Query: Mercury Testing Recommended Before Pregnancy

Relevant passages:
An evaluation of mercury concentrations in three brands of canned tuna. <=SEP=> There is widespread concern over the presence of Hg in fish consumed by humans. While studies have been focused on determining the Hg concentration in sport fish and some commercial fish, little attention has been directed to canned tuna; it is widely held that concentrations are low. In the present study, the amount of Hg present in canned tuna purchased in Las Vegas, Nevada, USA, was examined, and the brand, temporal variation, type, and packaging medium impacts on Hg concentrations in tuna were explored. A significant (p < 0.001) brand difference was noted: Brand 3 contained higher Hg concentrations ($\bar x$ standard deviation (SD) (0.777 +/- 0.320 ppm) than Brands 1 (0.541 +/- 0.114 ppm) and 2 (0.550 +/- 0.199 ppm). Chunk white tuna (0.619 +/- 0.212 ppm) and solid white tuna (0.576 +/- 0.178 ppm) were both significantly (p < 0.001) higher in mean Hg than chunk light tuna (0.137 +/- 0.063 ppm). No significant temporal variation was noted, and packaging had no significant effect on Hg concentration. In total, 55% of all tuna examined was above the U.S. Environmental Protection Agency's (U.S. EPA) safety level for human consumption (0.5 ppm), and 5% of the tuna exceeded the action level established by the U.S. Food and Drug Administration (U.S. FDA) (1.0 ppm). These results indicate that stricter regulation of the canned tuna industry is necessary to ensure the safety of sensitive populations such as pregnant women, infants, and children. According to the U.S. EPA reference dose of 0.1 microg/kg body weight per day and a mean Hg value of 0.619 ppm, a 25-kg child may consume a meal (75 g) of canned chunk white tuna only once every 18.6 d. Continued monitoring of the industry and efforts to reduce Hg concentrations in canned tuna are recommended. Environ. Copyright 2009 SETAC.

Hair mercury levels of women of reproductive age in Ontario, Canada: implications to fetal safety and fish consumption. <=SEP=> OBJECTIVE: To study hair mercury concentrations among women of reproductive age in relation to fish intake in Ontario, Canada. STUDY DESIGN: Three groups were studied: 22 women who had called the Motherisk Program for information on the reproductive safety of consuming fish during pregnancy, a group of Japanese residing in Toronto (n=23) consuming much larger amounts of fish, and a group of Canadian women of reproductive age (n=20) not seeking advice, were studied. Mercury concentrations in hair samples were measured using inductively coupled plasma mass spectrometry. Seafood consumption habits were recorded for each participant. Based on the types of fish consumed and consumption frequencies, the estimated monthly intake of mercury was calculated. Hair mercury concentrations were correlated to both the number of monthly seafood servings and the estimated ingested mercury dose. RESULTS: There were significant correlations between fish servings and hair mercury (Spearman r=0.73, P<.0001) and between amounts of consumed mercury and hair mercury concentrations (Spearman r=0.81, P<.0001). Nearly two thirds of the Motherisk callers, all of the Japanese women, and 15% of the Canadian women of reproductive age had hair mercury above 0.3 microg/g, which was shown recently to be the lowest observable adverse effect level in a large systematic review of all perinatal studies. CONCLUSIONS: Because of very wide variability, general recommendations for a safe number of fish servings may not be sufficient to protect the fetus. Analysis of hair mercury may be warranted before pregnancy in selected groups of women consuming more than 12 ounces of fish per week, as dietary modification can decrease body burden and ensure fetal safety. Copyright (c) 2010. Published by Mosby, Inc.

