Thirteen-year prospective study between fish consumption, long-chain n-3 fatty acids intakes and cognitive function

Fish consumption, cognitive impairment and dementia: an updated dose-response meta-analysis of observational studies

BACKGROUND

Cognitive impairment is projected to affect a preponderant proportion of the aging population. Lifelong dietary habits have been hypothesized to play a role in preventing cognitive decline. Among the most studied dietary components, fish consumptionhas been extensively studied for its potential effects on the human brain.

AIMS

To perform a meta-analysis of observational studies exploring the association between fish intake and cognitive impairment/decline and all types of dementia.

METHODS

A systematic search of electronic databases was performed to identify observational studies providing quantitative data on fish consumption and outcomes of interest. Random effects models for meta-analyses using only extreme exposure categories, subgroup analyses, and dose-response analyses were performed to estimate cumulative risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

The meta-analysis comprised 35 studies. Individuals reporting the highest vs. the lowest fish consumption were associated with a lower likelihood of cognitive impairment/decline (RR = 0.82, 95% CI: 0.75, 0.90, I2 = 61.1%), dementia (RR = 0.82, 95% CI: 0.73, 0.93, I2 = 38.7%), and Alzheimer's disease (RR = 0.80, 95% CI: 0.67, 0.96, I2 = 20.3%). The dose-response relation revealed a significantly decreased risk of cognitive impairment/decline and all cognitive outcomes across higher levels of fish intake up to 30% for 150 g/d (RR = 0.70, 95% CI: 0.52, 0.95). The results of this relation based on APOE ε4 allele status was mixed based on the outcome investigated.

CONCLUSIONS

Current findings suggest fish consumption is associated with a lower risk of cognitive impairment/decline in a dose-response manner, while for dementia and Alzheimer's disease there is a need for further studies to improve the strength of evidence.

The effect of n-3 polyunsaturated fatty acid supplementation on cognitive function outcomes in the elderly depends on the baseline omega-3 index

Both epidemiological and preclinical studies have shown the benefits of n-3 polyunsaturated fatty acid (n-3 PUFA) on dementia and cognitive impairment, yet the results of clinical randomized controlled trials (RCTs) performed to date are conflicting. The difference in the baseline omega-3 index (O3i) of subjects is a potential cause for this disparity, yet this is usually ignored. The present meta-analysis aimed to evaluate the effect of n-3 polyunsaturated fatty acid (n-3 PUFA) on cognitive function in the elderly and the role of baseline O3i. A systematic literature search was conducted in PubMed, Embase, Cochrane Library, and Web of Science up to June 27th, 2023. The mean changes in the mini-mental state examination (MMSE) score were calculated as weighted mean differences by using a fixed-effects model. Fifteen random controlled trials were included in the meta-analysis. Pooled analysis showed that n-3 PUFA supplementation did not significantly improve the MMSE score (WMD = 0.04, [-0.08, 0.16]; Z = 0.62, P = 0.53; I2 = 0.00%, P(I2) = 0.49). Out of the 15 studies included in the meta-analysis, only 7 reported O3i at baseline and outcome, so only these 7 articles were used for subgroup analysis. Subgroup analysis showed that the MMSE score was significantly improved in the higher baseline O3i subgroup (WMD = 0.553, [0.01, 1.095]; I2 = 0.00%, P(I2) = 0.556) and higher O3i increment subgroup (WMD = 0.525, [0.023, 1.026]; I2 = 0.00%, P(I2) = 0.545). The overall effect demonstrated that n-3 PUFA supplementation exerted no improvement on global cognitive function. However, a higher baseline O3i and higher O3i increment were associated with an improvement in cognitive function in the elderly.

Association between animal protein sources and risk of neurodegenerative diseases: a systematic review and dose-response meta-analysis

CONTEXT

Current findings about the differential effects of various sources of dietary animal protein on the risk of neurodegenerative diseases are contradictory.

OBJECTIVE

The current meta-analysis was conducted to investigate the associations between intake of dietary animal protein sources and the risk of neurodegenerative diseases.

