Dietary fish intake and plasma phospholipid n-3 polyunsaturated fatty acid concentrations in men and women in the European Prospective Investigation into Cancer-Norfolk United Kingdom cohort

Fish oil supplement use modifies the relationship between dietary oily fish intake and plasma n-3 PUFA levels: an analysis of the UK Biobank

Observational evidence linking dietary n-3 PUFA intake and health outcomes is limited by a lack of robust validation of dietary intake using blood n-3 PUFA levels and potential confounding by fish oil supplement (FOS) use. We investigated the relationship between oily fish intake, FOS use and plasma n-3 PUFA levels in 121 650 UK Biobank (UKBB) participants. Ordinal logistic regression models, adjusted for clinical and lifestyle factors, were used to quantify the contribution of dietary oily fish intake and FOS use to plasma n-3 PUFA levels (measured by NMR spectroscopy). Oily fish intake and FOS use were reported by 38 % and 31 % of participants, respectively. Increasing oily fish intake was associated with a higher likelihood of FOS use (P < 0·001). Oily fish intake ≥ twice a week was the strongest predictor of high total n-3 PUFA (OR 6·7 (95 % CI 6·3, 7·1)) and DHA levels (6·6 (6·3, 7·1). FOS use was an independent predictor of high plasma n-3 PUFA levels (2·0 (2·0, 2·1)) with a similar OR to that associated with eating oily fish < once a week (1·9 (1·8, 2·0)). FOS use was associated with plasma n-3 PUFA levels that were similar to individuals in the next highest oily fish intake category. In conclusion, FOS use is more common in frequent fish consumers and modifies the relationship between oily fish intake and plasma n-3 PUFA levels in UKBB participants. If unaccounted for, FOS use may confound the relationship between dietary n-3 PUFA intake, blood levels of n-3 PUFAs and health outcomes.

Relationship between dietary intake and erythrocyte PUFA in adolescents from a Western Australian cohort

BACKGROUND

Population-based studies show that the intake of omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFA) are associated with a range of health conditions. Therefore, the reliability of food frequency questionnaires (FFQ) as rapid and easily accessible screening tools for PUFA intake deserve investigation.

OBJECTIVE

We aimed to assess the relationship between erythrocyte fatty acids and fatty acid intake collected using the Commonwealth Scientific and Industrial Research Organisation (CSIRO) food frequency questionnaire in an adolescent cohort.

DESIGN

A cross-sectional study using data from 1155 young adolescents participating in the 14-year follow-up of the Raine Study. Bland-Altman plots were used to determine the agreement between dietary intake and erythrocyte levels of each fatty acid.

RESULTS

The main dietary source of n-3 long-chain (LC) PUFA was 'fresh fish' (53% of total n-3 LC-PUFA). Docosahexaenoic acid (DHA) showed the strongest correlation between erythrocyte and diet assessment (r = 0.274; p < 0.001), whilst linoleic acid (LA) (r = 0.103; p < 0.001) and arachidonic acid (AA) (r = -0.06; p = 0.042) showed weaker correlations, with limits of agreement relatively narrow. Bland-Altman plots showed a dose-dependent bias between the FFQ fatty acid data and corresponding erythrocyte data.

CONCLUSIONS

For the major n-3 and n-6 PUFA, dietary intakes derived from the FFQ showed weaker correlations and poorer agreement with erythrocyte levels, and the deviation between the two increased with higher intake levels.

Reduced levels of serum EPA and DHA identified in patients with non-small-cell lung cancer using a new rapid validated LC-MS/MS method

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been suggested to play roles in various diseases, yet there is little data on their changes in patients with non-small-cell lung cancer (NSCLC). A simple LC-MS/MS method for EPA and DHA determination is critical to exploring EPA and DHA level changes in NSCLC patients.

METHODS

25 µL of serum was mixed with 25 µL of internal standard working solution, and then 450 µL of acetonitrile for protein precipitation. After vortex and centrifugation, the supernatant was directly used for LC-MS/MS analysis. The method was well validated with linearity, precision, recovery, and matrix effect. The concentrations of EPA and DHA in serum samples from 211 NSCLC patients and 227 healthy controls were determined by this LC-MS/MS method.

RESULTS

Good separation and reliable quantification of EPA and DHA in serum samples were achieved by our method. Compared with healthy controls, serum EPA and DHA were significantly reduced in both adenocarcinoma and squamous cell carcinoma patients. The concentrations of EPA and DHA showed a progressive decrease in healthy controls, early- and advanced-stage NSCLC patients.

CONCLUSIONS

This study identified significant reductions in serum EPA and DHA in NSCLC patients through the development of an LC-MS/MS method.

Identifying Future Study Designs for Mental Health and Social Wellbeing Associated with Diets of a Cohort Living in Eco-Regions: Findings from the INSUM Expert Workshop

Diets influence our mental health and social wellbeing (MHSW) in multiple ways. A rising community concept, Eco-Regions, has gained interest. The research project "Indicators for assessment of health effects of consumption of sustainable, organic school meals in Ecoregions" (INSUM) aims to develop future-oriented research approaches to measure the potential health effects of more sustainable and healthy diets. This first part of the project focuses on MHSW with the goal to identify suitable study designs and indicators. The methodology is based on a 2-day workshop with an interdisciplinary group of experts. This paper describes commonly applied research methods on the nexus between diet and MHSW as presented by the experts and summarises key points from the discussions. The results show that the dominating tool to investigate MSHW is questionnaires. Questionnaires vary largely depending on the research design, such as participants or distribution channels. Cohort studies addressing families and including in-depth interventional and/or experimental studies may be suitable for an Eco-Region investigation. Those MHSW studies can be conducted and combined with measurements of somatic health effects. We conclude that indicators should be seen as complementary rather than independent. Explorative research designs are required to investigate complex Eco-Regions.

Development and validation of a metabolite score for red meat intake: an observational cohort study and randomized controlled dietary intervention

BACKGROUND

Self-reported meat consumption is associated with disease risk but objective assessment of different dimensions of this heterogeneous dietary exposure in observational and interventional studies remains challenging.

OBJECTIVES

We aimed to derive and validate scores based on plasma metabolites for types of meat consumption. For the most predictive score, we aimed to test whether the included metabolites varied with change in meat consumption, and whether the score was associated with incidence of type 2 diabetes (T2D) and other noncommunicable diseases.

METHODS

We derived scores based on 781 plasma metabolites for red meat, processed meat, and poultry consumption assessed with 7-d food records among 11,432 participants in the EPIC-Norfolk (European Prospective Investigation into Cancer and Nutrition-Norfolk) cohort. The scores were then tested for internal validity in an independent subset (n = 853) of the same cohort. In focused analysis on the red meat metabolite score, we examined whether the metabolites constituting the score were also associated with meat intake in a randomized crossover dietary intervention trial of meat (n = 12, Lyon, France). In the EPIC-Norfolk study, we assessed the association of the red meat metabolite score with T2D incidence (n = 1478) and other health endpoints.

RESULTS

The best-performing score was for red meat, comprising 139 metabolites which accounted for 17% of the explained variance of red meat consumption in the validation set. In the intervention, 11 top-ranked metabolites in the red meat metabolite score increased significantly after red meat consumption. In the EPIC-Norfolk study, the red meat metabolite score was associated with T2D incidence (adjusted HR per SD: 1.17; 95% CI: 1.10, 1.24).

CONCLUSIONS

The red meat metabolite score derived and validated in this study contains metabolites directly derived from meat consumption and is associated with T2D risk. These findings suggest the potential for objective assessment of dietary components and their application for understanding diet-disease associations.The trial in Lyon, France, was registered at clinicaltrials.gov as NCT03354130.

