Casein Compared with Whey Proteins Affects the Organization of Dietary Fat during Digestion and Attenuates the Postprandial Triglyceride Response to a Mixed High-Fat Meal in Healthy, Overweight Men.
BACKGROUND
Postprandial lipemia is a risk factor for cardiovascular disease. The potential impacts of the type/nature of dietary protein on postprandial lipemia and associated dysregulations have been insufficiently investigated.


OBJECTIVE
We investigated the postprandial effect of including in a high-fat meal some milk protein fractions that markedly differ in their physicochemical properties and composition [either casein (CAS), whey protein (WHE), or α-lactalbumin-enriched whey protein (LAC)].


METHODS
The protein fractions were incorporated as 15% energy in a high-fat meal in a 3-period, crossover postprandial study of 10 healthy overweight men with an elevated waist circumference (>94 cm). We measured postprandial changes in plasma lipids, amino acids, glucose, and oxidative stress markers, vascular function (using pulse contour analysis), and low-grade inflammation (using plasma markers). We also characterized in vitro the meal structures, including the size of the fat globule, and possible changes during digestion.


RESULTS
The type of protein did not affect postprandial plasma glucose, amino acids, insulin, or nonesterified fatty acids, but, compared with WHE and LAC, which did not differ, CAS markedly reduced postprandial triglycerides (TGs), achieving a 22 ± 10% reduction in the 6-h area under the curve (P < 0.05). Similar trends were shown for plasma chylomicrons [apolipoprotein (apo)B-48; P < 0.05]. However, there were no significant differences between the meals regarding postprandial oxidative stress (plasma hydroperoxides and malondialdehyde), endothelial dysfunction (salbutamol-induced changes in pulse contour analysis), or low-grade inflammation. In vitro studies showed that when the pH of the meal decreased to stomach pH values, the reduction in the solubility of casein resulted in a phase separation between fat and protein, whereas the proteins in the other meals remained suspended with fat globules.


CONCLUSIONS
In healthy overweight men, casein has specific physical interactions with fat that affect postprandial TGs, leading to the formation of fewer chylomicrons or an increase in chylomicron clearance. This trial was registered at clinicaltrials.gov as NCT00931151.
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; francois.mariotti@agroparistech.fr.
François
F
Mariotti
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Marion
M
Valette
INRA, UMR1253 Science and Technology of Milk and Egg, Rennes, France; Agrocampus Ouest, UMR1253 Science and Technology of Milk and Egg, Rennes, France; and.
Christelle
C
Lopez
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Hélène
H
Fouillet
INRA, UMR1253 Science and Technology of Milk and Egg, Rennes, France; Agrocampus Ouest, UMR1253 Science and Technology of Milk and Egg, Rennes, France; and.
Marie-Hélène
MH
Famelart
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Véronique
V
Mathé
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Gheorghe
G
Airinei
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Robert
R
Benamouzig
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Claire
C
Gaudichon
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Daniel
D
Tomé
Centre of Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany.
Dimitrios
D
Tsikas
AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France; INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France;
Jean François
JF
Huneau
D000328:Adult; D053283:Apolipoprotein B-48 / Q000097:blood; D002364:Caseins / Q000008:administration & dosage* / Q000737:chemistry; D055598:Chemical Phenomena; D002914:Chylomicrons / Q000097:blood; D018592:Cross-Over Studies; D059305:Diet, High-Fat; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D004044:Dietary Proteins / Q000008:administration & dosage; D004063:Digestion; D002149:Energy Intake; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D062407:Meals; D050177:Overweight / Q000378:metabolism*; D019518:Postprandial Period; D012995:Solubility; D014280:Triglycerides / Q000097:blood*; D055105:Waist Circumference; D000067816:Whey Proteins / Q000008:administration & dosage* / Q000737:chemistry
D053283:Apolipoprotein B-48; D002364:Caseins; D002914:Chylomicrons; D004041:Dietary Fats; D004044:Dietary Proteins; D014280:Triglycerides; D000067816:Whey Proteins
dietary protein; high-fat meal; humans; meal structure; metabolic dysregulation; milk protein; postprandial period; triglycerides