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

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 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 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 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 (15 mg) with 1 cup of either 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 will be collected at timed intervals over 72 h, and plasma will be analyzed by liquid chromatography with mass spectrometry to determine pharmacokinetic parameters 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, it is expected to show that a-T bioavailability increases in a milk fat-dependent manner and that dairy milk compared with soy milk significantly improves a-T bioavailability. The results are expected to 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.

Inclusion criteria

• specific criteria of the metabolic syndrome: large waist circumference (>102 or >89 cm for men and women, respectively), high fasting triglycerides (150-300 mg/dL), low fasting HDL (<40 and <50 mg/dL for men and women, respectively), high blood pressure (>130/85 mm Hg) and high fasting glucose (110-180 mg/dL)
• BMI: >30 kg/m2,
• non-dietary supplement users for >2-mo
• no use of medications known to affect lipid metabolism
• no history of gastrointestinal disorders
• resting blood pressure <140 mm Hg
• not taking any medications that control hypertension

Exclusion criteria

• lactose-intolerance
• excessive alcohol consumption (>3 drinks/d)
• >5 h/wk of aerobic activity
• women who are pregnant, lactating, or have initiated or changed birth control in the past 3-mo
• plasma alpha-tocopherol >20 μmol/L.