Safety of Lactiplantibacillus plantarum K014 in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled,...

Lactiplantibacillus plantarum is a widely studied probiotic species with well-documented benefits for gastrointestinal function and immune modulation. However, probiotic effects are strain-specific, and the safety of newly identified strains must be clinically established. L. plantarum K014, isolated from traditionally fermented vegetables, has not previously been evaluated in human subjects. This study aimed to evaluate the safety and tolerability of L. plantarum K014 in healthy Malaysian adults by assessing its effects on anthropometric measures, hematological indices, liver and renal function, gastrointestinal health, and selected immune-related outcomes, including the incidence and severity of common cold symptoms.

This single-center, randomized, double-blind, placebo-controlled trial was conducted over a 6-month period. Of 304 healthy adults screened, 152 were enrolled and randomized in a 1:1 ratio to receive either L. plantarum K014 (≥1 × 10⁹ CFU/day) or placebo (maltodextrin), administered daily in sachet form; 125 participants completed the study. Clinical assessments, including physical examination, anthropometric measurements, and blood analyses, were performed at baseline, Month 4, and Month 6. Gastrointestinal symptoms, stool characteristics, and immune-related outcomes were monitored weekly using structured online questionnaires.

L. plantarum K014 was well tolerated, with no probiotic-related adverse events reported. No clinically significant changes were observed in body weight, BMI, hematological indices, or renal function in either group. Exploratory analyses indicated that participants receiving L. plantarum K014 exhibited statistically significant differences in several liver function markers, as well as lower severity of diarrhea and abdominal pain compared with placebo, though these findings were not prespecified efficacy endpoints and should be interpreted cautiously. Similarly, lower weekly ratings of common cold symptoms interfering with work or study were observed in the probiotic group as an exploratory observation.

Daily consumption of L. plantarum K014 at a dose of ≥1 × 10⁹ CFU for six months was safe and well tolerated in healthy adults. The absence of adverse effects, together with observed trends toward lower gastrointestinal discomfort and immune-related symptoms, supports the suitability of L. plantarum K014 for further investigation in efficacy-driven clinical studies.