Kefir microbial composition is a deciding factor in the physiological impact of kefir in a mouse model of obesity

Abstract

Kefir consumption has been demonstrated to improve lipid and cholesterol metabolism, however our previous study identified that benefits vary between different commercial and traditional kefir. Here, we investigate the ability of pitched culture kefir, i.e., kefir produced by a small number of specific strains, to recapitulate health benefits of a traditional kefir, in a diet induced obesity mouse model, and examine how microbial composition of kefir impacts these benefits. Eight week old female C57BL/6 mice were fed a high fat diet (40% kcal from fat) supplemented with one of 5 kefir varieties (traditional, pitched, pitched with no Lactobacillus, pitched with no yeast, and commercial control) at 2mL in 20 grams of food for 8 weeks prior to analysis of plasma and liver lipid profiles, and liver gene expression profiles related to lipid metabolism. Both traditional and pitched kefir lowered plasma cholesterol by ~35% (P=0.0005) and liver triglycerides by ~55% (P=0.0001) when compared to commercial kefir despite no difference in body weight. Furthermore, pitched kefir produced without either yeast or Lactobacillus did not lower cholesterol. The traditional and pitched kefir with the full complement of microbes were able to impart corresponding decreases in the expression of the cholesterol and lipid metabolism genes encoding 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, peroxisome proliferator-activated receptor gamma (PPARγ), and CD36 in the liver. These results demonstrate that traditional kefir organisms can successfully be utilized in a commercial process, while highlighting the importance of microbial interactions during fermentation in the ability of fermented foods to benefit host health.

Exploitation of Yeasts with Probiotic Traits for Kefir Production: Effectiveness of the Microbial Consortium

“…Kefir, a fermented milk-based dairy product, has recently been recognized as a beverage with functional characteristics [6][7][8]. Within the past few years, kefir has gained wide consumer acceptance in Europe and in Italy, aided by its image as a 'healthy' food.…”

Biological Role of Nutrients, Food and Dietary Patterns in the Prevention and Clinical Management of Major Depressive Disorder

“…lactis , boosting their global benefits [ 159 ] Kefir is a fermented milk that comes from kefir grains, which include a specific and complex mixture of lactic acid and acetic acid bacteria that appears in symbiosis with lactose-fermenting and nonfermenting yeast [ 160 ]. Interestingly, kefir without bacteria or yeast in its composition seems to critically limit the benefits from this product [ 161 ]. Prior works have demonstrated that 3 weeks with daily consumption of probiotic yogurt improved the mood of those whose mood was initially poor [ 162 ].…”

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

“…Kefir in particular is gaining popularity, largely due to an increased appreciation of the potential health benefits. Benefits that have been attributed to specific kefirs include anti-cancer ( de Moreno de LeBlanc et al, 2006 ; Maalouf et al, 2011 ), immunomodulatory ( Vinderola et al, 2005 ; Lee et al, 2007 ), cholesterol lowering ( Bourrie et al, 2018 , 2021 ), and other metabolic health improvements ( Al-Shemmari et al, 2018 ; Ghizi et al, 2021 ).…”