Original title: A comparative review of microbial composition and health benefits of “milk-based” and “water-based” kefir grains
Kefir is made when communities of microbes ferment a liquid. This review compares grains grown in milk with grains grown in sugar water, which is common in parts of South America. The evidence suggests milk-based grains usually contain more kinds of microbes and produce a wider range of metabolitesSubstances produced as microbes carry out their life processes., the substances microbes make as they grow. But the review says claims that milk kefir is healthier often rely on assumptions, not direct comparisons.
Imagine making the same kind of soup with two different cooking liquids. The ingredients in each pot can change which flavours develop, and tasting one richer soup does not prove it is better for your health. In this paper, the cooking liquids stand for milk and sugar water, while the flavours stand for the microbes and substances each kind of kefir develops.
People choosing between milk-based and water-based kefir may hear that one is healthier because its ingredients seem more nutritious. This review compares the available evidence, helping separate documented differences between the two ferments from assumptions about their starting ingredients.
The review says research is heavily weighted toward milk-based kefir, with systematic study of water-based kefir still limited. It also notes that claims of greater health benefits for milk-based kefir often lack direct comparative evidence. The abstract does not provide details about the studies reviewed or establish which type is healthier.
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A comparative review of microbial composition and health benefits of “milk-based” and “water-based” kefir grains — FAN DING, Zhuoyu He, Jiayu He et al. — International Journal of Food Properties — doi:10.1080/10942912.2026.2715181
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.