DATA SOURCES

PubMed, Scopus, Web of Science, and Google Scholar databases were searched systematically until October 2021.

DATA EXTRACTION

Prospective cohort studies exploring the association between consumption of animal protein sources and risk of neurodegenerative diseases in the general population were included. Among 10 571 identified studies, 33 prospective cohort studies met the eligibility criteria.

DATA ANALYSIS

Dietary fish consumption was associated with a reduced risk of Alzheimer's disease (RR = 0.75; 95%CI, 0.57-0.97), dementia (RR = 0.84; 95%CI, 0.75-0.93), and cognitive impairment (RR = 0.85; 95%CI, 0.81-0.95). The risk of developing Parkinson's disease was significantly higher among those in the highest vs the lowest intake categories of total dairy (RR = 1.49; 95%CI, 1.06-2.10) and milk (RR = 1.40; 95%CI, 1.13-1.73). Moreover, dietary intake of total dairy (RR = 0.89; 95%CI, 0.80-0.99), total meat (RR = 0.72; 95%CI, 0.57-0.90), and poultry (RR = 0.82; 95%CI, 0.68-0.99) was significantly associated with a lower risk of cognitive impairment. A linear dose-response meta-analysis revealed that each 200-g increase in total daily dairy intake was associated with an 11% higher risk of Parkinson's disease and a 12% lower risk of cognitive impairment. Furthermore, there was a strong linear association between fish consumption and reduced risk of dementia.

CONCLUSION

Dairy consumption is associated with an increased risk of Parkinson's disease, but a higher intake of fish may be associated with lower risk of neurodegenerative disease. Future well-controlled, randomized clinical trials are essential to validate the present findings.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021281887.

The Role of Dietary Lipids in Cognitive Health: Implications for Neurodegenerative Disease

Neurodegenerative diseases are a group of disorders characterised by progressive loss of brain function. The most common of these is Alzheimer's disease, a form of dementia. Intake of macro- and micro-nutrients impacts brain function, including memory, learning, mood, and behaviour. Lipids, particularly phospholipids and sphingolipids, are crucial structural components of neural tissues and significantly affect cognitive function. The importance of functional foods in preventing cardiovascular disease is well-documented in the current literature. However, the significance of such foods for central nervous system health and neurodegenerative diseases is less recognized. Gut microbiome composition affects cognitive health and function, and dietary lipids are known to influence gut health. Thus, this review will discuss different sources of dietary lipids and their effect on cognitive functioning and their interaction with the gut microbiome in the context of neurodegenerative disease.

The EAT-Lancet reference diet and cognitive function across the life course

The EAT-Lancet Commission devised a sustainable reference diet with the aim of reducing the incidence of non-communicable diseases and mortality globally while improving food system sustainability. The extent to which the reference diet supports cognitive function across the life course, however, has not yet been evaluated. This Review assesses the evidence for diet supporting cognitive function from childhood into old age. A comprehensive but non-exhaustive literature search was done, synthesising studies that investigated the effect of whole foods on cognition in healthy, community-dwelling human participants. We found that the current evidence base is weak with mixed conclusions and multiple methodological caveats, which precludes strong conclusions pertaining to the suitability of dietary recommendations for each food group per age group. Long-term intervention and prospective cohort studies are needed to reduce this knowledge deficit. Revising dietary recommendations with the aim of maintaining an adequate nutrient intake to sustain healthy cognitive function across the life course could be worthwhile. This Review outlines recommendations for future work to help improve the current knowledge deficit regarding dietary intake and cognitive function across the life course and its implications for dietary guidelines such as the EAT-Lancet Commission.

Lipids: biomarkers of healthy aging

Life expectancy, and longevity have been increasing in recent years. However, this is, in most cases, accompanied by age-related diseases. Thus, it became essential to better understand the mechanisms inherent to aging, and to establish biomarkers that characterize this physiological process. Among all biomolecules, lipids appear to be a good target for the study of these biomarkers. In fact, some lipids have already been associated with age-related diseases. With the development of analytical techniques such as Mass Spectrometry, and Nuclear Magnetic Resonance, Lipidomics has been increasingly used to study pathological, and physiological states of an organism. Thus, the study of serum, and plasma lipidome in centenarians, and elderly individuals without age-related diseases can be a useful tool for the identification of aging biomarkers, and to understand physiological aging, and longevity. This review focus on the importance of lipids as biomarkers of aging, and summarize the changes in the lipidome that have been associated with aging, and longevity.