Serum ω-3 Fatty Acids and Cognitive Domains in Community-Dwelling Older Adults from the NuAge Study: Exploring the Associations with Other Fatty Acids and Sex

BACKGROUND

Omega-3 (n-3) PUFAs are suggested to play a role in the prevention of cognitive decline. The evidence may be inconsistent due to methodologic issues, including interrelations with other long-chain (14 or more carbons) fatty acids (LCFAs) and use of sex as a confounding factor rather than an effect modifier.

OBJECTIVES

This study evaluated the association between serum n-3 PUFAs and performance across 4 cognitive domains, overall and by sex, while controlling for other LCFAs.

METHODS

In total, 386 healthy older adults (aged 77.4 ± 3.8 y; 53% females) from the Quebec Longitudinal Study on Nutrition and Successful Aging underwent a cognitive evaluation and blood sampling. Verbal and nonverbal episodic memory, executive functioning, and processing speed were evaluated. Serum LCFA concentrations were measured by gas chromatography. LCFAs were grouped according to standard fatty acid classes and factor analysis using principal component analysis (FA-PCA). Multivariate linear regression models were performed, including unadjusted and adjusted models for other LCFAs.

RESULTS

Higher n-3 PUFA concentrations were associated with better nonverbal memory and processing speed in fully adjusted models not including other LCFAs (βs of 0.21 and 0.19, respectively). The magnitude of these associations varied when other LCFAs were entered in the model (βs of 0.27 and 0.32, respectively) or when FA-PCA factors were considered (βs of 0.27 and 0.21, respectively). Associations with verbal episodic memory were limited to higher concentrations of EPA, whereas there was no association between n-3 PUFAs and executive functioning. Higher n-3 PUFAs were associated with better verbal and nonverbal episodic memory in females and with better executive functioning and processing speed in males.

CONCLUSIONS

These results suggest that other LCFAs should be considered when evaluating the association between n-3 PUFAs and cognitive performance in healthy older adults. Sex differences across cognitive domains warrant further investigation.

The relationship between dietary intakes and plasma concentrations of PUFA in school-age children from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort

An adequate intake of PUFA plays a vital role in human health. Therefore, it is important to assess PUFA intakes in different populations and validate them with biomarkers, but only a few small studies are in paediatric populations. We calculated the dietary intake of PUFA and their main food sources in children and assessed associations between PUFA intakes and plasma proportions. Dietary intakes of 7-year-old children (n 8242) enrolled in the Avon Longitudinal Study of Parents and Children were calculated from the parental-completed FFQ. Plasma PUFA were measured in 5571 children 8 months later, and 4380 children had complete dietary and plasma data. The association between dietary and plasma PUFA proportions was estimated using Spearman's correlation coefficients, quintile cross-classification and Cohen's κ coefficients. Mean total PUFA intake was 13·2 g/d (sd 4·2), contributing 6·5 % of total energy intake; n-6 PUFA contributed 5·2 % and n-3 PUFA 0·7 %. The n-6:n-3 ratio was 7·9:1. Mean intakes of EPA and DHA were 35·7 mg/d and 49·7 mg/d, respectively. Most n-3 and n-6 PUFA intakes were weakly correlated with their respective plasma lipids (0·07 ≤ r ≤ 0·16, P < 0·001). The correlation between dietary and plasma DHA was stronger though (r = 0·34, P < 0·001), supported by a modest level of agreement between quintiles (k = 0·32). The results indicate that the FFQ was able to reasonably rank the long-chain (LC) PUFA, DHA, in this paediatric population. Public health initiatives need to address the suboptimal ratio of n-6:n-3 PUFA and very low n-3 LC-PUFA intakes in school-age children in the UK.

Hepatic endoplasmic reticulum calcium fluxes: effect of free fatty acids and KATP channel involvement

As a common sequel to obesity, plasma and intracellular free fatty acid (FFA) concentrations are elevated and, as a consequence, manifold disturbances in metabolism may ensue. Biochemical processes in the cytosol and organelles, such as mitochondria and endoplasmic reticulum (ER), can be disturbed. In the ER, the maintenance of a high calcium gradient is indispensable for viability. In sarcoplasmic reticulum, selective FFA can induce ER stress by disrupting luminal calcium homeostasis; however, there are limited studies in hepatic microsomes. Our studies found that FFA has a noxious effect on rat hepatic microsomal calcium flux, and the extent of which depended on the number of double bonds and charge. Furthermore, insofar as the FFA had no effect on microsomal calcium efflux, their inhibitory action primarily involves calcium influx. Finally, other cationic channels have been found in hepatic ER, and evidence is presented of their interaction with the Ca²⁺ ATPase pump.

Relationship between Serum Omega-3 Fatty Acid and Asthma Endpoints

Recent studies have highlighted the potential protective role of omega-3 polyunsaturated fatty acids (n-3 PUFA) in asthma. This study aimed at determining the association between seafood intake, serum PUFA composition and clinical endpoints of asthma in adults. A cross-sectional study of 642 subjects used the European Committee Respiratory Health Survey (ECRHS) questionnaire, skin prick tests, spirometry and methacholine challenge tests following ATS guidelines. Sera was analysed for n-3 and n-6 PUFA composition. Subjects had a mean age of 34 years, were largely female (65%) and 51% were current smokers. While 99% reported fish consumption, rock lobster, mussels, squid and abalone were also consumed less frequently. The prevalence of asthma symptoms was 11%, current asthma (ECRHS definition) was 8% and non-specific bronchial hyperresponsiveness (NSBH) was much higher (26%) In adjusted models the n-3 PUFAs 20:5 (EPA) and 22:5 (DPA) were significantly associated with a decreased risk of having NSBH. Total n-3 PUFA composition was associated with decreased NSBH risk (OR = 0.92), while high n-6 PUFA composition was associated with an increased risk (OR = 1.14).

The Maastricht FFQ: Development and validation of a comprehensive food frequency questionnaire for the Maastricht study

OBJECTIVE

The aim of this study was to develop and validate a comprehensive food frequency questionnaire (FFQ) for The Maastricht Study, a population-based prospective cohort study in Maastricht, The Netherlands.

METHODS

Item selection for the FFQ was based on explained variation and contribution to intake of energy and 24 nutrients. For validation, the FFQ was completed by 135 participants (25-70 y of age) of the Nutrition Questionnaires plus study. Per person, on average 2.8 (range 1-5) telephone-based 24-h dietary recalls (24HRs), two 24-h urinary samples, and one blood sample were available. Validity of 54 nutrients and 22 food groups was assessed by ranking agreement, correlation coefficients, attenuation factors, and ultimately deattenuated correlation coefficients (validity coefficients).

RESULTS

Median correlation coefficients for energy and macronutrients, micronutrients, and food groups were 0.45, 0.36, and 0.38, respectively. Median deattenuated correlation coefficients were 0.53 for energy and macronutrients, 0.45 for micronutrients, and 0.64 for food groups, being >0.50 for 18 of 22 macronutrients, 16 of 30 micronutrients and >0.50 for 17 of 22 food groups. The FFQ underestimated protein and potassium intake compared with 24-h urinary nitrogen and potassium excretion by -18% and -2%, respectively. Correlation coefficients ranged from 0.50 and 0.55 for (fatty) fish intake and plasma eicosapentaenoic acid and docosahexaenoic acid, and from 0.26 to 0.42 between fruit and vegetable intake and plasma carotenoids.

