Dairy proteins, dairy lipids, and postprandial lipemia in persons with abdominal obesity (DairyHealth): a 12-wk, randomized, parallel-controlled, double-blinded, diet intervention study2

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ABSTRACT

Background: Abdominal obesity and exaggerated postprandial lipemia are independent risk factors for cardiovascular disease (CVD) and mortality, and both are affected by dietary behavior.

Objective: We investigated whether dietary supplementation with whey protein and medium-chain saturated fatty acids (MC-SFAs) improved postprandial lipid metabolism in humans with abdominal obesity.

Design: We conducted a 12-wk, randomized, double-blinded, diet intervention study. Sixty-three adults were randomly allocated to one of 4 diets in a 2 × 2 factorial design. Participants consumed 60 g milk protein (whey or casein) and 63 g milk fat (with high or low MC-SFA content) daily. Before and after the intervention, a high-fat meal test was performed. We measured changes from baseline in fasting and postprandial triacylglycerol, apolipoprotein B-48 (apoB-48; reflecting chylomicrons of intestinal origin), free fatty acids (FFAs), insulin, glucose, glucagon, glucagon-like peptide 1 (GLP-1), and gastric inhibitory polypeptide (GIP). Furthermore, changes in the expression of adipose tissue genes involved in lipid metabolism were investigated. Two-factor ANOVA was used to examine the difference between protein types and fatty acid compositions, as well as any interaction between the two.

Results: Fifty-two participants completed the study. We found that the postprandial apoB-48 response decreased significantly after whey compared with casein (P = 0.025) independently of fatty acid composition. Furthermore, supplementation with casein resulted in a significant increase in the postprandial GLP-1 response compared with whey (P = 0.003). We found no difference in postprandial triacylglycerol, FFA, insulin, glucose, glucagon, or GIP related to protein type or MC-SFA content. We observed no interaction between milk protein and milk fat on postprandial lipemia.

Conclusion: We found that a whey protein supplement decreased the postprandial chylomicron response compared with casein in persons with abdominal obesity, thereby indicating a beneficial impact on CVD risk. This trial was registered at clinicaltrials.gov as NCT01472666.

Keywords:

dairy
milk protein
whey
casein
milk fat
medium-chain saturated fatty acid
abdominal obesity
postprandial lipemia
apoB-48
incretin
adipose tissue gene expression

ABBREVIATIONS

apoB-48
apolipoprotein B-48
CD36
cluster of differentiation 36 (fatty acid translocase)
CH
casein + high medium-chain SFA
CL
casein + low medium-chain SFA
CVD
cardiovascular disease
E%
energy percentage
FABP4
fatty acid binding protein 4
FAS
fatty acid synthase
FDR
false discovery rate
FFA
free fatty acid
GIP
gastric inhibitory polypeptide
GLP-1
glucagon-like peptide 1
GPR120
G protein–coupled receptor 120
LC-SFA
long-chain SFA
LPL
lipoprotein lipase
MC-SFA
medium-chain SFA
T2D
type 2 diabetes
WH
whey + high medium-chain SFA
WL
whey + low medium-chain SFA

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2

Supported by the Danish Council for Strategic Research (DSF 0603-004193), Arla Foods Ingredients Group P/S, and the Danish Dairy Research Foundation. Protein powder was kindly provided by Arla Foods Ingredients Group P/S. Analytical assistance was received from the Novo Nordisk Foundation Centre for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen and Unilabs A/S, Copenhagen, Denmark.