Determinants of aflatoxin levels in Ghanaians: sociodemographic factors, knowledge of aflatoxin and food handling and consumption practices

Aflatoxins are among the most potent of carcinogens found in staple foods such as groundnuts, maize and other oil seeds. This study was conducted to measure the levels of aflatoxin B(1) (AFB(1)) albumin adducts in blood and aflatoxin M(1) (AFM(1)) metabolite in urine of people in a heavy peanut and maize consuming region of Ghana and to examine the association between aflatoxin levels and several socio-demographic factors and food handling and consumption practices. A cross-sectional study was conducted in four villages in the Ejura Sekyedumase district of Ghana. A socio-demographic survey was administered to 162 participants. Blood samples were collected from 140 and urine samples from 91 of the participants and AFB(1) albumin-adduct levels in blood and AFM(1) levels in urine were measured. High AFB(1) albumin-adduct levels were found in the plasma (mean+/-SD=0.89+/-0.46pmol/mg albumin; range=0.12-3.00pmol/mg; median=0.80pmol/mg) and high AFM(1) levels in the urine (mean+/-SD=1,800.14+/-2602.01pg/mg creatinine; range=non-detectable to 11,562.36pg/mg; median=472.67pg/mg) of most of the participants. There was a statistically significant correlation (r=0.35; p=0.007) between AFB(1)-albumin adduct levels in plasma and AFM(1) levels in urine. Several socio-demographic factors, namely, educational level, ethnic group, the village in which participants lived, number of individuals in the household, and number of children in the household attending secondary school, were found to be significantly associated with AFB(1) albumin-adduct levels by bivariate analysis. By multivariate analyses, ethnic group (p=0.04), the village in which participants live (p=0.02), and the number of individuals in the household (p=0.01), were significant predictors of high AFB(1) albumin-adducts. These findings indicate strongly that there is need for specifically targeted post-harvest and food handling and preparation interventions designed to reduce aflatoxin exposure among the different ethnic groups in this region of Ghana.     

Detection of serum AFB1-lysine adduct in Malaysia and its association with liver and kidney functions

Aflatoxin is ubiquitously found in many foodstuffs and produced by Aspergillus species of fungi. Of many aflatoxin metabolites, AFB₁ is classified by the International Agency for Research on Cancer (IARC) as group one carcinogen and linked to the development of hepatocellular carcinoma (HCC). The study on molecular biomarker of aflatoxin provides a better assessment on the extent of human exposure to aflatoxin. In Malaysia, the occurrences of aflatoxin-contaminated foods have been documented, but there is a lack of data on human exposure to aflatoxin. Hence, this study investigated the occurrence of AFB₁-lysine adduct in serum samples and its association with liver and kidney functions. 5 ml fasting blood samples were collected from seventy-one subjects (n = 71) for the measurement of AFB₁-lysine adduct, albumin, total bilirubin, AST (aspartate aminotransferase), ALT (alanine transaminase), ALP (alkaline phosphatase), GGT (gamma-glutamyl transpeptidase), creatinine and BUN (blood urea nitrogen). The AFB₁-lysine adduct was detected in all serum samples (100% detection rate) with a mean of 6.85 ± 3.20 pg/mg albumin (range: 1.13–18.85 pg/mg albumin). Male subjects (mean: 8.03 ± 3.41 pg/mg albumin) had significantly higher adduct levels than female subjects (mean: 5.64 ± 2.46 pg/mg albumin) (p < 0.01). It was noteworthy that subjects with adduct levels greater than average (>6.85 pg/mg albumin) had significantly elevated level of total bilirubin (p < 0.01), GGT (p < 0.05) and creatinine (p < 0.01). Nevertheless, only the level of total bilirubin, (r = 0.347, p-value = 0.003) and creatinine (r = 0.318, p-value = 0.007) showed significant and positive correlation with the level of AFB₁-lysine adduct. This study provides a valuable insight on human exposure to aflatoxin in Malaysia. Given that aflatoxin can pose serious problem to the health, intervention strategies should be implemented to limit/reduce human exposure to aflatoxin. Besides, a study with a big sample size should be warranted in order to assess aflatoxin exposure in the general population of Malaysia.     

