Plasma omega-3 and psychological distress among Nunavik Inuit (Canada)

Emerging evidence on selenoneine and its public health relevance in coastal populations: a review and case study of dietary Se among Inuit populations in the Canadian Arctic

Selenium is an essential mineral yet both deficiency and excess are associated with adverse health effects. Dietary intake of Se in humans varies greatly between populations due to food availability, dietary preferences, and local geological and ecosystem processes impacting Se accumulation into agricultural products and animal populations. We argue there is a need to evaluate and reconsider the relevance of public health recommendations on Se given recent evidence, including the metabolic pathways and health implications of Se. This argument is particularly pertinent for Inuit populations in Northern Canada, who often exceed dietary tolerable upper intake levels and exhibit very high whole blood Se concentrations due to their dependence on local country foods high in the newly discovered Se compound, selenoneine. Since selenoneine appears to have lower toxicity compared to other Se species and does not contribute to the circulating pools of Se for selenoprotein synthesis, we argue that total dietary Se or total Se in plasma or whole blood are poor indicators of Se adequacy for human health in these populations. Overall, this review provides an overview of the current evidence of Se speciation, deficiency, adequacy, and excess and implications for human health and dietary recommendations, with particular reference to Inuit populations in the Canadian Arctic and other coastal populations consuming marine foods.

Drivers and health implications of the dietary transition among Inuit in the Canadian Arctic: a scoping review

OBJECTIVE

The current study undertook a systematic scoping review on the drivers and implications of dietary changes among Inuit in the Canadian Arctic.

DESIGN

A keyword search of peer-reviewed articles was performed using PubMed, Web of Science, CINAHL, Academic Search Premier, Circumpolar Health Bibliographic Database and High North Research Documents. Eligibility criteria included all full-text articles of any design reporting on research on food consumption, nutrient intake, dietary adequacy, dietary change, food security, nutrition-related chronic diseases or traditional food harvesting and consumption among Inuit populations residing in Canada. Articles reporting on in vivo and in vitro experiments or on health impacts of environmental contaminants were excluded.

RESULTS

A total of 162 studies were included. Studies indicated declining country food (CF) consumption in favour of market food (MF). Drivers of this transition include colonial processes, poverty and socio-economic factors, changing food preferences and knowledge, and climate change. Health implications of the dietary transition are complex. Micro-nutrient deficiencies and dietary inadequacy are serious concerns and likely exacerbated by increased consumption of non-nutrient dense MF. Food insecurity, overweight, obesity and related cardiometabolic health outcomes are growing public health concerns. Meanwhile, declining CF consumption is entangled with shifting culture and traditional knowledge, with potential implications for psychological, spiritual, social and cultural health and well-being.

CONCLUSIONS

By exploring and synthesising published literature, this review provides insight into the complex factors influencing Inuit diet and health. Findings may be informative for future research, decision-making and intersectoral actions around risk assessment, food policy and innovative community programmes.

Docosahexaenoic acid,22:6n-3: Its roles in the structure and function of the brain

Docosahexaenoic acid,22:6n-3 (DHA) and its metabolites are vital for the structure and functional brain development of the fetus and infants, and also for maintenance of healthy brain function of adults. DHA is thought to be an essential nutrient required throughout the life cycle for the maintenance of overall brain health. The mode of actions of DHA and its derivatives at both cellular and molecular levels in the brain are emerging. DHA is the major prevalent fatty acid in the brain membrane. The brain maintains its fatty acid levels mainly via the uptake of plasma free fatty acids. Therefore, circulating plasma DHA is significantly related to cognitive abilities during ageing and is inversely associated with cognitive decline. The signaling pathways of DHA and its metabolites are involved in neurogenesis, antinociceptive effects, anti-apoptotic effect, synaptic plasticity, Ca²⁺ homeostasis in brain diseases, and the functioning of nigrostriatal activities. Mechanisms of action of DHA metabolites on various processes in the brain are not yet well known. Epidemiological studies support a link between low habitual intake of DHA and a higher risk of brain disorders. A diet characterized by higher intakes of foods containing high in n-3 fatty acids, and/or lower intake of n-6 fatty acids was strongly associated with a lower Alzheimer's Disease and other brain disorders. Supplementation of DHA improves some behaviors associated with attention deficit hyperactivity disorder, bipolar disorder, schizophrenia, and impulsive behavior, as well as cognition. Nevertheless, the outcomes of trials with DHA supplementation have been controversial. Many intervention studies with DHA have shown an apparent benefit in brain function. However, clinical trials are needed for definitive conclusions. Dietary deficiency of n-3 fatty acids during fetal development in utero and the postnatal state has detrimental effects on cognitive abilities. Further research in humans is required to assess a variety of clinical outcomes, including quality of life and mental status, by supplementation of DHA.

