Effects of dioxin exposure on reproductive and thyroid hormone levels and male sexual function in airbase military workers in Vietnam.

Dioxins are endocrine disruptors that may disturb male sexual and reproductive function. Studies on human populations are limited, and their results are controversial. This study evaluated the impact of dioxin exposure on reproductive and thyroid hormone levels and sexual function in men. A total of 140 men working in four military airbases (three bases were formerly contaminated with dioxin by the herbicide spraying campaign in the Vietnam War) were recruited to measure the serum dioxin levels. Four reproductive hormones (testosterone, follicle-stimulating hormone, luteinizing hormone (LH), and prolactin) and three thyroid hormones (free triiodothyronine (FT3), free thyroxin (FT4), and thyroid stimulating hormone) were measured. Male sexual function endpoints including sexual drive, erection, ejaculation, problems, and overall satisfaction were assessed by the Brief Male Sexual Function Inventory. The percentage of subjects with low testosterone and LH levels was 19.6% and 16.7%, respectively. Dioxins, especially 2,3,7,8-tetrachlorodibenzo-P-dioxin and toxic equivalent concentrations of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans, were inversely associated with testosterone and prolactin levels, but positively associated with FT3 and FT4, and showed adverse relationships with sexual function, such as sexual drive, problems, and overall satisfaction. Our results suggested that exposure to dioxin disrupts the homeostasis of reproductive and thyroid hormones leading to adverse effects on male sexual function.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in blood samples from historically herbicide-sprayed areas and rural and industrialized unsprayed areas in Vietnam.

We investigated dioxin concentrations in the blood of residents living in areas with different sources of dioxin pollution in Vietnam. A total of 823 individual blood samples were collected in 2014-2015 from residents of 16 provinces in Vietnam who were born between 1972 and 1976, and who lived in rural unsprayed areas (the control area), industrialized unsprayed areas (the industrialized area), and areas in which herbicides were sprayed during the Vietnam War (the sprayed area). After blood collection, pooled samples were obtained by combining 10-25 individual samples by age and sex for each area. A total of 6, 10, and 26 pooled blood samples were obtained for the control area, industrialized area, and sprayed area, respectively. The concentrations of 17 polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans were quantified in each pooled blood sample. The concentrations of TCDD, 1,2,3,7,8,9-HxCDD, 1,2,3,7,8-PeCDF, and OCDF were significantly higher in the sprayed area than in the unsprayed area, which comprised the control and industrialized areas. The toxic equivalents of PCDDs, TCDD, 1,2,3,7,8-PeCDF, and 1,2,3,6,7,8-HxCDF were significantly higher in the sprayed area than in the control area. No significant difference in dioxin concentration was found between the sprayed and industrialized areas after adjusting for sex. The 1,2,3,6,7,8-HxCDF concentration was significantly higher in the industrialized area than in the control area. The findings indicate that there are different dioxin congener blood profiles in residents of industrialized areas and areas in which herbicides were historically sprayed during the Vietnam War.

Effect of astaxanthin in combination with alpha-tocopherol or ascorbic acid against oxidative damage in diabetic ODS rats.

The present study was performed to investigate the effect of astaxanthin in combination with other antioxidants against oxidative damage in streptozotocin (STZ)-induced diabetic Osteogenic Disorder Shionogi (ODS) rats. Diabetic-ODS rats were divided into five groups: control, astaxanthin, ascorbic acid, alpha-tocopherol, and tocotrienol. Each of the four experimental groups was administered a diet containing astaxanthin (0.1 g/kg), in combination with ascorbic acid (3.0 g/kg), alpha-tocopherol (0.1 g/kg), or tocotrienol (0.1 g/kg) for 20 wk. The effects of astaxanthin with other antioxidants on lipid peroxidation, urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion, serum creatinine (Cr) level, creatinine clearance (Ccr), and urinary protein content were assessed. The serum lipid peroxide levels and chemiluminescent (CL) intensity in the liver of the alpha-tocopherol and tocotrienol groups were significantly reduced in comparison to that of the control group. In the alpha-tocopherol group, urinary 8-OHdG excretion, serum Cr level, Ccr, urinary albumin excretion, and urinary protein concentration were significantly decreased as compared with those in the control group. Additionally, the CL intensity in the kidney of the alpha-tocopherol group was significantly lower, but that of the ascorbic acid group was significantly higher than that in the control group. These results indicate that dietary astaxanthin in combination with alpha-tocopherol has an inhibitory effect on oxidative stress. On the other hand, our study suggests that excessive ascorbic acid intake increases lipid peroxidation in diabetic rats.

Apolipoprotein E polymorphism in Vietnamese children and its relationship to plasma lipid and lipoprotein levels.

