Effects of Daily Beef Intake, as a Component of a Heart-Healthy Diet on Cellular Zinc

NCT ID: NCT05236374

Last Updated: 2025-12-05

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-10-01
• Study Completion Date: 2026-12-31

Brief Summary

The objective of the current study is to test the overarching hypothesis that the beef nutritive matrix is uniquely suited to direct dietary zinc to cellular compartments for improved metabolic function, leading to a greater effect on health outcomes. Specifically, whether beef, as a component of a healthy meal, will promote the absorption of zinc into cells, where the zinc will have greater effects on zinc-dependent metabolic processes supporting cardiovascular health. To maximize the observability of these beef-related effects, individuals who are 55- to 70-year-old who generally have a higher risk of zinc deficiency and cardiovascular disease will be enrolled.

Detailed Description

This study will examine whether daily beef intake will promote the absorption of dietary zinc into cells, leading to improved cellular zinc status and microvascular function. The study design will be a crossover comparison of a mixed diet including green leafy vegetables, fruits, whole grains, seeds, and nuts; with beef versus non-meat sources of additional protein and zinc, over two 4-week metabolic study periods.

Outcomes will include cellular zinc status determined by erythrocyte zinc tracer exchange (primary), and microvascular function expressed as reactive hyperemia index (RHI). Previous studies have demonstrated that zinc tracer exchange with red blood cells (RBC) is highly sensitive to changes in zinc nutriture. Thus, cellular zinc status will be determined using a novel and cost-effective adaptation of this approach, modeling zinc tracer exchange with freshly-sampled RBC. As intracellular zinc can regulate vascular tone, microvascular function will be measured, using digital peripheral tonometry, will be used as a functional index of both cellular zinc status and vascular health.

Conditions

Zinc Deficiency; Inflammation; Metabolic Diseases; Vascular Diseases

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

Beef Protein

A beef stew, providing 8.8 mg zinc, 37.9 mg protein (approximately 500 kcal/d energy);

Group Type: EXPERIMENTAL

Beef protein

Intervention Type: OTHER

Animal protein source

Animal Protein

A control plant protein stew, providing 8.8 mg zinc, 37.9 mg protein (approximately 500 kcal/d energy);

Group Type: ACTIVE_COMPARATOR

Beef protein

Intervention Type: OTHER

Animal protein source

Interventions

Beef protein

Animal protein source

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Male or postmenopausal female 55-70 years of age
• Women: lack of menses for at least two years.
• Subject is willing and able to comply with the study protocols.
• Subject is willing to participate in all study procedures
• Self-reported stable dose of prescribed medications for a minimum of 6 months
• BMI 18.5 - 29.9 kg/m2

Exclusion Criteria

• Self-reported use of daily anticoagulation agents including aspirin, NSAIDs
• Prescribed metaformin, statins or medications known to interfere with zinc, protein, or lipid metabolism
• Vegan, Vegetarians, food faddists or those consuming a non-traditional diet (e.g. Adkins, Keto, Paleo, etc.)
• Fruit consumption ≥ 3 cups/day
• Regular consumption of strawberries (2-3 servings/week)
• Vegetable consumption ≥ 4 cups/day
• Coffee/tea ≥ 3 cups/day
• Dark chocolate ≥ 3 oz/day
• Alcohol intake greater than 2 drinks in a day for men, or 1 drink in a day for women.
• Self-reported restriction of physical activity due to a chronic health condition
• Self-reported chronic/routine high intensity exercise
• Self-reported diabetes
• Blood pressure ≥ 140/90 mm Hg
• Self-reported renal or liver disease
• Self-reported heart disease, which includes cardiovascular events and stroke
• Peripheral artery disease Raynaud's syndrome or disease
• Inability to properly place or wear the PAT probes or abnormal measurements on pre-screening PAT
• Self-reported cancer within past 5 years
• Self-reported malabsorption
• Unwillingness to stop any supplement use six weeks prior to study initiation, including multivitamin/mineral, powders, herbal, plant or botanical, pro- and prebiotics, and oil supplements.
• Smoking, vaping, cannabis use
• Current enrollee in a clinical research study.

• Minimum Eligible Age: 55 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Cattlemen's Beef Association, a contractor to the Beef Checkoff

INDUSTRY

Sponsor Role: collaborator

University of California, Davis

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Carl L Keen, PhD

Role: PRINCIPAL_INVESTIGATOR

Distinguished Professor Emeritus of Nutrition

Locations

University of California, Davis; Department of Nutrition

Davis, California, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Roberta R Holt, PhD

Role: CONTACT

rrholt@ucdavis.edu

15304005952

Andrew Hall, PhD

Role: CONTACT

aghall@ucdavis.edu

Facility Contacts

Roberta Holt, PhD

Role: primary

rrholt@ucdavis.edu

530-752-4950

Other Identifiers

1806393

Identifier Type: -

Identifier Source: org_study_id