Effects of Milk-based Drinks on Gut Microbiome, Sleep and Cardiometabolic Markers

Summary

The purpose of this study is to evaluate the effects of kefir on gastrointestinal health, sleep quality, and biochemical parameters in adults who have sleep problems. Further measurements of cognitive function, arterial stiffness and blood pressure will also be assessed.

The following questions will be addressed during the study:

1. What effect does repeated ingestion of kefir have on the gut microbiome and can this positively influence sleep performance (quality and duration) in adults with sleep problems?
2. Does repeated ingestion of kefir impact LDL, triacyglycerols and non-HDLc in adults with sleep problems?
3. What effect does repeated ingestion of kefir have on cognitive function and mood?
4. What effect does repeated ingestion of kefir have on vascular function, inflammation and markers of immunity in adults with sleep problems?

In a randomised, crossover design study, participants will consume 250 ml of kefir (original flavour) or milk for 4 weeks with a 4-week washout.

Conditions

• Sleep
• Cardiovascular Diseases
• Gut Microbiome
• Cognitive Function and Mood
• LDL Cholesterol

Interventions

DIETARY_SUPPLEMENT

Original flavour kefir

Participants will consume 250ml of original flavour kefir daily for 4 weeks. According to the manufacturer, "packed with billions of live cultures to support Gut health".

OTHER

Milk

Participants will consume 250 ml milk daily for 4 weeks. This milk will not contain any live cultures.

Sponsors & Collaborators

• Biotiful

  collaborator UNKNOWN

• University of Leeds

  collaborator OTHER

• Nimble Science Ltd.

  collaborator INDUSTRY

• Sheffield Hallam University

  lead OTHER

Principal Investigators

• Tony Lynn, PhD · Sheffield Hallam University

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

40 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-08-31

Primary Completion

2026-03-31

Completion

2026-03-31

Countries

• United Kingdom

Study Locations