Benefits and risks of fish consumption Part I. A quantitative analysis of the intake of omega-3 fatty acids and chemical contaminants

In recent years, and based on the importance of fish as a part of a healthy diet, there has been a notable promotion of fish consumption. However, the balance between health benefits and risks, due to the intake of chemical contaminants, is not well characterized. In the present study, edible samples of 14 marine species were analyzed for the concentrations of omega-3 fatty acids, as well as a number of metals and organic pollutants. Daily intakes were specifically determined for a standard adult of 70 kg, and compared with the tolerable/admissible intakes of the pollutants, if available. Salmon, mackerel, and red mullet were the species showing the highest content of omega-3 fatty acids. The daily intakes of cadmium, lead, and mercury through fish consumption were 1.1, 2.0, and 9.9 μg, respectively. Dioxins and furans plus dioxin-like polychlorinated biphenyls (PCBs) intake was 38.0 pg WHO-TEQ/day, whereas those of polybrominated diphenyl ethers (PBDEs), polychlorinated diphenyl ethers (PCDEs), polychlorinated naphthalenes (PCNs) and hexachlorobenzene (HCB) were 20.8, 39.4, 1.53, and 1.50 ng/day, respectively. In turn, the total intake of 16 analyzed polycyclic aromatic hydrocarbons (PAHs) was 268 ng/day. The monthly fish consumption limits for human health endpoints based on the intake of these chemical contaminants were calculated for a 70 years exposure. In general terms, most marine species here analyzed should not mean adverse health effects for the consumers. However, the type of fish, the frequency of consumption, and the meal size are essential issues for the balance of the health benefits and risks of regular fish consumption.     

Benefits and risks of fish consumption Part II. RIBEPEIX, a computer program to optimize the balance between the intake of omega-3 fatty acids and chemical contaminants

In recent years, and based on the importance of fish as a part of a healthy diet, there has been a notable promotion of fish and seafood consumption. However, a number of recent studies have shown that fish may be a potential source of exposure to chemical pollutants, some of them with well known adverse effects on human health. Recently, we determined in 14 edible marine species the concentrations of eicosapentaenoic acid (EPA) and docosohexaenoic acid (DHA), as well as those of a number of chemical contaminants: Cd, Hg, Pb, polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls, hexachlorobenzene, polycyclic aromatic hydrocarbons, polychlorinated naphthalenes, polybrominated diphenylethers and polychlorinated diphenylethers. To quantitative establish the intake of these pollutants (risks) versus that of EPA + DHA (benefits), we designed a simple computer program, RIBEPEIX. The concentrations of EPA, DHA, and the chemical pollutants were introduced into the program. We here present how RIBEPEIX may be used as an easy tool to optimize fish consumption: most suitable species, frequency of consumption, and size of meals. RIBEPEIX can be useful not only for professionals (cardiologists, general physicians, nutritionists, toxicologists, etc.), but also for the general population. It is available at: http://www.fmcs.urv.cat/portada/ribepeix/.     

Commercial squids: Characterization,assessment of potential health benefits/risks and discrimination based on mineral,lipid and vitamin E concentrations

The most consumed squid species worldwide were characterized regarding their concentrations of minerals, fatty acids, cholesterol and vitamin E. Interspecific comparisons were assessed among species and geographical origin. The health benefits derived from squid consumption were assessed based on daily minerals intake and on nutritional lipid quality indexes. Squids contribute significantly to daily intake of several macro (Na, K, Mg and P) and micronutrients (Cu, Zn and Ni). Despite their low fat concentration, they are rich in long-chain omega-3 fatty acids, particularly docosahexaenoic (DHA) and eicosapentanoic (EPA) acids, with highly favorable ω-3/ω-6 ratios (from 5.7 to 17.7), reducing the significance of their high cholesterol concentration (140–549 mg/100 g ww). Assessment of potential health risks based on minerals intake, non-carcinogenic and carcinogenic risks indicated that Loligo gahi (from Atlantic Ocean), Loligo opalescens (from Pacific Ocean) and Loligo duvaucelii (from Indic Ocean) should be eaten with moderation due to the high concentrations of Cu and/or Cd. Canonical discriminant analysis identified the major fatty acids (C14:0, C18:0, C18:1, C18:3ω-3, C20:4ω-6 and C22:5ω-6), P, K, Cu and vitamin E as chemical discriminators for the selected species. These elements and compounds exhibited the potential to prove authenticity of the commercially relevant squid species.     

