NCT05840081

Dairy Fat and Fermentation Study

Effect of Full-Fat and Fat-Free Dairy, With and Without Fermentation, on Fecal Microbiome, Fecal and Serum Metabolome, and Host Cardiometabolic Risk Status

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 37 (actual)
• Sponsor: Tufts University · Academic / Other
• Sex: All
• Age: 50 Years
• Healthy volunteers: Accepted

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.

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

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2023-10-01
• Primary completion: 2025-08-19
• Completion: 2025-08-19
• First posted: 2023-05-03
• Last updated: 2025-12-12

Locations

1 site across 1 country: United States