Dietary intake of n−3 and n−6 fatty acids and the risk of clinical depression in women: a 10-y prospective follow-up study <=SEP=> Background: The associations between different sources of dietary n−3 (omega-3) and n−6 (omega-6) fatty acids and the risk of depression have not been prospectively studied. Objective: The objective was to examine the relation between different n−3 and n−6 types with clinical depression incidence. Design: We prospectively studied 54,632 US women from the Nurses' Health Study who were 50–77 y of age and free from depressive symptoms at baseline. Information on diet was obtained from validated food-frequency questionnaires. Clinical depression was defined as reporting both physician-diagnosed depression and regular antidepressant medication use. Results: During 10 y of follow-up (1996–2006), 2823 incident cases of depression were documented. Intake of long-chain n−3 fatty acids from fish was not associated with depression risk [relative risk (RR) for 0.3-g/d increment: 0.99; 95% CI: 0.88, 1.10], whereas α-linolenic acid (ALA) intake was inversely associated with depression risk (multivariate RR for 0.5-g/d increment: 0.82; 95% CI: 0.71, 0.94). The inverse association between ALA and depression was stronger in women with low linoleic acid (LA) intake (P for interaction = 0.02): a 0.5-g/d increment in ALA was inversely associated with depression in the first, second, and third LA quintiles [RR (95% CI): 0.57 (0.37, 0.87), 0.62 (0.41, 0.93), and 0.68 (0.47, 0.96), respectively] but not in the fourth and fifth quintiles. Conclusions: The results of this large longitudinal study do not support a protective effect of long-chain n−3 from fish on depression risk. Although these data support the hypothesis that higher ALA and lower LA intakes reduce depression risk, this relation warrants further investigation.

Occurrence of pharmaceuticals and personal care products in fish: results of a national pilot study in the United States. <=SEP=> Pharmaceuticals and personal care products are being increasingly reported in a variety of biological matrices, including fish tissue; however, screening studies have presently not encompassed broad geographical areas. A national pilot study was initiated in the United States to assess the accumulation of pharmaceuticals and personal care products in fish sampled from five effluent-dominated rivers that receive direct discharge from wastewater treatment facilities in Chicago, Illinois; Dallas, Texas; Orlando, Florida; Phoenix, Arizona; and West Chester, Pennsylvania, USA. Fish were also collected from the Gila River, New Mexico, USA, as a reference condition expected to be minimally impacted by anthropogenic influence. High performance liquid chromatography-tandem mass spectrometry analysis of pharmaceuticals revealed the presence of norfluoxetine, sertraline, diphenhydramine, diltiazem, and carbamazepine at nanogram-per-gram concentrations in fillet composites from effluent-dominated sampling locations; the additional presence of fluoxetine and gemfibrozil was confirmed in liver tissue. Sertraline was detected at concentrations as high as 19 and 545 ng/g in fillet and liver tissue, respectively. Gas chromatography-tandem mass spectrometry analysis of personal care products in fillet composites revealed the presence of galaxolide and tonalide at maximum concentrations of 2,100 and 290 ng/g, respectively, and trace levels of triclosan. In general, more pharmaceuticals were detected at higher concentrations and with greater frequency in liver than in fillet tissues. Higher lipid content in liver tissue could not account for this discrepancy as no significant positive correlations were found between accumulated pharmaceutical concentrations and lipid content for either tissue type from any sampling site. In contrast, accumulation of the personal care products galaxolide and tonalide was significantly related to lipid content. Results suggest that the detection of pharmaceuticals and personal care products was dependent on the degree of wastewater treatment employed.

Domoic acid and human exposure risks: a review. <=SEP=> Domoic acid is a potent neurotoxin that is naturally produced by several diatom species of the genus Pseudo-nitzschia. The toxin acts as a glutamate agonist and is excitotoxic in the vertebrate central nervous system and other glutamate receptor-rich organs. Human exposure to domoic acid occurs via the consumption of contaminated shellfish that have accumulated the toxin while filter feeding on toxigenic phytoplankton during blooms. The first reported human domoic acid poisoning event occurred in Canada in 1987 during which clinical signs of acute toxicity such as gastrointestinal distress, confusion, disorientation, memory loss, coma and death were observed. The illness was named amnesic shellfish poisoning (ASP) and due to effective seafood monitoring programs there have been no documented ASP cases since 1987. However, domoic acid poisoning has a significant effect on marine wildlife and multiple poisoning events have occurred in marine birds and mammals over the last few decades. Currently, domoic acid producing diatom blooms are thought to be increasing in frequency world wide, posing an increasing threat to wildlife and human health. Of particular concern are the potential impacts of long-term low-level exposure in "at risk" human populations. The impacts of repetitive low-level domoic acid exposure are currently unknown. This review provides a basic description of the mechanism of action of domoic acid as well as a synthesis of information pertaining to domoic acid exposure routes, toxin susceptibility, and the importance of effective monitoring programs. The importance of investigating the potential human health impacts of long-term low-level domoic acid exposure in "at risk" human populations is also discussed. Published by Elsevier Ltd.

