Monitoring of trace elements in oysters marketed in Recife, Pernambuco, Brazil

Samples of oysters marketed in Recife, Pernambuco, Brazil, were monitored for the concentration of trace elements (Hg, Zn, Fe, Cu, and Mn) for one year (from March 2001 to February 2002). Mercury was the principal contaminant found in oysters and the element posing the greatest public health risk. Mercury levels in oysters reached 551.12 g/kg (wet weight). These values suggest that oyster consumption should be restricted, especially among communities that gather them as a subsistence activity, as well as by children and pregnant women. Evaluation of mercury concentration in seafood is an important factor for assessing the risk of contamination among individuals who are not occupationally exposed.     

Sodium and potassium intake and balance in adults consuming self-selected diets

Twenty eight adults, 12 men and 16 women, participated in a 1-yr study designed to assess daily nutrient intake accurately. All subjects lived at home, consumed self-chosen diets, and maintained a detailed daily dietary record throughout the year. During four 7-day balance studies, one in each season of the year, meals, beverages, urine, and feces were analyzed for sodium and potassium content by atomic absorption spectrometry. Total intakes averaged 3.4 g/day for sodium and 2.8 g/day for potassium. The Na:K ratio for all diets analyzed averaged 1.3. Nutrient densities of sodium and potassium were 1.8 and 1.5 g/1000 kcal, respectively. Apparent absorptions of sodium and potassium were 98 and 85%, respectively, and did not change significantly over the wide range of intakes. Average urinary excretions of sodium and potassium were 86 and 77% of total intake, respectively. Mean metabolic balances were positive for sodium, +0.47 g/day, and potassium, +0.28 g/day. The data of this study provide useful information concerning the dietary intakes, excretions, and balances of sodium and potassium for adults based on analytic determination.     

Environmental exposure to trace elements and prostate cancer in three New Zealand ethnic groups

A stratified random sample of 176 men was taken from a larger community prostate study group of 1405 eligible subjects from three ethnic groups in the Wellington region of New Zealand, in order to examine ethnic differences in exposure to cadmium (Cd), selenium (Se) and zinc (Zn) and possible associations of blood levels of Cd, Se and Zn with the prevalence of elevated serum Prostate Specific Antigen (PSA); a marker of prostate cancer. Maori and Pacific Islands men were found likely to have higher Cd exposure than New Zealand Europeans through diet, occupation and smoking. However, there was no significant difference between ethnic groups in mean blood Cd levels. Pacific Islands men had significantly higher levels of blood Se than both New Zealand European men and Maori men. Maori men had significantly higher levels of blood Zn than both New Zealand European men and Pacific Islands men. A positive association was found between blood Cd and total serum PSA. Se and Zn levels were not associated with elevated PSA. Maori and Pacific Islands men have higher prostate cancer mortality rates than New Zealand European men. Ethnic differences in mortality could be contributed to by differences in rates of disease progression, influenced by exposure and/or deficiency to trace elements. However, results did not reflect a consistent ethnic trend and highlight the complexity of the risk/protective mechanisms conferred by exposure factors. Further research is needed to ascertain whether the associations found between Cd and PSA levels are biologically important or are merely factors to be considered when interpreting PSA results clinically.     

Magnesium and trace elements in the elderly: intake,status and recommendations

Imbalances between mineral intakes and recommended amounts have been observed in different groups of elderly subjects. Nevertheless, assessment of the status of magnesium and trace elements in the elderly is difficult, even for iron because infection and inflammation increases ferritin. Mineral bioavailability may change due to ageing. Therefore, formulation of mineral recommendations is complex and individual recommendations are sometimes necessary. A number of surveys show magnesium, zinc, selenium and chromium intakes by old persons to be lower than the corresponding reference nutrient intakes. Contrarily, intakes of iron are generally adequate or higher than recommended, and it has been suggested that increased storage of iron in the elderly may be related with the development of age-related diseases through the increase in oxidative stress. Low iron status together with iron excess may be common in an elderly population. The same applies for zinc. Magnesium and selenium deficiencies among the elderly are also well documented, especially among the institutionalised and people with pathologies. Chromium deficiency is associated with type II diabetes mellitus. Recommended iron intake is lower for elderly women compared to young, because menstruation ceases after menopause, but in old men, it is similar to that of young men. Dietary Reference Values for the rest of the elements are similar to those of adults, although several suggestions have been made about the quantities. This review examines various aspects of the changes in mineral bioavailability due to ageing, of data published on mineral intakes and status, and finally the dietary recommendations for this vulnerable population group.     