Comparison of the nutritional–toxicological conflict related to seafood consumption in different regions worldwide

This article discusses the seafood consumption worldwide as well as the related nutritional–toxicological conflict. An exposure assessment was performed using seafood consumption data from the Global Environment Monitoring System and nutrient and contaminant concentration data. The data indicated that the region of Japan, Korea, Madagascar and Philippines have the highest seafood consumption, followed by the Nordic–Baltic countries and South-East Asia. In Japan, Korea, Madagascar, Philippines and the Nordic–Baltic countries, pelagic marine fishes are highly consumed compared to fresh water fishes in South-East Asia. Because pelagic fishes are oily fishes, Japan, Korea, Madagascar, Philippines and the Nordic–Baltic countries have high omega-3 fatty acids and vitamin D intake. Iodine intake is influenced by the demersal fish consumption. The current intake of these nutrients via seafood consumption is still below the recommendations. From the toxicological side, the data indicate that none of the seafood groups had a median contaminant concentration above the EU maximum limits. Though, the results show that in some regions the contaminant intake exceeded the international health-based guidance values, mainly focussing on sensitive subpopulations. In contrast, when using less stringent guidance values relevant for non-sensitive subpopulations, the results show that the benefits of increased seafood consumption outweigh the risks.     

Enhancing and improving the extraction of omega-3 from fish oil

Omega-3 fatty acids DHA and EPA derived from fish oil are widely marketed across the world as valued dietary supplements offering numerous health benefits to children and adults alike. Traditional extraction processes are energy intensive and use organic solvents. Green and sustainable alternatives are needed with the aim to significantly expand and improve the production of omega-3 extracts, especially with the aim to obtain these essential polyunsaturated fatty acids from fish processing waste available in >20 million tonnes/year amount.     

Species,tissue and gender-related metal and element accumulation in fish species in a large reservoir (Turkey) and health risks and nutritional benefits for consumers

Concentrations of 18 metals and elements (MEs) in the gills, skin, muscle and liver of Carasobarbus luteus and Cyprinus carpio from the Atatürk Reservoir in Turkey were investigated. The results revealed that variations in the ME contents between fish species can be attributed to different diets. The highest contents of most MEs were recorded in the gills. Gender had no significant effect on the contents of most MEs in the tissues of fish species investigated. The relations between MEs in tissues and fish size were not clear and consistent. Health risk assessment methods indicated that consumption of the studied fish species is safe. It was estimated that daily consumption of 140 g of C. carpio or 170 g of C. luteus would not be expected to cause any health risks. Furthermore, it was found that fish species would provide significant benefits in terms of intake of essential MEs.     

Impact of a risk-benefit advisory on fish consumption and dietary exposure to methylmercury in France

We designed the CORAI (COnsumer Risk Advisory Inquiry) study to observe consumer reactions' after an advisory revealing risk of methylmercury contamination together with benefits of Long-Chain Poly Unsaturated Fatty Acids of the n-3 variety (LC n-3 PUFA). The message was very close to the ones commonly delivered by national food agencies and included recommendations for women of childbearing age and children below 15 years old. Two groups of subjects including consumers at risk were selected. Participants recorded the frequency of their fish consumption detailed by species for them and their family over a one-month period one month before, a month immediately after and 3 month after the advisory. Results were compared between consumers receiving the advisory and controls. Results show that the message revelation led to a significant decrease in total fish consumption which is greater for children below 6 years old than for the children between 6 and 15 years old and women. The consumption of the most contaminated fish quoted in the advisory, rarely consumed and poorly known by French consumers did not decrease in any group despite the advice to avoid their consumption. The consumption of other fish products quoted in the advisory but frequently consumed and better known, as canned tuna, did decrease and was a major contributor to the overall reduction of exposure for the advised group. Before the information, about 3% of women of childbearing age are exceeding the PTWI for MeHg and both the average and the high percentiles of the exposure to MeHg are decreasing significantly in the advised group. Regarding the number of subjects of the advised group exceeding the PTWI, they were 6, 3 and 2, respectively, in May, June and September. Accompanying questionnaires show that consumers imperfectly memorize most of the fish species quoted in the recommendation. This paper concludes that consumer advisory, which is a major tool for risk management, has a minimal effect under our experimental conditions to reduce the exposure of groups at risk. Messages to be carried to consumers should be carefully tested for long term memorization in order to become more effective.     

