Evaluation of nitrate and nitrite content in diets of preschool children]

The nitrate and nitrite contents in diets of preschool children were evaluated. The meals were taken from one of the kindergarten near Warsaw. Colorimetric method with Griess reagent and cadmium column for nitrates reduction was used. It was seen, that diets contained to much of nitrates and nitrites as to ADI. The main sources of these compound were vegetables, potatoes, meat and meat products and cereals.     

济宁市售蔬菜中硝酸盐和亚硝酸盐含量分析

对济宁市售８类２７种蔬菜中硝酸盐、亚硝酸盐含量的测定的结果表明：不同种类的蔬菜中硝酸盐的含量差别很大（１４０．６～２７６２．５ｍｇ／ｋｇ），亚硝酸盐的含量在新鲜蔬菜中很低，（０．２０～２．８５ｍｇ／ｋｇ）     

The effect of dietary nitrate on nitrate and nitrite excretion in man

Dietary nitrate and nitrite may affect colonic pathophysiology. These anions influence fermentation, and nitrite has been shown to augment sodium absorption by the colon and participate in the formation of N-nitroso compounds. There is, however, no general agreement as to how much dietary nitrate and nitrite reaches the colon. To help resolve this question, balance studies were performed on six healthy ileostomy subjects who were given diets that varied in nitrate content from 0.83 to 5.20 mmol/d. Nitrate and nitrite excretion in ileal effluent and urine were measured by anion-exchange chromatography with conductivity detection. There was no significant nitrite in the diets, urine or ileal effluent. Dietary nitrate was largely excreted in urine (1.31-4.25 mmol/d). The urinary excretion findings indicated net synthesis of nitrate at low dietary intakes and net catabolism of nitrate at high intakes. Nitrate losses in ileal effluent were very low (0.03-0.05 mmol/d, 0.03-0.06 mmol/kg) and unrelated to intake for all the diets. It is concluded that dietary nitrate and nitrite do not enter the colon from the small intestine in amounts that would affect fermentation and mucosal metabolism in man. The possibility of significant amounts of nitrate reaching the colon via blood in normal subjects has not been excluded.     

The diets of preschool children in Newcastle upon Tyne, 1968-71.

1. Ninety-one families containing 140 children under 4 years of age at enrolment were studied. At 1-monthly intervals, the children were weighed and measured and qualitative information about feeding habits was obtained. Weighed dietary surveys for periods of 5 d were made at approximately 8 months, 3 years, and 5 years of age; there were forty-six failures in 260 surveys attempted. 2. At the four specified ages, mean energy intakes were 3-75, 5-03, 5-82 and 6-75 MJ (896, 1203, 1392 and 1613 kcal)/d respectively. At 8 months, milk products provided on average, 43% of the total energy intake, and commerical baby foods provided 17%. These values decreased to 21 and 2% respectively at 20 months and there was little further change therafter. 3. Average intake of energy and of most nutrients met recommended intakes (Department of Health and Social Security, 1969). Iron intakes were marginal, and vitamin D intakes were low. 4. The energy intake of boys was significantly higher than that of the girls at 3 years of age, but the boys were not significantly heavier. The energy intake of children from "manual-worker" families was higher than that from "non-manual" families. Similarly, the energy intake of children from larger families was higher than that of children from smaller families. 5. Energy intakes were correlated with body-weights and with rates of gain in weight. Irrespective of body-weight, "big eaters" at 20 months tended to be "big eaters" at 3 years also.     

Quantitative analysis of nitrate and nitrite contents in vegetables commonly consumed in Delta State, Nigeria