Serum triglycerides in Alzheimer disease: Relation to neuroimaging and CSF biomarkers

OBJECTIVE

To investigate the association of triglyceride (TG) principal component scores with Alzheimer disease (AD) and the amyloid, tau, neurodegeneration, and cerebrovascular disease (A/T/N/V) biomarkers for AD.

METHODS

Serum levels of 84 TG species were measured with untargeted lipid profiling of 689 participants from the Alzheimer's Disease Neuroimaging Initiative cohort, including 190 cognitively normal older adults (CN), 339 with mild cognitive impairment (MCI), and 160 with AD. Principal component analysis with factor rotation was used for dimension reduction of TG species. Differences in principal components between diagnostic groups and associations between principal components and AD biomarkers (including CSF, MRI and [¹⁸F]fluorodeoxyglucose-PET) were assessed with a generalized linear model approach. In both cases, the Bonferroni method of adjustment was used to correct for multiple comparisons.

RESULTS

The 84 TGs yielded 9 principal components, 2 of which, consisting of long-chain, polyunsaturated fatty acid-containing TGs (PUTGs), were significantly associated with MCI and AD. Lower levels of PUTGs were observed in MCI and AD compared to CN. PUTG principal component scores were also significantly associated with hippocampal volume and entorhinal cortical thickness. In participants carrying the APOE ε4 allele, these principal components were significantly associated with CSF β-amyloid_1-42 values and entorhinal cortical thickness.

CONCLUSION

This study shows that PUTG component scores were significantly associated with diagnostic group and AD biomarkers, a finding that was more pronounced in APOE ε4 carriers. Replication in independent larger studies and longitudinal follow-up are warranted.

Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3)), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) may benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this.

OBJECTIVES

To assess the effects of increased intake of fish- and plant-based omega-3 fats for all-cause mortality, cardiovascular events, adiposity and lipids.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to February 2019, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to August 2019, with no language restrictions. We handsearched systematic review references and bibliographies and contacted trial authors.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation or advice to increase LCn3 or ALA intake, or both, versus usual or lower intake.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression.

MAIN RESULTS

We included 86 RCTs (162,796 participants) in this review update and found that 28 were at low summary risk of bias. Trials were of 12 to 88 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most trials assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet. LCn3 doses ranged from 0.5 g a day to more than 5 g a day (19 RCTs gave at least 3 g LCn3 daily). Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.93 to 1.01; 143,693 participants; 11,297 deaths in 45 RCTs; high-certainty evidence), cardiovascular mortality (RR 0.92, 95% CI 0.86 to 0.99; 117,837 participants; 5658 deaths in 29 RCTs; moderate-certainty evidence), cardiovascular events (RR 0.96, 95% CI 0.92 to 1.01; 140,482 participants; 17,619 people experienced events in 43 RCTs; high-certainty evidence), stroke (RR 1.02, 95% CI 0.94 to 1.12; 138,888 participants; 2850 strokes in 31 RCTs; moderate-certainty evidence) or arrhythmia (RR 0.99, 95% CI 0.92 to 1.06; 77,990 participants; 4586 people experienced arrhythmia in 30 RCTs; low-certainty evidence). Increasing LCn3 may slightly reduce coronary heart disease mortality (number needed to treat for an additional beneficial outcome (NNTB) 334, RR 0.90, 95% CI 0.81 to 1.00; 127,378 participants; 3598 coronary heart disease deaths in 24 RCTs, low-certainty evidence) and coronary heart disease events (NNTB 167, RR 0.91, 95% CI 0.85 to 0.97; 134,116 participants; 8791 people experienced coronary heart disease events in 32 RCTs, low-certainty evidence). Overall, effects did not differ by trial duration or LCn3 dose in pre-planned subgrouping or meta-regression. There is little evidence of effects of eating fish. Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20; 19,327 participants; 459 deaths in 5 RCTs, moderate-certainty evidence),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25; 18,619 participants; 219 cardiovascular deaths in 4 RCTs; moderate-certainty evidence), coronary heart disease mortality (RR 0.95, 95% CI 0.72 to 1.26; 18,353 participants; 193 coronary heart disease deaths in 3 RCTs; moderate-certainty evidence) and coronary heart disease events (RR 1.00, 95% CI 0.82 to 1.22; 19,061 participants; 397 coronary heart disease events in 4 RCTs; low-certainty evidence). However, increased ALA may slightly reduce risk of cardiovascular disease events (NNTB 500, RR 0.95, 95% CI 0.83 to 1.07; but RR 0.91, 95% CI 0.79 to 1.04 in RCTs at low summary risk of bias; 19,327 participants; 884 cardiovascular disease events in 5 RCTs; low-certainty evidence), and probably slightly reduces risk of arrhythmia (NNTB 91, RR 0.73, 95% CI 0.55 to 0.97; 4912 participants; 173 events in 2 RCTs; moderate-certainty evidence). Effects on stroke are unclear. Increasing LCn3 and ALA had little or no effect on serious adverse events, adiposity, lipids and blood pressure, except increasing LCn3 reduced triglycerides by ˜15% in a dose-dependent way (high-certainty evidence).