We investigated the frequency of apolipoprotein E (apoE) polymorphism and the effect of apoE polymorphism on plasma lipid and lipoprotein levels under different nutritional statuses in Vietnamese children living in urban and rural areas. Three hundred and forty-eight girls (aged 7 to 9 years) were randomly selected from urban and rural areas in southern Vietnam. Their apoE genotypes were analyzed by an Invader assay, and the plasma lipid and lipoprotein levels were determined by enzymatic methods using fasting blood samples. Dietary intake and anthropometry of children were also measured. The frequency of the allele epsilon 2 and epsilon 4 of the Vietnamese girls was 0.09 and 0.12, respectively. The levels of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) of the allele epsilon 2 carriers were significantly lower than those of the allele epsilon 3 carriers (P < .0001) in both the urban and rural groups. In contrast, the allele epsilon 4 carriers tended to show a higher LDL-C level than the allele epsilon 3 carriers, especially in subjects with a higher fat intake in urban area. The allele epsilon 2 carriers had the same high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) level as the allele epsilon 3 carriers, but the allele epsilon 4 carriers with a higher fat intake living in urban areas had lower HDL-C and higher TG level than allele epsilon 3 carriers. In conclusion, our findings showed that the LDL-C lowering effect of allele epsilon 2 was independent of the nutritional status, while allele epsilon 4 tended to lower HDL-C and increase the LDL-C level in a high-fat intake population. Therefore, the plasma lipid profiles of apoE epsilon 4 carriers may be a risk factor of atherogenesis in Vietnamese, who tend to have a westernized eating habit.

Macronutrient intake and nutritional status of primary school-aged girls in rural and urban areas of South Vietnam.

The dietary habits and nutritional status of Vietnamese primary school girls were investigated using a cross-sectional survey. We interviewed 348 girls aged 7 to 9 yr old, randomly selected from three rural (n=193) and two urban (n=155) primary schools. The nutritional status of the children was evaluated by anthropometric and biochemical data. Dietary data were calculated based on the results of a 24-h recall interview carried out for three consecutive days. The dietary macronutrient pattern of the rural group showed a deficiency of energy, fat, animal protein, and fiber content. On the other hand, high animal protein ratio, deficiency of fiber consumption, low polyunsaturated fatty acid, and high saturated fatty acid proportions were typically found in the urban group. A high number of rural children skipped lunches, resulting in low energy consumption: however, frequently skipped breakfast in the urban group did not influence total energy consumption because of extra meals taken. The mean height of rural children was 5.8 cm less than that of their urban counterparts. In addition, 11.4% of wasted rural children needed emergency intervention with energy supplementation. Moreover, a high proportion of children with a high atherogenic index (AI) (41.5%) and low HDL cholesterol (40.9%) were found in the rural group. In contrast, a tendency toward obesity, high cholesterol, LDL cholesterol, and high AI was observed in a proportion of the urban children (5.2%, 15.5%, 12.3%, and 29.0%, respectively).

Micronutrient status of primary school girls in rural and urban areas of South Vietnam.

Dietary habits, especially micronutrient intake, and nutritional status of Vietnamese primary school girls were investigated in a cross-sectional survey. We interviewed 284 girls aged 7 to 9 years old, randomly selected from three rural (N=148) and two urban (N=136) primary schools. Dietary data were calculated from the results of 24-h recall interviews over three consecutive days. The dietary micronutrient pattern of the rural group showed deficiency of iron, calcium, phosphorus, potassium, magnesium, beta-carotene, vitamin A and vitamin C. On the contrary, adequate consumption of these elements, except low beta-carotene, was observed in the urban group. Despite a low prevalence of anaemia, the prevalence of rural children with iron deficiency was close to the level regarded as being a public health problem. In contrast, 7.7% of urban children were found to have excessive iron status. Children with exhausted retinol stores (7.1%) requiring immediate retinol supplementation were only found in the rural group. Furthermore, the prevalence of children with marginal retinol stores in both the rural (35.7%) and urban (21.4%) groups was above the level of being a public health problem (20%). In both groups, more than 50% and 20% of children showed beta-carotene and tocopherol levels in the range of severe deficiency, respectively. Thus, nutritional education to improve the dietary habits of the two groups is necessary for Vietnamese primary school children.

Antioxidant and anti-cataract effects of Chlorella on rats with streptozotocin-induced diabetes.

The antioxidant activities of Chlorella in vitro and in vivo were investigated. Chlorella showed a strong antioxidant effect compared to various vegetables in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. To evaluate the antioxidant and anti-cataract effects in vivo, a 7.3% Chlorella powder was fed to rats with streptozotocin-induced diabetes for 11 wk. At the end of the experiment, Chlorella had decreased the blood glycated hemoglobin (hemoglobin A1c) and serum cholesterol levels significantly, however, it had not affected the serum glucose concentration. The serum lipid peroxide value (TBARS value) in the rats fed Chlorella was lower than that of the control rats. In the liver and kidney, Chlorella also reduced chemiluminescent intensities. In addition, it delayed the development of lens opacities. The lens lipid peroxide content of the rats fed Chlorella was lower than that of the control rats, however the differences were not significant. These results indicate that Chlorella has antioxidant activity and may be beneficial for the prevention of diabetic complications such as cataracts.