Benefits
Body weight and BMI in adults
A meta-analysis of 9 randomized trials in healthy adults reported lower body weight and BMI with L. plantarum than placebo, along with less abdominal fat and lower IL-6 and hs-CRP. The trials used different strains, effects were larger when more than two strains were combined, the analysis was funded by a probiotic maker, and the authors called for better trials.
Abdominal pain and bloating (strain 299v)
In a 4-week placebo-controlled trial in 214 people with IBS, strain 299v lowered abdominal pain and bloating, and 78.1 percent rated its effect good or excellent versus 8.1 percent on placebo. A 4-week trial in 40 patients also reported less pain, but in a trial of 120 patients 299v did not beat placebo.
Cholesterol levels (CECT 7527, 7528 and 7529 mix)
In a 12-week randomized, double-blind trial in 60 adults with high cholesterol, a three-strain L. plantarum mix at 1.2 billion CFU a day lowered total cholesterol by 13.6 percent versus placebo. LDL and oxidized LDL fell only in the subgroup with the highest starting cholesterol. The trial was small, and the result applies only to these strains.
Mechanism of action
Bacteriocin production
Many L. plantarum strains produce plantaricins, antimicrobial peptides active against other bacteria in laboratory tests. Whether this matters in the human gut is not established.
Bile salt hydrolase activity
Bile salt hydrolase deconjugates bile salts in the gut so more are excreted, and the liver then uses cholesterol to make new bile acids. This is the proposed basis for cholesterol effects.
Mannose-specific adhesion
Strain 299v carries mannose-binding adhesins that help it attach to the gut lining, which may let it compete with other bacteria for binding sites.
GABA production
Some strains make GABA, a signaling molecule, in laboratory culture; effects in people are not established.
Clinical trials
Systematic review and meta-analysis of 9 randomized controlled trials, funded by Grape King Bio (Li et al. 2024, Int J Mol Sci)
Healthy adults in 9 trials using different L. plantarum strains.
Body weight and BMI fell more with L. plantarum than placebo, with improvements in abdominal fat, IL-6 and hs-CRP. Combining more than two strains enhanced the effects. The authors noted variation in designs, strains and durations and called for more robust trials.
Double-blind, placebo-controlled, parallel trial: one capsule a day of L. plantarum 299v (DSM 9843) or placebo for 4 weeks (Ducrotté et al. 2012, World J Gastroenterol)
214 adults with IBS meeting Rome III criteria.
After 4 weeks, abdominal pain severity and daily frequency were lower with 299v than placebo, with similar results for bloating. 78.1 percent of the 299v group rated the effect excellent or good versus 8.1 percent on placebo.
Controlled, double-blind, randomized trial: L. plantarum 299V liquid suspension or placebo for 4 weeks (Niedzielin et al. 2001, Eur J Gastroenterol Hepatol)
40 patients with IBS (20 per group).
All 20 patients on 299V reported their abdominal pain resolved, versus 11 on placebo, and overall symptom improvement was reported by 95 versus 15 percent. A trend toward more normal stool frequency in constipated patients did not reach significance.
Randomized controlled trial of L. plantarum 299v versus placebo (Moeen-Ul-Haq et al. 2022, J Pak Med Assoc)
120 patients with IBS in Peshawar, Pakistan; 108 completed.
Abdominal pain, bloating and the feeling of complete rectal emptying did not differ significantly between groups, and the authors concluded no significant efficacy was established for 299v.
Randomized, double-blind, placebo-controlled trial: one capsule a day of 1.2 billion CFU of the three-strain mix or placebo for 12 weeks (Fuentes et al. 2013, Br J Nutr)
60 adults aged 18 to 65 with high cholesterol (30 per group).
Total cholesterol fell 13.6 percent versus placebo. In participants with higher starting cholesterol, total cholesterol, LDL and oxidized LDL fell 17.4, 17.6 and 15.6 percent; in those with lower starting values only total cholesterol fell (9.4 percent).