L. plantarum Lowered LDL by 17.6%: A 12-Week RCT in Hypercholesterolemic Adults

This 12-week randomized controlled trial tested whether a three-strain Lactobacillus plantarum probiotic (CECT 7527, 7528, and 7529) could lower cholesterol in adults with hypercholesterolemia. Published in the British Journal of Nutrition by researchers at AB-Biotics in Spain, the double-blind trial enrolled 60 participants and reported a 13.6% reduction in total cholesterol versus placebo overall -- and a 17.6% LDL reduction in the subgroup that started with the highest baseline cholesterol. The trial is one of the foundational human RCTs on the gut microbiome -- cardiovascular axis, a research area that informs how Olivea thinks about olive polyphenols and the broader food-as-medicine pipeline.

Why This Study Matters

Earlier probiotic-and-cholesterol research had been frustratingly mixed. Some trials showed modest reductions; others showed nothing. The inconsistency was widely attributed to two factors: strain selection (probiotic effects are strain-specific, not species-specific) and study population (effects tend to be larger in people whose biomarkers are abnormal at baseline).

This trial addressed both. The researchers used a defined three-strain L. plantarum consortium pre-screened for bile salt hydrolase activity -- the same mechanism that underlies several other successful probiotic-cholesterol trials. And they restricted enrollment to adults who already had elevated cholesterol, then ran a pre-planned subgroup analysis splitting the cohort by baseline severity: low initial values (LIV, total cholesterol 2000 to 2500 mg/L) and high initial values (HIV, 2510 to 3000 mg/L).

That subgroup design is what makes the trial worth paying attention to. Most probiotic-cholesterol studies report a single average effect. This one tested whether the effect tracked baseline risk -- and the answer was yes.

How It Was Designed

The basics are in the study design bar above: 60 hypercholesterolemic adults, 12 weeks, one capsule per day containing 1.2 billion colony-forming units of three L. plantarum strains, randomized double-blind placebo-controlled, conducted by AB-Biotics in Spain. A few methodological choices deserve attention.

The strain selection is the first one. CECT 7527, 7528, and 7529 were screened for bile salt hydrolase activity, acid tolerance, and bile tolerance -- the three properties a probiotic needs to survive gastric transit and act in the small intestine. Combining three different L. plantarum strains rather than relying on a single strain hedges against between-strain variability while keeping the mechanism (BSH-mediated bile acid deconjugation) consistent across the consortium.

The dose was modest: 1.2 billion CFU total per day, delivered in a single capsule. That is on the lower end of probiotic dosing in the cholesterol literature, which makes the magnitude of the cholesterol reductions more striking -- they were not driven by an unusually high CFU load.

The pre-specified subgroup split by baseline cholesterol allowed the researchers to test a clinically important hypothesis: does the probiotic work harder for the people who need it more? This is a question that single-effect-size trials cannot answer, and it has direct implications for who is likely to benefit from a probiotic intervention.

What They Found

Compared to placebo, the L. plantarum group showed statistically significant cholesterol reductions, with the largest effects in participants whose baseline cholesterol was highest:

Biomarker	Subgroup	Change vs. Placebo	What It Measures
Total cholesterol	Full cohort	-13.6%	All circulating cholesterol
Total cholesterol	High baseline (HIV)	-17.4%	All circulating cholesterol
LDL cholesterol	High baseline (HIV)	-17.6%	Primary atherogenic lipoprotein
Oxidized LDL	High baseline (HIV)	-15.6%	Atherogenic form of LDL
Total cholesterol	Low baseline (LIV)	-9.4%	All circulating cholesterol

Green indicates a favorable direction vs. placebo. All differences are statistically significant.

Reading the Results

The results split into two readings worth separating.