Amnesic shellfish poison. <=SEP=> Amnesic shellfish poisoning (ASP) is caused by consumption of shellfish that have accumulated domoic acid, a neurotoxin produced by some strains of phytoplankton. The neurotoxic properties of domoic acid result in neuronal degeneration and necrosis in specific regions of the hippocampus. A serious outbreak of ASP occurred in Canada in 1987 and involved 150 reported cases, 19 hospitalisations and 4 deaths after consumption of contaminated mussels. Symptoms ranged from gastrointestinal disturbances, to neurotoxic effects such as hallucinations, memory loss and coma. Monitoring programmes are in place in numerous countries worldwide and closures of shellfish harvesting areas occur when domoic acid concentrations exceed regulatory limits. This paper reviews the chemistry, sources, metabolism and toxicology of domoic acid as well as human case reports of ASP and discusses a possible mechanism of toxicity.

Monitoring of mercury, arsenic, and lead in traditional Asian herbal preparations on the Dutch market and estimation of associated risks. <=SEP=> Traditional herbal preparations used in Ayurveda, traditional Chinese medicine, traditional Tibetan medicine, and other Asian traditional medicine systems may contain significant amounts of mercury, arsenic or lead. Though deliberately incorporated in Asian traditional herbal preparations for therapeutic purposes, these constituents have caused intoxications worldwide. The aim of this study was therefore to determine mercury, arsenic, and lead levels in Asian traditional herbal preparations on the Dutch market. A total of 292 traditional herbal preparations used in Ayurveda, traditional Chinese medicine, and traditional Tibetan medicine were sampled between 2004 and 2007. Samples were mostly multi-ingredient traditional herbal preparations containing herbs and minerals. The labeling of less than 20% of the traditional herbal preparations suggested the presence of mercury, arsenic or lead. These elements were shown by inductively coupled mass spectrometry (ICP-MS) in 186 (64%) of 292 traditional herbal preparations. Estimated weekly mercury, arsenic, and lead intake levels were calculated for each traditional herbal preparation from the analytically determined concentrations and the recommended dose. A total of 59 traditional herbal preparations (20%) were likely to result in intakes of these elements significantly exceeding safety limits. Of these 59 traditional herbal preparations, intake estimates for 50 traditional herbal preparations significantly exceeded the safety limit for mercury (range = 1.4-1747 mg week(-1)); intake estimates for 26 traditional herbal preparations significantly exceeded the safety limit for arsenic (range = 0.53-427 mg week(-1)) and intake estimates for eight traditional herbal preparations were significantly above the safety limit for lead (range = 2.6-192 mg week(-1)). It is concluded that the mercury, arsenic, and lead contents of traditional herbal preparations used in Ayurveda, traditional Chinese medicine, and traditional Tibetan medicine remain a cause for concern and require strict control.

