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

Malnutrition of the fat-soluble nutrient vitamin K (phylloquinone; PQ) is problematic. Since PQ is rich in plant foods (e.g. spinach) that are mostly absent of accessible lipid, dietary patterns that can potentiate PQ 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 PQ) to validate eggs as a dietary tool to improve PQ 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 increase plasma bioavailability of spinach-derived deuterium-labeled PQ without affecting time to maximal concentrations or half-lives. Further, phospholipid-rich egg yolk lipid will enhance nutrient bioavailability compared with vegetable oil. The outcomes will serve as the foundation for easy-to-implement message of public health importance in support of whole eggs and egg whites as part of a plant-based dietary pattern.

Study Overview

• Status: Completed
• Conditions: Nutritional Requirements
• Intervention / Treatment: Other: Zero hard-boiled egg at 0 h; Other: One hard-boiled egg at 0 h; Other: Two hard-boiled eggs at 0 h; Other: Three hard-boiled eggs at 0 h; Other: One hard-boiled egg at 3 h; Other: One hard-boiled egg at 0 h + One hard-boiled egg at 3 h; Other: Two egg whites at 0 h; Other: Vegetable oil at 0 h

Detailed Description

In the US, 43-63% of men and women do not meet recommended intakes for PQ. Dietary recommendations strongly encourage a diet rich in fruits and vegetables to meet dietary PQ requirements. However, PQ 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 study is to demonstrate that an effective food pairing of spinach with phospholipid lipid-rich eggs promotes intestinal absorption of spinach-derived PQ, and hence achieve nutrient adequacy. Our hypothesis is that the bioavailability of PQ 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 PQ 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 PQ 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 500 μg PQ) 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 alone followed by 1 egg 3-hours later. In Study Arm 6, participants will ingest spinach with 1 egg followed by another egg 3-hours later. In Study Arm 7, participants will ingest spinach with two egg whites. In Study Arm 8, participants will ingest spinach with 9.6 grams of vegetable oil. Thus, Study Arms 1-4 will test the dose-dependent effects of eggs on PQ bioavailability, Study Arms 5-6 (with comparison to Study Arms 1 and 2) will test the 'timing'-dependent effects of eggs on PQ bioavailability, and Study Arms 7-8 will test the matrix effect on PQ bioavailability. Eucaloric diets will be controlled for PQ 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 PQ 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 establish that egg lipids substantially enhance plant-derived PQ bioavailability (based on AUC0-72 h, Cmax, and % estimated absorption) independent of any changes in oxidative distress.

The rationale for this study is that, by establishing the efficacy of eggs and egg yolk lipids 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 PQ.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Ohio
    • Columbus, Ohio, United States, 43210
      • Bruno Lab

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 61 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

8

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Zero hard-boiled egg; Deuterium-labeled spinach containing 500 μg PQ will be ingested alone prior to the 72-h pharmacokinetics trial.	Other: Zero hard-boiled egg at 0 h; No eggs will be consumed on test day along with spinach consumption
Experimental: One hard-boiled egg at 0 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested along with one hard-boiled egg prior to the 72-h pharmacokinetics trial.	Other: One hard-boiled egg at 0 h; One egg will be consumed on test day along with spinach consumption
Experimental: Two hard-boiled eggs at 0 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested with two whole eggs (9.6 g fat) prior to the 72-h pharmacokinetics trial.	Other: Two hard-boiled eggs at 0 h; Two eggs will be consumed on test day along with spinach consumption
Experimental: Three hard-boiled eggs at 0 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested along with three hard-boiled eggs prior to the 72-h pharmacokinetics trial.	Other: Three hard-boiled eggs at 0 h; Three eggs will be consumed on test day along with spinach consumption
Experimental: One hard-boiled egg at 3 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested alone at 0 h prior to the 72-h pharmacokinetics trial followed by one hard-boiled egg 3 hours after spinach consumption.	Other: One hard-boiled egg at 3 h; One egg will be consumed on test day three hours after spinach consumption
Experimental: One hard-boiled egg at 0 h + One hard-boiled egg at 3 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested along with one hard-boiled egg at 0 h prior to the 72-h pharmacokinetics trial followed by one egg 3 hours after spinach consumption.	Other: One hard-boiled egg at 0 h + One hard-boiled egg at 3 h; Two eggs will be consumed on test day: one along with spinach consumption and the other one three hours after spinach consumption
Experimental: Two egg whites at 0 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested along with two egg whites prior to the 72-h pharmacokinetics trial.	Other: Two egg whites at 0 h; Two egg whites will be consumed on test day along with spinach consumption
Experimental: Vegetable oil at 0 h; Deuterium-labeled spinach containing 500 μg PQ will be ingested along with 9.6 grams of vegetable oil prior to the 72-h pharmacokinetics trial.	Other: Vegetable oil at 0 h; 9.6 grams of Vegetable oil will be consumed on test day along with spinach consumption

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vitamin K Bioavailability	Area under the curve of deuterium-labeled phylloquinone	0, 3, 4.5, 6, 7.5, 9, 12, 24, 36, 48, 72 hours post-ingestion of spinach

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vitamin K Cmax	Maximum plasma concentration of deuterium-labeled phylloquinone	0-72 hours post-ingestion of spinach
Estimated Absorption (%Dose) of Vitamin K	Absorption of deuterium-labeled phylloquinone	0-72 hours post-ingestion of spinach
Vitamin K Tmax	Time to reach maximum plasma concentration of deuterium-labeled phylloquinone	0-72 hours post-ingestion of spinach
Chylomicron Vitamin K	Deuterium-labeled phylloquinone concentration in chylomicron	0, 3, 4.5, 6, 7.5, 9, 12 hours post-ingestion of spinach
Elimination Rate of Vitamin K	Rate of plasma elimination of deuterium-labeled phylloquinone	0-72 hours post-ingestion of spinach

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vitamin C	Baseline plasma vitamin C concentration	Prior to (0 hour) spinach consumption
Malondialdehyde	Baseline plasma malondialdehyde concentration	Prior to (0 hour) spinach consumption

Collaborators and Investigators

• Sponsor: Ohio State University
• Investigators: Principal Investigator: Richard Bruno, Ph.D., Ohio State University

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2021
• Primary Completion (Actual): July 15, 2024
• Study Completion (Actual): July 15, 2024

Study Registration Dates

• First Submitted: February 22, 2020
• First Submitted That Met QC Criteria: February 25, 2020
• First Posted (Actual): February 27, 2020

Study Record Updates

• Last Update Posted (Actual): June 3, 2025
• Last Update Submitted That Met QC Criteria: May 28, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: Egg; Spinach; Vitamin K
• Additional Relevant MeSH Terms: Molecular Mechanisms of Pharmacological Action; Protease Inhibitors; Enzyme Inhibitors; Anticoagulants; Serine Proteinase Inhibitors; Antithrombins; Antithrombin III
• Other Study ID Numbers: 2019H0504-B

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No