CONCLUSION

Overall, the validity of the 253-item Maastricht FFQ was satisfactory. The comprehensiveness of this FFQ make it well suited for use in The Maastricht Study and similar populations.

Omega-3 and omega-6 fatty acid levels in depressive and anxiety disorders

BACKGROUND

Blood levels of polyunsaturated fatty acids (PUFAs) have been associated to current depression. However, it is unclear whether this association extends to remitted depression and to anxiety disorders. This study examined the relationship of PUFAs with the presence and clinical characteristics of depressive and anxiety disorders.

METHODS

Cross-sectional data was used from the Netherlands Study of Depression and Anxiety, including persons with current pure depressive disorder (n=304), current pure anxiety disorder (n=548), current comorbid depressive and anxiety disorder (n=529), remitted depressive/anxiety disorder(s) (n=897), and healthy controls (n=634). Clinical characteristics included severity, subtypes, age of onset, duration of depression and anxiety and antidepressant use. Absolute values of omega-3 (N-3) and omega-6 (N-6) PUFAs and relative measures (as ratio of total Fatty Acids: the N-3:FA and N-6:FA ratio) in plasma were assessed using a nuclear magnetic resonance platform.

RESULTS

Compared to controls, current comorbid depressive and anxiety disorder patients had lower N-3 PUFA levels (Cohen's d=0.09, p=0.012), and lower N-3:FA ratios (p=0.002, Cohen's d=0.11) as did current pure depressive disorder patients (Cohen's d=0.13, p=0.021), whereas N-6 PUFA levels were not different. No differences in PUFA levels were found between remitted patients and controls. Within patients, lower N-3 PUFA levels were only associated with higher depression severity (Beta=-0.42, p=0.023), whereas for N-6 PUFA levels and other clinical characteristics no clear association was observed. PUFA alterations were not associated with pure anxiety.

CONCLUSION

It can be concluded that patients with a current depressive episode (especially the more severe cases with comorbid anxiety) have circulating N-3 PUFA levels lower than those in remission and healthy controls. No relationship was detected for N-6 PUFA levels.

Measurements of skeletal muscle mass and power are positively related to a Mediterranean dietary pattern in women

The age-related loss of skeletal muscle and function are risk factors for osteoporosis and fractures. We found that higher adherence to the Mediterranean diet score was significantly associated with greater fat-free mass and leg explosive power suggesting a role for the Mediterranean Diet in prevention of loss of muscle outcomes.

INTRODUCTION

The loss of skeletal muscle mass, strength, and function with age are contributing risk factors for the onset of sarcopenia, frailty, osteoporosis, fractures, and mortality. Nutrition may affect the progression and trajectory of these changes in skeletal muscle but the role of the micronutrient-rich Mediterranean diet (MD) has hardly been investigated in relation to these muscle outcomes.

METHODS

We examined associations between the MD score (MDS) and FFM% (fat-free mass / weight × 100), FFMI (fat-free mass/height2), hand grip strength, and leg explosive power (LEP, watts/kg) in a cross-sectional study in 2570 women aged 18-79 years from the TwinsUK study. Measurements of body composition were made using dual-energy X-ray absorptiometry and dietary intake assessed by a food frequency questionnaire. FFM%, FFMI, grip strength, and LEP were compared across quartiles of the MDS after adjustment for covariates, with CRP measured in a subgroup (n = 1658).

RESULTS

Higher adherence to the MDS was positively associated with measurements of muscle outcomes, with significant differences of 1.7 % for FFM% and 9.6 % for LEP (P trend <0.001), comparing extreme quartiles of intake, but not with grip strength or CRP concentrations.

CONCLUSIONS

For the first time in a northern European population, we have observed significant positive associations between the MDS and FFM% and LEP in healthy women that are potentially clinically relevant, independent of the factors known to influence muscle outcomes. Our findings emphasize the potential role for overall diet quality based on the MD in the prevention of age-related loss of skeletal muscle outcomes.

A national FFQ for the Netherlands (the FFQ-NL 1.0): validation of a comprehensive FFQ for adults

A standardised, national, 160-item FFQ, the FFQ-NL 1.0, was recently developed for Dutch epidemiological studies. The objective was to validate the FFQ-NL 1.0 against multiple 24-h recalls (24hR) and recovery and concentration biomarkers. The FFQ-NL 1.0 was filled out by 383 participants (25-69 years) from the Nutrition Questionnaires plus study. For each participant, one to two urinary and blood samples and one to five (mean 2·7) telephone-based 24hR were available. Group-level bias, correlation coefficients, attenuation factors, de-attenuated correlation coefficients and ranking agreement were assessed. Compared with the 24hR, the FFQ-NL 1.0 estimated the intake of energy and macronutrients well. However, it underestimated intakes of SFA and trans-fatty acids and alcohol and overestimated intakes of most vitamins by >5 %. The median correlation coefficient was 0·39 for energy and macronutrients, 0·30 for micronutrients and 0·30 for food groups. The FFQ underestimated protein intake by an average of 16 % and K by 5 %, relative to their urinary recovery biomarkers. Attenuation factors were 0·44 and 0·46 for protein and K, respectively. Correlation coefficients were 0·43-0·47 between (fatty) fish intake and plasma EPA and DHA and 0·24-0·43 between fruit and vegetable intakes and plasma carotenoids. In conclusion, the overall validity of the newly developed FFQ-NL 1.0 was acceptable to good. The FFQ-NL 1.0 is well suited for future use within Dutch cohort studies among adults.

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.

Effect of n-3 and n-6 Polyunsaturated Fatty Acids on Microsomal P450 Steroidogenic Enzyme Activities and In Vitro Cortisol Production in Adrenal Tissue From Yorkshire Boars

Dysregulation of adrenal glucocorticoid production is increasingly recognized to play a supportive role in the metabolic syndrome although the mechanism is ill defined. The adrenal cytochrome P450 (CYP) enzymes, CYP17 and CYP21, are essential for glucocorticoid synthesis. The omega-3 and omega-6 polyunsaturated fatty acids (PUFA) may ameliorate metabolic syndrome, but it is unknown whether they have direct actions on adrenal CYP steroidogenic enzymes. The aim of this study was to determine whether PUFA modify adrenal glucocorticoid synthesis using isolated porcine microsomes. The enzyme activities of CYP17, CYP21, 11β-hydroxysteroid dehydrogenase type 1, hexose-6-phosphate dehydrogenase (H6PDH), and CYP2E1 were measured in intact microsomes treated with fatty acids of disparate saturated bonds. Cortisol production was measured in a cell-free in vitro model. Microsomal lipid composition after arachidonic acid (AA) exposure was determined by sequential window acquisition of all theoretical spectra-mass spectrometry. Results showed that adrenal microsomal CYP21 activity was decreased by docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), eicosapentaenoic acid, α-linolenic acid, AA, and linoleic acid, and CYP17 activity was inhibited by DPA, DHA, eicosapentaenoic acid, and AA. Inhibition was associated with the number of the PUFA double bonds. Similarly, cortisol production in vitro was decreased by DPA, DHA, and AA. Endoplasmic enzymes with intraluminal activity were unaffected by PUFA. In microsomes exposed to AA, the level of AA or oxidative metabolites of AA in the membrane was not altered. In conclusion, these observations suggest that omega-3 and omega-6 PUFA, especially those with 2 or more double bonds (DPA, DHA, and AA), impede adrenal glucocorticoid production.