Acute and subacute toxicity of tyramine, spermidine, spermine, putrescine and cadaverine in rats. <=SEP=> The acute and subacute toxicity of five biogenic amines-tyramine, spermidine, spermine, putrescine and cadaverine-were examined in Wistar rats. Tyramine and cadaverine had a low acute oral toxicity of more than 2000 mg/kg body weight. Putrescine had an acute oral toxicity of 2000 mg/kg body weight and spermidine and spermine each of 600 mg/kg body weight. All amines investigated caused a dose-related decrease in blood pressure after intravenous administration, except for tyramine, where an increase was found. In 6-wk studies the biogenic amines were administered in the diet to groups of 10 male and 10 female rats. Tyramine and cadaverine were given at levels of 0, 200, 2000 or 10,000 ppm, spermine and putrescine at levels of 0, 200, 2000 or 5000 ppm and spermidine at levels of 0, 20, 200 or 500/1000 ppm in the first study and at levels of 0 or 10,000 ppm in a second study. Spermine was the most toxic. The high dose level showed a great number of changes, such as emaciation, aggressiveness, convulsions and paralysis of the hind legs. Growth, food intake and water intake were considerably decreased. Slight anaemia (males) and changes in plasma clinical chemistry occurred. The relative weights of the thyroid, adrenals, spleen and heart were increased and that of the liver decreased. Impaired kidney function, together with renal histopathological changes and changes in plasma electrolytes and urea, occurred with spermine. Histopathological examinations also revealed decreased glycogen content in the liver, reduction of spermatogenesis, severe depletion of splenic white pulp, acute involution of the thymus and moderate myocardial degeneration in the heart. Myocardial degeneration was also seen in one mid-dose male. Adverse effects were also observed in the top dose groups of all other amines. Decreased body weights associated with diminished food intake were generally seen. Slight increases in packed cell volume, haemoglobin concentration and thrombocytes occurred with cadaverine. With spermidine, decreased plasma creatinine, calcium and inorganic phosphate were observed and decreased potassium levels with cadaverine. The no-observed-adverse-effect level was 2000 ppm (180 mg/kg body weight/day) for tyramine, cadaverine and putrescine, 1000 ppm (83 mg/kg body weight/day) for spermidine and 200 ppm (19 mg/kg body weight/day) for spermine.

Determination of biogenic amines in Korean traditional fermented soybean paste (Doenjang). <=SEP=> Biogenic amines, produced by bacterial decarboxylation of amino acids, have been associated with toxicological symptoms in food products. Twenty-three samples of traditionally available Korean fermented soybean paste samples (Doenjang) were analyzed in order to determine the content of biogenic amines. Amines were extracted with 0.4M perchloric acid and derivatized with dansyl chloride. Nine biogenic amines were separated from Doenjang samples by high performance liquid chromatography using gradient elution (acetonitrile and ammonium acetate), and detected with spectrophotometric UV-vis detection at 254 nm. The pH value of all the samples was ranged from 4.8 to 6.0, and the strong amino acid decarboxylase activity was found to be in an acidic environment. The mean values of biogenic amines (tryptamine, 2-phenyl-ethylamine, putrescine, cadaverine, agmatine, histamine, tyramine, spermidine and spermine) determined in 23 Doenjang samples were found to be 18.37, 82.03, 70.84, 34.24, 47.32, 26.79, 126.66, 74.41 and 244.36 mg%, respectively. The findings of this study enhance the safety of not only Doenjang but other salted and/or fermented food products. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

A probabilistic characterization of the health benefits of reducing methyl mercury intake in the United States. <=SEP=> We developed a probabilistic model to characterize the plausible distribution of health and economic benefits that would accrue to the U.S. population following reduction of methyl mercury (MeHg) exposure. MeHg, a known human developmental neurotoxicant, may increase fatal heart attack risks. Model parameters reflect current understanding of the relationships between MeHg intake, health risks, and societal valuation of these risks. The expected monetary value of the annual health benefits generated by a 10% reduction in U.S. population exposure to MeHg for one year is $860 million; 80% of this is associated with reductions in fatal heart attacks and the remainder with IQ gains. The plausible distribution of the benefits is quite broad with 5th and 95th percentile estimates of approximately $50 million and $3.5 billion, respectively. The largest source of uncertainty is whether epidemiological associations between MeHg exposure and fatal heart attacks reflect causality. The next largest sources of uncertainty concern the slope of the relationship between maternal MeHg exposure and reduced intelligence among children and whether this relationship exhibits a threshold. Our analysis suggests that the possible causal relationship between MeHg exposure and fatal heart attacks should be better characterized, using additional epidemiological studies and formally elicited expert judgment.

