In:
British Journal of Nutrition, Cambridge University Press (CUP), Vol. 113, No. 2 ( 2015-01-28), p. 372-379
Abstract:
The present study examined the underlying mechanisms by which whey protein isolate (WPI) affects energy balance. C57BL/6J mice were fed a diet containing 10 % energy from fat, 70 % energy from carbohydrate (35 % energy from sucrose) and 20 % energy from casein or WPI for 15 weeks. Mice fed with WPI had reduced weight gain, cumulative energy intake and dark-phase V O2 compared with casein-fed mice ( P 〈 0·05); however, WPI intake had no significant effects on body composition, meal size/number, water intake or RER. Plasma levels of insulin, TAG, leptin, glucose and glucagon-like peptide 1 remained unchanged. Notably, the intake of WPI reduced stomach weight and both length and weight of the small intestine ( P 〈 0·05). WPI intake reduced the gastric expression of Wingless/int-1 5a ( Wnt5a ) ( P 〈 0·01) and frizzled 4 ( Fzd4 ) ( P 〈 0·01), with no change in the expression of receptor tyrosine kinase-like orphan receptor 2 ( Ror2 ) and LDL receptor-related protein 5 ( Lrp5 ). In the ileum, WPI increased the mRNA expression of Wnt5a ( P 〈 0·01) and caused a trend towards an increase in the expression of Fzd4 ( P = 0·094), with no change in the expression of Ror2 and Lrp5 . These genes were unresponsive in the duodenum. Among the nutrient-responsive genes, WPI specifically reduced ileal mRNA expression of peptide YY ( P 〈 0·01) and fatty acid transporter protein 4 ( P 〈 0·05), and decreased duodenal mRNA expression of the insulin receptor ( P = 0·05), with a trend towards a decreased expression of Na–glucose co-transporter 1 ( P = 0·07). The effects of WPI on gastrointestinal Wnt signalling may explain how this protein affects gastrointestinal structure and function and, in turn, energy intake and balance.
Type of Medium:
Online Resource
ISSN:
0007-1145
,
1475-2662
DOI:
10.1017/S0007114514004024
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2015
detail.hit.zdb_id:
2016047-1
SSG:
12
SSG:
21
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