Local country food sources of methylmercury, selenium and omega-3 fatty acids in Nunavik, Northern Quebec.

Country foods are central to Inuit culture and replete in selenium (Se) and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA). However, some marine country foods bioaccumulate high concentrations of methylmercury (MeHg). Se and n-3 are associated with several health benefits in Nunavik, Northern Quebec, but, recent studies show that prenatal MeHg exposure is associated with visual, cognitive and behavioral deficit later in childhood. The study objectives are to identify contemporary country food sources of MeHg, Se and long-chain n-3 PUFA in Nunavik, particularly among childbearing-age women, taking into account regional differences in consumption profiles. The contribution of different country foods to daily MeHg, Se, long-chain n-3 PUFA intake (µg/kg body weight/day) was estimated using: (i) country food consumption and blood biomarkers data from the 2004 Nunavik Health Survey (387 women, 315 men), and (ii) data on MeHg, Se, long-chain n-3 PUFA concentrations found in Nunavik wildlife species. In the region where most traditional beluga hunting takes place in Nunavik, the prevalence of at-risk blood Hg (≥ 8 µg/L) in childbearing-age women was 78.4%. While most country foods presently consumed contain low MeHg, beluga meat, not a staple of the Inuit diet, is the most important contributor to MeHg: up to two-thirds of MeHg intake in the beluga-hunting region (0.66 of MeHg intake) and to about one-third in other regions. In contrast, seal liver and beluga mattaaq - beluga skin and blubber - only mildly contributed to MeHg (between 0.06 and 0.15 of MeHg intake), depending on the region. Beluga mattaaq also highly contributed to Se intake (0.30 of Se intake). Arctic char, beluga blubber and mattaaq, and seal blubber contributed to most long-chain n-3 PUFA intake. This study highlights the importance of considering interconnections between local ecosystems and dietary habits to develop recommendations and interventions promoting country foods' benefits, while minimizing the risk of MeHg from beluga meat, especially for childbearing-age women.

Association of red blood cell n-3 polyunsaturated fatty acids with plasma inflammatory biomarkers among the Quebec Cree population.

BACKGROUND/OBJECTIVES: We examined the prevalence of elevated plasma high-sensitivity C-reactive protein (hs-CRP) concentrations and associations with red blood cell (RBC) long-chain n-3 polyunsaturated fatty acids (LCn-3PUFA) in the James Bay Cree population from the province of Quebec (Canada). SUBJECTS/METHODS: A total of 744 Cree adults (18-91 years) from seven communities of Eastern James Bay were included in these cross-sectional analyses. Associations between RBC LCn-3PUFA and proinflammatory markers (hs-CRP, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α)) were assessed by using multivariate general linear models with adjustment for sex, age and waist circumference. An arbitrary inflammation score was defined based on the sum of the quartiles of hs-CRP, IL-6 and TNF-α concentrations (range=3-12). RESULTS: Elevated hs-CRP concentrations (>3 mg/l) were present in 46.9% (95% confidence interval (CI) 43.3-50.5) of the James Bay Cree population. RBC docosapentaenoic acid (DPAn-3; C22:5n-3) was inversely associated with hs-CRP, TNF-α and the inflammation score (all P trend<0.02), whereas eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3) in RBC were not associated with inflammation (all P trend>0.18). Among participants with RBC DPAn-3 levels above the median of the population, odds ratio of having an elevated inflammation score (≥9) was 0.67 (95% CI, 0.48-0.93) compared with participants below the median. CONCLUSIONS: RESULTS indicate that low-grade systemic inflammation is highly prevalent and that higher RBC DPAn-3 levels are associated with a lower risk of systemic inflammation in the James Bay Cree population.

Identification of ML-9 as a lysosomotropic agent targeting autophagy and cell death.

The growing number of studies suggested that inhibition of autophagy enhances the efficacy of Akt kinase inhibitors in cancer therapy. Here, we provide evidence that ML-9, a widely used inhibitor of Akt kinase, myosin light-chain kinase (MLCK) and stromal interaction molecule 1 (STIM1), represents the 'two-in-one' compound that stimulates autophagosome formation (by downregulating Akt/mammalian target of rapamycin (mTOR) pathway) and inhibits their degradation (by acting like a lysosomotropic agent and increasing lysosomal pH). We show that ML-9 as a monotherapy effectively induces prostate cancer cell death associated with the accumulation of autophagic vacuoles. Further, ML-9 enhances the anticancer activity of docetaxel, suggesting its potential application as an adjuvant to existing anticancer chemotherapy. Altogether, our results revealed the complex effect of ML-9 on autophagy and indentified ML-9 as an attractive tool for targeting autophagy in cancer therapy through dual inhibition of both the Akt pathway and the autophagy.

Use of folk tests to detect ciguateric fish: a scientific evaluation of their effectiveness in Raivavae Island (Australes, French Polynesia).