Seafood consumption patterns, their nutritional benefits and associated sociodemographic and lifestyle factors among First Nations in British Columbia, Canada

Objective

To describe seafood consumption patterns in First Nations (FN) in British Columbia (BC) and examine lifestyle characteristics associated with seafood consumption; to identify the top ten most consumed seafood species and their contributions to EPA and DHA intake; and to estimate dietary exposure to methylmercury, polychlorinated biphenyls and dichlorodiphenyldichloroethylene.

Design

Dietary and lifestyle data from the First Nations Food Nutrition and Environment Study, a cross-sectional study of 1103 FN living in twenty-one communities across eight ecozones in BC, Canada, were analysed. Seafood consumption was estimated using a traditional FFQ. Seafood samples were analysed for contaminant contents.

Results

Seafood consumption patterns varied significantly across BC ecozones reflecting geographical diversity of seafood species. The top ten most consumed species represented 64 % of total seafood consumption by weight and contributed 69 % to the total EPA+DHA intake. Mean EPA+DHA intake was 660·5 mg/d in males, 404·3 mg/d in females; and 28 % of FN met the Recommended Intake (RI) of 500 mg/d. Salmon was the most preferred species. Seafood consumption was associated with higher fruit and vegetable consumption, lower smoking rate and increased physical activity. Dietary exposure to selected contaminants from seafood was negligible.

Conclusions

In FN in BC, seafood continues to be an essential part of the contemporary diet. Seafood contributed significantly to reaching the RI for EPA+DHA and was associated with a healthier lifestyle. Given numerous health benefits, seafood should be promoted in FN. Efforts towards sustainability of fishing should be directed to maintain and improve access to fisheries for FN.

Going Off, Growing Strong: A program to enhance individual youth and community resilience in the face of change in Nain, Nunatsiavut

Dispossession from social and ecological support systems is a major concern for many Indigenous communities. In response to community health challenges in these settings a number of initiatives such as youth mentorship programs have shown some value in enhancing adaptive capacity. The pilot Going Off, Growing Strong program provides opportunities for at-risk youth to engage in community- and land-based activities and build relationships with positive adult role models in Nain, Nunatsiavut (Labrador, Canada). This paper offers an interpretive description drawing from autobiographical accounts of the development of this innovative program. A collaboratively developed conceptual framework, based on the literature, is used to present and explain program operator’s experiences and rationale for program development. The emergent goals of Going Off, Growing Strong are to strengthen individual youth and collective community resilience through intergenerational exchange of land, social, and cultural skills and knowledge by drawing on social supports, such as a community freezer and experienced harvesters. We found that the process of collaborating over time with multiple stakeholders in creating this conceptual framework was an important one for solidifying the goals of Going Off, Growing Strong and creating context-specific, meaningful evaluation outcomes to enable future measurement of impacts on the community.

Global survey of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid in the blood stream of healthy adults

Studies reporting blood levels of the omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were systematically identified in order to create a global map identifying countries and regions with different blood levels. Included studies were those of healthy adults, published in 1980 or later. A total of 298 studies met all inclusion criteria. Studies reported fatty acids in various blood fractions including plasma total lipids (33%), plasma phospholipid (32%), erythrocytes (32%) and whole blood (3.0%). Fatty acid data from each blood fraction were converted to relative weight percentages (wt.%) and then assigned to one of four discrete ranges (high, moderate, low, very low) corresponding to wt.% EPA+DHA in erythrocyte equivalents. Regions with high EPA+DHA blood levels (>8%) included the Sea of Japan, Scandinavia, and areas with indigenous populations or populations not fully adapted to Westernized food habits. Very low blood levels (≤4%) were observed in North America, Central and South America, Europe, the Middle East, Southeast Asia, and Africa. The present review reveals considerable variability in blood levels of EPA+DHA and the very low to low range of blood EPA+DHA for most of the world may increase global risk for chronic disease.

