NCT05840081

Brief 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. 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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
37

participants targeted

Target at P25-P50 for not_applicable

Timeline
Completed

Started Oct 2023

Typical duration for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

April 21, 2023

Completed
12 days until next milestone

First Posted

Study publicly available on registry

May 3, 2023

Completed
5 months until next milestone

Study Start

First participant enrolled

October 1, 2023

Completed
1.9 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

August 19, 2025

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

August 19, 2025

Completed
Last Updated

December 12, 2025

Status Verified

December 1, 2025

Enrollment Period

1.9 years

First QC Date

April 21, 2023

Last Update Submit

December 11, 2025

Conditions

Heart DiseasesMicrobial ColonizationInflammation

Keywords

gut microbiomegut microbiotayogurtmilkheart disease

Outcome Measures

Primary Outcomes (3)

  • gut microbiome

    Determine the effects of dairy fat in milk, with and without fermentation, on gut microbiome

    3 weeks

  • fecal metabolome

    Determine the effects of dairy fat in milk, with and without fermentation, on fecal metabolome

    3 weeks

  • serum metabolome

    Determine the effects of dairy fat in milk, with and without fermentation, on serum metabolome

    3 weeks

Study Arms (4)

Full-fat milk beverage

EXPERIMENTAL

Beverage made with full-fat milk

Other: Milk or yogurt beverage

Fat-free milk beverage

EXPERIMENTAL

Beverage made with fat-free milk

Other: Milk or yogurt beverage

Full-fat yogurt beverage

EXPERIMENTAL

Beverage made with full-fat yogurt

Other: Milk or yogurt beverage

Fat-free yogurt beverage

EXPERIMENTAL

Beverage made with fat-free yogurt

Other: Milk or yogurt beverage

Interventions

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.

Fat-free milk beverageFat-free yogurt beverageFull-fat milk beverageFull-fat yogurt beverage

Eligibility Criteria

Age50 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • 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.

You may not qualify if:

  • 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
  • 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
  • +12 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Jean Mayer Human Nutrition Research Center on Aging

Boston, Massachusetts, 02111, United States

Location

MeSH Terms

Conditions

Heart DiseasesCommunicable DiseasesInflammation

Interventions

Milk

Condition Hierarchy (Ancestors)

Cardiovascular DiseasesInfectionsDisease AttributesPathologic ProcessesPathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

BeveragesDiet, Food, and NutritionPhysiological PhenomenaDairy ProductsFoodFood and Beverages

Study Officials

  • Alice H Lichtenstein, D. Sc.

    Tufts University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
TREATMENT
Intervention Model
CROSSOVER
Model Details: randomized crossover design
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
D.Sc.

Study Record Dates

First Submitted

April 21, 2023

First Posted

May 3, 2023

Study Start

October 1, 2023

Primary Completion

August 19, 2025

Study Completion

August 19, 2025

Last Updated

December 12, 2025

Record last verified: 2025-12

Locations

US(1)