Heart DiseasesNCT05840081
Dairy Fat and Fermentation Study
A study testing Milk or yogurt beverage in people with Heart Diseases and Microbial Colonization, run by Tufts University at 1 site in United States.
Trial summary
The purpose of the study is to compare the effect of consuming full-fat (regular) and fat-free (skim) milk, as well as full-fat and fat-free yogurt (a fermented dairy product), on microorganisms in your gut as well as the products produced by the gut microbes. Read more about this study
- Who is it for?
- Ages 50 years and olderHealthy volunteers can take part
- Conditions the study is for
- Heart Diseases, Microbial Colonization, Inflammation
- What is being tested?
- Milk or yogurt beverage
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 37 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Oct 2023to 19 Aug 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 50 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age >50 years
- Men and postmenopausal women
- BMI >25 and <35 kg/m2
- No milk allergy, lactose intolerance or adherence to vegan or other dietary pattern that excludes dairy products
- Non-smoker
- Usual pattern of bowel movements at least every other day.
Who cannot join
- Women and men <50 years
- Women, pre- or peri-menopausal
- BMI <25 and >35 kg/m2
- Current smokers or former smoker who quit < 6 months
- Use of nicotine replacement products within last 6 months
- Replacement or gender affirming hormonal therapy use
Show all 27Show fewer
- Weight gain of >15 pounds within last 6 months
- Infrequent bowel movements
- History of anemia within past 2 years or confirmation of anemia at first study visit
- Blood donation within last 2 months
- Untreated hypertension
- Oral antibiotics use within 2 weeks of study entry
- Steroid use (including dental prophylaxis use within 2 wks prior to or during study, except non-prescription topical and nasal steroids, e. g. Flonase)
- Use of lipid lowering medications
- Chronic use of aspirin, non-steroidal anti-inflammatory medications (NSAIDS), laxatives, anti-diarrheal medication
- Regular use (>2 times per week) of acid lowering medication: antacids, proton pump inhibitors, or H2 Blockers.
- Use of dietary supplements other than multi-vitamins, including pre- and probiotics, within 2 months of study entry
- Milk allergy, lactose intolerance or adherence to vegan or other dietary patterns that exclude dairy products
- Colonoscopy within 3 weeks of study entry or during study period
- Diagnosis of malabsorption, inflammatory bowel disease (ulcerative colitis or Crohn's Disease), cirrhosis, history of gastrointestinal resection (other than appendectomy), chronic pancreatitis or any other chronic GI disease that in the opinion of the study physician would alter the study results
- Chronic heart, liver, thyroid, renal or kidney disease
- Type I or type II diabetes
- Alcohol consumption >7 drinks/week for women and >14 drinks/week for men
- Inadequate refrigerator storage capacity to store 21 8-oz containers of milk or yogurt
- Participation in other dietary intervention research study during the same time
- No social security number
- Not willing to commit to adhering to the protocol
Trial locations and contacts
1 site in 1 country.
United States1 site
Jean Mayer Human Nutrition Research Center on Aging
Boston, Massachusetts, 02111
About this study
Official title: Effect of Full-Fat and Fat-Free Dairy, With and Without Fermentation, on Fecal Microbiome, Fecal and Serum Metabolome, and Host Cardiometabolic Risk Status
The purpose of the study is to compare the effect of consuming full-fat (regular) and fat-free (skim) milk, as well as full-fat and fat-free yogurt (a fermented dairy product), on microorganisms in your gut as well as the products produced by the gut microbes. We will also determine whether consuming these dairy products affects risk factors for heart disease.The findings of the study will help us determine if heart disease risk factors are modified by the fat content and fermentation of milk. The results may facilitate refinement of public health dietary guidance for cardiovascular disease risk reduction.
Read the detailed description
A randomized-controlled cross-over trial will be conducted to compare the effect of two servings per day of full-fat and fat-free milk, and full-fat and fat-free yogurt (hence forth referred to as dairy food items) on the gut microbiome, fecal and serum metabolome, and determine their relation to cardiometabolic risk factors (CMRF) and functional pathways associated with the differences identified. Participants will be provided with 2 servings per day of the test dairy products and requested not to consume additional bovine (cow) milk or yogurt during each 3-week diet phase.They will be allowed to use dairy substitutes such as plant-based milk alternatives and consume other types of dairy products (e.g. cheese).
The study consists of four diet phases: fat-free milk phase, full-fat milk phase, fat-free yogurt phase and full-fat yogurt phase. Each diet phase is 3 weeks in duration, separated by a 2 week break. Participants will be provided with 2 servings of a dairy based food item per day specific to their assigned phase and asked to consume them at two separate times during the day - morning and evening. Weight, waist circumference and blood pressure will be measured, blood and stool samples will be collected, and participants will complete two 24-hr food recall questionnaires during each phase.
- Conditions
- Heart Diseases, Microbial Colonization, Inflammation
- Being tested
- Milk or yogurt beverage
- Keywords
- gut microbiome, gut microbiota, yogurt, milk, heart disease
- Medical subject headings
- Heart Diseases, Communicable Diseases, Inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Milk or yogurt beverageOther
Commercially available milk or yogurt (depending on experimental arm) will be incorporated into flavored drinks/smoothies to minimize perceived differences among these items, preserving the double-blind nature of the study design.
| Study group | Role | What they receive |
|---|---|---|
| Full-fat milk beverage | Experimental | Beverage made with full-fat milk Receives: Other: Milk or yogurt beverage |
| Fat-free milk beverage | Experimental | Beverage made with fat-free milk Receives: Other: Milk or yogurt beverage |
| Full-fat yogurt beverage | Experimental | Beverage made with full-fat yogurt Receives: Other: Milk or yogurt beverage |
| Fat-free yogurt beverage | Experimental | Beverage made with fat-free yogurt Receives: Other: Milk or yogurt beverage |
What is being measured
The primary outcome is the main question the study is designed to answer.
gut microbiome
Determine the effects of dairy fat in milk, with and without fermentation, on gut microbiome
Measured: 3 weeks
fecal metabolome
Determine the effects of dairy fat in milk, with and without fermentation, on fecal metabolome
Measured: 3 weeks
serum metabolome
Determine the effects of dairy fat in milk, with and without fermentation, on serum metabolome
Measured: 3 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 May 2023
- Study start1 Oct 2023
- Primary completion19 Aug 2025
- Study completion19 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Heart DiseasesStudies of the same condition, open and under way.