Omega-3 PUFAs Lower the Propensity for Arachidonic Acid Cascade Overreactions

A productive view of the benefits from omega-3 (n-3) nutrients is that the dietary essential omega-6 (n-6) linoleic acid has a very narrow therapeutic window which is widened by n-3 nutrients. The benefit from moderate physiological actions of the arachidonic acid cascade can easily shift to harm from excessive pathophysiological actions. Recognizing the factors that predispose the cascade to an unwanted overactivity gives a rational approach for arranging beneficial interactions between the n-3 and n-6 essential nutrients that are initial components of the cascade. Much detailed evidence for harmful cascade actions was collected by pharmaceutical companies as they developed drugs to decrease those actions. A remaining challenge is to understand the factors that predispose the cascade toward unwanted outcomes and create the need for therapeutic interventions. Such understanding involves recognizing the similar dynamics for dietary n-3 and n-6 nutrients in forming the immediate precursors of the cascade plus the more vigorous actions of the n-6 precursor, arachidonic acid, in forming potent mediators that amplify unwanted cascade outcomes. Tools have been developed to aid deliberate day-to-day quantitative management of the propensity for cascade overactivity in ways that can decrease the need for drug treatments.

Plasma levels of n-3 fatty acids in bipolar patients: deficit restricted to DHA

Epidemiological studies suggest that n-3 polyunsaturated fatty acid (n-3 FA) deficiency is a risk factor for bipolar disorders (BDs). The aim of this study was to determine whether such a deficit does exist in patients with BD and to characterize the overall plasma fatty acid (FA) profile in these patients. Using gas chromatography/mass spectrometry, we measured fasting plasma levels of 15 FAs in 42 patients diagnosed with BD according to DSM-IV criteria and in 57 age- and gender-matched healthy controls. Plasma docosahexaenoic acid (DHA) levels were significantly decreased in bipolar patients (p < 0.001 versus healthy controls). Compared with controls, patients had higher plasma levels of all other FAs, including arachidonic acid (AA, p < 0.001), alpha-linolenic acid (ALA, p < 0.001), and eicosapentaenoic acid (EPA) (p < 0.001). Although in the present study we observed significant DHA deficits in the plasma of bipolar patients our findings do not support the therapeutic use of ALA and/or EPA supplementation. DHA may provide a basis for possible pharmacological intervention in psychiatric disorders at the level of second messengers linked to the phosphatidylinositol cycle. Finally, measurement of FA levels in plasma seems to be more reliable and reproducible than assays of erythrocyte FA content.

Omega-3 fatty acids and brain resistance to ageing and stress: body of evidence and possible mechanisms

The increasing life expectancy in the populations of rich countries raises the pressing question of how the elderly can maintain their cognitive function. Cognitive decline is characterised by the loss of short-term memory due to a progressive impairment of the underlying brain cell processes. Age-related brain damage has many causes, some of which may be influenced by diet. An optimal diet may therefore be a practical way of delaying the onset of age-related cognitive decline. Nutritional investigations indicate that the ω-3 poyunsaturated fatty acid (PUFA) content of western diets is too low to provide the brain with an optimal supply of docosahexaenoic acid (DHA), the main ω-3 PUFA in cell membranes. Insufficient brain DHA has been associated with memory impairment, emotional disturbances and altered brain processes in rodents. Human studies suggest that an adequate dietary intake of ω-3 PUFA can slow the age-related cognitive decline and may also protect against the risk of senile dementia. However, despite the many studies in this domain, the beneficial impact of ω-3 PUFA on brain function has only recently been linked to specific mechanisms. This review examines the hypothesis that an optimal brain DHA status, conferred by an adequate ω-3 PUFA intake, limits age-related brain damage by optimizing endogenous brain repair mechanisms. Our analysis of the abundant literature indicates that an adequate amount of DHA in the brain may limit the impact of stress, an important age-aggravating factor, and influences the neuronal and astroglial functions that govern and protect synaptic transmission. This transmission, particularly glutamatergic neurotransmission in the hippocampus, underlies memory formation. The brain DHA status also influences neurogenesis, nested in the hippocampus, which helps maintain cognitive function throughout life. Although there are still gaps in our knowledge of the way ω-3 PUFA act, the mechanistic studies reviewed here indicate that ω-3 PUFA may be a promising tool for preventing age-related brain deterioration.

