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PLoS One. 2014 Feb 10;9(2):e88904. doi: 10.1371/journal.pone.0088904. eCollection 2014.

Protein quality and the protein to carbohydrate ratio within a high fat diet influences energy balance and the gut microbiota in C57BL/6J mice.

Author information

1
Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland ; Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland.
2
Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland ; Department of Microbiology, University College Cork, Cork, Ireland.
3
Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland ; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
4
Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland.
5
Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland ; Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland.
6
Department of Microbiology, University College Cork, Cork, Ireland.
7
UCD Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin, Ireland.

Abstract

Macronutrient quality and composition are important determinants of energy balance and the gut microbiota. Here, we investigated how changes to protein quality (casein versus whey protein isolate; WPI) and the protein to carbohydrate (P/C) ratio within a high fat diet (HFD) impacts on these parameters. Mice were fed a low fat diet (10% kJ) or a high fat diet (HFD; 45% kJ) for 21 weeks with either casein (20% kJ, HFD) or WPI at 20%, 30% or 40% kJ. In comparison to casein, WPI at a similar energy content normalised energy intake, increased lean mass and caused a trend towards a reduction in fat mass (P = 0.08), but the protein challenge did not alter oxygen consumption or locomotor activity. WPI reduced HFD-induced plasma leptin and liver triacylglycerol, and partially attenuated the reduction in adipose FASN mRNA in HFD-fed mice. High throughput sequence-based analysis of faecal microbial populations revealed microbiota in the HFD-20% WPI group clustering closely with HFD controls, although WPI specifically increased Lactobacillaceae/Lactobacillus and decreased Clostridiaceae/Clostridium in HFD-fed mice. There was no effect of increasing the P/C ratio on energy intake, but the highest ratio reduced HFD-induced weight gain, fat mass and plasma triacylglycerol, non-esterified fatty acids, glucose and leptin levels, while it increased lean mass and oxygen consumption. Similar effects were observed on adipose mRNA expression, where the highest ratio reduced HFD-associated expression of UCP-2, TNFα and CD68 and increased the diet-associated expression of β3-AR, LPL, IR, IRS-1 and GLUT4. The P/C ratio also impacted on gut microbiota, with populations in the 30/40% WPI groups clustering together and away from the 20% WPI group. Taken together, our data show that increasing the P/C ratio has a dramatic effect on energy balance and the composition of gut microbiota, which is distinct from that caused by changes to protein quality.

PMID:
24520424
PMCID:
PMC3919831
DOI:
10.1371/journal.pone.0088904
[Indexed for MEDLINE]
Free PMC Article

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