Achieving Nutritional Adequacy Of Vitamin E With An Egg/Plant-Based Food Pairing

In the US, 92-96% of men and women do not meet recommended intakes for αT. Dietary recommendations strongly encourage a diet rich in fruits and vegetables to meet dietary αT requirements. However, αT bioavailability from most plant foods is quite poor, thereby emphasizing a need for effective food pairings that can enhance the absorption and promote adequate status of these health-promoting nutrients. The objective of this application is to use deuterium-labeled spinach (containing stable isotopes of αT) to validate eggs as a dietary tool to improve αT bioavailability directly from a model plant food, and hence achieve nutrient adequacy. Our hypothesis is that the bioavailability of αT from deuterium-labeled spinach will be potentiated by egg intake in a dose-dependent manner by increasing their secretion in intestinal-derived chylomicrons. Furthermore, phospholipid-rich whole eggs will enhance spinach-derived αT bioavailability compared with vegetable oil, and will be most functionally responsible for the benefits of eggs to enhance nutrient absorption. Additionally, egg whites will more greatly promote nutrient bioaccessibility compared with spinach alone.

To test this, our specific aim is to assess egg-mediated improvements in αT bioavailability by conducting a cross-over pharmacokinetic study in healthy men and women. In Study Arms 1-4, participants will ingest deuterium-labeled spinach (containing 5 mg αT) with 0, 1, 2, or 3 hardboiled eggs (containing 0, 4.8, 9.6, or 14.4 g total fat, respectively). In Study Arm 5, participants will ingest spinach with two egg whites. In Study Arm 6, participants will ingest spinach with 9.6 grams of vegetable oil. In Study Arm 5, participants will ingest spinach alone followed by 1 egg 3-hours later. In Study Arm 7, participants will ingest spinach with 1 egg followed by another egg 3-hours later. In Study Arm 8, participants will ingest spinach with 1 egg followed by another egg 3-hours later. Thus, Study Arms 1-6 will test the dose-dependent and food matrix effects of eggs on αT bioavailability, and study Arms 7-8 will test the meal timing effects of eggs on αT bioavailability. Eucaloric diets will be controlled for αT intakes for 3 d prior to and during the initial 24 h of each trial to minimize heterogeneity of pharmacokinetic responses. Spinach-derived deuterium-labeled αT will be measured in plasma and isolated chylomicrons collected at timed intervals from 0-72 h post-meal ingestion, and biomarkers of antioxidant status and oxidative distress will be assessed at baseline (0 h) of each trial. Outcomes from this study are expected to demonstrate a dose- and time-dependent function of eggs to increase deuterium-labeled αT bioavailability (based on area under the curve (AUC) 0-72 h, Cmax, and % estimated absorption).

The rationale for this study is that, by establishing the efficacy of eggs to potentiate plant-derived fat-soluble nutrient bioavailability, a strong framework will exist for an easily implementable health-promoting food pairing strategy to overcome malnutrition of αT.

Inclusion criteria

• Body Mass Index (BMI) = 19-25 kg/m2
• Normolipidemic (total cholesterol <240 mg/dL; triglyceride <150 mg/dL)
• Fasting glucose <100 mg/dL
• Normal hematocrit level (41%-50% for men and 36%-48% for women)
• Normal hemoglobin level (13.5-17.5 g/dL for men and 12.0-15.5 g/dL for women)
• No use of dietary supplements for >1 month
• No use of medications that affect lipid or glucose metabolism
• Non-smoker
• No history of gastrointestinal disorders

Exclusion criteria

• Egg allergy
• Alcohol intake > 2 drinks per day
• Aerobic activity >7 h/wk
• Body mass change >2 kg in the past 1 month
• Women who are pregnant, lactating, or initiated or changed birth control in the past 3 month
• Vegetarian