For the good of the patient: risks and benefits of medicines

The basis of regulation of medicines is an assessment of risk and benefit. As the process of drug development has evolved with the advances in scientific knowledge, new and more precise methods of measuring drug efficacy have been created. Pharmacovigilance must also change with as much emphasis being placed on demonstrating the safety of a medicine as on preventing harm. Communication of these issues to interested parties remains problematical with room for considerable improvement.     

To sea or not to sea: benefits and risks of gestational fish consumption

Prenatal nutritional status and the gestational environmental milieu have increasingly been identified as major determinants of long-term morbidity and mortality for the developing child. While omega-3 fatty acids - found abundantly in fish - are required for normal fetal development as well as for optimal maternal outcome, recent public health warnings to limit some types of seafood intake because of potential contamination with chemical toxicants have resulted in a dilemma for prenatal educators and maternity care providers. This paper reviews the benefits and harms of gestational seafood consumption and provides practical recommendations to address this important public health dilemma.     

Perceived risks and benefits of quitting smoking in non-treatment seekers

Little is known about beliefs about quitting and treatment motivation in non-treatment seeking smokers. One hundred eighty-eight daily cigarette smokers not currently motivated to quit smoking completed measures of perceived risks and benefits of quitting and motivation to quit. Self esteem related to quitting was positively related to desire to quit, expected success at quitting, confidence in quitting, and motivation to quit. Greater perceived risks of cravings was related to greater expected difficulty of remaining abstinent, and greater perceived risk of increased negative affect was related to decreased expectation of success at quitting, confidence for quitting, and increased expectation for difficulty remaining abstinent. Greater perceived risk of weight gain was related to being less likely to have a goal of complete abstinence. There were no gender, ethnicity, age, or education differences in the relationship of perceived risks and benefits of quitting and motivation. Knowing the risks and benefits that relate to motivation to quit for non-treatment seeking smokers provides the foundation for targeting this group in campaigns to increase quit motivation.     

Food survey: Levels and potential health risks of chromium,lead, zinc and copper content in fruits and vegetables consumed in Algeria

A food survey was carried out with the aim to investigate the levels of lead (Pb), zinc (Zn), copper (Cu) and chromium (Cr) in various fruits and vegetables sold in Algeria. Concentrations (mg/kg dry wt.) in selected foodstuffs were detected within the following ranges: 4–29.49, 11.17–49, 12.33–39.33 and 3–16.33 for Cu, Zn, Pb and Cr respectively. The food ingestion rate of the selected items was investigated by self-administered questionnaires which were filled by a total of 843 people randomly recruited at the exit of markets. The potential health risk for consumers was investigated by estimating the daily intake (EDI) and the target hazard quotient (THQ) for each heavy metal. For all foodstuffs, the EDI and the THQ were below the threshold values for Cu, Zn and Cr while they exceeded the thresholds for Pb (EDI: 15.66 μg Pb/kg body weight/day; THQ: 4.37), indicating an obvious health risk over a life time of exposure.     

Risk and benefits from consuming salmon and trout: a Canadian perspective.

