The study, funded by their commercial partner, Malaysian pharmaceutical and nutraceutical group Pharm-D Health Science Sdn. Bhd, involved 152 participants who took the daily probiotic or placebo for six months.
“Overall, the results support the safety of L. plantarum K014 for long-term consumption in healthy individuals; however, further adequately powered studies are warranted to determine whether this strain confers clinically meaningful health benefits,” they wrote in the journal Nutrients.
Strain-specific effects
L. plantarum has been established as generally safe in human populations, and is included in dietary supplements and fermented foods. Due to its positive effects on gut health and the immune system, strains of the probiotic have been reported to benefit weight loss, loose stools, cognitive performance, and sleep.
However, the current study notes that L. plantarum has also shown adverse or non-beneficial effects in some previous clinical studies, worsening IBS symptoms, and failing to improve intestinal permeability. This highlights that the effects of probiotics can be strain-dependent and need specific safety and tolerance validation.
The strain L. plantarum K014 was isolated from local Malaysian cabbage by researchers at Universiti Sains Malaysia and is patented and marketed as Lassica KO14.
The study aimed to assess this previously uncharacterized strain in an early-phase safety trial.
“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,” the researchers wrote.
Study details
The researchers randomly assigned 152 healthy adults to consume L. plantarum K014 (≥1 × 109 CFU/day) or a placebo daily for six months. They were clinically assessed at baseline, month four, and month 6, including anthropometric measurements and blood analyses for safety assessment, blood sugar, cholesterol profile, and immune markers. Using weekly online questionnaires, the researchers monitored gastrointestinal symptoms, stool characteristics, and immune-related outcomes.
The blood test results revealed that red and white blood cells remained within normal physiological ranges and did not differ between groups. There were no adverse effects on glucose or lipid metabolism, with values remaining stable throughout the study. Assessment of liver and kidney function revealed no adverse effects and “a possible supportive effect on protein metabolism and immune-related globulin synthesis.”
There were no significant between-group differences for gastrointestinal symptoms, with exploratory analyses showing reductions in diarrhea and abdominal pain in the probiotic group.
Common cold symptoms and daily functioning were similar in both groups, with an exploratory analysis showing a small, significant improvement in the number of workdays affected in the probiotic group.
The researchers acknowledged the study limitations, such as a homogeneous population and self-reported outcomes, and called for future studies that better evaluate safety across more diverse groups.
Source: Nutrients 2026, 18(9), 1406; doi: https://doi.org/10.3390/nu18091406; “Safety of Lactiplantibacillus plantarum K014 in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Trial.” Authors: K.S. Goh et al.