Browsing by Author "Williams, J.H."

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Calcium montmorillonite clay reduces urinary biomarkers of fumonisin B1 exposure in rats and humans
(2012) Robinson, A.; Johnson, N.M.; Strey, A.; Taylor, J.F.; Marroquin-Cardona, A.; Mitchell, N.J.; Afriyie-Gyawu, E.; Ankrah, N.A.; Williams, J.H.; Wang, J.S.; Jolly, P.E.; Nachman, R.J.; Phillips, T.D.
Fumonisin B1 (FB1) 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 FB1 (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 FB1 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 FB1 control, FB1þ2% NS or absolute control group. FB1 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 from weeks 8 and 10 were collected from the study participants for analysis. In rats, NS significantly reduced urinary FB1 biomarker by 20% in 24 h and 50% after 48 h compared to controls. In the humans, 56% of the urine samples analysed (n¼186) had detectable levels of FB1. Median urinary FB1 levels were significantly (p50.05) decreased by 490% 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 FB1 (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 FB1. This is important since AF is a proven dietary risk factor for hepatocellular carcinoma (HCC) in humans and FB1 is suspected to be a dietary risk factor for HCC and oesophageal cancer in humans.
HIV and hepatocellular and esophageal carcinomas related to consumption of mycotoxin-prone foods in sub-Saharan Africa
(Am J Clin Nutr., 2010) Williams, J.H.; Grubb, J.A.; Davis, J.W.; Wang, J.-S.; Jolly, P.E.; Ankrah, N.-A.; Ellis, W.L.; Afriyie-Gyawu, E.; Johnson, N.M.; Robinson, A.G.; Phillips, T.D.
Background: Promotion of the HIV epidemic by aflatoxin is postulated but not yet established. Sub-Saharan populations commonly consume food contaminated by mycotoxins; particularly aflatoxins predominantly found in peanut, maize, rice and cassava; and fumonisins which occur primarily in maize. Aflatoxin promotes hepatocellular cancer and fumonisin may promote oesophageal cancer. Objective: This analysis was undertaken to test the hypotheses that consumption of mycotoxin8 prone staple foods is: 1) related to incidence of HIV infection in Africa; and 2) related to ‘signature’ cancer rates confirming exposure to aflatoxins and fumonisins. Data & Analyses: WHO data for causes-of-death and the FAO per capita consumption data for commodities in Sub-Saharan Africa were used. Per capita GDP and percent Muslim were social-economic data sets exploited. Relationships between causes of mortality; consumption of mycotoxin-prone foods; and socio-economic variables were evaluated. Models for HIV transmission rate as a function of maize consumption and Muslim prevalence were estimated. Results: HIV and oesophageal cancer deaths were significantly related to maize; but were inversely related to Muslim%, and rice consumption. HIV infections were minimized (74 v 435 100,000-1 17 people: OR=2.41: 95% CI 1.73, 3.24: P=<0.0001) by the combination of low maize consumption and above-median Muslim prevalence. Hepatocellular cancer deaths were positively related to rice but negatively to maize consumption. Conclusions: HIV transmission frequency increases with maize consumption. Cancer relationships to foods suggest that fumonisin contamination and not aflatoxin is the mostly likely feature in maize promoting HIV. Changing maize quality may avoid up to 1,000,000 transmissions annually.
NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis. I. Study design and clinical outcomes
(Food Additives and Contaminants 25(1):76-87, 2008) Afriyie-Gyawu, E.; Ankrah, N. A.; Huebner, H.J.; Ofosuhene, M.; Kumi, J.; Johnson, N.M.; Tang, L.; Xu, L.; Jolly, P.E.; Ellis, W.O.; Ofori-Adjei, D.; Williams, J.H.; Wang, J.S.; Phillips, T.D.
In a phase I clinical trial in the U.S., NovaSil clay (NS) showed no significant adverse health effects in humans. In this study (3 month duration), a double-blinded, placebo controlled clinical trial was conducted in Ghana to investigate the safety, tolerance, and aflatoxin sorption efficacy of dietary NS. Volunteers (507 subjects, ages from 18 – 58 yrs) were clinically screened to evaluate their general health, pregnancy status, and levels of blood AFB1-Albumin adducts. Of these subjects, 177 (101 males, 76 females) were randomly assigned to 3 groups: high-dose (HD), low-dose (LD) and placebo-control (PL) groups receiving 3.0, 1.5 and 0 g NS/day in capsules. As a safety precaution, 3.0 g NS was selected as the highest dose since it represented the MED (minimal effective dose) of NS for AFs based on previous animal studies. NS capsules were administered to each participant under the supervision of trained study monitors prior to meals. Blood and urine samples were collected for laboratory analysis. Physical examinations were performed monthly and follow-up was taken to record any side effects daily. Ninety-four percent of the participants (166 of 177) completed the study and compliance rate was 97.4%, 96.4%, and 98.5% for HD, LD, and PL groups, respectively. Overall, 99.4% of person-time reported no side effects throughout the study. Mild to moderate health events were recorded in some of the participants. Throughout the study duration, the total reported side effects with respect to complaints were 0.66%, 0.68%, and 0.48% for HD, LD, and PL, respectively. Symptoms included nausea, vomiting, diarrhea, flatulence, abdominal discomfort, heartburn and dizziness. These side effects were neither dose-dependent nor statistically significant among the three groups. Also, some participants (in all groups) reported having increased appetite in the course of the study. No significant differences were shown in hematology, liver and kidney function, electrolytes, and vital signs in the three groups. These findings demonstrate that application of NS clay for the protection of humans at high risk for aflatoxicosis may represent a novel and economically feasible approach
NovaSil™clay for the management of dietary aflatoxins in human populations
(Mycotoxins: Detection Methods, Management, Public Health and Agricultural Trade, 2008-05) Afriyie-Gyawu, E.; Williams, J.H.; Huebner, H.J.; Ankrah, N.A.; Ofori-Adjei, D.; Jolly, P.E.; Wang, J.S.; Phillips, T.D.
