Zinc DeficiencyNCT05236374
Effects of Daily Beef Intake, as a Component of a Heart-Healthy Diet on Cellular Zinc
A study testing Beef protein in people with Zinc Deficiency and Inflammation, run by University of California, Davis at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 55 to 70 yearsHealthy volunteers can take part
- Conditions the study is for
- Zinc Deficiency, Inflammation, Metabolic Diseases
- What is being tested?
- Beef protein
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Oct 2022to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 55 to 70 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Show all 22Show fewer
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Andrew Hall, PhD contact
United States1 site, 1 recruiting
- Recruiting
University of California, Davis; Department of Nutrition
Davis, California, 95616
Roberta Holt, PhD, 530-752-4950, rrholt@ucdavis.edu
About this study
Official title: Effects of Daily Beef Intake, as a Component of a Heart-Healthy Diet, on Cellular Zinc Status and Vascular Function in Older Adults
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.
Read the 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
- Being tested
- Beef protein
- Medical subject headings
- Inflammation, Metabolic Diseases, Vascular Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Beef proteinOther
Animal protein source
| Study group | Role | What they receive |
|---|---|---|
| Beef Protein | Experimental | A beef stew, providing 8.8 mg zinc, 37.9 mg protein (approximately 500 kcal/d energy); Receives: Other: Beef protein |
| Animal Protein | Active comparator | A control plant protein stew, providing 8.8 mg zinc, 37.9 mg protein (approximately 500 kcal/d energy); Receives: Other: Beef protein |
What is being measured
The primary outcome is the main question the study is designed to answer.
microvascular function
microvascular function as measured by digital tonometry (EndoPAT2000)
Measured: 4 weeks
intracellular zinc status
intracellular zinc status determined by erythrocyte zinc tracer exchange
Measured: 4 weeks
Secondary outcomes (3)
plasma lipids
Circulating level of total cholesterol, triglycerides, HDL cholesterol, non-HDL cholesterol, with LDL cholesterol (calculated)
Measured: 4 weeks
plasma fatty acids
Circulating levels of non-esterified fatty acids
Measured: 4 weeks
plasma oxylipins
enzyme and non-enzyme derived non-esterified fatty acid metabolites
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Feb 2022
- Study start1 Oct 2022
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Zinc DeficiencyStudies of the same condition, open and under way.
- More trials run by University of California, DavisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- 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.
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Davis
- Sponsor type
- University, hospital or other
- Collaborators
- National Cattlemen's Beef Association, a contractor to the Beef Checkoff
- Responsible party
- Sponsor
- Investigators
- Carl L Keen, PhD, Principal investigator, Distinguished Professor Emeritus of Nutrition
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05236374
- Sponsor's protocol ID
- 1806393
- Status last verified
- Feb 2026
- First submitted
- 2 Feb 2022
- Last updated
- 9 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Daily Beef Intake, as a Component of a Heart-Healthy Diet, on Cellular Zinc Status and Vascular Function in Older Adults
- ClinicalTrials.gov ID
- NCT05236374
- Acronym / sponsor ID
- 1806393
- Conditions
- Zinc Deficiency, Inflammation, Metabolic Diseases, Vascular Diseases
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University of California, DavisUniversity, hospital or other
- Collaborators
- National Cattlemen's Beef Association, a contractor to the Beef Checkoff
- Study start
- 1 Oct 2022 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 11 Feb 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| Beef Protein | Experimental | Other: Beef proteinA beef stew, providing 8.8 mg zinc, 37.9 mg protein (approximately 500 kcal/d energy); |
| Animal Protein | Active comparator | Other: Beef proteinA control plant protein stew, providing 8.8 mg zinc, 37.9 mg protein (approximately 500 kcal/d energy); |
Who may qualify
- Ages
- 55 to 70 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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
Key exclusion criteria (22 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Beef proteinAnimal protein source | Other | Animal Protein, Beef Protein |
Primary outcome
microvascular function
Time frame: 4 weeks
microvascular function as measured by digital tonometry (EndoPAT2000)
intracellular zinc status
Time frame: 4 weeks
intracellular zinc status determined by erythrocyte zinc tracer exchange
3 secondary outcomes
plasma lipids
Time frame: 4 weeks
plasma fatty acids
Time frame: 4 weeks
plasma oxylipins
Time frame: 4 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Feb 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Andrew Hall, PhD contact
Carl L Keen, PhD principal investigator
Distinguished Professor Emeritus of Nutrition
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Beef protein in people with Zinc Deficiency and Inflammation, run by University of California, Davis at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 22 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 9 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Roberta R Holt, PhD (15304005952, rrholt@ucdavis.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
microvascular function (time frame: 4 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Feb 2026.