Exploration of biomarkers for total fish intake in pregnant Norwegian women. <=SEP=> OBJECTIVE: Few biomarkers for dietary intake of various food groups have been established. The aim of the present study was to explore whether selenium (Se), iodine, mercury (Hg) or arsenic may serve as a biomarker for total fish and seafood intake in addition to the traditionally used n-3 fatty acids EPA and DHA. DESIGN: Intake of fish and seafood estimated by an FFQ was compared with intake assessed by a 4 d weighed food diary and with biomarkers in blood and urine. SETTING: Validation study in the Norwegian Mother and Child Cohort Study (MoBa). SUBJECTS: One hundred and nineteen women. RESULTS: Total fish/seafood intake (median 39 g/d) calculated with the MoBa FFQ was comparable to intake calculated by the food diary (median 30 g/d, rS = 0.37, P < 0.001). Erythrocyte DHA and blood Hg, Se and arsenic concentrations were positively correlated with intake of fish and seafood, but the association for DHA was weakened by the widespread use of supplements. The main finding was the consistent positive association between the intake of fish/seafood and blood arsenic concentration. In multivariate analyses, blood arsenic was associated with blood Hg and fish and seafood intake. In these models, arsenic turned out to be the best indicator of intake of fish and seafood, both totally and in subgroups of fish/seafood intake. CONCLUSIONS: While DHA reflected the intake of fatty fish and n-3 PUFA supplements, blood arsenic concentration also reflected the intake of lean fish and seafood. Blood arsenic appears to be a useful biomarker for total fish and seafood intake.

Nowhere to hide: Chemical toxicants and the unborn child. <=SEP=> Contemporary reproductive aged women and their offspring are facing an unprecedented onslaught of toxicant exposures from myriad sources in their day-to-day life. Public health recommendations regarding optimal diet and nutrition in pregnancy must incorporate several considerations including safety of available foodstuffs, cultural practices and lifestyle issues. Gestational consumption of contaminated seafood remains a potential source of toxicant exposure, including mercury, for the developing child. Health care professionals responsible for the care of women and their developing children need to become apprised of: a) risks associated with toxicant bioaccumulation in pregnancy; b) ongoing information emerging in the important field of reproductive toxicology; and c) strategies within the clinical setting to facilitate nutritional sufficiency and precautionary avoidance of adverse exposure among young women.

Urinary excretion of total isothiocyanates from cruciferous vegetables shows high dose-response relationship and may be a useful biomarker for isot... <=SEP=> BACKGROUND: Isothiocyanates (ITCs), hydrolysis products from glucosinolates, are a family of biologically active compounds originating from cruciferous vegetables. Many ITCs are assumed to have cancer preventive effects and to further evaluate these potential health effects, reliable biomarkers of ITC exposure are needed. AIM OF THE STUDY: In this study we investigated the ability of urinary ITC excretion to reflect a low or high daily intake of cruciferous vegetables. METHODS: The design was a controlled human crossover study (n = 6). Subjects consumed a self-restricted glucosinolate-free diet 48 h before the study-day where a basic diet supplemented with 80 or 350 g of mixed cruciferous vegetables was consumed. All urine was collected in intervals during the 48 h period after ingestion of the cruciferous vegetables. Total ITC in the cruciferous mixture and total ITC and their metabolites in urine was quantified as the cyclocondensation product of 1,2-bezenedithiol by high performance liquid chromatography. RESULTS: The total urinary excretion of ITCs correlated significantly with the two doses of ITC from diets with high or low cruciferous content (r (s )= 0.90, P < 0.01). The fraction of urinary ITC excreted was 69.02 +/- 11.57% and 74.53 +/- 8.39% of the amounts ingested for 80 and 350 g cruciferous vegetables, respectively. CONCLUSION: The results in this study indicate that the urinary excretion of ITCs, measured by use of the cyclocondesation reaction, is a useful and precise tool that may be used as a biomarker of ITC exposure in population based studies.