Mercury and other trace elements in farmed and wild salmon from British Columbia, Canada

The present study reports measured levels of Hg and other trace elements in commercial salmon feed; farmed Atlantic, coho, and chinook salmon (n = 110); and wild coho, chinook, chum, sockeye, and pink salmon (n = 91). Metal concentrations in farmed and wild salmon from British Columbia, Canada, were relatively low and below human health consumption guidelines. Methylmercury in all salmon samples (range, 0.03-0.1 microg/g wet wt) were below the 0.5 microg/g guideline set by Health Canada. Negligible differences in metal concentrations were observed between the various species of farmed and wild salmon. Metal concentrations generally were higher in commercial salmon feed compared to farmed salmon. Mercury showed slight bioaccumulation potential in farmed salmon, with biomagnification factors (BMFs) ranging between 0.8 and 1.9. Other metals, such as Cd, Pb, and Ni, exhibited biodilution, with BMFs of much less than one. The relatively low degree of biomagnification of metals observed in farmed salmon likely resulted from the combination of low gastrointestinal absorption efficiency, negligible transfer to muscle tissue relative to other compartments, and a high degree of growth dilution in these fish. Human dietary exposure calculations indicate intakes of Hg, Cd, Pb, Cu, As, and Ni via farmed and wild British Columbia salmon are a relatively small percentage of total intakes (0.05-32%) compared to other Canadian foodstuffs, such as fruits, vegetables, chicken, and beef (68-99%). Although total dietary exposure of Cd, Pb, and Cu approached provisional tolerable daily intake levels, the contribution from British Columbia salmon was less than 2%. Our findings indicate farmed and wild British Columbia salmon remain a safe source of omega-3 highly unsaturated fatty acid intake for cardioprotective and, possibly, other health benefits.     

Maternal and umbilical cord blood levels of mercury, lead, cadmium, and essential trace elements in Arctic Canada

Maternal and umbilical cord blood levels of mercury (Hg), lead (Pb), cadmium (Cd), and the trace elements copper (Cu), zinc (Zn), and selenium (Se) are reported for Inuit, Dene/Métis, Caucasian, and Other nonaboriginal participants from Arctic Canada. This is the first human tissue monitoring program covering the entire Northwest Territories and Nunavut for multiple contaminants and establishes a baseline upon which future comparisons can be made. Results for chlorinated organic pesticides and PCBs for these participants have been reported elsewhere. Between May 1994 and June 1999, 523 women volunteered to participate by giving their written informed consent, resulting in the collection of 386 maternal blood samples, 407 cord samples, and 351 cord:maternal paired samples. Geometric mean (GM) maternal total mercury (THg) concentrations ranged from 0.87 microg/L (SD = 1.95) in the Caucasian group of participants (n = 134) to 3.51 microg/L (SD = 8.30) in the Inuit group (n = 146). The GM of the Inuit group was 2.6-fold higher than that of the Dene/Métis group (1.35 microg/L, SD = 1.60, n = 92) and significantly higher than those of all other groups (P<0.0001). Of Inuit women participants, 3% (n = 4) were within Health Canada's level of concern range (20-99 microg/L) for methylmercury (MeHg) exposure. Of Inuit and Dene/Métis cord samples, 56% (n = 95) and 5% (n = 4), respectively, exceeded 5.8 microg/L MeHg, the revised US Environmental Protection Agency lower benchmark dose. GM maternal Pb was significantly higher in Dene/Métis (30.9 microg/L or 3.1 microg/dL; SD = 29.1 microg/L) and Inuit (31.6 microg/L, SD = 38.3) participants compared with the Caucasian group (20.6 microg/L, SD = 17.9) (P < 0.0001). Half of all participants were smokers. GM blood Cd in moderate smokers (1-8 cigarettes/day) and in heavy smokers (> 8 cigarettes/day) was 7.4-fold higher and 12.5-fold higher, respectively, than in nonsmokers. The high percentage of smokers among Inuit (77%) and Dene/Métis (48%) participants highlights the need for ongoing public health action directed at tobacco prevention, reduction, and cessation for women of reproductive age. Pb and THg were detected in more than 95% of all cord blood samples, with GMs of 21 microg/L and 2.7 microg/L, respectively, and Cd was detected in 26% of all cord samples, with a GM of 0.08 microg/L. Cord:maternal ratios from paired samples ranged from 0.44 to 4.5 for THg, from 0.5 to 10.3 for MeHg, and 0.1 to 9.0 for Pb. On average, levels of THg, MeHg, and Zn were significantly higher in cord blood than in maternal blood (P < 0.0001), whereas maternal Cd, Pb, Se, and Cu levels were significantly higher than those in cord blood (P < 0.0001). There was no significant relationship between methylmercury and selenium for the range of MeHg exposures in this study. Ongoing monitoring of populations at risk and traditional food species, as well as continued international efforts to reduce anthropogenic sources of mercury, are recommended.     

