Insights into digestion and absorption of major nutrients in humans

Abstract

Nutrient digestion and absorption is necessary for the survival of living organisms and has evolved into the complex and specific task of the gastrointestinal (GI) system. While most people simply assume that their GI tract will work properly to use nutrients, provide energy, and release wastes, few nonscientists know the details about how various nutrients are digested and how the breakdown products traverse the cells lining the small intestine to reach the blood stream and to be used by the other cells of the body. There have been several recent discoveries of new transporters that likely contribute to the absorption of oligopeptides and fatty acids. In addition, details are being clarified about how transporters work and in what forms nutrients can be absorbed. The enzymes that digest basic carbohydrates, proteins, and fats have been identified in various segments of the GI tract, and details are becoming clearer about what types of bonds they hydrolyze. Usually, detailed information about the digestion of basic nutrients is presented and learned in biochemistry courses and detailed information about absorption via transepithelial transport of the breakdown products of digestion is studied in physiology courses. The goal of this Staying Current article is to combine the details of the biochemistry of digestion with the updated information about the physiology of nutrient absorption into one source for teachers of physiology. Insights are included about some of the diseases and conditions that can bring about malabsorption of food in the GI tract and their consequences.

The draft genome of the grass carp (Ctenopharyngodon idellus) provides insights into its evolution and vegetarian adaptation

“…Comparably, the grass carp genes involved in the GCSD were not only associated with immune-related genes but also with development-related genes ( Fig. 3 and Supplementary Table 15) and were involved in cell proliferation and differentiation (for example, the focal adhesion pathway and the extracellular matrix (ECM)-receptor interaction pathway 30,31 ), nutritional homeostasis (for example, the protein digestion and absorption pathway 32,33 ) and organ size control (for example, the Hippo signaling pathway 34,35 ). Comparison of genes involved in the overview maps of metabolism (reference map ko01100 of the KEGG database) also indicated that grass carp genes involved in the GCSD clustered in carbohydrate metabolism and nucleotide metabolism (Supplementary Fig.…”

Besinsel Lipit Bileşenlerinin Emilimi

“…SCFA epitel hücrelere enerji sağlar, kemoterapi gibi stres durumlarda iltihaplanmayı azaltır, epitel hücre gelişmesini destekler, bağırsakların zarar görmesini engeller ve bağırsak geçirgenliğini arttırarak kalsiyum ve magnezyum emilimini iyileştirir (Ziegler ve Evans, 2003;Parodı, 2009;Jacobi ve Odle, 2012). (Hinsberger ve Sandhu, 2004;Jackson ve McLaughlin, 2009;Goodman, 2010;Boudry ve ark., 2010;Yeap ve ark., 2013).…”

“…Tüm bunlara ek olarak safra kesesinden günde 10-15 g fosfolipit ve 1-2 g endojen kolesterol salgılanmaktadır. Ayrıca sindirim kanalında dökülen ölü epitel hücreler ve ölü bakteri hücreleri kaynaklı endojen membran lipitler ve fosfolipitler de organizmaya günde 40-60 g lipit sağlamaktadır (Hinsberger ve Sandhu, 2004;Jackson ve McLaughlin, 2009;Yong ve ark., 2009;Boudry ve ark., 2010;Goodman, 2010;Jacobi ve Odle, 2012;Rein ve ark., 2012).…”

“…Butirat, propionat ve asetat gibi kısa zincirli yağ asitleri bol miktarlarda sütte bulunmasının yanında sindirilemeyen diyet lif, yağ ve polisakkaritlerin kolon flora bakterileri tarafından fermente edilmesi sonucunda da oluşmaktadır. Beslenmede yağlar, asesiyle ω-3' lerden (Omega-3 fatty acids, n-3 fatty acids) olan α-linolenik asit ALA (α-Linolenic acid) gibi çoklu doymamış PUFA (polyunsaturated fatty acids) ve tekli doymamış MUFA (monounsaturated fatty acids) yağ asitlerinin kaynağıdır (Ziegler ve Evans, 2003;Parodı, 2009;Boudry ve ark., 2010;Goodman, 2010).…”

Improving Nutrition Through the Design of Food Matrices

“…Many of them can form gels that will constitute their structure and also enhance viscosity of solutions owing to their high molecular weight (Aguilera & Stanley, 1999). Although carbohydrates are not essential in the diet, they generally make up ~40-45% of the total daily caloric intake of humans, with plant starches generally comprising 50-60% of the carbohydrate calories consumed (Goodman, 2010). Hence, starch becomes the most important source of energy in the human diet.…”