AUTHORS' CONCLUSIONS

This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and low-certainty evidence suggests that increasing LCn3 slightly reduces risk of coronary heart disease mortality and events, and reduces serum triglycerides (evidence mainly from supplement trials). Increasing ALA slightly reduces risk of cardiovascular events and arrhythmia.

Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Researchers have suggested that omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this.

OBJECTIVES

To assess effects of increased intake of fish- and plant-based omega-3 for all-cause mortality, cardiovascular (CVD) events, adiposity and lipids.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to April 2017, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to September 2016, with no language restrictions. We handsearched systematic review references and bibliographies and contacted authors.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation and/or advice to increase LCn3 or ALA intake versus usual or lower intake.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression.

MAIN RESULTS

We included 79 RCTs (112,059 participants) in this review update and found that 25 were at low summary risk of bias. Trials were of 12 to 72 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most studies assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet. LCn3 doses ranged from 0.5g/d LCn3 to > 5 g/d (16 RCTs gave at least 3g/d LCn3).Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (RR 0.98, 95% CI 0.90 to 1.03, 92,653 participants; 8189 deaths in 39 trials, high-quality evidence), cardiovascular mortality (RR 0.95, 95% CI 0.87 to 1.03, 67,772 participants; 4544 CVD deaths in 25 RCTs), cardiovascular events (RR 0.99, 95% CI 0.94 to 1.04, 90,378 participants; 14,737 people experienced events in 38 trials, high-quality evidence), coronary heart disease (CHD) mortality (RR 0.93, 95% CI 0.79 to 1.09, 73,491 participants; 1596 CHD deaths in 21 RCTs), stroke (RR 1.06, 95% CI 0.96 to 1.16, 89,358 participants; 1822 strokes in 28 trials) or arrhythmia (RR 0.97, 95% CI 0.90 to 1.05, 53,796 participants; 3788 people experienced arrhythmia in 28 RCTs). There was a suggestion that LCn3 reduced CHD events (RR 0.93, 95% CI 0.88 to 0.97, 84,301 participants; 5469 people experienced CHD events in 28 RCTs); however, this was not maintained in sensitivity analyses - LCn3 probably makes little or no difference to CHD event risk. All evidence was of moderate GRADE quality, except as noted.Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20, 19,327 participants; 459 deaths, 5 RCTs),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25, 18,619 participants; 219 cardiovascular deaths, 4 RCTs), and CHD mortality (1.1% to 1.0%, RR 0.95, 95% CI 0.72 to 1.26, 18,353 participants; 193 CHD deaths, 3 RCTs) and ALA may make little or no difference to CHD events (RR 1.00, 95% CI 0.80 to 1.22, 19,061 participants, 397 CHD events, 4 RCTs, low-quality evidence). However, increased ALA may slightly reduce risk of cardiovascular events (from 4.8% to 4.7%, RR 0.95, 95% CI 0.83 to 1.07, 19,327 participants; 884 CVD events, 5 RCTs, low-quality evidence with greater effects in trials at low summary risk of bias), and probably reduces risk of arrhythmia (3.3% to 2.6%, RR 0.79, 95% CI 0.57 to 1.10, 4,837 participants; 141 events, 1 RCT). Effects on stroke are unclear.Sensitivity analysis retaining only trials at low summary risk of bias moved effect sizes towards the null (RR 1.0) for all LCn3 primary outcomes except arrhythmias, but for most ALA outcomes, effect sizes moved to suggest protection. LCn3 funnel plots suggested that adding in missing studies/results would move effect sizes towards null for most primary outcomes. There were no dose or duration effects in subgrouping or meta-regression.There was no evidence that increasing LCn3 or ALA altered serious adverse events, adiposity or lipids, except LCn3 reduced triglycerides by ˜15% in a dose-dependant way (high-quality evidence).

