Oral doses of calcium montmorillonite clay reduced urinary biomarkers and bioavailability of Fumonisin B1 and aflatoxin, two contaminants of grain that are carcinogenic. - GreenMedInfo Summary

Fumonisin B(1) (FB(1)) is often a co-contaminant with aflatoxin (AF) in grains and may enhance AF's carcinogenicity by acting as a cancer promoter. Calcium montmorillonite (i.e. NovaSil, NS) is a possible dietary intervention to help decrease chronic aflatoxin exposure where populations are at risk. Previous studies show that an oral dose of NS clay was able to reduce AF exposure in a Ghanaian population. In vitro analyses from our laboratory indicated that FB(1) (like aflatoxin) could also be sorbed onto the surfaces of NS. Hence, our objectives were to evaluate the efficacy of NS clay to reduce urinary FB(1) in a rodent model and then in a human population highly exposed to AF. In the rodent model,male Fisher rats were randomly assigned to either FB(1) control, FB(1) + 2% NS or absolute control group. FB(1) alone or with clay was given as a single dose by gavage. For the human trial, participants received NS (1.5 or 3 g day(-1)) or placebo (1.5 g day(-1)) for 3 months. Urines fromweeks 8 and 10 were collected from the study participants for analysis. In rats, NS significantly reduced urinary FB(1) biomarker by 20% in 24 h and 50% after 48 h compared to controls. In the humans, 56% of the urine samples analysed (n = 186) had detectable levels of FB(1). Median urinaryFB(1) levels were significantly (p < 0.05) decreased by>90% in the high dose NS group (3 g day(-1)) compared to the placebo. This work indicates that our study participants in Ghana were exposed to FB(1) (in addition to AFs) from the diet. Moreover, earlier studies have shown conclusively that NS reduces the bioavailability of AF and the findings from this study suggest that NS clay also reduces the bioavailability FB(1). This is important since AF is a proven dietary risk factor for hepatocellular carcinoma (HCC) in humans and FB(1) is suspected to be a dietary risk factor for HCC and oesophageal cancer in humans.