学龄儿童微量元素锌、铁膳食水平与感染易感性关系

目的了解学龄儿童铁(Fe)、锌(Zn)膳食水平及其对感染易感性的影响。方法选取1 023名1~6年级学生进行一般情况、膳食摄入和反复呼吸道感染(RRTI)患病情况调查和评价;每年级抽取1个班共262名学生经家长知情同意后采静脉血测定免疫功能指标。结果 学龄儿童Zn平均摄入量达到推荐摄入量(RNI的60%~80%,各年龄段摄入充足的仅占20%~30%,Fe的摄入量达适宜摄入量(AI)的100%~180%,但来源于血红素铁仅占9.9%;儿童免疫指标CD3⁺细胞百分比、CD4⁺/CD8⁺和IgA水平均低于参考值,患反复呼吸道感染率为13%;当Zn摄入水平分别达到80%RNI、80%RNI、60%RNI、40%RNI以上时,受其影响的CD4⁺ 、CD4⁺/CD8⁺、IgA、IgM等免疫指标水平分别达到正常值范围;当Fe摄入水平分别达到200%AI、120%AI、160%AI以上时,受其影响的CD3⁺、IgA和IgM水平分别达到正常值范围。结论 >50%学龄儿童Zn摄入不足,Fe食物来源较差;Zn、Fe摄入水平分别至少≥80%RNI和≥200%AI时,各免疫指标才能维持在正常水平。     

Smoking among Maoris and other minorities in New Zealand

Frequently, minority groups within countries exhibit different smoking behavior from the majority. This discussion identifies reasons for this different behavior in New Zealand, suggesting educational platforms which may apply to minority groups in general. The first people to settle New Zealand were Polynesians about the 10th century A.D. Their descendants are known as Maoris. The 2nd migration wave started from Britain in the 19th century. Currently, some 90% of the population is of European descent; the dominant culture is Anglo Saxon. The Maoris were allegedly a fit and healthy people when Captain Cook arrived in New Zealand in 1769. Tribal wars were most likely the main cause of premature mortality. The Maori population of 250,000 in the early 1800s had diminished to perhaps 40,000 by 1890. In the early part of this century there was a marked improvement in Maori health. By 1945 there were 98,000 Maoris. By 1975 there were 275,000 and there will probably be close to 500,000 at the turn of the century. From the earliest contact with Europeans, tobacco smoking became popular among men and women. Cigarette smoking is more prevalent among Maoris than among other population groups. This high smoking incidence coincides with the incidence of lung cancer deaths. Maori women are believed to have one of the world's highest female rates. Possible reasons why so many Maoris smoke include: Maoris are social and live and work in groups, and tobacco smoking in many cultures has been a social pasttime; Maoris are mostly in the lower socioeconomic groups, and this class background places more value on short term rather than longterm gains; the Maoris suffer from low self esteem (high unemployment and women poorly treated by their husbands), and people with poor opinions of themselves are unlikely to worry about their future health; Maoris have had to adapt and become bicultural; and land is held communally with no concept of individual ownership. Until recently no differentiation was made on the basis of race or class in smoking education programs. Recently, the awareness of the high rate of smoking among Maoris, with its associated morbidity and mortality, has prompted many health educators to look for ways of focusing on Maoris as a target group. In a series of seminars recently held in Auckland, New Zealand on the delivery of health education to minorities, participants from minority groups made the following suggestions: the educator should be from the same cultural group to enhance communication, empathy, cultural understanding, and acceptance; changes should not be made too quickly; and oral communication is better than written.     