Plasma thiocyanate has been reported to be high among cassava-eating populations such as that in Nigeria because of the cyanide content of cassava. Thiocyanate, which is secreted into the stomach contents of animals, has been demonstrated to catalyse the formation of nitrosamines (potent carcinogens) in the stomach from secondary amines and nitrite. The main source of the nitrite precursor in this environment is vegetables, primarily eaten as the chief supplier of proteins. The present study attempts to analyse the levels of nitrate and nitrite in vegetables commonly grown and consumed in Delta State, Nigeria. The nitrate and nitrite contents in green vegetable (Amaranthus spp.), bitter leaf (Vernonia amygdalina), pumpkin (Telfaria occidentalis) and water leaf (Talinum triangulare) grown in different localities of the state were determined by standard analytical procedures. The results show that those vegetables grown in the industrialised urban centres of the state had higher nitrate (223 (SD 71) mg/kg dry weight; P<0.05) and nitrite (12.6 (SD 1.7) mg/kg dry weight; P>0.05) levels when compared with the same species (188 (SD 77) mg nitrate/kg dry weight and 10.9 (SD 1.1) mg nitrite/kg dry weight) cultivated in less industrialised suburbs. We conclude that frequent consumption of such vegetables whose nitrate and nitrite contents are high by cassava-eating individuals might put them at risk of developing stomach cancer and other possible results of nitrate and/or nitrite toxicity. In order to avoid an outbreak in our communities, appropriate agencies should monitor and regulate the release of chemicals into the environment. In the meantime, the cultivation and consumption of vegetables grown in industrialised areas of the state should be discouraged.     

The evaluation of nitrate,nitrite and antioxidant vitamin intake in daily food ration of children aged 1-6 year of age

The aim of this study was evaluation of nitrates, nitrites and antioxidant vitamins intake in daily food rations of children aged 1-6 years. The levels of nitrites and nitrates in daily food rations were calculated using menu data and literature nitrites and nitrates content data in food products and compared with the acceptable daily intake (ADI). The percentage contribution of selected groups of products in nitrates and nitrites supply was calculated. Antioxidant vitamins level was calculated with using menu data and Food composition tables and compared to the recommendations. Nitrates content exceeded acceptable daily intake (ADI) for children aged 1-6 twice, but level of nitrites was below (88% ADI). The main food source of nitrates were vegetables supplied 90% of one. The main sources of nitrite were meat products supplied 27.6% of one, vegetables and their products--26.2% and cereals supplied 24.6% of nitrites. All calculated vitamins (A, E, C) exceeded recommendations what protected children from high level of nitrates.     

延吉市学龄前儿童血清微量元素的水平

目的:了解延吉市儿童血清锌、镁、钙、铁、磷等微量元素的含量,以提高儿童的保健水平。方法:随机采集384例0~7岁儿童血清,利用日本产AU640全自动生化仪测定铁、锌、钙、镁、磷等微量元素含量。结果:学龄前儿童中铁元素缺乏现象居首位,其次为锌元素缺乏,钙、镁、磷缺乏现象不明显。不同性别儿童钙、锌之间存在统计学意义(P0.01,P0.05),铁、镁、磷元素无统计学差异(P0.05)。结论:延吉市学龄前儿童血清微量元素水平与膳食结构有一定的相关性。     

Assessment of organophosphorous pesticide exposures in the diets of preschool children in Washington State

Twenty-four hour duplicate diet sampling was employed to investigate dietary pesticide exposures of children aged 2 to 5 years. Duplicate diets were collected from seven children living in the Seattle metropolitan area and six children living in Chelan and Douglas counties in Central Washington. Diet samples were collected from each child in the summer and again in the fall, and total daily diets were divided into four food categories: fresh fruits and vegetables, beverages, processed foods, and dairy products. A total of 88 individual food category samples were collected and analyzed for 15 organophosphorous (OP) pesticides. Three of the 13 children had no detectable OP pesticides in either of their diet samples, and 14 of the 26 duplicate diets did not contain detectable levels of OP pesticides. Sixteen individual food category samples contained detectable levels of at least one OP pesticide and two of these samples contained detectable levels of two OP pesticides. Of the 15 targeted pesticides, 6 were detected: azinphosmethyl, chlorpyrifos, malathion, methidathion, methyl parathion, and phosmet. Azinphosmethyl was detected most frequently (10% of all samples), particularly in samples containing apples or apple juice. The fresh fruits and vegetable category had the most frequent pesticide determinations, followed by beverages. OP pesticides were not present at detectable levels in any of the dairy samples. Malathion was the only OP pesticide detected in processed food samples, appearing in 4 of the 26 samples (15%). No detections were above the legal tolerances for residues on produce, however the acute population-adjusted reference dose (aPAD) for chlorpyrifos exposure of 1.7 microg/kg/day was exceeded by one subject during one sampling event. This subject's cumulative daily dose of chlorpyrifos equivalents was estimated to be 2.5 microg/kg/day.     