Translating plasma and whole blood fatty acid compositional data into the sum of eicosapentaenoic and docosahexaenoic acid in erythrocytes

Specific blood levels of eicosapentaenoic plus docosahexaenoic acid (EPA+DHA, wt% of total) in erythrocytes or "the omega-3 index" have been recommended for cardio-protection, but fatty acids are often measured in different blood fractions. The ability to estimate the % of EPA+DHA in erythrocytes from the fatty acid composition of other blood fractions would enable clinical assessments of omega-3 status when erythrocyte fractions are not available and increase the ability to compare blood levels of omega-3 fatty acids across clinical studies. The fatty acid composition of baseline plasma, erythrocytes and whole blood samples from participants (n=1104) in a prospective, multicenter study examining acute coronary syndrome were determined. The ability to predict the % of EPA+DHA in erythrocytes from other blood fractions were examined using bivariate and multiple linear regression modelling. Concordance analysis was also used to compare the actual erythrocytes EPA+DHA values to values estimated from other blood fractions. EPA+DHA in erythrocytes was significantly (p<0.001) correlated EPA+DHA in plasma (r(2)=0.54) and whole blood (r(2)=0.79). Using multiple linear regression to predict EPA+DHA in erythrocytes resulted in stronger coefficients of determination in both plasma (R(2)=0.70) and whole blood (R(2)=0.84). Concordance analyses indicated agreement between actual and estimated EPA+DHA in erythrocytes, although estimating from plasma fatty acids appears to require translation by categorization rather than by translation as continuous data. This study shows that the fatty acid composition of different blood fractions can be used to estimate erythrocyte EPA+DHA in a population with acute coronary syndrome.

Cross-sectional relationships between dietary fat intake and serum cholesterol fatty acids in a Swedish cohort of 60-year-old men and women

BACKGROUND

The present study aimed to describe the relationship between self-reported dietary intake and serum cholesterol fatty acids (FAs) in a Swedish population of 60-year-old men and women.

METHODS

Cross-sectional data collected in 1997-1998 from 4232 individuals residing in Stockholm County were used. Five diet scores were created to reflect the intake of saturated fats in general, as well as fats from dairy, fish, processed meat and vegetable oils and margarines. Gas chromatography was used to assess 13 FAs in serum cholesterol esters. The association between each diet score and specific FAs was assessed by percentile differences (PD) with 95% confidence intervals (CI) at the 10th, 25th, 50th, 75th and 90th percentile of each FA across levels of diet scores using quantile regression.

RESULTS

Fish intake was associated with high proportions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). For each point increase in fish score, the 50th PD in EPA and DHA was 32.78% (95% CI = 29.22% to 36.35%) and 10.63% (95% CI = 9.52% to 11.74%), respectively. Vegetable fat intake was associated with a high proportion of linoleic acid and total polyunsaturated fatty acids (PUFA) and a low proportion of total saturated fatty acids (SFA). The intake of saturated fats in general and dairy fat was slightly associated with specific SFA, although the intake of fat from meat was not.

CONCLUSIONS

In the present study population, using a rather simple dietary assessment method, the intake of fish and vegetable fats was clearly associated with serum PUFA, whereas foods rich in saturated fats in general showed a weak relationship with serum SFA. Our results may contribute to increased knowledge about underlying biology in diet-cardiovascular disease associations.

Polyunsaturated fatty acid intake and risk of cardiovascular mortality in a low fish-consuming population: a prospective cohort analysis

PURPOSE

The aim of this study was to examine the relationship between polyunsaturated fatty acids (PUFA) intake (n-6 and n-3) and mortality in a population-based sample with a low fish intake.

METHODS

Cox regression was used to examine the relationships between dietary PUFA intake and all-cause or CVD mortality in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) cohort, a population of 11,247 Australians aged ≥25 years recruited in 1999/2000 and followed until 2012. Demographic, lifestyle and behavioural information were collected by questionnaire and fasting blood tests undertaken. Dietary intake was collected by a 121-item food frequency questionnaire. Vital status and causes of death were collected by death registry linkage.

RESULTS

Those in the highest quintile of n-6 PUFA intake had lower risk of CVD mortality (HR 0.57, 95 % CI 0.38-0.86) after age and sex adjustment, but this failed to retain significance after further risk factor adjustment. Consumption of ≥1 serves/week of non-fried fish was associated with reduced risk of CVD mortality (HR 0.64, 95 % CI 0.45-0.91, p = 0.013) compared to those eating less than 1 serve/month, after sex and age adjustment, but did not retain significance after further adjustment. However, long-chain n-3 intake was not associated with CVD mortality, and those in the highest quintile of n-3 intake had a higher risk of all-cause mortality.

CONCLUSIONS

These findings do not support previous suggestions that n-6 PUFA have adverse effects on CVD risk. Greater intake of non-fried fish was associated with lower risk of CVD mortality, but those with the highest total n-3 intake were at slightly increased risk of all-cause mortality.

Evaluating the effectiveness of fish consumption advisories: modeling prenatal, postnatal, and childhood exposures to persistent organic pollutants

BACKGROUND

Because human exposure to persistent organic pollutants (POPs) occurs mainly through ingestion of contaminated food, regulatory bodies issue dietary consumption advisories to describe safe intake levels for food items of concern, particularly fish.

OBJECTIVES

Our study goal was to estimate the effectiveness of fish consumption advisories in reducing exposure of infants and children to POPs.

METHODS

We used the time-variant mechanistic model CoZMoMAN to estimate and compare prenatal, postnatal, and childhood exposure to polychlorinated biphenyl congener PCB-153 under different scenarios of maternal guideline adherence for both hypothetical constant and realistic time-variant chemical emissions. The scenarios differed in terms of length of compliance (1 vs. 5 years), extent of fish substitution (all vs. half), and replacement diet (uncontaminated produce vs. beef). We also estimated potential exposure reductions for a range of theoretical chemicals to explore how guideline effectiveness varies with a chemical's partitioning and degradation properties.

RESULTS

When assuming realistic time periods of advisory compliance, our findings suggest that temporarily eliminating or reducing maternal fish consumption is largely ineffective in reducing pre- and postnatal exposure to substances with long elimination half-lives in humans, especially during periods of decreasing environmental emissions. Substituting fish with beef may actually result in higher exposure to certain groups of environmental contaminants. On the other hand, advisories may be highly effective in reducing exposure to substances with elimination half-lives in humans shorter than the length of compliance.

CONCLUSIONS

Our model estimates suggest that fish consumption advisories are unlikely to be effective in reducing prenatal, postnatal, and childhood exposures to compounds with long elimination half-lives in humans.

Age and sex differences in the incorporation of EPA and DHA into plasma fractions, cells and adipose tissue in humans

The aim of the present study was to determine whether age and sex influence both the status and incorporation of EPA and DHA into blood plasma, cells and tissues. The study was a double-blind, randomised, controlled intervention trial, providing EPA plus DHA equivalent to 0, 1, 2 or 4 portions of oily fish per week for 12 months. The participants were stratified by age and sex. A linear regression model was used to analyse baseline outcomes, with covariates for age or sex groups and by adjusting for BMI. The change in outcomes from baseline to 12 months was analysed with additional adjustment for treatment and average compliance. Fatty acid profiles in plasma phosphatidylcholine, cholesteryl esters, NEFA and TAG, mononuclear cells (MNC), erythrocyte membranes, platelets, buccal cells (BU) and adipose tissue (AT) were determined. At baseline, EPA concentrations in plasma NEFA and DHA concentrations in MNC, BU and AT were higher in females than in males (all P< 0·05). The concentrations of EPA in AT (P= 0·003) and those of DHA in plasma TAG (P< 0·01) and AT (P< 0·001) were higher with increasing age. Following 12-month supplementation with EPA plus DHA, adjusted mean difference for change in EPA concentrations in plasma TAG was significantly higher in females than in males (P< 0·05) and was greater with increasing age (P= 0·02). Adjusted mean difference for change in DHA concentrations in AT was significantly smaller with increasing age (P= 0·02). Although small differences in incorporation with age and sex were identified, these were not of sufficient magnitude to warrant a move away from population-level diet recommendations for n-3 PUFA.

