The Effect of Kefir Consumption on Blood Pressure and C-Reactive Protein: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Abstract

Background Kefir, a traditional fermented milk beverage, has been increasingly promoted for its various health benefits. This systematic review and meta-analysis of randomised controlled trials (RCTs) aimed to assess the effects of kefir on blood pressure and C-reactive protein (CRP) levels.Methods A literature search was conducted using databases such as ISI Web of Science, Scopus and PubMed for articles published until January 2025, with no restrictions. A random-effects meta-analysis was conducted for all key outcome measures. The inverse-variance weighted mean difference (WMD) was calculated with a 95 confidence interval (CI).Results A total of seven RCTs, comprising 385 subjects, were included in the meta-analysis. We involved RCTs conducted on adult participants (over 18 years old). These studies generally administered kefir for at least 2 weeks and compared the outcomes to those in the control group. The findings showed that kefir consumption had no significant impact on systolic blood pressure (SBP) (WMD: -1.76 mmHg; 95 CI: -5.21, 1.69; p = 0.317), diastolic blood pressure (DBP) (WMD: -1.19 mmHg; 95 CI: -3.40, 1.03; p = 0.295) or CRP levels (WMD: -0.17 mg/L; 95 CI: -0.84, 0.49; p = 0.609) compared to those who did not consume kefir. However, subgroup analysis indicated that CRP levels significantly decreased with longer durations of kefir consumption (>= 8 weeks).Conclusion Kefir consumption in adults did not result in significant reductions in systolic or diastolic blood pressure or CRP levels. Nonetheless, there is some evidence that long-term kefir consumption may improve CRP levels over time.