Recent reports on the presence of persistent organic chemicals in wild and farmed salmon have left consumers and health professionals confused regarding the safety of regular fish consumption. The objectives of this study were (1) to compare concentrations of key contaminants and the essential nutrients omega-3 fatty acids between farmed and wild salmon and trout, and (2) to balance risks and benefits from regularly consuming these species. Concentrations of mercury, polychlorinated biphenyls, dioxins and furans as well as omega-3 fatty acids were determined in fillets from farmed salmon and trout bought in various markets located in Quebec, Canada, as well as in fillets from wild salmonids obtained from fishermen and various Canadian agencies. While differences were observed between market (farmed) and wild fish with regard to the concentrations of mercury and polychlorinated biphenyls, overall the concentrations of contaminants were low, such that the regular consumption of these fish would not cause tolerable daily intakes to be exceeded. Our results indicate that salmon and trout sold in Quebec markets, which as in markets located elsewhere in North America originate for the most part from Chilean farms, can be consumed regularly to achieve optimal nutritional benefits from omega-3 fatty acids, without incurring significant contaminant related health risks.     

Polycyclic aromatic hydrocarbons in commercial squids from different geographical origins: Levels and risks for human consumption

The concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) were determined in five commercially valuable squid species from different geographical origins (Atlantic, Indic and Pacific Oceans). Out of the 18 quantified PAHs (the 16 PAHs considered by US EPA as priority pollutants, dibenzo(a,l)pyrene and benzo(j)fluoranthene) only dibenz(a,h)anthracene was not detected. The total concentrations of PAHs varied by a factor of more than 100-fold, from 0.22 (Loligo gahi) to 60.9 μg/kg ww (Loligo reynaudii). Intra- and inter-specific variability of PAH levels was statistically assessed. Nine carcinogenic (probable/possible) PAHs accounted for 1% (L. reynaudii) to 26% (Loligo opalescens) of the total PAHs content being the main contributors naphthalene (in Loligo duvaucelii, L. reynaudii and Loligo vulgaris species), chrysene (in L. opalescens) and indeno(1,2,3-cd)pyrene (in L. gahi). PAHs source analysis indicated that four of the five zones of capture of the different squid species are significantly affected by both petrogenic and pyrolytic sources. Assessment of the target carcinogenic risks, established by the US EPA, suggested that L. gahi (Atlantic Ocean) and L. opalescens (from Pacific Ocean) may pose additional risks for consumers, if not eaten in moderation, derived from benzo(a)pyrene ingestion.     

Intake of chemical contaminants through fish and seafood consumption by children of Catalonia, Spain: health risks.

The intake of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenylethers (PBDEs), polychlorinated diphenylethers (PCDEs), hexachlorobenzene, and polycyclic aromatic hydrocarbons through fish and seafood consumption by children of Catalonia, Spain, was assessed. In 2005, samples of the 14 most consumed marine species in Catalonia were randomly acquired in various cities of the country. Analysis of the above chemical contaminants were determined according to the appropriate analytical techniques and the daily intakes were estimated. For most pollutants, intake was higher in boys than in girls. Average exposure of children to contaminants through fish and seafood consumption did not exceed the respective tolerable daily intake of those pollutants for which it has been already established (metals, PCDD/Fs plus dioxin-like PCBs, HCB, and PAHs). In relation to body weight, intake by children of most contaminants was higher than that found for other age groups of the general population of Catalonia.     

Evaluating heavy metals contamination in soil and vegetables in the region of North India: Levels,transfer and potential human health risk analysis

This study determined the heavy metals (HMs) accumulation in different vegetables in different seasons and attributed a serious health hazard to human adults due to the consumption of such vegetables in Jhansi. The total amounts of zinc (Zn), lead (Pb), nickel (Ni), manganese (Mn), copper (Cu), cobalt (Co), and cadmium (Cd) were analysed in 28 composite samples of soil and vegetables (Fenugreek, spinach, eggplant, and chilli) collected from seven agricultural fields. The transfer factor (TF) of HMs from soil to analysed vegetables was calculated, and significant non-carcinogenic health risks due to exposure to analysed heavy metals via consumption of these vegetables were computed. The statistical analysis involving Principal Component Analysis (PCA) and Pearson's correlation matrix suggested that anthropogenic activities were a major source of HMs in the study areas. The target hazard quotient of Cd, Mn, and Pb for fenugreek (2.156, 2.143, and 2.228, respectively) and spinach (3.697, 3.509, 5.539, respectively) exceeded the unity, indicating the high possibilities of non-carcinogenic health risks if regularly consumed by human beings. This study strongly suggests the continuous monitoring of soil, irrigation water, and vegetables to prohibit excessive accumulation in the food chain.     

