An interventional study of Milk or yogurt beverage in Heart Diseases, Microbial Colonization and Inflammation, sponsored by Tufts University. Completed at 1 site in United States. Open to participants aged 50 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-12.
Sponsored by Tufts University · Not applicable, Interventional, and Treatment
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.
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.
3,639 studies on the registry are indexed under Heart Diseases; 461 are open to participants now.
This study's enrollment of 37 is below the median of 100 across 1,778 interventional studies indexed under Heart Diseases.
Browse Heart Diseases studies →Tufts University is the lead sponsor of 225 studies on the registry; 24 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 7 (70%) have results posted.
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Exclusion Criteria:
Beverage made with full-fat milk
Other: Milk or yogurt beverage
Beverage made with fat-free milk
Other: Milk or yogurt beverage
Beverage made with full-fat yogurt
Other: Milk or yogurt beverage
Beverage made with fat-free yogurt
Other: Milk or yogurt beverage
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.
gut microbiome
Determine the effects of dairy fat in milk, with and without fermentation, on gut microbiome
Time frame: 3 weeks
fecal metabolome
Determine the effects of dairy fat in milk, with and without fermentation, on fecal metabolome
Time frame: 3 weeks
serum metabolome
Determine the effects of dairy fat in milk, with and without fermentation, on serum metabolome
Time frame: 3 weeks
This study is completed, as verified in Dec 2025. You cannot join it, but the record below documents what was studied.
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Tufts University