Sub-clinical neurobehavioral abnormalities associated with low level of mercury exposure through fish consumption. <=SEP=> In order to assess early neurotoxic effects associated with relatively low levels of mercury absorbed through fish eating, two groups of 22 adult male subjects, habitual consumers of tuna fish, and 22 controls were examined using a cross-sectional field study. The assessment included neurobehavioral tests of vigilance and psychomotor function, hand tremor measurements and serum prolactin assessment. Mercury in urine (U-Hg) and serum prolactin (sPRL) were measured in all exposed subjects and controls, whereas measurements of the organic component of mercury in blood (O-Hg) were available for only 10 exposed and six controls. U-Hg was significant higher among exposed subjects (median 6.5 microg/g of creatinine, range 1.8-21.5) than controls (median 1.5 microg/g of creatinine, range 0.5-5.3). The median values of O-Hg were 41.5 microg/l among the tuna fish eaters and 2.6 microg/l in the control group. Both U-Hg and O-Hg were significantly correlated with the quantity of fish consumed per week. Significant differences in sPRL were found between exposed (12.6 ng/ml) and controls (9.1 ng/ml). Individual sPRL were significantly correlated with both U-Hg and O-Hg levels. The neurobehavioral performance of subjects who consumed tuna fish regularly was significantly worse on color word reaction time, digit symbol reaction time and finger tapping speed (FT). After considering the education level and other covariates, the multiple stepwise regression analysis indicated that O-Hg concentration was most significantly associated with individual performance on these tests, accounting for about 65% of the variance in test scores.

Role of environmental estrogens in the deterioration of male factor fertility. <=SEP=> OBJECTIVE: To evaluate the role of the environmental estrogens polychlorinated biphenyls (PCBs) and phthalate esters (PEs) as potential environmental hazards in the deterioration of semen parameters in infertile men without an obvious etiology. DESIGN: Randomized controlled study. SETTING: Tertiary care referral infertility clinic and academic research center. PATIENT(S): Twenty-one infertile men with sperm counts <20 million/mL and/or rapid progressive motility <25% and/or <30% normal forms without evidence of an obvious etiology and 32 control men with normal semen analyses and evidence of conception. Semen and blood samples were obtained as part of the treatment protocol. MAIN OUTCOME MEASURE(S): Evaluation of semen parameters such as ejaculate volume, sperm count, motility, morphology, vitality, osmoregulatory capacity, sperm chromatin stability, and sperm nuclear DNA integrity. RESULT(S): PCBs were detected in the seminal plasma of infertile men but not in controls, and the concentration of PEs was significantly higher in infertile men compared with controls. Ejaculate volume, sperm count, progressive motility, normal morphology, and fertilizing capacity were significantly lower in infertile men compared with controls. The highest average PCB and PE concentrations were found in urban fish eaters, followed by rural fish eaters, urban vegetarians, and rural vegetarians. The total motile sperm counts in infertile men were inversely proportional to their xenoestrogen concentrations and were significantly lower than those in the respective controls. CONCLUSION(S): PCBs and PEs may be instrumental in the deterioration of semen quality in infertile men without an obvious etiology.

Fish consumption, methylmercury and child neurodevelopment <=SEP=> Purpose of review To summarize recent evidence regarding associations of early life exposure to mercury from maternal fish consumption during pregnancy, thimerosal in vaccines and dental amalgam with child neurodevelopment. Recent findings Recent publications have built upon previous evidence demonstrating mild detrimental neurocognitive effects from prenatal methylmercury exposure from maternal fish consumption during pregnancy. New studies examining the effects of prenatal fish consumption as well as methylmercury suggest there are benefits from prenatal fish consumption, but also that consumption of fish high in mercury should be avoided. Future studies incorporating information on both the methylmercury and the docosahexaenoic acid contained within fish will help to refine recommendations to optimize outcomes for mothers and children. Additional recent studies have supported the safety of vaccines containing thimerosal and of dental amalgam for repair of dental caries in children. Summary Exposure to mercury may harm child development. Interventions intended to reduce exposure to low levels of mercury in early life must, however, be carefully evaluated in consideration of the potential attendant harm from resultant behavior changes, such as reduced docosahexaenoic acid exposure from lower seafood intake, reduced uptake of childhood vaccinations and suboptimal dental care.

