Efeitos do consumo agudo de amido de milho cru no esvaziamento gástrico e trânsito intestinal de indivíduos saudáveis: estudo clínico randomizado e caracterização físico-química

Abstract

Corn starch is widely used in human nutrition and the food industry and is also used empirically in the treatment of diarrhea. However, there is a lack of studies investigating the effect of raw corn starch on the human gastrointestinal tract. The present study aimed to characterize the physicochemical properties of raw corn starch and evaluate the impact of acute consumption on gastric emptying and intestinal transit in healthy volunteers. The physicochemical characterization included the determination of centesimal composition, resistant starch content, viscosity, water solubility, and swelling power. A randomized, placebo-controlled, double-blind crossover clinical trial was then conducted. Healthy volunteers of both sexes, without diagnoses of diseases that alter gastrointestinal motility, were included. On two separate occasions, with a minimum washout period of seven days, after fasting for 8 hours, the volunteers ingested a standardized test meal consisting of: bread, an omelet made with the whites of two eggs and strawberry jam, and a glass of plain water or water containing 20 grams of raw corn starch. One millicurie of 99m-technetium-colloidal tin was incorporated into the omelet. To obtain the percentage of gastric emptying, the percentage of material passed through the small intestine, and colonic transit, scintigraphy with images of the abdomen was used immediately after ingestion of the test meal and every hour during the 6-hour period, in addition to a final image 24 hours after ingestion of the meal. Feelings of hunger, satiety, and desire to eat were assessed using numerical scales from 0 to 10 applied during fasting and at 30 minutes and 1, 2, 3, 4, 5, and 6 hours after ingestion of each test meal. Statistical analyses were performed using the Statistical Package for the Social Sciences and Graphpad Prism software, considering p ≤ 0.05 values to be significant. The analysis revealed that corn starch is composed mainly of carbohydrates (86.44%), with residual protein (1.19%) and lipids (0.16%), without the presence of dietary fiber. Resistant starch accounted for only 0.55% of total starch. The starch suspension exhibited dilating non-Newtonian rheological behavior and low flow resistance. Solubility and swelling power were limited, especially at physiological temperature. For the clinical trial, 18 healthy volunteers with a median age of 24.5 (18-53) years were included. The intake of raw corn starch did not influence the percentage of gastric emptying and colonic transit when compared to the control (p > 0.05). For the percentage of material transited through the small intestine in 4 hours, lower values were observed for the meal containing raw corn starch [64.63% (14.55-79.84)] compared to the control [68.50% (48.19-91.81)] (p ≤ 0.05). No significant differences were observed between the groups in terms of feelings of hunger, satiety, and desire to eat (p > 0.05). It was concluded that raw corn starch slowed intestinal transit, reducing the percentage of material passing through the small intestine.