- 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- randomized crossover design
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 37 participants (actual)
Sponsor and investigators
- Lead sponsor
- Tufts University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Alice Lichtenstein, Tufts University
- Investigators
- Alice H Lichtenstein, D. Sc., Principal investigator, Tufts University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05840081
- Sponsor's protocol ID
- 3070
- Status last verified
- Dec 2025
- First submitted
- 21 Apr 2023
- Last updated
- 12 Dec 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Full-Fat and Fat-Free Dairy, With and Without Fermentation, on Fecal Microbiome, Fecal and Serum Metabolome, and Host Cardiometabolic Risk Status
- ClinicalTrials.gov ID
- NCT05840081
- Acronym / sponsor ID
- 3070
- Conditions
- Heart Diseases, Microbial Colonization, Inflammation
- Keywords
- gut microbiome, gut microbiota, yogurt, milk, heart disease
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 37 participants (actual)
- Lead sponsor
- Tufts UniversityUniversity, hospital or other
- Study start
- 1 Oct 2023 (actual)
- Primary completion
- 19 Aug 2025 (actual)
- Study completion
- 19 Aug 2025 (actual)
- First posted
- 3 May 2023 (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 purpose of the study is to compare the effect of consuming full-fat (regular) and fat-free (skim) milk, as well as full-fat and fat-free yogurt (a fermented dairy product), on microorganisms in your gut as well as the products produced by the gut microbes. We will also determine whether consuming these dairy products affects risk factors for heart disease.The findings of the study will help us determine if heart disease risk factors are modified by the fat content and fermentation of milk. The results may facilitate refinement of public health dietary guidance for cardiovascular disease risk reduction.
Detailed description
A randomized-controlled cross-over trial will be conducted to compare the effect of two servings per day of full-fat and fat-free milk, and full-fat and fat-free yogurt (hence forth referred to as dairy food items) on the gut microbiome, fecal and serum metabolome, and determine their relation to cardiometabolic risk factors (CMRF) and functional pathways associated with the differences identified. Participants will be provided with 2 servings per day of the test dairy products and requested not to consume additional bovine (cow) milk or yogurt during each 3-week diet phase.They will be allowed to use dairy substitutes such as plant-based milk alternatives and consume other types of dairy products (e.g. cheese).
The study consists of four diet phases: fat-free milk phase, full-fat milk phase, fat-free yogurt phase and full-fat yogurt phase. Each diet phase is 3 weeks in duration, separated by a 2 week break. Participants will be provided with 2 servings of a dairy based food item per day specific to their assigned phase and asked to consume them at two separate times during the day - morning and evening. Weight, waist circumference and blood pressure will be measured, blood and stool samples will be collected, and participants will complete two 24-hr food recall questionnaires during each phase.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 4
- Model description
- randomized crossover design
| Arm | Type | Receives |
|---|---|---|
| Full-fat milk beverage | Experimental | Other: Milk or yogurt beverageBeverage made with full-fat milk |
| Fat-free milk beverage | Experimental | Other: Milk or yogurt beverageBeverage made with fat-free milk |
| Full-fat yogurt beverage | Experimental | Other: Milk or yogurt beverageBeverage made with full-fat yogurt |
| Fat-free yogurt beverage | Experimental | Other: Milk or yogurt beverageBeverage made with fat-free yogurt |
Who may qualify
- Ages
- 50 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age >50 years
- Men and postmenopausal women
- BMI >25 and <35 kg/m2
- No milk allergy, lactose intolerance or adherence to vegan or other dietary pattern that excludes dairy products
- Non-smoker
Key exclusion criteria (27 listed)
- Women and men <50 years
- Women, pre- or peri-menopausal
- BMI <25 and >35 kg/m2
- Current smokers or former smoker who quit < 6 months
- Use of nicotine replacement products within last 6 months
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 |
|---|---|---|
| Milk or yogurt beverageCommercially available milk or yogurt (depending on experimental arm) will be incorporated into flavored drinks/smoothies to minimize perceived differences among these items, preserving the double-blind nature of the study design. | Other | Fat-free milk beverage, Fat-free yogurt beverage, Full-fat milk beverage, Full-fat yogurt beverage |
Primary outcome
gut microbiome
Time frame: 3 weeks
Determine the effects of dairy fat in milk, with and without fermentation, on gut microbiome
fecal metabolome
Time frame: 3 weeks
Determine the effects of dairy fat in milk, with and without fermentation, on fecal metabolome
serum metabolome
Time frame: 3 weeks
Determine the effects of dairy fat in milk, with and without fermentation, on serum metabolome
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Dec 2025.
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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. This study is not recruiting at the moment.
Alice H Lichtenstein, D. Sc. principal investigator
Tufts University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Milk or yogurt beverage in people with Heart Diseases and Microbial Colonization, run by Tufts University 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 27 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: finished, as of the sponsor's last update on 12 Dec 2025. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
gut microbiome (time frame: 3 weeks). The study lists 3 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 12 Dec 2025.