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U2Biome Research Center Publishes Microbiome Data from 3,450 Koreans in International Scientific Journal
Detection Rate of Body Fat Reduction-Associated Bifidobacterium breve in Obese Group Only 60% of That in Normal-Weight Group

A large-scale analysis of gut microbiome data from 3,450 Koreans has revealed that six out of ten people possess only 0–2 of the 19 probiotic strains recognized by Korea’s Ministry of Food and Drug Safety (MFDS). In particular, the detection rate of Bifidobacterium breve (B. breve), a key probiotic strain associated with body fat reduction, was nearly 1.7 times lower in the obese group than in the normal-weight group. The findings provide evidence that the gut environment supporting beneficial bacteria may deteriorate rapidly as body weight increases.

The study was conducted by the U2Biome Research Center and was published in the January 2026 issue of the international scientific journal Frontiers in Microbiology.

The MFDS recognizes a total of 19 probiotic strains as beneficial to gut health that can be consumed through health functional foods, fermented foods, and other products. However, the results of gut microbiome analyses conducted among healthy Koreans revealed a striking pattern.

No probiotic strains were detected in 6% of participants, while 22% had just one strain and 30% had two strains. In total, 58% of Koreans were found to have only 0–2 of the 19 MFDS-recognized probiotic strains in their gut, indicating a state of “beneficial bacteria deficiency.” These findings were clearly demonstrated through an analysis of large-scale gut microbiome test report data accumulated by U2Biome.

Which People Have More Vulnerable Gut Microbiome Environments?

According to the study, individuals in the obese group with higher body mass indexes (BMIs) had noticeably fewer of the 19 MFDS-recognized probiotic strains compared with those in the normal-weight group. The proportion of individuals carrying four or more probiotic strains was also significantly lower in the obese group.

A multivariable logistic regression analysis examining the detection of specific bacterial strains found that the detection rate of Bifidobacterium breve (B. breve), a beneficial bacterium associated with body fat reduction, decreased significantly as body weight increased.

The detection rate was 17.5% in the normal-weight group, compared with just 11.1% in the obese group (p < 0.0001).

As body weight increases and the gut metabolic environment deteriorates, dysbiosis—the imbalance of the gut microbiome closely associated with obesity—may become more pronounced. This can interfere with the colonization of beneficial bacteria and potentially create a harmful cycle that makes further weight loss more difficult.

The study is the first domestic analysis to examine patterns of probiotic strain detection using a large-scale cohort of 3,450 Koreans while simultaneously taking into account various demographic and lifestyle factors, including BMI, age, sex, and smoking status.

Until now, gut microbiome research has often relied on data from Western populations as a reference standard. However, differences in dietary habits and lifestyles mean that the gut microbiome landscape of Koreans differs significantly from that of Western populations.

Because this study examined changes in the gut microbiome landscape based on real-world data from Koreans, it is expected to provide important scientific evidence for establishing Korea-specific reference standards for individualized gut health management in the future.

The findings also suggest that, particularly in the context of obesity, proactively assessing an individual’s gut microbiome composition and supplementing deficient strains in a personalized manner may be more effective than waiting until outcome-based indicators such as BMI or body weight have deteriorated before taking action.

Sinae Park, Director of the U2Biome Research Center and a co-author of the study, explained, “Our analysis of a large-scale Korean cohort confirmed that obesity, smoking, aging, and other factors are deeply associated with the distribution of the gut microbiome. Probiotic intake interacts with microorganisms already present in the gut and can help create an environment that is more favorable for beneficial bacteria to establish themselves. Therefore, accurately assessing the composition of beneficial and potentially harmful bacteria in one’s gut and then taking probiotics tailored to individual needs can provide practical support for gut health management.”

A U2Biome representative added, “Building on this study, we plan to raise awareness of the importance of proactive healthcare, moving beyond treating obesity after it has already developed toward enabling individuals to manage their gut microbiome during the pre-obesity stage. We will continue to expand access to our services so that anyone can easily assess and manage their own gut microbiome ecosystem.”

Go to Article : [MaekyungHealth] Six in Ten Koreans Have Just 0–2 Probiotic Strains Recognized by the Ministry of Food and Drug Safety