AUTHORS' CONCLUSIONS

This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. Low-quality evidence suggests ALA may slightly reduce CVD event and arrhythmia risk.

Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Evidence on the health effects of total polyunsaturated fatty acids (PUFA) is equivocal. Fish oils are rich in omega-3 PUFA and plant oils in omega-6 PUFA. Evidence suggests that increasing PUFA-rich foods, supplements or supplemented foods can reduce serum cholesterol, but may increase body weight, so overall cardiovascular effects are unclear.

OBJECTIVES

To assess effects of increasing total PUFA intake on cardiovascular disease and all-cause mortality, lipids and adiposity in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to April 2017 and clinicaltrials.gov and the World Health Organization International Clinical Trials Registry Platform to September 2016, without language restrictions. We checked trials included in relevant systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing higher with lower PUFA intakes in adults with or without cardiovascular disease that assessed effects over 12 months or longer. We included full texts, abstracts, trials registry entries and unpublished data. Outcomes were all-cause mortality, cardiovascular disease mortality and events, risk factors (blood lipids, adiposity, blood pressure), and adverse events. We excluded trials where we could not separate effects of PUFA intake from other dietary, lifestyle or medication interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts, assessed trials for inclusion, extracted data, and assessed risk of bias. We wrote to authors of included trials for further data. Meta-analyses used random-effects analysis, sensitivity analyses included fixed-effects and limiting to low summary risk of bias. We assessed GRADE quality of evidence.

MAIN RESULTS

We included 49 RCTs randomising 24,272 participants, with duration of one to eight years. Eleven included trials were at low summary risk of bias, 33 recruited participants without cardiovascular disease. Baseline PUFA intake was unclear in most trials, but 3.9% to 8% of total energy intake where reported. Most trials gave supplemental capsules, but eight gave dietary advice, eight gave supplemental foods such as nuts or margarine, and three used a combination of methods to increase PUFA.Increasing PUFA intake probably has little or no effect on all-cause mortality (risk 7.8% vs 7.6%, risk ratio (RR) 0.98, 95% confidence interval (CI) 0.89 to 1.07, 19,290 participants in 24 trials), but probably slightly reduces risk of coronary heart disease events from 14.2% to 12.3% (RR 0.87, 95% CI 0.72 to 1.06, 15 trials, 10,076 participants) and cardiovascular disease events from 14.6% to 13.0% (RR 0.89, 95% CI 0.79 to 1.01, 17,799 participants in 21 trials), all moderate-quality evidence. Increasing PUFA may slightly reduce risk of coronary heart disease death (6.6% to 6.1%, RR 0.91, 95% CI 0.78 to 1.06, 9 trials, 8810 participants) andstroke (1.2% to 1.1%, RR 0.91, 95% CI 0.58 to 1.44, 11 trials, 14,742 participants, though confidence intervals include important harms), but has little or no effect on cardiovascular mortality (RR 1.02, 95% CI 0.82 to 1.26, 16 trials, 15,107 participants) all low-quality evidence. Effects of increasing PUFA on major adverse cardiac and cerebrovascular events and atrial fibrillation are unclear as evidence is of very low quality.Increasing PUFA intake probably slightly decreases triglycerides (by 15%, MD -0.12 mmol/L, 95% CI -0.20 to -0.04, 20 trials, 3905 participants), but has little or no effect on total cholesterol (mean difference (MD) -0.12 mmol/L, 95% CI -0.23 to -0.02, 26 trials, 8072 participants), high-density lipoprotein (HDL) (MD -0.01 mmol/L, 95% CI -0.02 to 0.01, 18 trials, 4674 participants) or low-density lipoprotein (LDL) (MD -0.01 mmol/L, 95% CI -0.09 to 0.06, 15 trials, 3362 participants). Increasing PUFA probably has little or no effect on adiposity (body weight MD 0.76 kg, 95% CI 0.34 to 1.19, 12 trials, 7100 participants).Effects of increasing PUFA on serious adverse events such as pulmonary embolism and bleeding are unclear as the evidence is of very low quality.