The headline effect: total cholesterol fell 13.6% across the whole cohort. A double-digit reduction in total cholesterol from a once-daily probiotic capsule, with no diet change and no exercise prescription, is in the same range as several low-dose pharmacological interventions. The mechanism is consistent with the broader bile salt hydrolase literature: BSH-active bacteria deconjugate bile acids in the intestine, the liver compensates by synthesizing new bile acids from circulating cholesterol, and serum cholesterol falls as a consequence.

The more interesting effect: the response scaled with baseline risk. In participants who entered the trial with the highest cholesterol (the HIV subgroup), total cholesterol fell 17.4%, LDL fell 17.6%, and oxidized LDL -- the form of cholesterol that actually drives arterial plaque -- fell 15.6%. In the LIV subgroup, the total cholesterol drop was 9.4%, still significant but roughly half the magnitude. The interpretation: the probiotic works harder for people whose biology has more room to move. This is biologically plausible (more substrate for BSH-mediated deconjugation when cholesterol synthesis is upregulated) and clinically useful (the patients who need the help most are the ones most likely to respond).

The oxidized LDL signal is worth a separate note. Oxidized LDL is the form that gets taken up by macrophages in the artery wall to form the foam cells that initiate atherosclerotic plaque. Reducing oxidized LDL specifically -- rather than just total LDL -- is mechanistically closer to reducing actual cardiovascular risk. The 15.6% reduction in the HIV subgroup is one of the cleaner oxidized LDL signals from a probiotic intervention in the literature.

What Didn't Change

The trial did not report significant probiotic effects on HDL cholesterol or triglycerides, consistent with the BSH mechanism specifically targeting cholesterol absorption and bile acid recycling. The effect in the LIV subgroup was smaller, meaning the trial does not establish equivalent benefit across the full range of mildly-to-moderately elevated cholesterol. The trial was 12 weeks; longer-term durability was not assessed in this report. No serious adverse events were reported and the probiotic was well tolerated.

Broader Context

This trial is part of a small but growing set of well-designed human RCTs demonstrating that gut bacteria can directly modulate cardiovascular risk factors. The L. plantarum CECT consortium and the L. reuteri NCIMB 30242 strain are the two most cited examples in the BSH-mediated cholesterol-lowering literature. Both produced double-digit cholesterol reductions in hypercholesterolemic adults within 9 to 12 weeks. Both depend on the same biochemistry -- deconjugation of conjugated bile acids in the small intestine -- but reached the same outcome through different strains and different multi-strain configurations, which strengthens the underlying mechanism case.

The gut-cardiovascular axis is also where olive polyphenols become interesting in a new way. Hydroxytyrosol and oleuropein have an authorized EFSA health claim for protection of blood lipids from oxidative damage at 5 mg/day. They also reach the colon largely intact, where they are metabolized by gut bacteria into bioactive secondary metabolites that modulate the microbiome itself. The intersection of olive polyphenols and mechanism-targeted probiotic strains is an active frontier in gut-cardiovascular research.

Related Research

Continue exploring the gut-cardiovascular axis and probiotic evidence:

• L. reuteri NCIMB 30242 Lowered LDL by 11.6%: A Bile Salt Hydrolase RCT
• Gut Microbiome Explains 6% of Blood Triglyceride Variance in 893 Adults
• Probiotic Consortium Lowered Cholesterol in Mice: A Bile Salt Hydrolase Mechanism

Source: View the original study on PubMed

Olivea's Dosage

This trial tested a specific three-strain L. plantarum probiotic -- not an Olivea product. Olivea's current portfolio focuses on the polyphenol side of the gut-cardiovascular axis: a single tablespoon of Olivea extra virgin olive oil delivers the EFSA-recognized polyphenol dose, and each Olivea capsule delivers over 20 mg of hydroxytyrosol per serving (third-party certificate of analysis confirmed 23.5 mg per capsule).

We share this research for transparency. This is an independent study -- we did not fund it, design it, or conduct it.

Editorial Information

Research note. This article summarizes third-party research published in a peer-reviewed journal. Olivea did not conduct or fund the study. Findings reflect the cited paper only and do not establish efficacy of Olivea products.

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