Chromium intake, absorption and excretion of subjects consuming self-selected diets

Chromium (Cr) content of the self-selected diets of 10 adult males and 22 females was determined. Each subject collected duplicate food and beverage samples on a daily basis for seven consecutive days. The 7-day average intake for males was 33 +/- 3 micrograms (mean +/- SEM), range 22-48 micrograms, and intake for females was 25 +/- 1, range 13-36. Mean Cr intake per 1000 cal was approximately 15 micrograms. Approximately 90% of the diets analyzed were below the minimum suggested safe and adequate daily intake for Cr of 50 micrograms. Chromium absorption was inversely related to dietary intake; absorption at a dietary Cr intake of 10 micrograms was approximately 2% and, with increasing intake to 40 micrograms, Cr absorption decreased to 0.5%. These data demonstrate that the average daily intake of chromium from self-selected diets is well below the minimum suggested safe and adequate intake and that Cr absorption, at levels found in typical US diets, is inversely related to dietary intake.     

不同年龄成年男性血清微量元素含量比较

目的 了解中国6个省市不同年龄的男性血清锌、铜、锰、铅、镉含量的差别及变化。方法 2001年12月～2002年12月，在石家庄、郑州、太原、贵阳、杭州和青岛6个地区的市区和郊县选择在当地居住10年及以上的男性为研究对象。进行结构式问卷调查和血清微量元索的原子吸收分光光度法检测。采用 单因素和多因素相结合的方法分析年龄对血清微量元素含量的影响。结果 6个地区调查对象的血清锌、铜、锰、铅、镉含量有所不同；年龄对血清微量元素也有一定的影响，随着年龄组的增加血清铜、锰、铅、镉含量均增加。结论 人体内血清微量元素含量存在着地区差异；中国6个地区20～59周岁之间成年男性的血清铜、锰、铅、镉含量随年龄组增加而增加。     

Effect of hereditary haemochromatosis genotypes and iron overload on other trace elements

Purpose

Hereditary haemochromatosis is a common genetic disorder involving dysregulation of iron absorption. There is some evidence to suggest that abnormal iron absorption and metabolism may influence the status of other important trace elements. In this study, the effect of abnormal HFE genotypes and associated iron overload on the status of other trace elements was examined.

Methods

Dietary data and blood samples were collected from 199 subjects (mean age = 55.4 years; range = 21–81 years). Dietary intakes, serum selenium, copper and zinc concentrations and related antioxidant enzymes (glutathione peroxidase and superoxide dismutase) in subjects with normal HFE genotype (n = 118) were compared to those with abnormal HFE genotype, with both normal iron status (n = 42) and iron overload (n = 39).

Results

For most dietary and biochemical variables measured, there were no significant differences between study groups. Red cell GPx was significantly higher in male subjects with normal genotypes and normal iron status compared to those with abnormal genotypes and normal iron status (P = 0.03) or iron overload (P = 0.001). Red cell GPx was also highest in normal women and significantly lower in the abnormal genotype and normal iron group (P = 0.016), but not in the iron overload group (P = 0.078).

Conclusion

Although it may not be possible to exclude a small effect between the genotype groups on RBC GPx, overall, haemochromatosis genotypes or iron overload did not appear to have a significant effect on selenium, copper or zinc status.     