Variability in aflatoxin-albumin adduct levels and effects of hepatitis B and C virus infection and glutathione S-transferase M1 and T1 genotype

Exposure to aflatoxin B1 (AFB1), an important cofactor in the etiology of hepatocellular carcinoma in Taiwan, is influenced by dietary and other factors. The present study examined the intraindividual variability in AFB1-albumin adducts, the most reliable long-term biomarker of AFB1 exposure, and whether the baseline or follow-up adduct levels and the intraindividual variability in adduct levels are modified by endogenous and environmental factors. The study measured AFB1-albumin adduct levels among 264 healthy male residents of three townships (Hu-Hsi, Ma-Kung, and Pai-Hsa) of Penghu Islets, Taiwan, at two different time points with a median interval of 1.68 years (range 1.00-3.17 years). There was a generalized reduction in the adduct levels, with the median values being 22.1 pmol/mg (range 5.0-355.8 pmol/mg) at time 1 and 14.3 pmol/mg (range 5.0-205.2 pmol/mg) at time 2. This intraindividual variability in adduct levels was inversely associated with the age of subjects and the time interval between the two blood draws. The variability in adduct levels was lower among subjects in Hu-Hsi and Pai-Hsa townships as compared to those in Ma-Kung. No significant association was observed for the intraindividual variability in AFB1-albumin adducts with regard to the season when blood was drawn. There was also no significant association between intraindividual variability and hepatitis B surface antigen, anti-hepatitis C virus (anti-HCV), glutathione S-transferase (GST) M1, or GSTT1 status. In conclusion, we found substantial intraindividual variability in the AFB1 exposure (as determined by AFB1-albumin adducts) in Taiwan, which was probably more likely related to dietary or other environmental influences rather than to endogenous factors (e.g., hepatitis B/C viral infection or GST M1/T1 genetic status).     

Prevalence and Risk Factors of Vitamin B12 Deficiency among Pregnant Women in Rural Bangladesh

Vitamin B₁₂ deficiency is associated with an increased risk of pregnancy complications and adverse birth outcomes. However, data on vitamin B₁₂ deficiency in pregnant Bangladeshi women are limited. This study examines vitamin B₁₂ deficiency and marginal deficiency in rural Bangladeshi women during early and late pregnancies. Some 522 women whose gestational age was <20 weeks were recruited. Serum vitamin B₁₂ concentrations were measured at baseline and after 14 weeks of iron-folate supplementation. Logistic regression analysis examined the association of various socio-demographic, dietary, and pregnancy-related factors with vitamin B₁₂ deficiency and marginal deficiency. Overall, 19% of the women during early pregnancy had vitamin B₁₂ deficiency (serum vitamin B₁₂ concentration < 203 pg/mL) and nearly 40% had marginal deficiency (serum vitamin B₁₂ concentration 203 to <300 pg/mL). Vitamin B₁₂ deficiency doubled to 38% during late pregnancy, while marginal deficiency slightly increased to 41.7%. The pregnant women with a gestational age of ≥27 weeks had a higher risk of developing vitamin B₁₂ deficiency (OR = 2.61; 95% CI = 1.096–6.214) than those of a gestational age of <27 weeks. Vitamin B₁₂ deficiency was significantly higher in pregnant women in rented accommodation (OR = 13.32; 95% CI = 1.55–114.25) than in those living in their own house. Vitamin B₁₂ deficiency was significantly higher among women who consumed red or organ meat <3 times a week than in those who consumed it more often (OR = 2.327, 95% CI = 1.194–4.536). None of these factors were significantly associated with marginal vitamin B₁₂ deficiency. In conclusion, vitamin B₁₂ deficiency and marginal deficiency among pregnant rural Bangladeshi women increased as their pregnancies progressed. Increasing gestational age, living in a rented house, and the consumption of red or organ meat <3 times a week were identified as the independent risk factors of vitamin B₁₂ deficiency in this population. Further research with more in-depth assessments of dietary vitamin B₁₂ intakes is needed to develop an intervention program preventing vitamin B₁₂ deficiency in this population.     

