Lactobacillus plantarum is a probiotic bacterium that has been investigated for its effects on gut health, including its potential role in supporting or treating "Leaky Gut Syndrome" (also known as increased intestinal permeability). While "Leaky Gut Syndrome" is not universally recognized as a formal medical diagnosis, increased intestinal permeability is a real phenomenon studied in gastrointestinal research.

Several animal studies and limited human data suggest that L. plantarum can help strengthen intestinal barrier function. These studies indicate that L. plantarum may enhance tight junction protein expression and reduce inflammation, which are mechanisms potentially relevant to intestinal permeability. For example, a 2015 review in Frontiers in Microbiology summarizes preclinical data showing that L. plantarum improves epithelial barrier integrity and modulates immune responses.

However, robust clinical trials in humans specifically addressing "Leaky Gut Syndrome" are limited. Most available human studies examine general gut health or related conditions (such as IBS or IBD), not leaky gut per se. Thus, while there is growing scientific interest and some supportive mechanistic data, the evidence is currently preliminary, and more well-designed human studies are needed to confirm specific benefits for leaky gut.