南京市市售蔬菜硝酸盐含量及居民暴露量评估

目的 掌握南京市市售蔬菜中硝酸盐污染情况,对居民蔬菜硝酸盐暴露量进行评估.方法 在农贸市场和蔬菜批发市场共11个采集点采集10大类,44种蔬菜样品980份,按GB/T5009.33的规定检测蔬菜硝酸盐含量;在4个区县的4个居委会随机抽取各50户居民,以记账法和半定量食物频率法对居民日常蔬菜摄入量进行调查,并据此进行居民蔬菜硝酸盐暴露量评估.结果 特菜类(芦蒿)硝酸盐含量最高(中位数达2.64×103 mg/kg),其次为叶菜类(中位数为1.60×103 mg/kg);硝酸盐含量依次为特菜类＞叶菜类＞茎类＞块根类＞瓜菜类＞甘蓝类＞果菜类＞豆类＞鳞茎类＞菌类;同一类蔬菜不同品种的硝酸盐含量差别较大,同一品种的蔬菜中硝酸盐含量差别也很大.居民每日通过蔬菜摄入的硝酸盐量为463 mg(以中位数计),是WHO/FAO推荐ADI值(300 mg/d)的1.5倍,其中暴露量居前3位的依次是叶菜类、茎类、块根类.结论 南京市市售蔬菜的硝酸盐污染较严重,居民仅由蔬菜摄入的硝酸盐量已明显高于ADI值.     

Organophosphorus pesticide exposure of urban and suburban preschool children with organic and conventional diets

We assessed organophosphorus (OP) pesticide exposure from diet by biological monitoring among Seattle, Washington, preschool children. Parents kept food diaries for 3 days before urine collection, and they distinguished organic and conventional foods based on label information. Children were then classified as having consumed either organic or conventional diets based on analysis of the diary data. Residential pesticide use was also recorded for each home. We collected 24-hr urine samples from 18 children with organic diets and 21 children with conventional diets and analyzed them for five OP pesticide metabolites. We found significantly higher median concentrations of total dimethyl alkylphosphate metabolites than total diethyl alkylphosphate metabolites (0.06 and 0.02 micro mol/L, respectively; p = 0.0001). The median total dimethyl metabolite concentration was approximately six times higher for children with conventional diets than for children with organic diets (0.17 and 0.03 micro mol/L; p = 0.0003); mean concentrations differed by a factor of nine (0.34 and 0.04 micro mol/L). We calculated dose estimates from urinary dimethyl metabolites and from agricultural pesticide use data, assuming that all exposure came from a single pesticide. The dose estimates suggest that consumption of organic fruits, vegetables, and juice can reduce children's exposure levels from above to below the U.S. Environmental Protection Agency's current guidelines, thereby shifting exposures from a range of uncertain risk to a range of negligible risk. Consumption of organic produce appears to provide a relatively simple way for parents to reduce their children's exposure to OP pesticides.     

Food consumption and height/weight status of Dutch preschool children on alternative diets

The effects of alternative dietary practices on nutrient intake and height/weight status were studied in three groups of Dutch preschool children: 33 vegetarians, 26 anthroposophics, and 33 macrobiotics. Fifty children on omnivorus diets composed the control group. The children fed vegetarian and anthroposophic diets were somewhat lighter and shorter than the children on omnivorous diets but were within normal limits. The children fed macrobiotic diets were significantly lighter and shorter. Results of the 5-day weighing record method used to measure food consumption were compared with the Dutch Recommended Dietary Allowances (RDAs), which recommend higher protein and lower iron for children than the RDAs for the U.S. The diets of the anthroposophically and vegetarian-fed children were most similar and conformed better to the Dutch RDAs than the diets of the omnivorously and macrobiotically fed children. The omnivorously fed children had intakes of iron and polyunsaturated fat below the Dutch RDAs and intakes of mono- and disaccharides and cholesterol above the Dutch RDAs. The intakes of calcium, riboflavin, and vitamin D recorded for the macrobiotically fed children were substantially below the Dutch RDAs. The vitamin D content of the diets of all four groups was low; however, most of the omnivorously fed children used vitamin D supplements, and the other three groups of children were sent out in the sun as much as possible. A high risk for rickets existed in the combination of periods of bad weather and a low intake of both calcium and vitamin D.     