AUTHORS' CONCLUSIONS

This is the most extensive systematic review of RCTs conducted to date to assess effects of increasing PUFA on cardiovascular disease, mortality, lipids or adiposity. Increasing PUFA intake probably slightly reduces risk of coronary heart disease and cardiovascular disease events, may slightly reduce risk of coronary heart disease mortality and stroke (though not ruling out harms), but has little or no effect on all-cause or cardiovascular disease mortality. The mechanism may be via TG reduction.

Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Evidence on the health effects of total polyunsaturated fatty acids (PUFA) is equivocal. Fish oils are rich in omega-3 PUFA and plant oils in omega-6 PUFA. Evidence suggests that increasing PUFA-rich foods, supplements or supplemented foods can reduce serum cholesterol, but may increase body weight, so overall cardiovascular effects are unclear.

OBJECTIVES

To assess effects of increasing total PUFA intake on cardiovascular disease and all-cause mortality, lipids and adiposity in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to April 2017 and clinicaltrials.gov and the World Health Organization International Clinical Trials Registry Platform to September 2016, without language restrictions. We checked trials included in relevant systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing higher with lower PUFA intakes in adults with or without cardiovascular disease that assessed effects over 12 months or longer. We included full texts, abstracts, trials registry entries and unpublished data. Outcomes were all-cause mortality, cardiovascular disease mortality and events, risk factors (blood lipids, adiposity, blood pressure), and adverse events. We excluded trials where we could not separate effects of PUFA intake from other dietary, lifestyle or medication interventions.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts, assessed trials for inclusion, extracted data, and assessed risk of bias. We wrote to authors of included trials for further data. Meta-analyses used random-effects analysis, sensitivity analyses included fixed-effects and limiting to low summary risk of bias. We assessed GRADE quality of evidence.

