It is well documented that aflatoxin contamination in foods presents
significant economic and public health burdens worldwide. Aflatoxins,
particularly aflatoxin B1 (AFB1), have been implicated in the etiology of disease
and death in many parts of the world, necessitating research initiatives for
intervention strategies designed to diminish biological exposure. Calcium
montmorillonite clays (e.g. NovaSil Plus, NSP) have been found to tightly bind
and inactivate aflatoxins in the gastrointestinal tract of multiple animal species.
In the future, the hypothesis is that this strategy may also be appropriate for
humans. Thus, the overall research goal was to investigate NSP suitability for
human use through in vitro characterization followed by in vivo evaluation of
NSP-AFB1 sorption and most importantly, safety of the clay.
The first objective was to characterize the in vitro and in vivo sorption
efficiency of NSP-AFB1 sorption and determine potential interactions with
vitamin A (VA). Isothermal analysis suggested that NSP binds AFB1 with high
capacity, affinity, and specificity in aqueous solution and further indicated that
NSP does not appear to interact with VA. Subsequent short-term studies in
Sprague-Dawley (S-D) rats and broiler chicks indicated that dietary inclusion of
NSP (0.25%) significantly reduced AFB1 bioavailability without exerting overt
toxicity.
The second objective was to evaluate potential adverse effects of chronic
ingestion of dietary NSP using male and female S-D rats in the absence of
aflatoxins. Although statistically significant changes to a few parameters were
noted, the differences did not appear to be NSP- or dose-dependent, suggesting
that NSP at dietary inclusion levels as great as 2.0% (w/w) does not produce
overt toxicity. Thus, this information increases the feasibility for using NSP in
human trials in populations at high risk for aflatoxicosis.
The third objective was to establish representative baseline data on
human exposure to aflatoxins by collecting and quantifying urinary AFM1 in
volunteers living in four separate communities in Ejura district of Ghana. Results
revealed that urinary AFM1 in the study population was substantially high (mean
= 1,850.86 ± 274.59 pg/mg creatinine), indicating that this particular population
was highly exposed to aflatoxins and could be used for future intervention trials.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/3192 |
| Date | 12 April 2006 |
| Creators | Afriyie-Gyawu, Evans |
| Contributors | Phillips, Timothy D. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 3726115 bytes, electronic, application/pdf, born digital |
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