Plasma omega-3 and omega-6 concentrations and risk of cutaneous basal and squamous cell carcinomas in Australian adults

Laboratory-based evidence suggests that omega-3 and omega-6 polyunsaturated fatty acids may affect skin photocarcinogenesis, but epidemiologic evidence is inconsistent. In 1,191 White Australian adults, we prospectively investigated associations between baseline plasma concentrations of omega-3 and omega-6 fatty acids and cutaneous basal cell carcinomas (BCC) and squamous cell carcinomas (SCC). Relative risks (RR) and 95% confidence intervals (CI) were estimated on the basis of number of histologically confirmed tumors diagnosed during follow-up (1997-2007). Plasma eicosapentaenoic acid (EPA) concentrations and omega-3/-6 ratio showed significant inverse associations with SCC tumors, comparing higher tertiles with the lowest, in age- and sex-adjusted models (Ptrend = 0.02 and 0.03, respectively) which weakened after adjustment for past sun exposure. Associations between EPA and SCC were stronger among participants with a history of skin cancer at baseline (n = 378; highest vs. lowest tertile: RR = 0.50; 95% CI, 0.28-0.92; Ptrend = 0.01). Total omega-6 was inversely associated with BCC tumors in multivariate models (P = 0.04; highest vs. lowest tertile: RR = 0.71; 95% CI, 0.51-0.99), and more strongly in the subgroup with past skin cancer. Linoleic and linolenic acids were also inversely associated with BCC occurrence in this subgroup. When fatty acids were analyzed as continuous variables, however, there was no evidence of any linear or nonlinear associations. This study provides some support for reduced skin cancer risk with high plasma concentrations of omega-3 and omega-6 fatty acids, but results depended on how fatty acid data were modeled. Further investigation of these associations in larger datasets is needed.

Synergism of α-linolenic acid, conjugated linoleic acid and calcium in decreasing adipocyte and increasing osteoblast cell growth

Whole fat milk and dairy products (although providing more energy compared to low- or non-fat products), are good sources of α-linolenic acid (ALA), conjugated linoleic acid (CLA) and calcium, which may be favorable in modulating bone and adipose tissue metabolism. We examined individual and/or synergistic effects of ALA, CLA and calcium (at levels similar to those in whole milk/dairy products) in regulating bone and adipose cell growth. ST2 stromal, MC3T3-L1 adipocyte-like and MC3T3-E1 osteoblast-like cells were treated with: (a) linoleic acid (LNA):ALA ratios = 1-5:1; (b) individual/combined 80-90 % c9, t11 (9,11) and 5-10 % t10, c12 (10,12) CLA isomers; (c) 0.5-3.0 mM calcium; (d) combinations of (a), (b), (c); and (e) control. Local mediators, including eicosanoids and growth factors, were measured. (a) The optimal effect was found at the 4:1 LNA:ALA ratio where insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) production was the lowest in MC3T3-L1 cells. (b) All CLA isomer blends decreased MC3T3-L1 and increased MC3T3-E1 cell differentiation. (c) 1.5-2.5 mM calcium increased ST2 and MC3T3-E1, and decreased MC3T3-L1 cell proliferation. (d) Combination of 4:1 LNA:ALA + 90:10 % CLA + 2.0 mM calcium lowered MC3T3-L1 and increased MC3T3-E1 cell differentiation. Overall, the optimal LNA:ALA ratio to enhance osteoblastogenesis and inhibit adipogenesis was 4:1. This effect was enhanced by 90:10 % CLA + 2.0 mM calcium, indicating possible synergism of these dietary factors in promoting osteoblast and inhibiting adipocyte differentiation in cell cultures.

Health benefits of seafood; is it just the fatty acids?

There is a considerable body of literature suggesting a wide range of health benefits associated with diets high in seafood. However, the demand for seafood across the world now exceeds that available from capture fisheries. This has created a rapidly increasing market for aquaculture products, the nutrient composition of which is dependent on feed composition. The use of fishmeal in this food chain does little to counteract the environmental impact of fisheries and so the on-going development of alternative sources is to be welcomed. Nevertheless, an in-depth understanding as to which nutrients in seafood provide benefit is required to permit the production of foods of maximal health benefit to humans. This paper reviews our current knowledge of the beneficial nutrient composition of seafood, in particular omega-3 fatty acids, selenium, taurine, vitamins D and B12, in the context of the development of environmentally sustainable aquaculture.

Theoretical dietary modelling of Australian seafood species to meet long-chain omega 3 fatty acid dietary recommendations

Background

Several agencies recommend seafood to be consumed 2–3 times per week. In Australia, there is a lack of nutrient composition data for seafood species and it is not known whether including different seafood species in a diet would provide sufficient long-chain omega 3 fatty acids (LC n–3 PUFA) to meet various national recommendations.

Objective

To utilise recent nutrient composition data for major Australian seafood groups (n=24) with the addition of two tuna options (total n=26) to: (1) determine whether including these species into a diet based on the Australian Guide to Healthy Eating (AGHE) will achieve LC n–3 PUFA recommendations [Adequate Intake (AI: 160 mg/d men, 90 mg/d women)], Suggested Dietary Target (SDT), 500 mg/d Heart Foundation (HF) recommendation and (2) determine the weekly number of servings of seafood to meet recommendations using either lower fat (n=23, <10% total fat) or higher fat (n=3, ≥10% total fat) seafood.

Design

Two simulation models incorporated all 26 species of seafood or only lower fat seafood into a diet based on the AGHE. Two further models identified the number of servings of lower or higher fat seafood required to meet recommendations.

Results

Including 2 and 3 servings/week of any seafood would enable 89% of women and 66% of men to meet the AI. Including only lower fat seafood would enable 83% of women and 47% of men to meet the AI. Half a serving/week of higher fat seafood would enable 100% of men and women to meet the AI.

Conclusions

Including the recommended 2–3 servings of seafood/week requires at least some higher fat seafood to be consumed in order for most men and women to meet the AI. Further messages and nutrition resources are needed which provide options on how to increase intake of LC n–3 PUFA, specifically through consumption of the higher fat seafood.

Bifidobacterium breve with α-linolenic acid and linoleic acid alters fatty acid metabolism in the maternal separation model of irritable bowel syndrome

The aim of this study was to compare the impact of dietary supplementation with a Bifidobacterium breve strain together with linoleic acid & α-linolenic acid, for 7 weeks, on colonic sensitivity and fatty acid metabolism in rats. Maternally separated and non-maternally separated Sprague Dawley rats (n = 15) were orally gavaged with either B. breve DPC6330 (10(9) microorganisms/day) alone or in combination with 0.5% (w/w) linoleic acid & 0.5% (w/w) α-linolenic acid, daily for 7 weeks and compared with trehalose and bovine serum albumin. Tissue fatty acid composition was assessed by gas-liquid chromatography and visceral hypersensitivity was assessed by colorectal distension. Significant differences in the fatty acid profiles of the non-separated controls and maternally separated controls were observed for α-linolenic acid and arachidonic acid in the liver, oleic acid and eicosenoic acid (c11) in adipose tissue, and for palmitoleic acid and docosahexaenoic acid in serum (p<0.05). Administration of B. breve DPC6330 to MS rats significantly increased palmitoleic acid, arachidonic acid and docosahexaenoic acid in the liver, eicosenoic acid (c11) in adipose tissue and palmitoleic acid in the prefrontal cortex (p<0.05), whereas feeding B. breve DPC6330 to non separated rats significantly increased eicosapentaenoic acid and docosapentaenoic acid in serum (p<0.05) compared with the NS un-supplemented controls. Administration of B. breve DPC6330 in combination with linoleic acid and α-linolenic acid to maternally separated rats significantly increased docosapentaenoic acid in the serum (p<0.01) and α-linolenic acid in adipose tissue (p<0.001), whereas feeding B. breve DPC6330 with fatty acid supplementation to non-separated rats significantly increased liver and serum docosapentaenoic acid (p<0.05), and α-linolenic acid in adipose tissue (p<0.001). B. breve DPC6330 influenced host fatty acid metabolism. Administration of B. breve DPC6330 to maternally separated rats significantly modified the palmitoleic acid, arachidonic acid and docosahexaenoic acid contents in tissues. The effect was not observed in non-separated animals.

