Does Supplementation with Lactobacillus casei Shirota Prevent Aflotoxin Absorption?

Written by Angeline A. De Leon, Staff Writer. Study suggests that Lactobacillus casei Shirota may be useful as a dietary approach to prevent human exposure to aflatoxin by reducing its absorption in the gastrointestinal tract.

Aflatoxins are a family of toxins produced by fungi found on agricultural crops, primarily Aspergillus flavus and Aspergillus paraciticus ¹. In developing countries, consumption of aflatoxin-contaminated foods has been linked to outbreaks of hepatic encephalopathy and aflatoxicosis-related death ². To prevent aflatoxin absorption, epidemiological studies have proposed the adoption of probiotic-mediated detoxification through dietary intervention ^3,4. The probiotic Lactobacillus casei Shirota (LcS) demonstrates the ability to limit intestinal absorption of aflatoxins by binding the chemical compounds to its bacterial cell wall ⁵. In rodents, for example, LcS has been shown to effectively reduce blood serum levels of aflatoxins ⁶. Although certain probiotic formulations have been seen to effectively reduce aflatoxin concentrations in humans ⁷, the clinical utility of LcS in preventing exposure to aflatoxins requires further investigation in human patients. In a 2016 study ⁸ published in the British Journal of Nutrition, scientists evaluated the relationship between supplementation with fermented milk containing LcS and biomarkers of aflatoxin, serum AFB₁-lys (aflatoxin B₁-lysine adduct, associated with longer-term exposure ⁹ and urinary AFM₁ (aflatoxin M1, associated with shorter-term exposure (8)), testing whether probiotic intake would prevent aflatoxin absorption.

A total of 71 healthy subjects (50.7% males, mean age = 34.34 years) with detectable levels of urinary AFM₁ (> 0.005 ng/ml) were enrolled in a randomized, double-blind, placebo-controlled, cross-over trial. Subjects were randomized to ingest 80 ml of a fermented milk beverage containing 3.0 x 10¹⁰ CFU of LcS or a placebo beverage twice daily for 4 weeks (Group 1). After a 2-week washout period, participants then completed the alternate treatment arm of the study for another 4 weeks (Group 2). At baseline and every 2 weeks, urine and fasting blood samples were collected in order to quantify serum levels of AFB₁-lys and AFM₁. Food intake among subjects was also monitored using a 2-day food record.

Results did not support evidence of an overall significant difference between treatment groups in concentrations of serum AFB₁-lys or AFM₁ during the intervention. However, within-group analyses indicated that subjects in Group 1 receiving the probiotic beverage had a 17.63% lower concentration of AFB₁-lys after 2 weeks of supplementation (from 6.24 +/- 3.42 pg/mg albumin to 5.14 +/- 2.15 pg/mg albumin) (p = 0.048). By Week 4, AFB₁-lys concentrations were found to be significantly lower for those in Group 1 receiving the LcS probiotic vs. placebo (5.48 +/- 2.25 pg/mg albumin vs. 6.35 +/- 2.41 pg/mg albumin, respectively) (p = 0.005). No such trends were observed for Group 2, either for AFB₁-lys or AFM₁.

Although probiotic supplementation with LcS did not prove to significantly change aflatoxin biomarkers, relative to placebo, during the intervention, findings suggest that beneficial effects were apparent for select subjects, specifically those who received LcS in the first phase of the intervention (Group 1). In this group, participants ingesting the probiotic beverage showed significantly lower concentrations of AFB₁-lys, compared to placebo, suggesting that the order of probiotic intervention may influence the efficacy of LcS in preventing aflatoxin absorption. A potential explanation for the difference in clinical outcome observed between groups may be related to changes in subjects’ dietary intake between the first and second phase of intervention (food records indicated significantly higher intake of foods containing aflatoxin among subjects in Group 2). Study limitations include a relatively short wash-out period, a relatively small sample size, and the absence of fecal analysis. Additional studies accounting for these limitations are needed to further clarify the role of LcS in preventing aflatoxin absorption in humans.

Source: Redzwan SM, Mutalib MSA, Wang JS, et al. Effect of supplementation of fermented milk drink containing probiotic Lactobacillus casei Shirota on the concentrations of aflatoxin biomarkers among employees of Universiti Putra Malaysia: a randomised, double-blind, cross-over, placebo-controlled study. British Journal of Nutrition. 2016; 115: 39-54. DOI: 10.1017/20007114515004109.

© The Authors 2015

Posted June 9, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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