Gender differences in the long-chain polyunsaturated fatty acid status: systematic review of 51 publications

BACKGROUND/AIMS

Sex hormones may influence the activity of enzymes which are involved in the synthesis of long-chain polyunsaturated fatty acids. The objective of this review was to assess the role of gender in determining the fatty acid composition of human samples, like plasma and erythrocyte membrane lipids, and adipose tissue.

METHODS

The method included a structured search strategy on MEDLINE, Scopus and the Cochrane databases, with formal inclusion/exclusion criteria, data extraction procedure and meta-analysis.

RESULTS

We evaluated 51 publications, dated from 1975 to 2011. Meta-analysis showed significantly lower values of both arachidonic acid (AA) and docosahexaenoic acid (DHA) in total plasma lipids (32 and 33 studies) and in plasma phospholipids (PL; 21 and 23 studies) in men than in women. Primary analysis of the phospholipid fraction showed the mean difference in AA to be 0.42% weight/weight (95% CI: 0.18-0.65, n = 7,769) and in DHA 0.37% weight/weight (95% CI: 0.24-0.51, n = 8,541), while there was no gender difference in the values of linoleic acid and α-linolenic acid.

CONCLUSIONS

This systematic review based on 51 publications showed significantly lower contribution of AA and DHA to plasma total lipids and plasma PL in men than in women. Gender distribution should be regarded as a significant potential confounding factor in every study assessing data on fatty acid composition.

Fish consumption and severely depressed mood, findings from the first national nutrition follow-up study

The evidence obtained from prospective studies to support the hypothesis that fish consumption may improve mental status remains limited. The current study prospectively assessed a low frequency of fish consumption as a risk factor for depressed mood. Included were 5068 adults aged 25-74 years examined in 1971-1975 as the baseline of the First National Health and Nutrition Examination Survey Follow-up Study. Frequency of eating fish at baseline was obtained using a 3-month food frequency questionnaire. Severely depressed mood (SDM) was defined as the Center for Epidemiologic Studies Depression Scale scores ≥22 or taking anti-depressants. After an average of 10.6 years of follow-up, among men (n=2039), the percentage of individuals with SDM was 11.7%. Compared with frequent consumers (more than once a week), the odds ratios (ORs) were 1.43 (95%CI=0.66-3.11) and 2.08 (1.08-4.09) respectively for the men eating fish once a week and less than once a week (p for trend=0.03). Among women (n=3029), the percentage of individuals with SDM was 17.89%. The ORs were 1 (reference), 0.91 (0.68-1.22) and 1.15 (0.83-1.59) respectively for the women eating fish more than once, once, and less than once a week. These estimates were obtained after adjustment for indicators of social deprivation and major physical diseases. The study concluded that independently from social deprivation and physical diseases, low fish consumption was a risk factor for SDM among men. Further studies are needed to confirm these findings and elucidate mechanisms for the difference between men and women.

Omega-3 fatty acids for major depressive disorder associated with the menopausal transition: a preliminary open trial

OBJECTIVES

We sought to obtain preliminary data regarding the efficacy of omega-3 fatty acids for major depressive disorder associated with the menopausal transition. Secondary outcomes were assessed for vasomotor symptoms (or hot flashes).

