Improving Health Outcomes With Kefir

Overview

The purpose of the study is to ascertain whether traditional kefir not only enhances vascular health but also contributes to improved immune outcomes in both male and female participants at higher risk or living with Type 2 Diabetes (T2D) after 12 weeks of treatment.

Detailed description

Participants who sign the written consent form will undergo a screening process to determine eligibility for study entry. At the baseline visit, recruited participants will be randomized in a double-blind manner (participant and study coordinator) to consume either 350 mL of traditional fermented kefir or 350 mL of a placebo (milk) daily. During the 12 weeks of intervention, health outcomes will be measured and collected for further analysis.

Interventions

• Dietary supplement Traditional Kefir
  350 mL/day of traditional fermented/prepared kefir
• Dietary supplement Milk (placebo)
  350 mL/day of commercial 2% fat milk

Primary outcome measures

• Change in Glycated Hemoglobin (HbA1c) Levels (Percentage) [Time frame: Baseline, 6 weeks, 12 weeks]

Secondary outcome measures (10)

• Change in Fasting Plasma Glucose Levels (mmol/L) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Total Cholesterol (mmol/L) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Low-Density Lipoprotein Cholesterol (LDL-C) (mmol/L) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in High-Density Lipoprotein Cholesterol (LDL-C) (mmol/L) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Triglyceride levels (mmol/L) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Circulating C-Reactive Protein (CRP) Levels (mg/L) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Interleukin-2 (IL-2) in Supernatant of Ex Vivo Stimulated Cells from Whole Blood (pg/mL) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in T Helper Cell Response Measured by Interferon-Gamma (IFN-γ) Levels in Supernatant of Ex Vivo Stimulated Cells from Whole Blood (pg/mL) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Tumor Necrosis Factor-Alpha (TNF-α) Levels in Supernatant of Ex Vivo Stimulated Cells from Whole Blood (pg/mL) [Time frame: Baseline, 6 weeks, 12 weeks]
• Change in Gut Microbiome Composition and Functional Capacity (Relative Abundance) [Time frame: Baseline, 6 weeks, 12 weeks]

Eligibility criteria

Inclusion criteria

• females and males (24-70 years old) living in Edmonton (or Edmonton area/driving distance);
• overweight or obesity (BMI >25 Caucasian, >23 Asian);
• at higher risk of T2D (fasting blood glucose ≥ 5.6 - 6.9 mmol/L or/and HbA1C ≥ 5.5 - 6.4%); or
• with diagnosis of T2D (fasting blood glucose ≥ 7.0 mmol/L or/and HbA1C ≥ 6.5%).

Exclusion criteria

• a usual high intake (maximum intake 3 servings/week) of fermented foods excluding cheese (i.e., kefir, kombucha, kimchi, etc.) for the past 3 months;
• gastrointestinal (GI) disorders of any kind;
• being pregnant or breastfeeding;
• monogenic dyslipidemias and endocrine disorders except for diabetes;
• use of medications within the last 3 months (i.e., antibiotics or antifungals, corticosteroids, methotrexate, or immunosuppressive cytotoxic agents);
• any health conditions deemed to interfere with primary outcomes at the investigator's discretion (e.g., kidney disease, liver disease, cancer, GI surgery, heavy alcohol consumption, etc.);
• having a pacemaker or any electrical medical device that prevents the individual from undergoing the bioelectrical impedance analysis bioimmunoassay (BIA) test."

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Canada · 1 center

• University of Alberta — Edmonton

Publications

• Wastyk HC, Fragiadakis GK, Perelman D, Dahan D, Merrill BD, Yu FB, Topf M, Gonzalez CG, Van Treuren W, Han S, Robinson JL, Elias JE, Sonnenburg ED, Gardner CD, Sonnenburg JL. Gut-microbiota-targeted diets modulate human immune status. Cell. 2021 Aug 5;184(16):4137-4153.e14. doi: 10.1016/j.cell.2021.06.019. Epub 2021 Jul 12. PMID 34256014
• Savaiano DA, Hutkins RW. Yogurt, cultured fermented milk, and health: a systematic review. Nutr Rev. 2021 Apr 7;79(5):599-614. doi: 10.1093/nutrit/nuaa013. PMID 32447398
• Braga Tibaes JR, Barreto Silva MI, Makarowski A, Cervantes PB, Richard C. The nutrition and immunity (nutrIMM) study: protocol for a non-randomized, four-arm parallel-group, controlled feeding trial investigating immune function in obesity and type 2 diabetes. Front Nutr. 2023 Sep 1;10:1243359. doi: 10.3389/fnut.2023.1243359. eCollection 2023. PMID 37727636
• Bourrie BC, Willing BP, Cotter PD. The Microbiota and Health Promoting Characteristics of the Fermented Beverage Kefir. Front Microbiol. 2016 May 4;7:647. doi: 10.3389/fmicb.2016.00647. eCollection 2016. PMID 27199969
• Bourrie, B, Cotter, P, Willing, BP, 2018. Traditional kefir reduces weight gain and improves plasma and liver lipid profiles more successfully than a commercial equivalent in a mouse model of obesity. Journal of Functional Foods, 46: 29-37. https://doi.org/10.1016/j.jff.2018.04.039
• Bourrie BCT, Richard C, Willing BP. Kefir in the Prevention and Treatment of Obesity and Metabolic Disorders. Curr Nutr Rep. 2020 Sep;9(3):184-192. doi: 10.1007/s13668-020-00315-3. PMID 32472367
• Bourrie BCT, Ju T, Fouhse JM, Forgie AJ, Sergi C, Cotter PD, Willing BP. Kefir microbial composition is a deciding factor in the physiological impact of kefir in a mouse model of obesity. Br J Nutr. 2021 Jan 28;125(2):129-138. doi: 10.1017/S0007114520002743. Epub 2020 Jul 20. PMID 32684173
• Bourrie BCT, Forgie AJ, Ju T, Richard C, Cotter PD, Willing BP. Consumption of the cell-free or heat-treated fractions of a pitched kefir confers some but not all positive impacts of the corresponding whole kefir. Front Microbiol. 2022 Nov 24;13:1056526. doi: 10.3389/fmicb.2022.1056526. eCollection 2022. PMID 36504827

Identifiers

NCT: NCT06695221 · Pro00139307

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