body of slow digestion, fullness, and extended macronutrient delivery to the body after a meal.