Association between fish consumption, long chain omega 3 fatty acids, and risk of cerebrovascular disease: systematic review and meta-analysis

OBJECTIVE

To clarify associations of fish consumption and long chain omega 3 fatty acids with risk of cerebrovascular disease for primary and secondary prevention.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Studies published before September 2012 identified through electronic searches using Medline, Embase, BIOSIS, and Science Citation Index databases.

ELIGIBILITY CRITERIA

Prospective cohort studies and randomised controlled trials reporting on associations of fish consumption and long chain omega 3 fatty acids (based on dietary self report), omega 3 fatty acids biomarkers, or supplementations with cerebrovascular disease (defined as any fatal or non-fatal ischaemic stroke, haemorrhagic stroke, cerebrovascular accident, or transient ischaemic attack). Both primary and secondary prevention studies (comprising participants with or without cardiovascular disease at baseline) were eligible.

RESULTS

26 prospective cohort studies and 12 randomised controlled trials with aggregate data on 794,000 non-overlapping people and 34,817 cerebrovascular outcomes were included. In cohort studies comparing categories of fish intake the pooled relative risk for cerebrovascular disease for 2-4 servings a week versus ≤ 1 servings a week was 0.94 (95% confidence intervals 0.90 to 0.98) and for ≥ 5 servings a week versus 1 serving a week was 0.88 (0.81 to 0.96). The relative risk for cerebrovascular disease comparing the top thirds of baseline long chain omega 3 fatty acids with the bottom thirds for circulating biomarkers was 1.04 (0.90 to 1.20) and for dietary exposures was 0.90 (0.80 to 1.01). In the randomised controlled trials the relative risk for cerebrovascular disease in the long chain omega 3 supplement compared with the control group in primary prevention trials was 0.98 (0.89 to 1.08) and in secondary prevention trials was 1.17 (0.99 to 1.38). For fish or omega 3 fatty acids the estimates for ischaemic and haemorrhagic cerebrovascular events were broadly similar. Evidence was lacking of heterogeneity and publication bias across studies or within subgroups.

CONCLUSIONS

Available observational data indicate moderate, inverse associations of fish consumption and long chain omega 3 fatty acids with cerebrovascular risk. Long chain omega 3 fatty acids measured as circulating biomarkers in observational studies or supplements in primary and secondary prevention trials were not associated with cerebrovascular disease. The beneficial effect of fish intake on cerebrovascular risk is likely to be mediated through the interplay of a wide range of nutrients abundant in fish.

Omega-3 fatty acids status in human subjects estimated using a food frequency questionnaire and plasma phospholipids levels

BACKGROUND

Intakes of omega-3 (n-3) fatty acids (FA) are associated with several health benefits. The aim of this study was to verify whether intakes of n-3 FA estimated from a food frequency questionnaire (FFQ) correlate with n-3 FA levels measured in plasma phospholipids (PL).

METHODS

The study sample consisted of 200 French-Canadians men and women aged between 18 to 55 years. Dietary data were collected using a validated FFQ. Fasting blood samples were collected and the plasma PL FA profile was measured by gas chromatography.

RESULTS

Low intakes of n-3 long-chain FA together with low percentages of n-3 long-chain FA in plasma PL were found in French-Canadian population. Daily intakes of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) were similar between men and women. Yet, alpha-linolenic acid (ALA) and total n-3 FA intakes were significantly higher in men compared to women (ALA: 2.28 g and 1.69 g, p < 0.0001, total n-3 FA: 2.57 g and 1.99 g, p < 0.0001; respectively). In plasma PL, DPA and DHA percentages were significantly different between men and women (DPA: 1.03% and 0.88%, p < 0.0001, DHA: 3.00% and 3.43%, p = 0.0005; respectively). Moreover, DHA (men: r = 0.52, p < 0.0001; women: r = 0.57, p < 0.0001) and total n-3 FA (men: r = 0.47, p < 0.0001; women: r = 0.52, p < 0.0001) intakes were positively correlated to their respective plasma PL FA levels. In women, EPA (r = 0.44, p < 0.0001) and DPA (r = 0.23, p = 0.02) intakes were also correlated respectively with EPA and DPA plasma PL FA percentages.

CONCLUSION

Estimated n-3 long-chain FA intake among this young and well-educated French-Canadian population is lower than the recommendations. Further, FFQ data is comparable to plasma PL results to estimate DHA and total n-3 FA status in healthy individuals as well as to evaluate the EPA and DPA status in women. Overall, this FFQ could be used as a simple, low-cost tool in future studies to rank n-3 FA status of individuals.

A restricted cubic spline approach to assess the association between high fat fish intake and red blood cell EPA + DHA content

BACKGROUND AND AIMS

Fish, especially fatty fish, are the main contributor to eicosapentaenoic (EPA) and docosahexaenoic (DHA) intake. EPA and DHA concentrations in red blood cells (RBC) has been proposed as a cardiovascular risk factor, with <4% and >8% associated with the lowest and greatest protection, respectively. The relationship between high fat fish (HFF) intake and RBC EPA + DHA content has been little investigated on a wide range of fish intake, and may be non-linear. We aimed to study the shape of this relationship among high seafood consumers.

METHODS AND RESULTS

Seafood consumption records and blood were collected from 384 French heavy seafood consumers and EPA and DHA were measured in RBC. A multivariate linear regression was performed using restricted cubic splines to consider potential non-linear associations. Thirty-six percent of subjects had an RBC EPA + DHA content lower than 4% and only 5% exceeded 8%. HFF consumption was significantly associated with RBC EPA + DHA content (P [overall association] = 0.021) adjusted for sex, tobacco status, study area, socioeconomic status, age, alcohol, other seafood, meat, and meat product intakes. This relationship was non-linear: for intakes higher than 200 g/wk, EPA + DHA content tended to stagnate. Tobacco status and fish contaminants were negatively associated with RBC EPA + DHA content.

CONCLUSION

Because of the saturation for high intakes, and accounting for the concern with exposure to trace element contaminants, intake not exceeding 200 g should be considered.

Risks and benefits of consumption of Great Lakes fish

BACKGROUND

Beneficial effects of fish consumption on early cognitive development and cardiovascular health have been attributed to the omega-3 fatty acids in fish and fish oils, but toxic chemicals in fish may adversely affect these health outcomes. Risk-benefit assessments of fish consumption have frequently focused on methylmercury and omega-3 fatty acids, not persistent pollutants such as polychlorinated biphenyls, and none have evaluated Great Lakes fish consumption.