Fish oil concentrate delays sensitivity to thermal nociception in mice

Fish oil has been used to alleviate pain associated with inflammatory conditions such as rheumatoid arthritis. The anti-inflammatory property of fish oil is attributed to the n-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid. Contrarily, vegetable oils such as safflower oil are rich in n-6 fatty acids which are considered to be mediators of inflammation. This study investigates the effect of n-3 and n-6 fatty acids rich oils as dietary supplements on the thermally induced pain sensitivity in healthy mice. C57Bl/6J mice were fed diet containing regular fish oil, concentrated fish oil formulation (CFO) and safflower oil (SO) for 6 months. Pain sensitivity was measured by Plantar test and was correlated to the expression of acid sensing ion channels (ASICs), transient receptor potential vanilloid 1 (TRPV1) and c-fos in dorsal root ganglion cells. Significant delay in sensitivity to thermal nociception was observed in mice fed CFO compared to mice fed SO (p < 0.05). A significant diminution in expression of ion channels such as ASIC1a (64%), ASIC13 (37%) and TRPV1 (56%) coupled with reduced expression of c-fos, a marker of neuronal activation, was observed in the dorsal root ganglion cells of mice fed CFO compared to that fed SO. In conclusion, we describe here the potential of fish oil supplement in reducing sensitivity to thermal nociception in normal mice.     

Evaluation of fish oil-rich in MUFAs for anti-diabetic and anti-inflammation potential in experimental type 2 diabetic rats

The advantages of monounsaturated fatty acids (MUFAs) on insulin resistance and type 2 diabetes mellitus (T2DM) have been well established. However, the molecular mechanisms of the anti-diabetic action of MUFAs remain unclear. This study examined the anti-hyperglycemic effect and explored the molecular mechanisms involved in the actions of fish oil- rich in MUFAs that had been acquired from hybrid catfish (Pangasius larnaudii×Pangasianodon hypophthalmus) among experimental type 2 diabetic rats. Diabetic rats that were fed with fish oil (500 and 1,000 mg/kg BW) for 12 weeks significantly reduced the fasting plasma glucose levels without increasing the plasma insulin levels. The diminishing levels of plasma lipids and the muscle triglyceride accumulation as well as the plasma leptin levels were identified in T2DM rats, which had been administrated with fish oil. Notably, the plasma adiponectin levels increased among these rats. The fish oil supplementation also improved glucose tolerance, insulin sensitivity and pancreatic histological changes. Moreover, the supplementation of fish oil improved insulin signaling (p-Akt^Ser473 and p-PKC-ζ/λ^Thr410/403), p-AMPK^Thr172 and membrane GLUT4 protein expressions, whereas the protein expressions of pro-inflammatory cytokines (TNF-α and nuclear NF-κB) as well as p-PKC-θ^Thr538 were down regulated in the skeletal muscle. These data indicate that the effects of fish oil-rich in MUFAs in these T2DM rats were partly due to the attenuation of insulin resistance and an improvement in the adipokine imbalance. The mechanisms of the anti-hyperglycemic effect are involved in the improvement of insulin signaling, AMPK activation, GLUT4 translocation and suppression of pro-inflammatory cytokine protein expressions.     

Potential effects of omega-3 fatty acids on anemia and inflammatory markers in maintenance hemodialysis patients

Background

Anemia is a common complication among hemodialysis (HD) patients. Although intravenous iron and erythropoiesis-stimulating agents revolutionized anemia treatment, about 10% of HD patients show suboptimal response to these agents. Systemic inflammation and increased serum hepcidin level may contribute to this hyporesponsiveness. Considering the anti-inflammatory properties of omega-3 fatty acids, this study aimed to evaluate potential role of these fatty acids in improving anemia and inflammation of chronic HD patients.

