A new study, published in The Journal of Nutrition, concluded that pasta consumption results in lower blood glucose and insulin responses, when compared with other durum semolina responses, making pasta a healthier carbohydrate source. As shown in this study, this is largely attributed to the pasta structure, which is slowly disintegrated during chewing and digestion.
Starch digestibility and blood glucose response to carbohydrate-rich foods can vary according to the structural properties of food. Therefore, products with similar ingredients, but different processing methods and structures, can induce very different post-meal responses. Slow starch digestibility has been suggested to result from the structural properties of pasta at macroscopic (low surface-to-weight ratio), microscopic (encapsulation of starch by proteins), and molecular (retrogradation of starch, complex formation) levels.
To explain the post-meal glycemic features of 2 pasta products, couscous, and bread by their structural changes during mastication and digestion, Saara Vanhatalo (VTT Technical Research Centre of Finland Ltd) and colleagues conducted two randomized controlled trials in healthy, normal-weight adults. Post-meal glucose metabolism was measured in response to durum wheat semolina spaghetti, penne, couscous, and bread each containing 50 g of available carbohydrate. To investigate mastication processes and changes in particle size distribution and microstructure after mastication and digestion, a trial involving 26 adults was also conducted.
Pasta consumption resulted in lower post-meal glucose and insulin responses, when compared with other durum semolina products, making pasta a healthy source of available carbohydrates. This characteristic was attributed to the pasta structure, which was slowly disintegrated during mastication and digestion. Differences in pasta shapes and sizes demonstrated a lower blood glucose response of the long pasta (spaghetti) compared with the short pasta (penne). There were no clear differences in the amount of saliva, particle size distribution or starch digestion rates of spaghetti and penne that could explain the difference seen in these responses. Preservation of the pasta structure during mastication and digestion explains the lower digestion rate, lower post-meal blood glucose rise, and hence, lower glycemic index of pasta compared with bread or couscous prepared with the same durum wheat semolina flour in healthy adults. This study highlights an important facet of carbohydrate foods, namely, the issue of digestibility as a driver of physiological effects.
A companion editorial by Korbua Srichaikul and David JA Jenkins (University of Toronto) provides further insights of the significance of these novel findings and how a better understanding of insulin and glucose dynamics in response to the rate of digestion of carbohydrate foods may be a potential link between carbohydrate nutrition and chronic disease.
References
Saara Vanhatalo, Margherita Dall’Asta, Marta Cossu, Laura Chiavaroli, Veronica Francinelli, Giuseppe Di Pede, Rossella Dodi, Johanna Närväinen, Monica Antonini, Matteo Goldoni, Ulla Holopainen-Mantila, Alessandra Dei Cas, Riccardo Bonadonna, Furio Brighenti, Kaisa Poutanen, Francesca Scazzina, Pasta Structure Affects Mastication, Bolus Properties, and Postprandial Glucose and Insulin Metabolism in Healthy Adults, The Journal of Nutrition, Volume 152, Issue 4, April 2022, Pages 994–1005, https://doi.org/10.1093/jn/nxab361.
Korbua Srichaikul, David J A Jenkins, The Glycemic Index, Rate of Digestion of Carbohydrate Foods, and Their Potential Link with Cardiovascular Disease, The Journal of Nutrition, Volume 152, Issue 4, April 2022, Pages 920–921, https://doi.org/10.1093/jn/nxab427.
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