OBJECTIVES

The risks and benefits of fish consumption have been established primarily for marine fish. Here, we examine whether sufficient data are available to evaluate the risks and benefits of eating freshwater fish from the Great Lakes.

METHODS

We used a scoping review to integrate information from multiple state, provincial, and federal agency sources regarding the contaminants and omega-3 fatty acids in Great Lakes fish and fish consumers, consumption rates and fish consumption advisories, and health effects of contaminants and omega-3 fatty acids.

DATA SYNTHESIS

Great Lakes fish contain persistent contaminants--many of which have documented adverse health effects--that accumulate in humans consuming them. In contrast, data are sparse on omega-3 fatty acids in the fish and their consumers. Moreover, few studies have documented the social and cultural benefits of Great Lakes fish consumption, particularly for subsistence fishers and native communities. At this time, federal and state/provincial governments provide fish consumption advisories based solely on risk.

CONCLUSIONS

Our knowledge of Great Lakes fish has critical gaps, particularly regarding the benefits of consumption. A risk-benefit analysis requires more information than is currently available on the concentration of omega-3 fatty acids in Great Lakes fish and their absorption by fish eaters in addition to more information on the social, cultural, and health consequences of changes in the amount of fish consumed.

Does diet influence physical performance in community-dwelling older people? Findings from the Hertfordshire Cohort Study

BACKGROUND

recent studies suggest that diet may affect the physical performance of older adults, but the impact of variations in the UK diet on physical performance has not been assessed.

OBJECTIVE

to examine relationships between diet and physical performance in community-dwelling older men and women.

SETTING AND PARTICIPANTS

a total of 628 men and women aged 63-73 years who were taking part in the Hertfordshire Cohort Study.

METHODS

diet was assessed using an administered food frequency questionnaire; physical performance was assessed by the time taken to complete a 3-m walk, chair-rise test and one-legged balance test.

RESULTS

in women, higher intakes of the antioxidant nutrients, β-carotene and selenium, were associated with shorter 3-m walk times; higher β-carotene and vitamin C intakes were associated with shorter chair-rise times (all P < 0.05). Higher vitamin D intakes and percentage energy from protein were also associated with faster 3-m walk times (both P < 0.05), but they were not related to chair-rise time. There were no associations between any measure of dietary intake and balance in the women studied. After adjustment for the effects of confounding influences, we found no associations between diet and physical performance among men.

CONCLUSIONS

these data indicate that variations in the diets of community-dwelling older women may be linked to differences in physical performance, but further work is needed to determine the role of variations in diet on physical performance and its decline with age among older adults in the UK.

High dietary and plasma levels of the omega-3 fatty acid docosahexaenoic acid are associated with decreased dementia risk: the Rancho Bernardo study

OBJECTIVE

This study examined the association of plasma DHA, dietary DHA, and fish intake with dementia and Alzheimer's Disease (AD) in older adults.

DESIGN

Case-cohort study.

SETTING

Clinic visit in 1991-93.

PARTICIPANTS

266 community dwelling men and women aged 67-100 years (mean=80.2).

MEASUREMENTS

Participants had neurological and neuropsychological evaluations for dementia in 1991-93. Plasma DHA was measured in blood samples obtained at that visit. Dietary intakes of DHA and fish were obtained from an earlier (1988-91) visit. Three DHA exposure variables were used in separate analyses; plasma DHA, dietary DHA, and consumption of cold-water fish. All-cause dementia included AD and other types of possible or probable dementia.

RESULTS

Among these 266 participants, 42 had dementia and 30 had possible or probable AD. Plasma DHA in the highest tertile was associated with a 65% reduced odds of all-cause dementia (95% CI: 0.17, 0.92) and a 60% reduced odds of AD (95% CI: 0.15, 1.10). Dietary DHA in the highest tertile was associated with a 73% reduced odds of all-cause dementia (95% CI: 0.09, 0.79) and a 72% reduced odds of AD (95% CI: 0.09, 0.93). Fish intake had similar, though not significant, reduced odds of dementia (OR = 0.51; 95% CI: 0.20, 1.32) and AD (OR = 0.55; 95% CI: 0.20, 1.48).

CONCLUSIONS

Plasma and dietary DHA appear to protect against dementia. Increasing DHA intake from marine sources may be recommended for reducing dementia risk.

Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the product-precursor ratio [corrected] of α-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort

BACKGROUND

Intakes of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) are important for health. Because fish is the major source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), non-fish-eaters may have suboptimal n-3 PUFA status, although the importance of the conversion of plant-derived α-linolenic acid (ALA) to EPA and DHA is debated.

OBJECTIVE

The objective was to determine intakes, food sources, and status of n-3 PUFAs according to dietary habit (fish-eaters and non-fish-eating meat-eaters, vegetarians, or vegans) and estimated conversion between dietary ALA and circulating long-chain n-3 PUFAs.

DESIGN

This study included 14,422 men and women aged 39-78 y from the EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk cohort with 7-d diary data and a substudy in 4902 individuals with plasma phospholipid fatty acid measures. Intakes and status of n-3 PUFAs were measured, and the product-precursor ratio [corrected] of ALA to circulating n-3 PUFAs was calculated.

RESULTS

Most of the dietary intake of EPA and DHA was supplied by fish; however, meat was the major source in meat-eaters, and spreading fats, soups, and sauces were the major sources in vegetarians. Total n-3 PUFA intakes in non-fish-eaters were 57-80% of those in fish-eaters, but status differences were considerably smaller [corrected]. The estimated product-precursor ratio [corrected] was greater in women than in men and greater in non-fish-eaters than in fish-eaters.

CONCLUSIONS

Substantial differences in intakes and in sources of n-3 PUFAs existed between the dietary-habit groups, but the differences in status were smaller than expected, possibly because the product-precursor ratio [corrected] was greater in non-fish-eaters than in fish-eaters, potentially indicating increased estimated conversion of ALA. If intervention studies were to confirm these findings, it could have implications for fish requirements.

Meat, poultry and fish and risk of colorectal cancer: pooled analysis of data from the UK dietary cohort consortium

OBJECTIVE

Some but not all epidemiological studies have reported that high intakes of red and processed meat are associated with an increased risk of colorectal cancer. In the UK Dietary Cohort Consortium, we examined associations of meat, poultry and fish intakes with colorectal cancer risk using standardised individual dietary data pooled from seven UK prospective studies.

METHODS

Four- to seven-day food diaries were analysed, disaggregating the weights of meat, poultry and fish from composite foods to investigate dose-response relationships. We identified 579 cases of colorectal cancer and matched with 1,996 controls on age, sex and recruitment date. Conditional logistic regression models were used to estimate odds ratios for colorectal cancer associated with meat, poultry and fish intakes, adjusting for relevant covariables.

RESULTS

Disaggregated intakes were moderately low, e.g. mean red meat intakes were 38.2 g/day among male and 28.7 g/day among female controls. There was little evidence of association between the food groups examined and risk for colorectal cancer: Odds ratios (95% confidence intervals) for a 50 g/day increase were 1.01 (0.84-1.22) for red meat, 0.88 (0.68-1.15) for processed meat, 0.97 (0.84-1.12) for red and processed meat combined, 0.80 (0.65-1.00) for poultry, 0.92 (0.70-1.21) for white fish and 0.89 (0.70-1.13) for fatty fish.

CONCLUSIONS

This study using pooled data from prospective food diaries, among cohorts with low to moderate meat intakes, shows little evidence of association between consumption of red and processed meat and colorectal cancer risk.

