Malnutrition of the fat-soluble nutrient vitamin E (α-tocopherol; αT) is problematic. Since αT is rich in plant foods (e.g. spinach) that are mostly absent of accessible lipid, dietary patterns that can potentiate αT bioavailability by pairing vegetables with lipid-rich foods have been emphasized. The purpose of this study 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. It is expected that compared with deuterium-labeled spinach alone, co-ingestion of eggs will dose- and time-dependently increase plasma bioavailability of spinach-derived deuterium-labeled αT without affecting time to maximal concentrations or half-lives. Further, phospholipid-rich egg yolk lipid will enhance nutrient bioavailability compared with vegetable oil. The outcome will therefore support an egg-based food pairing that can enhance the health benefits of plant-centric dietary patterns.
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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
8
No eggs will be consumed on test day along with spinach consumption
One egg will be consumed on test day along with spinach consumption
Two eggs will be consumed on test day along with spinach consumption
Three eggs will be consumed on test day along with spinach consumption
One egg will be consumed on test day three hours after spinach consumption
Two eggs will be consumed on test day: one along with spinach consumption and the other one three hours after spinach consumption
Two egg whites will be consumed on test day along with spinach consumption
9.6 grams of Vegetable oil will be consumed on test day along with spinach consumption
Ohio State University
Columbus, Ohio, United States
Vitamin E Area Under the Curve (0-72 h)
Area under the concentration-time curve of plasma deuterium-labeled alpha-tocopherol over 72 hours post ingestion.
Time frame: 0, 3, 4.5, 6, 7.5, 9, 12, 24, 36, 48, 72 hours post-ingestion of spinach
Vitamin E Cmax
Maximum plasma concentration of deuterium-labeled alpha-tocopherol
Time frame: 0-72 hours post-ingestion of spinach
Vitamin E Tmax (hr)
Time to reach maximum plasma concentration of deuterium-labeled alpha-tocopherol
Time frame: 0-72 hours post-ingestion of spinach
Half-Life (hr)
The time required for the plasma concentration of vitamin E to decrease by 50%.
Time frame: 0-72 hours post-ingestion of spinach
Estimated Absorption (%Dose) of Vitamin E
Absorption of deuterium-labeled alpha-tocopherol
Time frame: 0-72 hours post-ingestion of spinach
Chylomicron Vitamin E
Deuterium-labeled alpha-tocopherol concentration in chylomicron
Time frame: 0, 3, 4.5, 6, 7.5, 9, 12 hours post-ingestion of spinach
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