Data published in Nutrients indicated that the probiotic–phytonutrient blends also increased levels of beneficial short chain fatty acids (SCFAs) in feces, particularly butyrate.
Reductions in levels of the gut barrier-related marker zonulin were also detected, with these reaching statistical significance in overweight participants.
“Collectively, these findings suggest that probiotic–phytonutrient supplementation may influence gut microbial activity and gut barrier-related biomarkers through microbiome-mediated metabolic modulation,” wrote the study’s authors, led by Ah Young Hwang from HEM Pharma in South Korea.
Products
The study included two distinct products. The first, called Probiotic Blend containing Phytonutrients 1 (PBP1), was formulated with Lacticaseibacillus rhamnosus HEM648 (L. rhamnosus Nutrilite 648) and L. paracasei HEM272 (L. paracasei Nutrilite 272) plus the dandelion root powder and citrus bioflavonoid complex to provide 3 billion CFUs per day.
The second probiotic–phytonutrient blend (PBP2) was formulated with Bifidobacterium animalis subsp. lactis IDCC 4301, L. rhamnosus IDCC 3201, and Lactobacillus acidophilus IDCC 3302, L. rhamnosus HEM648, and L. paracasei HEM272 plus the same dandelion root powder and citrus bioflavonoid complex. Each capsule was designed to provide 10 billion CFUs per day.
Commenting on the study’s findings, Yosep Ji, CEO of HEM Pharma Inc. and co-author on the new study, told NutraIngredients: “What’s worth highlighting here is the strain selection process behind PBP1 and PBP2.
“As I discussed at IPC, we use PMAS, our colon-mimetic screening platform, to evaluate candidate strains against real human fecal microbiomes before they ever reach a clinical trial — something that’s simply not feasible at that scale in conventional preclinical or clinical designs. L. rhamnosus Nutrilite 648 and L. paracasei Nutrilite 272, the two strains shared across both PBP1 and PBP2, were prioritized through that process," said Ji.
“What this trial shows is that the functional signal we look for at the screening stage translated into the clinic: both blends significantly increased fecal SCFAs, including butyrate, and in participants with BMI 25–30, they also produced a significant reduction in zonulin (gut permeability biomarker). That’s the real value of a platform like PMAS — it lets us pre-screen for functional outcomes across a level of inter-individual variability that’s impossible to sample for in a standard trial, so the strains that make it to human studies are more likely to perform predictably. We see this as the model going forward: use PMAS to narrow the field before clinical testing, so that clinical results become something we can anticipate rather than discover.”
Study details
The new randomized, double-blind, placebo-controlled trial included 60 adults, with 54 included in the final analysis. The participants were randomly assigned to one of three groups: Placebo, PBP1, or PBP2 for eight weeks.
Results showed that both probiotic–phytonutrient blends led to significant increases in the proportion of normal stool types, measured as types 3-5 on the Bristol Stool Form Scale.
“These results suggest that PBP1 and PBP2 supplementation may contribute to the normalization of bowel habits by increasing normal stool types while reducing abnormal stool forms,” wrote the researchers. “In addition to changes in stool patterns, some gastrointestinal symptom-related questionnaire items showed improvement following supplementation. Notably, urgency of postprandial bowel movements was significantly reduced in the PBP1 group compared with the placebo group.”
The data also showed that PBP1 and PBP2 led to significant increases in fecal SCFA levels, with butyrate levels significantly increased compared with placebo.
Tryptophan levels were found to decrease, while indole metabolites increased, said the researchers, which suggested microbiome-mediated conversion of tryptophan to indoles.
“Indole and its derivatives are well-recognized microbial signaling molecules that contribute to intestinal homeostasis,” explained the researchers. “In this context, the observed increase in indole metabolites following PBP1 and PBP2 supplementation may reflect a functionally relevant metabolic shift toward barrier-supportive signaling, consistent with the concurrent reduction in zonulin levels.”
Analysis of the microbiome revealed that both probiotic-phytonutrient formulations were associated with increased abundances of microbes linked to fermentation of carbohydrates, including Prevotella, Eubacterium group, and Oscillibacter. All of these may explain the increase in SCFA production.
“These compositional changes are consistent with the observed increases in fecal butyrate levels and reductions in zonulin, suggesting a potential link between microbiome modulation and improved intestinal barrier function,” wrote the researchers.
“Given the exploratory nature of the study and the reliance on surrogate outcome measures, further studies are needed to confirm these findings and determine their clinical significance,” they concluded.
Source: Nutrients, 2026, 18(13), 2085; doi: 10.3390/nu18132085. “Effects of Probiotic–Phytonutrient Blends on Defecation, Intestinal Barrier Function, and Gut Microbiota: A Randomized, Placebo-Controlled Trial”. Authors: A.Y. Hwang, et al.