Dietary n-3 polyunsaturated fatty acids and the aetiology of ulcerative colitis: a UK prospective cohort study

OBJECTIVES

The aetiology of ulcerative colitis (UC) is largely unknown, although it is plausible that dietary n-3 polyunsaturated fatty acids (PUFAs) may be protective. Metabolites derived from n-3 PUFAs are less proinflammatory than those from n-6 PUFAs. Earlier, no prospective cohort studies have investigated this hypothesis, using dietary information collected from food diaries. The aim of this study was to investigate the total dietary intake of n-3 PUFAs and the specific n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the risk of developing incident UC.

METHODOLOGY

Twenty-five thousand six hundred and thirty-nine participants, living in Norfolk UK, aged 45-74 years (median age at recruitment of 59.2 years), completed 7-day food diaries. These were interpreted using a computer programme, which converted food items into nutrients, including n-3 PUFAs. The cohort was monitored for participants who developed UC. Each case was matched with four controls and an analysis performed using conditional logistic regression.

RESULTS

In the cohort, 22 incident cases of UC were identified after a median follow-up time of 4.2 years (range 1.8-8.3 years). A statistically significant protective odds ratio (OR) for the trend across tertiles was found for DHA [OR = 0.43, 95% confidence interval (CI)=0.22-0.86, P = 0.02] and borderline statistically significant differences for trends for total total n-3 PUFAs (OR = 0.56, 95% CI=0.28-1.13, P = 0.10) and EPA (OR = 0.53, 95% CI=0.27-1.03, P = 0.06) after adjusting for age, sex, total energy intake, smoking, and other fatty acids.

CONCLUSION

Total dietary n-3 PUFAs, EPA, and DHA, particularly DHA were associated with protection from UC in a cohort aged over 45 years. If the association is causal, then increasing the population's intake of n-3 PUFAs from oily fish may help prevent UC.

Fish consumption and polyunsaturated fatty acids in relation to psychological distress

BACKGROUND

It has been suggested that high fish consumption improves mental well-being. The aim of this study was to assess whether high fish consumption or omega-3 polyunsaturated fatty acid (PUFA) intake was associated with reduced self-reported psychological distress.

METHODS

We used three cross-sectional data sets, the nationwide Health 2000 Survey (n = 5840), the Fishermen Study on Finnish fishermen and their family members (n = 1282) and the Finntwin16 Study on young adults (n = 4986). Data were based on self-administered questionnaires, interviews, health examinations and blood samples. Psychological distress was measured using the 12-item and 21-item General Health Questionnaires (GHQs). Fish consumption was measured by a food frequency questionnaire (FFQ, g/day) and independent frequency questions (times/month). Dietary intake (g/day) and serum concentrations (% from fatty acids) of PUFAs were determined. Relationships were analysed using regression analysis.

RESULTS

Regardless of the measure, fish consumption and omega-3 PUFA dietary intake were not associated with distress in any of the data sets. In contrast to the hypothesis, high serum docosahexaenoic acid was associated with high distress in the Fisherman Study men. Some non-linear associations were detected between serum omega-3 PUFAs or fish consumption (times/month) and distress. In the Fishermen Study, the associations were modified by alcohol consumption, smoking and physical activity.

CONCLUSIONS

Our results do not support the hypothesis that fish consumption or omega-3 PUFA intake are associated with reduced psychological distress in the general population or in a population with high fish consumption.

Intakes of (n-3) fatty acids and fatty fish are not associated with cognitive performance and 6-year cognitive change in men participating in the Veterans Affairs Normative Aging Study

High intake of fish and (n-3) PUFA may protect against age-related cognitive decline. However, results are inconsistent and limited data exist regarding changes in multiple cognitive functions over a longer period of time. In this study, we assessed the association between fatty fish intake as well as (n-3) PUFA intake with cognitive performance and cognitive change over 6 y in 1025 elderly men. Participants were from the Veterans Affairs Normative Aging Study. Cognitive function was assessed with a battery of cognitive tests focusing on factors representing memory/language, speed, and visuospatial/attention. Dietary intakes were assessed with a validated FFQ. We used general linear models to assess cross-sectional associations and mixed models to assess the associations over time. Models were adjusted for age, education, BMI, smoking, diabetes, and intake of alcohol, saturated fat, vitamin C, and vitamin E. The mean age of participating men was 68 y at baseline. Median fish consumption ranged from 0.2 to 4.2 servings/wk across quartiles. Cross-sectional analyses showed no association between fatty fish or (n-3) PUFA intake and cognitive performance. Longitudinal analyses, over 6 y of follow-up, also did not show any significant associations between fatty fish or (n-3) PUFA intake and cognitive change. In this population of elderly men, intake of neither fatty fish nor (n-3) PUFA was associated with cognitive performance.

Correlation between serum phospholipid fatty acids and dietary intakes assessed a few years earlier

The fatty acid composition of serum phospholipids has been shown to reflect dietary intakes in the previous weeks or months. However, how serum phospholipids relate to fatty acid intakes over a few years has hardly been examined. We designed a cross-sectional study within the E3N cohort, the French component of the European Prospective Investigation into Cancer and Nutrition in which female participants completed a 208-item diet history questionnaire in 1993-1995 and provided blood samples in 1995-1998. The study included 1,114 women who were free of cancer at the time of blood collection. Serum phospholipid fatty acid composition was assessed by capillary gas chromatography. Partial Spearman correlations adjusted for age and body mass index showed weak to moderate, although statistically significant, positive associations between dietary and serum oleic, linoleic, arachidonic, eicosapentaenoic, and docosahexaenoic acids. Moreover, serum oleic acid was directly associated with olive oil, linoleic acid with sunflower oil, pentadecanoic acid with dairy products, long-chain n-3 fatty acids with fatty fish, and trans-monounsaturated fatty acids with manufactured foods. In conclusion, serum phospholipid pentadecanoic acid, oleic, trans-monounsaturated, and polyunsaturated fatty acids are suitable biomarkers for usual dietary intakes, although the association may weaken as the time lag between dietary assessment and blood collection increases.

Self-reported dietary intake of omega-3 fatty acids and association with bone and lower extremity function

OBJECTIVES

To assess the relationship between self-reported omega-3 fatty acid (O3FA) intake and bone mineral density (BMD) and lower extremity function in older adults.

DESIGN

Cross-sectional analysis of baseline information from three separate ongoing studies of older adults, pooled for this analysis.

SETTING

Academic health center.

PARTICIPANTS

Two hundred forty-seven men (n=118) and women (n=129) residing in the community or an assisted living facility.

MEASUREMENTS

Self-reported dietary intake (O3FA, omega-6 fatty acids (O6FA), protein, and total calorie); BMD of the hip or heel; and lower extremity function including leg strength, chair rise time, walking speed, Timed Up and Go, and frailty.

RESULTS

The mean reported intake of O3FA was 1.27 g/day. Correlation coefficients (r) between O3FA and T-scores from total femur (n=167) were 0.210 and 0.147 for combined femur and heel T scores. Similar correlations were found for leg strength (r=0.205) and chair rise time (r=-0.178), but the significance was lost when corrected for protein intake. Subjects with lower reported O3FA intake (<1.27 g/day) had lower BMD than those with higher reported O3FA intake. In a multiple regression analysis with femoral neck BMD as the dependent variable and reported intake of O3FA, O6FA, protein, and vitamin D as independent variables, reported O3FA intake was the only significant variable, accounting for 6% of the variance in BMD.

CONCLUSION

Older adults had low reported intakes of O3FA. There was an association between greater reported O3FA intake and higher BMD. There was no independent association between reported O3FA intake and lower extremity function. Results from this preliminary report are promising and suggest further investigation.