Domestic nitrogen oxide exposure, urinary nitrate, and asthma prevalence in preschool children.

A South Australian preschool study carried out in 1993 showed that the prevalence of respiratory symptoms was significantly associated with use of unflued gas appliances for cooking and heating. The authors sought to determine an association between domestic exposure to nitrogen dioxide and the excretion of total urinary nitrate and nitrite, and their association with asthma prevalence. The results indicated that the geometric mean concentrations of nitrogen dioxide were much higher in homes that had natural gas appliance(s) and other types of appliances (i.e., electric and solid fuel). Higher levels of nitrogen dioxide were found in homes of suburban areas with higher prevalence of asthma and respiratory symptoms. Nitrogen dioxide levels were lower in the summer, and there was a higher level in kitchens than in bedrooms. Urinary nitrate excretion was evaluated in 1,335 preschool children from the same sampling areas. No association existed between nitrogen dioxide levels and urinary nitrates, nor was there a relationship between urinary nitrates and asthma prevalence. These findings confirm that there is a positive association between nitrogen dioxide exposure from gas appliances and the prevalence of respiratory symptoms, but urinary nitrate is not a useful biomarker of exposure at these levels.     

Accumulations of nitrite and nitrate in the tissues of Penaeus monodon exposed to a combined environment of elevated nitrite and nitrate

Penaeus monodon (11.86 ± 0.63 g) exposed individually to six different nitrite and nitrate regimes [nitrite at 0.002 (control), 0.360, and 1.455 mM combined with nitrate at 0.005 (control) and 7.275 mM] in 25 ppt sea water were examined for the nitrite and nitrate concentrations in tissues and nitrite uptake and nitrate uptake after 24 h in 25.3°C. In P. monodon following exposure to 1.455 mM nitrite only, nitrite levels increased by factors of 0.33, 1.05, 1.36, 1.79, 2.10, 2.16, 2.21, and 3.58 in muscle, hepatopancreas, gill, foregut, hemolymph, heart, eyestalk, and midgut, respectively, over the ambient nitrite level. In P. monodon, following exposure to combined solutions of 1.455 mM nitrite and 7.275 mM nitrate, nitrite levels were factors of 0.34, 1.05, 1.44, 1.86, 2.21, 2.30, 2.67, and 3.83 in muscle, hepatopancreas, gill, foregut, heart, hemolymph, eyestalk, and midgut, respectively, over the ambient nitrite levels, whereas nitrate levels were factors of 0.06, 0.11, 0.27, 0.29, 0.45, 0.51, 0.57, and 0.61 in muscle, hepatopancreas, foregut, heart, hemolymph, gill, midgut, and eyestalk, respectively, over the ambient nitrate levels. It is concluded that incorporation of nitrite is converted to nitrate in midgut, heart, hemolymph, foregut, and eyestalk, whereas incorporation of nitrate in tissues is converted to nitrite and accumulated in eyestalk when P. monodon are exposed to combined nitrite and nitrate environments. Received: 1 June 2001/Accepted: 7 January 2002     

幼儿园儿童蛲虫感染综合防治效果观察

[目的] 了解杭州市幼儿园儿童蛲虫感染现状及综合防治的效果,为制定最佳的防治对策提供科学依据。[方法] 选择杭州市江干区2所乙级幼儿园,采用均衡对照法设立实验组和对照组。1所幼儿园的220名儿童作为实验组,采用健康教育、卫生习惯改善、集体驱虫等综合防治方法;另1所幼儿园的131名儿童作为对照组,采用单纯驱虫法。分别调查防治前后的蛲虫感染率,比较防治前后总感染率的保护率、效果指数,对防治措施进行评价。[结果] 实验组蛲虫感染率由综合防治前的3.64%（8/220）下降至防治后的1.82%（4/220）,保护率为50.00%,效果指数为2.00。对照组蛲虫感染率由综合防治前的3.82%（5/131）下降至防治后的3.05%（4/131）,保护率为20.16%,效果指数为1.25。[结论] 加强健康教育、改善卫生习惯、开展集体驱虫等综合防治措施比单纯驱虫能更有效控制蛲虫再感染。