Ciguatera fish poisoning is a seafood intoxication commonly afflicting island communities in the Pacific. These populations, which are strongly dependent on fish resources, have developed over centuries various strategies to decrease the risk of intoxication, including the use of folk tests to detect ciguateric fish. This study aims to evaluate the effectiveness of two folk tests commonly used in Raivavae Island (Australes, French Polynesia): the rigor mortis test (RMT) and the bleeding test (BT). A total of 107 fish were collected in Raivavae Lagoon, among which 80 were tested by five testers using the RMT versus 107 tested by four testers using BT. First, the performance between testers was compared. Second, the efficiency of these tests was compared with toxicity data obtained via the receptor binding assay (RBA) by assessing various parameter's values such as sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV). Comparisons of outcomes between folk tests and RBA analyses were considered: tests used separately or in a parallel versus the series approach by each tester. The overall efficiency of the RMT and BT tests was also evaluated when the judgments of all testers were "pooled". The results demonstrate that efficiencies varied between testers with one showing the best scores in detecting toxic fish: 55% with RMT and 69.2% with BT. BT gave the best results in detecting toxic fish as compared with RMT, giving also better agreement between testers. If high NPV and Se values were to be privileged, the data also suggest that the best way to limit cases of intoxication would be to use RMT and BT tests in a parallel approach. The use of traditional knowledge and a good knowledge of risky versus healthy fishing areas may help reduce the risk of intoxication among communities where ciguatera fish poisoning is highly prevalent.

Balancing the risks and the benefits of local fish consumption in Bermuda.

Fish consumption today is widely recognized as highly beneficial since it constitutes a good source of several essential nutrients, such as selenium and polyunsaturated fatty acids (n-3 PUFA). However, fish can also contain contaminants such as mercury, which make the consumer, especially pregnant women, confused about the risk-benefit balance associated with fish consumption. This is particularly true for tropical fish species for which little information is available. We have previously reported that some Bermudian neonates had elevated mercury in their umbilical blood compared with international guidelines. The objective of this study was to give precise and balanced information on the content of mercury, selenium and PUFA in the most consumed fish species in Bermuda. In 2003 and 2006, a total of 307 fish were collected from 43 fish species and 351 samples were analysed (305 flesh samples, 44 liver samples, one roe and one fat sample) by inductively coupled plasma-mass spectrometry (ICP-MS) (metals) and high-resolution gas chromatography (HRGC) (fatty acids). Results show that mercury varies among species from 0.03 to 3.3 microg g(-1) and that it is possible for at-risk groups such as pregnant women to make informed choices concerning fish consumption, e.g. maximizing fish species rich in nutrients and low in mercury.

n-3 Fatty acids and cardiovascular disease risk factors among the Inuit of Nunavik.

BACKGROUND: Inuit traditionally consume large amounts of marine foods rich in n-3 fatty acids. Evidence exists that n-3 fatty acids have beneficial effects on key risk factors for cardiovascular disease. OBJECTIVE: Our goal was to verify the relation between plasma phospholipid concentrations of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and various cardiovascular disease risk factors among the Inuit of Nunavik, Canada. DESIGN: The study population consisted of 426 Inuit aged 18-74 y who participated in a 1992 health survey. Data were obtained through home interviews and clinical visits. Plasma samples were analyzed for phospholipid fatty acid composition. RESULTS: Expressed as the percentage of total fatty acids, geometric mean concentrations of EPA, DHA, and their combination in plasma phospholipids were 1.99%, 4.52%, and 6.83%, respectively. n-3 Fatty acids were positively associated with HDL-cholesterol concentrations and inversely associated with triacylglycerol concentrations and the ratio of total to HDL cholesterol. In contrast, concentrations of total cholesterol, LDL cholesterol, and plasma glucose increased as n-3 fatty acid concentrations increased. There were no significant associations between n-3 fatty acids and diastolic and systolic blood pressure and plasma insulin. CONCLUSIONS: Consumption of marine products, the main source of EPA and DHA, appears to beneficially affect some cardiovascular disease risk factors. The traditional Inuit diet, which is rich in n-3 fatty acids, is probably responsible for the low mortality rate from ischemic heart disease in this population.

The Inuit diet. Fatty acids and antioxidants, their role in ischemic heart disease, and exposure to organochlorines and heavy metals. An international study.

Traditional food is culturally, economically and nutritionally important for the Greenlandic Inuit people. In the 1970s the preventive effect of marine fat on cardiovascular disease, thrombosis and atherosclerosis was described. The low incidence of ischemic heart disease among Greenlanders has been related to the high intake of marine food. Since 1990 routine autopsies have taken place in two towns in Greenland, Nuuk and Ilulissat. The autopsies represent 26% of the total number of deaths in these two towns. Samples have been collected from 104 autopsies. International cooperative studies have analysed specimens in relation to ischemic heart disease as a benefit related to diet, as well as the level of heavy metals and organochlorine in organs as a risk related to diet. High amounts of mono-unsaturated and Omega-3 poly-unsaturated fatty acid were found in adipose tissue. Liver analyses of selenium have confirmed the expected high intake among Greenlanders. Reduced atherosclerotic lesions were found in the coronary arteries. Blood pressure levels calculated from renovascholopathia of hypertension indicate prevailing levels similar to those in industrialized countries. Some factors in Greenland may be protecting the coronary arteries, thereby of setting the expected effect of hypertension. The level of methyl mercury in organs is generally high. PCB concentrations found in organs of Greenlanders are higher than among other populations. Health and risk effects of the traditional foods need further investigation.