Aflatoxin exposure in utero causes growth faltering in Gambian infants

BACKGROUND: Growth faltering in West African children has previously been associated with dietary exposure to aflatoxins, particularly upon weaning. However, in animal studies in utero exposure to low levels of aflatoxin also results in growth faltering. OBJECTIVE: This study investigated the effect of in utero aflatoxin exposure on infant growth in the first year of life in The Gambia. METHODS: Height and weight were measured for 138 infants at birth and at regular monthly intervals for one year. Aflatoxin-albumin (AF-alb) adduct level was measured in maternal blood during pregnancy, in cord blood and in infants at age 16 weeks. RESULTS: The geometric mean AF-alb levels were 40.4 pg/mg (range 4.8-260.8 pg/mg), 10.1 pg/mg (range 5.0-189.6 pg/mg) and 8.7 pg/mg (range 5.0-30.2 pg/mg) in maternal, cord and infant blood, respectively. AF-alb in maternal blood was a strong predictor of both weight (P = 0.012) and height (P = 0.044) gain, with lower gain in those with higher exposure. A reduction of maternal AF-alb from 110 pg/mg to 10 pg/mg would lead to a 0.8 kg increase in weight and 2 cm increase in height within the first year of life. CONCLUSIONS: This study shows a strong effect of maternal aflatoxin exposure during pregnancy on growth in the first year of life and thus extends earlier observations of an association between aflatoxin exposure during infancy and growth faltering. The findings imply value in targeting intervention strategies at early life exposures.     

Fatty acid composition of breast milk from three racial groups from Penang, Malaysia

The fatty acid composition of samples of breast milk obtained from 51 mothers (26 Malay, 15 Chinese, 10 Indian) residing in Penang, Malaysia was determined by gas chromatography. Despite living in close physical proximity the mothers from the three racial groups showed distinct cultural differences in dietary intake. These differences were reflected in differences in the fatty acid composition of breast milk samples. The milk of Chinese mothers was generally less saturated (41%) than that of Malay and Indian mothers (52 and 50% respectively). The milk of Chinese mothers was also richer in linoleic acid (17%) than that of Malay and Indian mothers (9% and 11% respectively). Overall the level of individual fatty acids fell within the range of values reported for Western mothers on well nourished diets and pointed to breast milk of high standard despite large variations in the diet of Malaysian mothers.     

Dietary source of vitamin B12 intake and vitamin B12 status in female elderly Koreans aged 85 and older living in rural area

Recently, we found and analyzed vitamin B₁₂ in some Korean traditional plant foods which had not reported, yet. This study was to investigate vitamin B₁₂ intake and its dietary sources and the vitamin B₁₂ status in the very old elderly Koreans. We measured serum vitamin B₁₂ level and estimated the amounts of vitamin B₁₂ intake from different dietary sources in female elderly Koreans aged 85 and over who had consumed a relatively low animal traditional diet for the whole life. The average age of the subjects (n = 127) was 98.0 years (85-108 years). The assessment on energy and nutrient intake involved a one-day 24-hour recall, and serum vitamin B₁₂ concentration was measured by radioimmunoassay. Overall diet pattern was not different between the 85-99 yr-old group and centenarians, except centenarians were taking more dairy product. The average ratio of plant food to animal food consumption was 87.5:12.5 in weight. The average vitamin B₁₂ intake of our subjects was 3.2 µg/day, and 52.7% of subjects consumed under estimated average requirement, 2.0 µg/day. On dietary source, 67.3% of dietary vitamin B₁₂ was from meat, eggs and fishes and 30.6% was from plant foods, such as soybean-fermented foods, seaweeds, and kimchi. The average serum vitamin B₁₂ concentration was 450.5 pg/mL, and low serum vitamin B₁₂ (< 200 pg/mL) was found in 9.6% of subjects. Dietary vitamin B₁₂ intake was significantly lower in subjects with low serum vitamin B₁₂ (0.79 µg/day) than those with normal serum vitamin B₁₂ (3.47 µg/day). There were no significant difference in vitamin B₁₂ intake and its dietary sources and serum vitamin B₁₂ level between the 85-99 yr-old group and centenarians. In conclusion, several plant-origin foods including seaweed, soybean-fermented foods, and kimchi, may contribute significantly to good vitamin B₁₂ status in very old elderly Koreans.     

