Characterization and safety of uniform particle size NovaSil clay as a potential aflatoxin enterosorbent

Abstract

NovaSil (NS) clay, a common anti-caking agent in animal feeds, has been shown to adsorb aflatoxins and diminish their bioavailability in multiple animal models. The safety of long-term dietary exposure to NS has also been demonstrated in a 6-month sub-chronic study in rats and in a 3-month intervention in humans highly exposed to aflatoxins. Uniform particle size NovaSil (UPSN) is a refined material derived from parent NS; it contains lower levels of dioxins/furans, and has been selected for a more consistent uniform particle size. Nevertheless, the efficacy and potential safety/toxicity of UPSN for long term-use has not yet been determined. In this research, 4-week-old male and female Sprague Dawley rats were fed rations free of clay (control) and containing UPSN at low dose (0.25%) and high dose (2%) for 13 weeks. AFB1 sorption characteristics remained the same for both clays. When compared to the control, total body weight gain was unaffected in either sex at the doses tested. No UPSN-dependent differences in relative organ weights or gross appearance were observed. Isolated differences between UPSN groups and the control were observed for some biochemical parameters and selected vitamins and minerals. None of these differences were dose-dependent, and all parameters fell between ranges reported as normal for rats less than 6 month old. The Na/K ratio, Na and vitamin E concentrations were the only parameters that were increased in both males and females in the low dose and high dose UPSN groups. Serum Zn levels in males from the 2% UPSN treatment were lower compared to the control. Serum K levels were lower in the males of UPSN groups than in the control. However, neither Na/K ratio, K, nor Zn values were dose dependent and fell outside ranges reported as normal. These results suggest that dietary inclusion of UPSN at levels as high as 2% (w/w) does not result in overt toxicity. Nevertheless, further research on the effects of clays on Na, Zn, K and vitamin E is warranted.

Short-Term Safety and Efficacy of Calcium Montmorillonite Clay (UPSN) in Children

“…65 Increases in Ca 2+ have been observed after administration of the parent NS product and UPSN in rats, which was attributed to dissolution of calcite and exchangeable Ca 2+ ions from montmorillonite. 46,47 However, in this study, total Ca 2+ levels were decreased in all treatment groups, including the placebo (calcium carbonate). Calcium carbonate and, to a lesser extent, NS clay typically act as calcium supplements; thus, it is likely that this overall reduction in serum levels is a result of dietary changes during the intervention trial.…”

“…Metal and dioxin analyses of both NS (BASF) and UPSN were reported to be similar and well under the tolerable daily intake (TDI) or provisional tolerable daily intake (PTDI) set forth by the World Health Organization (WHO) and the Joint Food and Agriculture Organization/WHO Expert Committee on Food Additives (JECFA). 46 UPSN was sterilized by electron beam irradiation to prevent any possible bacterial or viral contamination before trial initiation.…”

“…The new product, Uniform Particle Size NovaSil (UPSN), displayed a similar AFB 1 sorption capacity to that of NS during isothermal analysis and was deemed to be more palatable for human consumption. 46 In vivo efficacy of UPSN was verified in Ghanaian adults during a crossover-designed *Address correspondence to Nii-Ayi Ankrah, Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana. E-mail: NAnkrah@noguchi.ug.edu.gh trial, in which UPSN was added to participants' food before ingestion.…”

“…45 Results from mineralogical analyses of UPSN and NS indicated similar structural, morphological, and chemical characteristics; therefore, the two materials are thought to possess similar safety profiles. 46 Safety assessment of both NS and UPSN has been conducted in animal and adult human trials. 36,[46][47][48] Results of NS clay phase I and II clinical trials suggest that ingestion of up to 3 g/ day in adults is safe for a 3-month period.…”

“…46 Safety assessment of both NS and UPSN has been conducted in animal and adult human trials. 36,[46][47][48] Results of NS clay phase I and II clinical trials suggest that ingestion of up to 3 g/ day in adults is safe for a 3-month period. [49][50][51] Based on detailed studies conducted in animals and humans, it was determined that ingestion of UPSN at levels efficacious for reducing AFB 1 biomarkers would be reasonably safe in children.…”