A risk-benefit analysis of French high fish consumption: a QALY approach. <=SEP=> The health risk and the nutritional benefit of a food are usually assessed separately. Toxicologists recommend limiting the consumption of certain fish because of methylmercury; while nutritionists recommend eating more oily fish because of omega 3. A common evaluation is imperative to provide coherent recommendations. In order to evaluate the risks along with the benefits related to fish consumption, a common metric based on the quality-adjusted life year (QALY) method has been used. The impact of a theoretical change from a medium n-3 PUFAs intake to a high intake is studied, in terms of the cardiovascular system (CHD mortality, stroke mortality and morbidity) and on fetal neuronal development (IQ loss or gain). This application can be considered as a sensitive analysis of the model used and looks at the impact of changing the dose-response relationships between cardiovascular diseases and n-3 PUFAs intakes. Results show that increasing fish consumption may have a beneficial impact on health. However, the confidence interval of the overall estimation has a negative lower bound, which means that this increase in fish consumption may have a negative impact due to MeHg contamination. Some limits of the QALY approach are identified. The first concerns determination of the dose-response relationships. The second concerns the economic origins of the approach and of individual preferences. Finally, since only one beneficial aspect and one risk element were studied, consideration should be given to how other beneficial and risk components may be integrated in the model.

Nutrient and methyl mercury exposure from consuming fish. <=SEP=> There is controversy about the risks and benefits of consuming fish. Fish consumption provides nutrients, some of which are essential for brain growth and development. All fish, however, contain methyl mercury (MeHg), a known neurotoxicant. The toxic effect of MeHg seems most damaging during brain development, and thus, prenatal exposure is of greatest concern. At present the level of prenatal exposure associated with risk to a child's neurodevelopment is not known. Balancing the rewards and possible risks of fish consumption presents a dilemma to consumers and regulatory authorities. We review the nutrients in fish that are important in brain development and the current evidence of risk from MeHg at exposure levels achieved by consuming fish. We then review the findings from a large prospective cohort study of a population that consumes fish daily, the Seychelles Child Development Study. The MeHg content of the fish consumed in the Seychelles is similar to that of ocean fish available in industrialized countries, so they represent a sentinel population for any risk from fish consumption. In the Seychelles, evaluations of the children through 9 y of age show no consistent pattern of adverse associations with prenatal MeHg exposure. Recent studies in the Seychelles have focused on nutrients in fish that might influence a child's development, including long-chain polyunsaturated fatty acids, iodine, iron, and choline. Preliminary findings from this study suggest that the beneficial influence of nutrients from fish may counter any adverse effects of MeHg on the developing nervous system.

Public health guidance on cardiovascular benefits and risks related to fish consumption <=SEP=> Historically, concerns with fish consumption have addressed risks from contaminants (e.g., methylmercury (MeHg), and PCBs). More recently public health concerns have widened in appreciation of the specific benefits of fish consumption such as those arising from polyunsaturated fatty acids (PUFAs) in fish oil. Fish contains varying levels of PUFAs and MeHg. Since both address the same health outcomes (in opposite directions) and occur together in fish, great care must be exercised in providing public health guidance. Mozaffarian and Rimm in a recent article (JAMA. 2006, 296:1885–99) have made a strong case for the beneficial effects of PUFAs in reducing the risk of coronary heart disease, but at the same time, have also broadly discounted the increased risks of coronary heart disease posed by MeHg in fish, stating that "... among adults... the benefits of fish intake exceed the potential risks." This conclusion appears to be based on an inaccurate and insufficiently critical analysis of the literature. This literature is re-examined in light of their conclusions, and the available and appropriate public health options are considered.

Nutrient and contaminant tradeoffs: exchanging meat, poultry, or seafood for dietary protein. <=SEP=> When making food choices, consumers are faced with the dilemma of reconciling differences between health benefits and exposure to potential toxins. Analyses to estimate likely intake and exposure outcomes for young children and women of child-bearing age shows that seafood, chicken, and beef, while approximately equivalent in protein, vary in key nutrients of importance as well as in levels of certain contaminants. Increasing the variety of choices among meats, poultry, and seafood and consuming them in amounts consistent with current dietary guidelines and advisories will contribute toward meeting nutritional needs while reducing exposure to any single type of contaminant.