Associations of plasma aflatoxin B1-albumin adduct level with plasma selenium level and genetic polymorphisms of glutathione S-transferase M1 and T1

Mortality from hepatocellular carcinoma (HCC) is extraordinarily high in Matzu, an island off the coast of Southeastern China. To investigate factors associated with plasma aflatoxin B1 (AFB1)-albumin adduct level, we studied 304 healthy adult residents from Matzu. AFB1-albumin adducts were determined by competitive enzyme-linked immunosorbent assay, hepatitis B surface antigen status by enzyme immunoassay, genotypes of glutathione S-transferase (GST) M1 and T1 by polymerase chain reaction, plasma selenium by atomic absorption spectrometry, and plasma retinol, alpha-tocopherol, alpha-carotene, and beta-carotene levels by high-performance liquid chromatography. Men had higher AFB1-albumin adduct levels than women. GSTM1-nonnull and GSTT1-null genotypes and low plasma selenium level were significantly associated with an increased level of AFB1-albumin adducts among men, whereas age was significantly correlated with adduct level among women. High intake of fermented beans was associated with an increased adduct level among men and women. The inverse associations between plasma selenium level and AFB1-albumin adducts were statistically significant among those with null genotypes of GSTM1 and GSTT1, but not among the nonnull genotypes. This study provides insight into the dietary and genetic factors influencing AFB1-albumin adduct formation in an isolated population with high liver cancer mortality.     

烟台市售食品黄曲霉毒素污染状况及膳食暴露评估

目的 了解烟台市售食品黄曲霉毒素污染状况及居民膳食来源暴露风险水平。方法 免疫亲和层析高效液相色谱法测定样品中黄曲霉毒素,点评估方法估算人群黄曲霉毒素暴露量。结果 检测的市售食品中AFB1检出率为4.19%（19/453）,超标率为0.22%（1/453）,均值为0.86 μg/kg。AFB2、AFG1、AFG2和AFM1检出率分别为2.13%（9/423）、1.65%（7/423）、0.95%（4/423）和41.90%（44/105）,均值分别为0.29、0.64、0.33和 0.03 μg/kg。食品中存在AFB1、AFB2、AFG1和AFG2多重污染情况。AFB1的检出均值占到黄曲霉毒素(AFB1、AFB2、AFG1和AFG2)均值总和的47.18%。AFB1、AFB2、AFG1、AFG2和AFM1的日膳食暴露量分别为4.326、1.733、3.143、2.423和0.168 ng/（kg·bw·d）。AFB1、AFB2、AFG1、AFG2和AFM1的膳食暴露贡献率分别占到总体的36.69%、14.70%、26.65%、20.55%和1.42%。谷类及其制品的膳食暴露贡献最大,食用植物油的贡献次之。结论 AFB1总体检出率和均值均高于AFB2、AFG1和AFG2,是主要的污染品种。谷类及其制品和食用植物油是主要的AFB1、AFB2、AFG1和AFG2膳食暴露来源。乳制品是主要的AFM1的膳食暴露来源。烟台市居民AFB1和AFM1膳食暴露导致肝癌发病率为0.101/10万人和0.004/10万人。     

