PROBIOTICS & YEASTS

Kefir grains contain a diverse community of approximately 30–60 species of beneficial bacteria and yeasts, including Lactobacillus, Lactococcus, Streptococcus, and Saccharomyces species. These microorganisms produce enzymes and short-chain fatty acids that support digestion and metabolic health. They adhere to intestinal cells, strengthen the mucosal barrier, improve lactose digestion, and help regulate immune function.

ORGANIC ACIDS

During fermentation, kefir microbes produce organic acids—primarily lactic and acetic acid. These compounds lower gut pH, creating an environment that inhibits harmful and pathogenic bacteria. In combination with naturally occurring ethanol (trace amounts) and bacteriocins, they support a balanced and resilient gut ecosystem.

BIOACTIVE PEPTIDES

Milk proteins are broken down during fermentation into bioactive peptides. These compounds have demonstrated anti-inflammatory, antimicrobial, and immune-modulating effects. They help regulate inflammatory signaling and may reduce intestinal inflammation associated with chronic conditions.

KEFIRAN

Kefiran is a unique polysaccharide produced by kefir cultures that forms the structural matrix of the grains. It functions as a prebiotic, selectively feeding beneficial bacteria. Kefiran has antioxidant and anti-inflammatory properties and may enhance mucosal immunity by increasing secretory IgA.

CONTRAINDICATIONS & PRECAUTIONS

Kefir is generally well tolerated; however, use caution if you are:

• Pregnant or breastfeeding (limited research available) • Immunocompromised (live cultures may pose risk) • Sensitive to dairy or histamines

When first introducing kefir, mild symptoms such as bloating, cramping, or constipation may occur. Kefir contains trace amounts of naturally occurring alcohol due to fermentation; individuals taking medications such as disulfiram should avoid use. Consult a healthcare professional if you have underlying conditions or are on immunosuppressive therapy.

REFERENCES

1. Prado MR, Blandón LM, Vandenberghe LPS, et al. Milk kefir: composition, microbial cultures, biological activities, and related products. Front Microbiol. 2015;6:1177.
2. Bourrie BCT, Willing BP, Cotter PD. The microbiota and health promoting characteristics of the fermented beverage kefir. Front Microbiol. 2016;7:647.
3. Leite AMO, Miguel MAL, Peixoto RS, et al. Microbiological, technological and therapeutic properties of kefir: a natural probiotic beverage. Braz J Microbiol. 2013;44(2):341-349.
4. Rosa DD, Dias MMS, Grześkowiak ŁM, Reis SA, Conceição LL, Peluzio MDCG. Milk kefir: nutritional, microbiological and health benefits. Nutr Res Rev. 2017;30(1):82-96.
5. Farnworth ER. Kefir – a complex probiotic. Food Sci Technol Bull Funct Foods. 2005;2(1):1-17.
6. Fiorda FA, de Melo Pereira GV, Thomaz-Soccol V, Rakshit SK, Pagnoncelli MGB, Soccol CR. Microbiological, biochemical, and functional aspects of sugary kefir fermentation. Food Microbiol. 2017;66:86-95.