Document Detail


High-protein, reduced-carbohydrate weight-loss diets promote metabolite profiles likely to be detrimental to colonic health.
MedLine Citation:
PMID:  21389180     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Diets that are high in protein but reduced in carbohydrate contents provide a common approach for achieving weight loss in obese humans. However, the effect of such diets on microbiota-derived metabolites that influence colonic health has not been established.
OBJECTIVE: We designed this study to assess the effect of diets with reduced carbohydrate and increased protein contents on metabolites considered to influence long-term colonic health, in particular the risk of colorectal disease.
DESIGN: We provided 17 obese men with a defined weight-maintenance diet (85 g protein, 116 g fat, and 360 g carbohydrate/d) for 7 d followed by 4 wk each of a high-protein and moderate-carbohydrate (HPMC; 139 g protein, 82 g fat, and 181 g carbohydrate/d) diet and a high-protein and low-carbohydrate (HPLC; 137 g protein, 143 g fat, and 22 g carbohydrate/d) diet in a crossover design. Fecal samples were analyzed to determine concentrations of phenolic metabolites, short-chain fatty acids, and nitrogenous compounds of dietary and microbial origin.
RESULTS: Compared with the maintenance diet, the HPMC and HPLC diets resulted in increased proportions of branched-chain fatty acids and concentrations of phenylacetic acid and N-nitroso compounds. The HPLC diet also decreased the proportion of butyrate in fecal short-chain fatty acid concentrations, which was concomitant with a reduction in the Roseburia/Eubacterium rectale group of bacteria, and greatly reduced concentrations of fiber-derived, antioxidant phenolic acids such as ferulate and its derivatives.
CONCLUSIONS: After 4 wk, weight-loss diets that were high in protein but reduced in total carbohydrates and fiber resulted in a significant decrease in fecal cancer-protective metabolites and increased concentrations of hazardous metabolites. Long-term adherence to such diets may increase risk of colonic disease.
Authors:
Wendy R Russell; Silvia W Gratz; Sylvia H Duncan; Grietje Holtrop; Jennifer Ince; Lorraine Scobbie; Garry Duncan; Alexandra M Johnstone; Gerald E Lobley; R John Wallace; Garry G Duthie; Harry J Flint
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2011-03-09
Journal Detail:
Title:  The American journal of clinical nutrition     Volume:  93     ISSN:  1938-3207     ISO Abbreviation:  Am. J. Clin. Nutr.     Publication Date:  2011 May 
Date Detail:
Created Date:  2011-04-21     Completed Date:  2011-07-15     Revised Date:  2011-12-15    
Medline Journal Info:
Nlm Unique ID:  0376027     Medline TA:  Am J Clin Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1062-72     Citation Subset:  AIM; IM    
Affiliation:
Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Antioxidants / analysis
Carcinogens / analysis
Colonic Diseases / epidemiology
Cross-Over Studies
Diet, Carbohydrate-Restricted / adverse effects*
Diet, Reducing / adverse effects*
Dietary Fiber / administration & dosage,  metabolism
Dietary Proteins / adverse effects*,  metabolism
Eubacterium / growth & development,  isolation & purification
Fatty Acids, Volatile / analysis,  chemistry
Feces / chemistry,  microbiology
Humans
Male
Middle Aged
Nitroso Compounds / analysis
Obesity / complications,  diet therapy*
Phenols / analysis
Phenylacetates / analysis,  chemistry
Risk
Young Adult
Chemical
Reg. No./Substance:
0/Antioxidants; 0/Carcinogens; 0/Dietary Proteins; 0/Fatty Acids, Volatile; 0/Nitroso Compounds; 0/Phenols; 0/Phenylacetates; 103-82-2/phenylacetic acid
Comments/Corrections
Comment In:
Z Gastroenterol. 2011 Nov;49(11):1487-8   [PMID:  22069049 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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