Carcinogenic effects of aflatoxin B1 among wheat handlers

Background:

Epidemiological studies have demonstrated that serum aflatoxin B1 (AFB1) is a hepatocarcinogenic mycotoxin and contributor to the high rate of hepatocellular carcinoma (HCC). The prevalence of liver cancer in Egypt is particularly worrisome. In a registry-based analysis of occupational risk for HCC, significant excesses were observed especially for grain mill workers.

Objective:

The aim of this study was to assess the hepatic carcinogenicity of AFB1 in wheat handlers.

Methods:

Serum AFB1/albumin (AFB1/Alb), alpha-fetoprotein (AFP), alpha-l-fucosidase (AFU), and arginase were estimated in exposed wheat handlers including millers and bakers. The control group was composed of non-occupationally exposed workers.

Results:

AFB1/Alb and AFU were significantly higher among workers employed as bakers compared to mill workers and controls. Mill workers had higher levels of AFB1/Alb than the controls. AFB1/Alb, AFP, and AFU were all significantly higher and arginase was significantly lower among HCC cases compared to the other groups. There was a significant correlation between AFU and AFB1/Alb in bakers and between AFP and AFB1/Alb in HCC cases. Arginase was inversely correlated with AFB1/Alb in HCC cases. AFB1/Alb was significantly correlated with the duration of exposure in bakers.

Conclusion:

Wheat handlers exposed to Aspergillus flavus have a high risk of elevated serum AFB1/Alb levels and AFU.     

Determinants of benzo[a]pyrene diol epoxide adducts to albumin in workers exposed to polycyclic aromatic hydrocarbons

The present study was undertaken among 260 subjects [133 controls and 127 persons exposed to polycyclic aromatic hydrocarbons (PAHs)] from two steel foundries and a graphite electrode producing plant in order to investigate the relationship between the benzo[a]-pyrene-diol epoxide adducts to albumin (BPDE-alb) and the intensity of exposure to PAHs. Blood samples were collected from each subject and BPDE-alb adduct determination was performed using a high-pressure liquid chromatography technique with fluorescence detection. Exposure to PAHs was assessed by measuring airborne concentration of 13 PAHs including benzo[a]pyrene (BaP) using personal air sampling and 1-hydroxypyrene excretion (1-HOP) in postshift urine. Significantly higher BPDE-alb adduct levels were observed in exposed workers compared to controls but wide interindividual variation was observed between subjects with the same level of exposure. BPDE-alb adduct level was weakly but significantly associated with the airborne concentrations of total PAHs (r = 0.35, P = 0.0001) and BaP (r = 0.30, P = 0.0001), and urinary 1-HOP excretion (r = 0.29, P = 0.0001). Alcohol and dietary habits, place of residence, and renal and hepatic status were not found to influence the concentration of BPDE-alb adducts significantly. However, for the same level of exposure to BaP, smokers had a higher probability of having an elevated BPDE-alb adduct level than nonsmokers. As long as BPDE-protein adduct levels have not been demonstrated to be better related to the risk of adverse genotoxic effects caused by PAHs in target organs than the 1-HOP level in urine, the latter remains the most practical biological parameter for assessing the risk of exposure to PAHs.     