METHODS

After a single-blind placebo lead-in, participants received 8 weeks of treatment with open-label omega-3 fatty acid capsules (eicosapentaenoic acid and docosahexaenoic acid, 2 g/d). The Montgomery-Asberg Depression Rating Scale (MADRS) was the primary outcome measure. Hot flashes were monitored prospectively using daily diaries and the Hot Flash Related Daily Interference Scale. Blood samples for plasma pretreatment and posttreatment essential fatty acid assays were obtained. Because of the small sample size, data were analyzed using nonparametric techniques.

RESULTS

Of 20 participants treated with omega-3 fatty acids, 19 (95%) completed the study. None discontinued because of adverse effects. The pretreatment and final mean MADRS scores were 24.2 and 10.7, respectively, reflecting a significant decrease in MADRS scores (P < 0.0001). The response rate was 70% (MADRS score decrease of ≥50%), and the remission rate was 45% (final MADRS score of ≤). Responders had significantly lower pretreatment docosahexaenoic acid levels than nonresponders did (P = 0.03). Hot flashes were present in 15 (75%) participants. Among those with hot flashes at baseline, the number of hot flashes per day improved significantly from baseline (P = 0.02) and Hot Flash Related Daily Interference Scale scores decreased significantly (P = 0.006).

CONCLUSIONS

These data support further study of omega-3 fatty acids for major depressive disorder and hot flashes in women during the menopausal transition.

Plasma omega 3 polyunsaturated fatty acid status and monounsaturated fatty acids are altered by chronic social stress and predict endocrine responses to acute stress in titi monkeys

Disturbances in fatty acid (FA) metabolism may link chronic psychological stress, endocrine responsiveness, and psychopathology. Therefore, lipid metabolome-wide responses and their relationships with endocrine (cortisol, insulin, and adiponectin) responsiveness to acute stress (AS) were assessed in a primate model of chronic social stress (CS). Compared to controls (not exposed to CS), CS increased (P≤0.05) circulating triacylglycerol (TG) and phosphatidylethanolamine (PE) n-6/n-3 and reduced (P≤0.05) cholesterol ester (CE) 16:1n7 and phosphatidylcholine (PC) 18:1n7, suggesting lower omega-3 FA status and stearoyl-CoA desaturase activity, respectively. Cortisol responses to AS positively correlated with TG n-6/n-3 (r=0.93; P=0.007), but only in CS monkeys. The adiponectin response to AS inversely correlated with CE n-6/n3 (r=-0.89; P=0.045) and positively with TG 16:1n7 (r=0.98; P=0.004), only in CS monkeys. Our results are consistent with previously reported FA profiles in stress-related psychopathology and suggest that compositional changes of specific lipid FAs may form new functional markers of chronic psychological stress.

Plasman-3 fatty acids and psychological distress in aboriginal Cree Indians (Canada)

Objective

To examine the relationship between psychological distress (PD) and plasman-3 long-chain (LC) PUFA, i.e. EPA, docosapentaenoic acid (DPAn-3) and DHA.

Design

Population-based, cross-sectional Santé-Québec Health Survey (1991). Participants were categorized as high-level PD if they scored over the 80th percentile of the PD Index in the Santé-Québec Survey; non-distressed subjects were those who scored less than this cut-off. Associations between tertiles ofn-3 fatty acids (FA) and the risk of high-level PD were expressed as odds ratios, with the lowest tertile as the reference group.

Setting

Québec, Canada.

Subjects

Data were analysed from a representative sample of 852 James Bay Cree Indian adults aged 18 years and over.

Results

Proportions ofn-3 FA were statistically significantly lower in the PD than in the non-distressed group. After adjustment for confounders, EPA was the only individualn-3 FA significantly associated with the risk of high-level PD. Combinations of EPA + DHA or EPA + DPAn-3 + DHA or the sum ofn-3 were also associated with the risk of high-level PD. Compared with the lowest tertile of EPA + DHA, the OR for high-level PD was 0·89 (95 % CI 0·59, 1·36) for the second and 0·56 (95 % CI 0·32, 0·98) for the third tertile, after controlling for confounders.

Conclusions

In the present retrospective, cross-sectional study, we found that proportions ofn-3 LC PUFA in plasma phospholipids, markers ofn-3 LC PUFA consumption from fish, were inversely associated with PD.