Lead, cadmium, and mercury dietary intake in Croatia

This paper gives an overview of published data on levels of lead, cadmium, total and methyl-mercury in various food items, and of a daily dietary intake assessment in Croatia focusing on the last 10 years. It briefly describes the most reliable methods for quantitative analysis of lead, cadmium, and mercury in biological material. Lead and cadmium concentrations in vegetables and in organs of domestic animals refer to non-exposed rural areas. Mercury concentrations in fish and mussels refer to industrially polluted and non-polluted areas of the Adriatic. The daily dietary intake of lead and cadmium was assessed on the basis of duplicate-diet-collection and food-disappearance method. The assessment of the total and methyl-mercury dietary intake was based on dietary surveys of family seafood consumption. Lead and cadmium intake through food in the general population was 6-40% of the Provisional Tolerable Weekly Intake (PTWI), depending on the assessment method. The only Croatian population consuming more mercury through seafood is the one living in Dalmatia, approaching the PTWI defined by WHO.     

Vegetable and fruit intake and mortality from chronic disease in New Zealand

OBJECTIVE: To estimate mortality attributable to inadequate vegetable and fruit intake in New Zealand in 1997, and the burden of disease that could be avoided in 2011 if modest increases in vegetable and fruit intake were to occur. METHODS: Comparative risk assessment methodology was used to estimate both attributable and avoidable mortality due to inadequate vegetable and fruit consumption (< 600 g/day). Vegetables and fruit were defined as all fresh, frozen, canned, dried or juiced vegetables and fruit, except potatoes, nuts, seeds and pulses. Disease outcomes assessed were mortality from ischaemic heart disease, ischaemic stroke, and lung, oesophageal, stomach and colorectal cancers. RESULTS: In 1997, mean vegetable and fruit intake was 420 g/day in males and 404 g/day in females. Inadequate vegetable and fruit intake is estimated to have contributed to 1,559 deaths (6% of all deaths) in that year, including 1,171 from ischaemic heart disease, 179 from ischaemic stroke and 209 from cancer. Modest increases in vegetable and fruit intake (40 g/day above the historic trend) could prevent 334 deaths each year from 2011, mostly from ischaemic heart disease. CONCLUSIONS: Inadequate vegetable and fruit intake is an important cause of mortality in New Zealand. Small increases in vegetable and fruit intake could have a major impact on population health within a decade.     

Content of zinc in serum, urine, hair, and toenails of New Zealand adults.

The content of zinc in samples of serum, hair, and toenails and in a 24 hr urine from groups of the New Zealand population was investigated. The 110 normal healthy adults were mainly male and female students; the female students had a higher serum zinc and hair zinc concentration but a lower urinary zinc excretion than did the male students. The range in values within the normal groups was wide. No strong relationship was found with linear regression analysis or with multiple regression analysis of the data for the male or the female students. Other groups studied were oyster openers with a higher dietary intake of zinc from oysters, industrial workers exposed to zinc in their occupations, and hospital patients with leg ulcers or various dermatoses and with a potentially low zinc status. Only external exposure to zinc from an industrial source (galvanizing) or from the use of zinc-based creams increased the zinc concentration in the samples measured, and then only in hair and toenails. The hospital patients did not appear to have a lower zinc status comparable with adults from other countries. It was concluded that the measurement of zinc in serum, urine, hair, and toenails did not provide a sensitive indication of zinc status.     

Daily intake of lead,cadmium, copper,and zinc from drinking water: the seattle study of trace metal exposure

The daily intake of lead, cadmium, copper, and zinc from drinking water is estimated for men, women, and children living in Seattle based on their reported water consumption and the metal concentrations in water from their homes. Metal concentrations were closely associated with the type of plumbing in the home, which was found to be accurately reported by the subjects. Residents of homes with copper plumbing consumed a substantial proportion of their daily required copper from their drinking water, an important finding in view of the possible suboptimal copper levels in American diets. Lead intake levels from water in new homes was comparable to estimated U.S. dietary intakes, but was low relative to levels thought to be toxic. The results suggest practical methods for assessing the associations of chronic diseases with long-term, low-level exposures to these metals.