黄曲霉素B1诱导铁过载鼠肝细胞DNA损伤的研究

[目的]研究黄曲霉素B1(AFB1)对正常鼠与铁过载鼠肝细胞DNA损伤情况。[方法]采用8-羟基-2′-脱氧鸟苷(8-OHdG)和AFB1单克隆抗体,通过免疫组化方法分析不同AFB1剂量组下两组鼠肝细胞DNA的损伤情况。[结果]AFB1诱导的DNA损伤主要发生在肝门静脉区和胆管区,随剂量的加大损伤加重,且铁过载组DNA损伤大于正常组。[结论]铁过载可加重AFB1对鼠肝细胞的DNA损伤。     

High frequency of maternal vitamin B12 deficiency as an important cause of infantile vitamin B12 deficiency in Sanliurfa province of Turkey

Summary Background Vitamin B₁₂ deficiency in infancy may cause failure to thrive, severe neurological disorders and megaloblastic pancytopenia. It is well known that infants born with deficient vitamin B₁₂ storage have increased the risk of vitamin B₁₂ deficiency. Vitamin B₁₂ deficiency is more prevalent in infancy in Sanliurfa province (at the southeast region of Turkey). Aim of the study The aim of this study was to determine the frequencies of vitamin B₁₂, folic acid and iron deficiencies in pregnants and their babies at birth and to what extend the mothers’ deficiency becomes effective on babies’ deficiencies. Methods The study groups were constituted by 180 pregnant women and their single and term babies. Venous blood samples of pregnants were obtained 1–3 h before delivery and babies’ cord bloods were collected at birth. Vitamin B₁₂ and folic acid levels were measured with electro chemiluminiscence method; serum iron and iron binding capacities were measured by colorimetric method and complete blood counts were performed by automatic blood counter. Results Mean vitamin B₁₂ levels in maternal and cord blood serum were 130 ± 61.7 pg/ml and 207 ± 141 pg/ml; mean folic acid levels were 8.91 ± 6.46 ng/ml and 17.8 ± 11.8 ng/ml; mean serum iron levels were 56.9 ± 37.5 μg/dl and 147 ± 43.2 μg/dl; and mean transferrin saturations were 11.8 ± 8% and 65.6 ± 24%, respectively. There were vitamin B₁₂ deficiency (<160 pg/ml) in 72% of the mothers and 41% of the babies, and severe deficiency (<120 pg/ml) in 48% of the mothers and 23% of the babies. Folic acid deficiency was found in 12% of the mothers, but was not found in the babies. There were iron deficiency in 62% of the mothers and 1% of the babies. There were statistically significant correlation between maternal and cord blood serum vitamin B₁₂ levels (r = 0.395, P < 0.001) and folic acid levels (r = 0.227, P = 0.017), while there were no correlation between maternal and cord blood iron levels and transferrin saturations. Conclusion The study results showed that vitamin B₁₂ deficiency is prevalent in pregnants in this region and that 41% of infants have born with deficient vitamin B₁₂ storages. Therefore, prophylactic use of vitamin B₁₂ by pregnant women in Sanliurfa and other poor communities could have considerable benefits to prevent vitamin B₁₂ deficiency and its complications in infants.     

Carnitine alters binding of aflatoxin to DNA and proteins in rat hepatocytes and cell-free systems.

The objective of this study was to determine effects of L-carnitine on aflatoxin B(1) (AFB(1))-DNA adduct formation in isolated rat hepatocytes, its dose response, specificity and mode of action. All experiments were conducted in either freshly isolated rat hepatocytes or cell-free systems. There was negative linear correlation between the dosage of carnitine and formation of [(3)H]AFB(1)-DNA adducts in the hepatocytes; however, the partitioning of AFB(1) into cellular compartments was not affected by carnitine. The attenuating effect of carnitine on AFB(1)-DNA adduct formation was also present in a cell-free system, but there was lack of specificity because acetylcarnitine and gamma-aminobutyric acid (GABA) were equally effective. Carnitine appears to interfere with bioactivation of AFB(1) and binding of AFB(1)-epoxide to DNA. On the contrary, carnitine enhanced the binding of AFB(1) and its epoxide to microsomal proteins, plasma proteins and bovine serum albumin. These results indicate that carnitine diverts AFB(1)-epoxide away from DNA by promoting binding to proteins. We conclude that modulation of AFB(1) binding to proteins and DNA by carnitine alters the carcinogenic and hepatotoxic potential of AFB(1) and poses concerns about the human AFB(1)-exposure data based on the AFB(1)-albumin adduct concentrations as a biomarker.     

