kiny
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Amount and fate of egg protein escaping assimilation in the small intestine of humans
1999
P Evenepoel, D Claus, B Geypens, M Hiele, K Geboes, P Rutgeerts, Y Ghoos
University Leuven, Belgium
The availability of stable isotope-labeled protein allowed us to determine the amount and fate of dietary protein escaping digestion and absorption in the small intestine of healthy volunteers using noninvasive tracer techniques. Ten healthy volunteers were studied once after ingestion of a cooked test meal, consisting of 25 g of (13)C-, (15)N-, and (2)H-labeled egg protein, and once after ingestion of the same but raw meal. Amounts of 5.73% and 35.10% (P < 0.005) of cooked and raw test meal, respectively, escaped digestion and absorption in the small intestine. A significantly higher percentage of the malabsorbed raw egg protein was recovered in urine as fermentation metabolites. These results 1) confirm that substantial amounts of even easily digestible proteins may escape assimilation in healthy volunteers and 2) further support the hypothesis that the metabolic fate of protein in the colon is affected by the amount of protein made available.
Amino acid absorption in the small intestine is generally considered highly efficient, likely because most studies measure this in athletes and use whey for example to study absorption.
But as Rutgeerts his old study points out, eating raw egg protein for example, is a lot less efficient. As much as 35.10% of the protein escapes digestion by the host in the small intestine, which would make a lot of dietary protein available to be metabolized by microbes in the ileum and colon. However, only 5.73% escapes host digestion if the egg was cooked.
The small intestine is critically dependent on protein for healing and repair of the intestinal lining, so making sure the protein one consumes is available to the host instead of the bacteria, and avoiding protein malabsorption, is important.
1999
P Evenepoel, D Claus, B Geypens, M Hiele, K Geboes, P Rutgeerts, Y Ghoos
University Leuven, Belgium
The availability of stable isotope-labeled protein allowed us to determine the amount and fate of dietary protein escaping digestion and absorption in the small intestine of healthy volunteers using noninvasive tracer techniques. Ten healthy volunteers were studied once after ingestion of a cooked test meal, consisting of 25 g of (13)C-, (15)N-, and (2)H-labeled egg protein, and once after ingestion of the same but raw meal. Amounts of 5.73% and 35.10% (P < 0.005) of cooked and raw test meal, respectively, escaped digestion and absorption in the small intestine. A significantly higher percentage of the malabsorbed raw egg protein was recovered in urine as fermentation metabolites. These results 1) confirm that substantial amounts of even easily digestible proteins may escape assimilation in healthy volunteers and 2) further support the hypothesis that the metabolic fate of protein in the colon is affected by the amount of protein made available.
Amino acid absorption in the small intestine is generally considered highly efficient, likely because most studies measure this in athletes and use whey for example to study absorption.
But as Rutgeerts his old study points out, eating raw egg protein for example, is a lot less efficient. As much as 35.10% of the protein escapes digestion by the host in the small intestine, which would make a lot of dietary protein available to be metabolized by microbes in the ileum and colon. However, only 5.73% escapes host digestion if the egg was cooked.
The small intestine is critically dependent on protein for healing and repair of the intestinal lining, so making sure the protein one consumes is available to the host instead of the bacteria, and avoiding protein malabsorption, is important.
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