Document Detail


Low-carbohydrate diet does not affect intramyocellular lipid concentration or insulin sensitivity in lean, physically fit men when protein intake is elevated.
MedLine Citation:
PMID:  20423743     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
It has been speculated that dietary carbohydrate restriction is solely responsibly for mobilization of endogenous lipid stores, elevation of plasma free fatty acid (FFA) concentration, and an associated reduction in insulin sensitivity seen in starvation and low-carbohydrate diets. In 6 healthy men, dietary carbohydrate was eliminated but gluconeogenic substrate supply was maintained by 3 days of very low-carbohydrate/high-protein (HPLC) diet. Results were compared with 3-day starvation and 3-day mixed-carbohydrate diet. Intramyocellular lipid (IMCL) concentration was measured by ¹H magnetic resonance spectroscopy, and insulin sensitivity was determined by intravenous glucose tolerance test. Fasting plasma glucose was significantly reduced ([starvation] 3.5 ± 0.3 vs [HPLC] 4.2 ± 0.4 and [mixed] 4.5 ± 0.3 mmol L⁻¹, P < .01), and IMCL to water ratio (25.6 ± 5.9 vs 13.6 ± 6.1 and 13.6 ± 3.3 × 10⁻³, P < .01) and fasting FFA (1179 ± 294 vs 387 ± 232 and 378 ± 120 μmol L⁻¹, P < .05) were significantly elevated after starvation but were unchanged after HPLC. Minimal model insulin sensitivity was reduced after starvation (5.7 ± 1.5 vs 14.5 ± 4.8 and 16.5 ± 6.8 L min⁻¹ mU⁻¹, P < .05). Plasma glucose, plasma FFAs, IMCLs, and insulin sensitivity are maintained when an HPLC diet is consumed, despite other forms of carbohydrate deprivation producing marked changes in these measures. We conclude that dietary carbohydrate restriction does not cause circulating FFA to become elevated. However, it remains possible that circulating carbohydrate status has an important influence on plasma FFA and therefore insulin sensitivity in healthy people.
Authors:
Jackson G Green; Nathan A Johnson; Toos Sachinwalla; Christopher W Cunningham; Martin W Thompson; Stephen R Stannard
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2010-04-27
Journal Detail:
Title:  Metabolism: clinical and experimental     Volume:  59     ISSN:  1532-8600     ISO Abbreviation:  Metab. Clin. Exp.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-26     Completed Date:  2010-12-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0375267     Medline TA:  Metabolism     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1633-41     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Inc. All rights reserved.
Affiliation:
Research Centre for Maori Health and Development, Massey University, 4442, New Zealand. j.green@massey.ac.nz
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MeSH Terms
Descriptor/Qualifier:
Adult
Blood Glucose
Diet, Carbohydrate-Restricted*
Dietary Proteins / administration & dosage*
Energy Intake
Fatty Acids, Nonesterified / blood
Humans
Insulin Resistance*
Lipids / analysis*
Male
Middle Aged
Muscle Cells / chemistry*
Physical Fitness*
Starvation
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Dietary Proteins; 0/Fatty Acids, Nonesterified; 0/Lipids

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


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