Methods

In this randomized, placebo-controlled trial, 54 adult patients with HD duration of at least 3 months were randomized to ingest 1800 mg of either omega-3 fatty acids or matching placebo per day for 4 months. Anemia parameters including blood hemoglobin, serum iron, transferrin saturation (TSAT), erythropoietin resistance index, and required dose of intravenous iron and erythropoietin, and serum concentrations of inflammatory/anti-inflammatory markers including interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10, C-reactive protein (CRP), hepcidin, ferritin, intact parathyroid hormone (iPTH), and ratios of IL-10 to IL-6 and IL-10 to TNF-α were measured at baseline and after 4 months of the intervention.

Results

45 subjects (25 in the omega-3 and 20 in the placebo group) completed the study. No significant changes were observed in blood hemoglobin, serum iron, TSAT, and required dose of intravenous iron in either within or between group comparisons. Additionally, erythropoietin resistance index as well as required dose of intravenous erythropoietin showed no significant change in the omega-3 group compared to the placebo group. Although a relative alleviation in inflammatory state appeared in the omega-3 group, the mean differences of inflammatory and anti-inflammatory markers between the two groups did not reach statistically significant level except for IL-10-to-IL-6 ratio and serum ferritin level which showed significant changes in favor of omega-3 treatment (P <0.001 and P = 0.003, respectively).

Conclusion

Omega-3 fatty acids relatively improved systemic inflammation of chronic HD patients without any prominent benefits on anemia. However, future well-designed studies on larger number of patients may determine utility of omega-3 fatty acids in HD patients with respect to inflammation and anemia.     

Polycyclic aromatic hydrocarbon levels in three pelagic fish species from Atlantic Ocean: inter-specific and inter-season comparisons and assessment of potential public health risks

The concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) were determined in three commercially valuable fish species (sardine, Sardina pilchardus; chub mackerel, Scomber japonicus; and horse mackerel, Trachurus trachurus) from the Atlantic Ocean. Specimens were collected seasonally during 2007–2009. Only low molecular weight PAHs were detected, namely, naphthalene, acenaphthene, fluorene and phenanthrene. Chub mackerel (1.80–19.90 μg/kg ww) revealed to be significantly more contaminated than horse mackerel (2.73–10.0 μg/kg ww) and sardine (2.29–14.18 μg/kg ww). Inter-specific and inter-season comparisons of PAHs bioaccumulation were statistically assessed. The more relevant statistical correlations were observed between PAH amounts and total fat content (significant positive relationships, p ? 0.05), and season (sardine displayed higher amounts in autumn–winter while the mackerel species showed globally the inverse behavior). The health risks by consumption of these species were assessed and shown to present no threat to public health concerning PAH intakes.     

Assessment of the health risks related to the presence of drug residues in water for human consumption: application to carbamazepine

Pharmaceutical residues have been detected at low (usually ng/L) concentrations in drinking water sources. The detection of drugs in water intended for human consumption (WIHC) has raised questions of safety. In the absence of regulatory or other official guidance, water utilities are faced with a problem of which pharmaceutical residues should be monitored and the toxicological limits that should be required. In this essay, we define an approach for the assessment of health risks related to chemicals found in drinking water. We use the examples of carbamazepine and its main metabolite 10,11-epoxycarbamazepine to demonstrate our approach, which involves application of the following algorithm: (1) when there is human or animal toxicity data, a toxicity reference value (TRV) can be calculated; (2) when this is not applicable, an attempt should be made to derive the TRV using known information about the minimum therapeutic dose (MTD); and (3) when no applicable data is available, at all, a threshold of toxicological concern (TTC) should be estimated. In the case of carbamazepine, where relevant toxicological data exists, we derived a TRV, based on the known minimum therapeutic dose (MTD). For carbamazepine's metabolite 10,11-epoxycarbamazepine, there is no toxicological data, so we applied the TTC approach. Using this approach, and combining our estimates with what is known about these chemicals' margin of exposure (MOE), suggests that there is likely to be no appreciable risk to human health exposure to carbamazepine or its major metabolite, even given the inevitable uncertainties in exposure scenarios.