Evaluation of vitamin B6 intake and status of 20- to 64-year-old Koreans

BACKGROUND/OBJECTIVES

Recent research regarding vitamin B₆ status including biochemical index is limited. Thus, this study estimated intakes and major food sources of vitamin B₆; determined plasma pyridoxal 5''-phosphate (PLP); and assessed vitamin B₆ status of Korean adults.

MATERIALS/METHODS

Three consecutive 24-h diet recalls and fasting blood samples were collected from healthy 20- to 64-year-old adults (n = 254) living in the Seoul metropolitan area, cities of Kwangju and Gumi, Korea. Vitamin B₆ intake and plasma PLP were analyzed by gender and by vitamin B₆ supplementation. Pearson''s correlation coefficient was used to determine associations of vitamin B₆ intake and plasma PLP.

RESULTS

The mean dietary and total (dietary plus supplemental) vitamin B₆ intake was 1.94 ± 0.64 and 2.41 ± 1.45 mg/day, respectively. Median (50th percentile) dietary intake of men and women was 2.062 and 1.706 mg/day. Foods from plant sources provided 70.61% of dietary vitamin B₆ intake. Only 6.3% of subjects consumed total vitamin B₆ less than Estimated Average Requirements. Plasma PLP concentration of all subjects was 40.03 ± 23.71 nmol/L. The concentration of users of vitamin B₆ supplements was significantly higher than that of nonusers (P < 0.001). Approximately 16% of Korean adults had PLP levels < 20 nmol/L, indicating a biochemical deficiency of vitamin B₆, while 19.7% had marginal vitamin B₆ status. Plasma PLP concentration showed positive correlation with total vitamin B₆ intake (r = 0.40984, P < 0.0001).

CONCLUSIONS

In this study, vitamin B₆ intake of Korean adults was generally adequate. However, one-third of subjects had vitamin B₆ deficiency or marginal status. Therefore, in some adults in Korea, consumption of vitamin B₆-rich food sources should be encouraged.     

Dietary Intake Adequacy and Food Sources of Nutrients Involved in the Methionine-Methylation Cycle in Women of Childbearing Age from the ANIBES Spanish Population

Growing evidence confirms choline as a critical perinatal nutrient. However, intake levels of choline and betaine among the Spanish fertile population remain unknown. Given their role in one-carbon metabolism with potential epigenetic effects, the aim of the present study was to evaluate the dietary intakes, their adequacy to existing guidelines and the main food sources together with other micronutrients involved in the methylation-methionine cycle (vitamin B₆, folates and vitamin B₁₂) in women of childbearing age. The ANIBES study, a cross-sectional study of a representative sample of women of childbearing age (18–45 years, n = 641) resident in Spain, was used. The sample was divided into younger women (18–30 years, n = 251) and older women (31–45 years, n = 390). Dietary intake was assessed by a three-day dietary record by using a tablet device. Total median intakes for the total sample were 303.9 mg/d for choline; 122.6 mg/d for betaine; 1.3 mg/d for vitamin B₆; 140.8 μg/d for folates, and 3.8 μg/d for vitamin B₁₂. The older subgroup showed significantly higher choline (p < 0.05), betaine (p < 0.001) and folates (p < 0.05) intakes than younger women. Main food sources for the whole sample were meat and meat products for choline (28.3%), vitamin B₆ (25.7%) and vitamin B₁₂ (22.8%); cereals and derivatives (79.9%) for betaine; vegetables (20.0%) for folates. Overall intake adequacy was only observed for vitamin B₁₂, with a very limited number of participants showing adequate intakes for all the other micronutrients. These results illustrate there is a relevant need to raise awareness about optimizing the status of the methionine cycle-related vitamins and cofactors in this potentially vulnerable population.     