Cost-effective interventions that reduce human diseases and death from aflatoxin exposure are high priorities particularly for developing nations. A calcium montmorillonite clay, Nova- Sil™, when mixed at low inclusion rates with animal feeds can act as a selective enterosorbent for aflatoxins. NovaSil™ sequesters aflatoxins in the gastrointestinal tract and neutralizes their toxic effects by reducing the bioavailability of the toxins in the blood and other organs. These findings are especially significant for developing countries since clay-based strategies for managing aflatoxicosis would be practical, culturally acceptable, sustainable and unique in reducing external exposure and risk. When included in the diet of animals at levels up to 2.0% (w/w), NovaSil™ clay did not interfere with vitamin or micronutrient utilization. These results also support the hypothesis that NovaSil™ clay interventions in developing countries could have a major impact on health and well-being of susceptible humans who are highly and frequently exposed to these dietary toxins without compromising their nutritional status. Recent work has confirmed the relative safety of NovaSil™ in a long-term rodent study at and in a Phase I Adverse Events trial. No significant NovaSil™- related effects were observed in either study, and the conclusions were that NovaSil™ should be tested in a Phase II human trial in Ghana. A study population in Ghana has been identified that is exposed to high levels of dietary aflatoxins based on biomarkers in their blood and urine samples. This study will evaluate the consequences of NovaSil™ treatment on aflatoxin exposure over a 3-month period. In summary,enterosorption strategies, based on dietary NovaSil™ clay, hold great promise for the management of aflatoxins in highrisk human populations especially in developing countries. The remedy is novel, inexpensive and easily disseminated. © CAB International 2008.
PAH exposure in a Ghanaian population at high risk for aflatoxicosis
(Sci Total Environ. 407(6): 1886-91, 2009) Ofori-Adjei, D.; Johnson, N.M.; Afriyie-Gyawu, E.; Huebner, H.; Marroquin-Cardona, A.; Robinson, A.; Tang, L.; Xu, L.; Ankrah, N.A.; Ofori-Adjei, D.; Jolly, P.E.; Williams, J.H.; Wang, J.S.; Phillips, T.D.
It was postulated that a population in sub-Saharan Africa, known to be at high risk for aflatoxicosis due to frequent ingestion of aflatoxin (AF)-contaminated foods could also be exposed to polycyclic aromatic hydrocarbons (PAHs) from a variety of environmental sources. Previously, participants in this population were shown to be highly exposed to AFs, and this exposure was significantly reduced by intervention with NovaSil clay (NS). Objectives of this study were 1) to assess PAH exposure in participants from the AF study using urinary biomarker 1-hydroxypyrene (1-OHP); 2) examine the effect of NS clay and placebo (cellulose) treatment on 1-OHP levels; and 3) determine potential association(s) between AF and PAH exposures. A clinical trial was conducted in 177 Ghanaians who received either NS capsules as high dose or low dose, or placebo (cellulose) for a period of 3 months. At the start and end of the study, urine samples were analyzed for 1-OHP. Of the 279 total samples, 98.9% had detectable levels of 1-OHP. Median 1-OHP excretion in nonsmokers was 0.64 micromol/mol creatinine at baseline and 0.69 micromol/mol creatinine after 3 months. Samples collected at both time points did not show significant differences between placebo and NS-treated groups. There was no linear correlation between 1-OHP and AF-albumin adduct levels. Results show that this population is highly exposed to PAHs (and AFs), that NS and cellulose treatment had no statistically significant effect on 1-OHP levels, and that this urinary biomarker was not linearly related with AF exposure.
Safety of "sachet water" and raw milk
(Ghana Med. Journal 41(2): 37, 2007) Ofori-Adjei, D.; Afriyie-Gyawu, E.; Ankrah, N. A.; Huebner, H.J.; Ofosuhene, M.; Kumi, J.; Johnson, N.M.; Tang, L.; Xu, L.; Jolly, P.E.; Ellis, W.O.; Williams, J.H.; Wang, J.S.; Phillips, T.D.
A 3-month double-blind and placebo-controlled, phase IIa clinical trial was conducted in Ghana to investigate the safety, tolerance and aflatoxin-sorption efficacy of dietary NovaSil (NS). Volunteers (507 subjects) were clinically screened to evaluate their general health, pregnancy status and blood AFB(1)-albumin adduct levels. Of these subjects, 177 were randomly assigned to three groups: high-dose (HD), low-dose (LD) and placebo-control (PL) groups receiving 3.0, 1.5 and 0 g NS day(-1) in capsules. Trained study-monitors supervised NS capsule administration to participants and recorded side-effects daily. Physical examinations were performed monthly. Blood and urine samples were collected for laboratory analysis. Approximately 92% of the participants (162 of 177) completed the study and compliance rate was over 97%. Overall, 99.5% of person x time reported no side-effects throughout the study. Mild to moderate health events (approximately 0.5% of person x time) were recorded in some participants. Symptoms included nausea, diarrhea, heartburn and dizziness. These side-effects were statistically similar among all three groups. No significant differences were shown in hematology, liver and kidney function or electrolytes in the three groups. These findings demonstrate that NS clay is apparently safe and practical for the protection of humans against aflatoxins in populations at high risk for aflatoxicosis.