Dairy Fat as a Mediator of Vitamin E Adequacy in Individuals With Metabolic Syndrome

• Plasma deuterium labeled and unlabeled alpha-tocopherol [ Time Frame: 0, 3, 6, 9, 12, 24, 36, 48, and 72 h post test meal ] [ Designated as safety issue: No ]
  Plasma alpha-tocopherol concentrations will be assessed from blood samples that will be collected prior to (0 h) and at 3, 6, 9, 12, 24, 36, 48, and 72 h following each test meal.
  
  

• Plasma alpha-CEHC [ Time Frame: 0, 3, 6, 9, 12, 24, 36, 48, and 72 h post test meal ] [ Designated as safety issue: No ]
  Alpha-CEHC concentrations will be assessed from blood samples that will be collected prior to (0 h) and at 3, 6, 9, 12, 24, 36, 48, and 72 h following each test meal.
  
  
• Urinary alpha-CEHC [ Time Frame: 0, 8, 16, 24 h post test meal ] [ Designated as safety issue: No ]
  Alpha-CEHC concentrations will be assessed from urine samples collected prior to (0 h) and 8, 16, and 24 h following each test meal.
  
  

Nonalcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome and affects >70 million Americans. Weight loss and vitamin E supplementation are leading strategies for preventing and/or treating NASH. However, the long-term success of weight loss is limited and >92% of Americans fail to meet dietary recommendations for vitamin E. Thus, the investigators' objective is to define the extent to which dairy fat facilitates adequate vitamin E status in individuals with metabolic syndrome, a population at high-risk for NASH, by improving α-tocopherol bioavailability. The investigators' central hypothesis is that full-fat dairy will substantially increase alpha-tocopherol (a-T) bioavailability to the extent needed to facilitate production of alpha-carboxyethyl-hydroxy-chromanol (a-CEHC), a metabolite of a-T that predict a-T status. The investigators will therefore complete the following specific aims: 1) define milk fat-mediated improvements in a-T bioavailability, and 2) define dairy fat-mediated improvements in a-T status. This study involves a randomized crossover study design where healthy adults and those with metabolic syndrome (n = 10/group) will ingest deuterium-labeled a-T with fat-free milk, low-fat milk, whole milk, or soy milk. Urine and blood samples will be collected at timed intervals prior to and following milk consumption. Blood collection will be performed using single needle sticks or cannula (for frequent blood collections) by skilled personnel. Plasma samples will be analyzed by liquid chromatography with mass spectrometry to determine pharmacokinetic parameters and vitamin E adequacy by measuring labeled and unlabeled a-T and a-CEHC. Risk to participants is expected to be minimal and will be outlined in the informed consent form in clear and simple terms. Upon successful completion of this study, the investigators expect to demonstrate that whole milk, compared to low-fat and fat-free milk, increases a-T bioavailability in a milk fat-dependent manner and that low-fat milk compared to soy milk (both beverages contain identical amounts of total fat, but differ in fatty acid profile), significantly improves a-T bioavailability. The investigators' results will provide timely evidence demonstrating the amount and type of fat needed to achieve optimal vitamin E status specifically in a population of significant public health concern. Overall, these studies will fill a substantial knowledge gap regarding the importance of dairy fat in contributing to optimal health and provide a simple dietary approach to ameliorate poor vitamin E status among a significant proportion of Americans.