广西地区人群gstM1和gstT1编码基因型多态性与肝细胞癌易感性分析

目的探讨解毒酶基因gstM1和gstT1的空白基因型（null）与黄曲霉毒素B1（AFB1）相关肝细胞癌（HCC）的易感性。方法应用聚合酶链反应技术对广西地区AFB1高污染区140例HCC患者和536例对照人群的gstM1和gstT1基因多态性进行检测，进行以医院为基础的病例对照研究。结果①gstM1-present基因型和gstT1-present基因型为HCC保护基因型，而二者的null基因型为HCC风险基因型，其校正OR值（95％CI）分别为2．07（1．20～3．57）和1．44（0．85～2．45）；②在同时有gstM1和gstT1两个基因缺失的个体中其患癌风险比单一缺失者大（校正OR=2．43，95％CI：1．19～4．97）；③gstM1-和gstT1-null基因型与AFB1暴露程度在HCC发病中具有协同作用，从中低度至高度AFB1暴露时，其校正OR值（95％CI）分别升高达12．76（5．38～30．24）和7．82（3．61～16．90）。结论解毒酶基因gstM1和gstT1多态性与HCC易感性相关，二者的null基因型均增加患HCC风险，二者同时出现时患HCC风险更为明显；gstM1和gstT1的null基因型在HCC发病中与AFB1暴露程度呈正相关。     

Aflatoxins and ochratoxin A in food and risks to human health

OBJECTIVES: The presence of mycotoxins in food has been associated with several human diseases, and health authorities have taken actions to decrease the ingestion of these compounds in the diet. A study was carried out to assess aflatoxins and ochratoxin A concentrations found in food, and to evaluate the potential risk to human health resulting from mycotoxin exposure. METHODS: Between July 1998 to December 2001, 366 food samples were analyzed, including peanuts and its products, nuts, maize, oat and/or wheat products, rice and beans. Samples were processed and the extracted mycotoxins were detected and separated using thin layer chromatography, and then quantified with fluorescence. RESULTS: Aflatoxins were detected in 19.6% of the samples: raw peanuts and its products, pop corn, maize and Brazilian nuts (>2mg/kg). Peanuts and its products showed the highest levels of aflatoxin contamination (34.7%) with up to 1280 mg/kg of AFB1+AFG1 and 1706 mg/kg of total aflatoxins. Of the positive samples, AFB1 was detected in 98.5%, AFB2 in 93%, AFG1 in 66.7%, and AFG2 in 65.4%. Ochratoxin A was not detected (<25 mg/kg) in any sample analyzed. CONCLUSION: It was found that contamination levels mainly seen in peanuts and its products exceed Brazilian regulated standards, and they can be a potential risk to regular consumers of these products. Food producers' awareness allied to monitoring programs is essential to reduce human exposure to these compounds and prevent ensuing chronic diseases.     

Effects of dietary selenium and vitamin E on covalent binding of aflatoxin to chick liver cell macromolecules

Day-old single comb white Leghorn chicks of both sexes maternally depleted in selenium (Se) and vitamin E (VE) were fed a low Se and VE-free semipurified basal diet or that diet supplemented with graded levels of Se (0.2 - 20.0 ppm as Na2SeO3) of VE (100 IU/g as all-rac-alpha-tocopheryl acetate), or both. At 14 days of age, chicks were given 1 mg/kg [3H] aflatoxin B1 (AFB1) i.p. and killed either 2 or 24 hours later. Covalent binding of AFB1 to liver DNA and RNA in chicks fed the basal diet was significantly greater than in chicks supplemented with Se or VE, or both. Phenobarbital treatment prior to administration of AFB1 decreased adduct formation in most groups, and abolished differences in adduct formation due to diet. These results suggest that combined Se-VE deficiency enhances activation or inhibits detoxification of AFB1 in vivo.