MAIN RESULTS

We included 49 RCTs randomising 24,272 participants, with duration of one to eight years. Eleven included trials were at low summary risk of bias, 33 recruited participants without cardiovascular disease. Baseline PUFA intake was unclear in most trials, but 3.9% to 8% of total energy intake where reported. Most trials gave supplemental capsules, but eight gave dietary advice, eight gave supplemental foods such as nuts or margarine, and three used a combination of methods to increase PUFA.Increasing PUFA intake probably has little or no effect on all-cause mortality (risk 7.8% vs 7.6%, risk ratio (RR) 0.98, 95% confidence interval (CI) 0.89 to 1.07, 19,290 participants in 24 trials), but probably slightly reduces risk of coronary heart disease events from 14.2% to 12.3% (RR 0.87, 95% CI 0.72 to 1.06, 15 trials, 10,076 participants) and cardiovascular disease events from 14.6% to 13.0% (RR 0.89, 95% CI 0.79 to 1.01, 17,799 participants in 21 trials), all moderate-quality evidence. Increasing PUFA may slightly reduce risk of coronary heart disease death (6.6% to 6.1%, RR 0.91, 95% CI 0.78 to 1.06, 9 trials, 8810 participants) andstroke (1.2% to 1.1%, RR 0.91, 95% CI 0.58 to 1.44, 11 trials, 14,742 participants, though confidence intervals include important harms), but has little or no effect on cardiovascular mortality (RR 1.02, 95% CI 0.82 to 1.26, 16 trials, 15,107 participants) all low-quality evidence. Effects of increasing PUFA on major adverse cardiac and cerebrovascular events and atrial fibrillation are unclear as evidence is of very low quality.Increasing PUFA intake slightly reduces total cholesterol (mean difference (MD) -0.12 mmol/L, 95% CI -0.23 to -0.02, 26 trials, 8072 participants) and probably slightly decreases triglycerides (MD -0.12 mmol/L, 95% CI -0.20 to -0.04, 20 trials, 3905 participants), but has little or no effect on high-density lipoprotein (HDL) (MD -0.01 mmol/L, 95% CI -0.02 to 0.01, 18 trials, 4674 participants) or low-density lipoprotein (LDL) (MD -0.01 mmol/L, 95% CI -0.09 to 0.06, 15 trials, 3362 participants). Increasing PUFA probably causes slight weight gain (MD 0.76 kg, 95% CI 0.34 to 1.19, 12 trials, 7100 participants).Effects of increasing PUFA on serious adverse events such as pulmonary embolism and bleeding are unclear as the evidence is of very low quality.

AUTHORS' CONCLUSIONS

This is the most extensive systematic review of RCTs conducted to date to assess effects of increasing PUFA on cardiovascular disease, mortality, lipids or adiposity. Increasing PUFA intake probably slightly reduces risk of coronary heart disease and cardiovascular disease events, may slightly reduce risk of coronary heart disease mortality and stroke (though not ruling out harms), but has little or no effect on all-cause or cardiovascular disease mortality. The mechanism may be via lipid reduction, but increasing PUFA probably slightly increases weight.

Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease

BACKGROUND

Researchers have suggested that omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this.

OBJECTIVES

To assess effects of increased intake of fish- and plant-based omega-3 for all-cause mortality, cardiovascular (CVD) events, adiposity and lipids.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to April 2017, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to September 2016, with no language restrictions. We handsearched systematic review references and bibliographies and contacted authors.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation and/or advice to increase LCn3 or ALA intake versus usual or lower intake.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression.

MAIN RESULTS

We included 79 RCTs (112,059 participants) in this review update and found that 25 were at low summary risk of bias. Trials were of 12 to 72 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most studies assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet.Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (RR 0.98, 95% CI 0.90 to 1.03, 92,653 participants; 8189 deaths in 39 trials, high-quality evidence), cardiovascular mortality (RR 0.95, 95% CI 0.87 to 1.03, 67,772 participants; 4544 CVD deaths in 25 RCTs), cardiovascular events (RR 0.99, 95% CI 0.94 to 1.04, 90,378 participants; 14,737 people experienced events in 38 trials, high-quality evidence), coronary heart disease (CHD) mortality (RR 0.93, 95% CI 0.79 to 1.09, 73,491 participants; 1596 CHD deaths in 21 RCTs), stroke (RR 1.06, 95% CI 0.96 to 1.16, 89,358 participants; 1822 strokes in 28 trials) or arrhythmia (RR 0.97, 95% CI 0.90 to 1.05, 53,796 participants; 3788 people experienced arrhythmia in 28 RCTs). There was a suggestion that LCn3 reduced CHD events (RR 0.93, 95% CI 0.88 to 0.97, 84,301 participants; 5469 people experienced CHD events in 28 RCTs); however, this was not maintained in sensitivity analyses - LCn3 probably makes little or no difference to CHD event risk. All evidence was of moderate GRADE quality, except as noted.Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20, 19,327 participants; 459 deaths, 5 RCTs),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25, 18,619 participants; 219 cardiovascular deaths, 4 RCTs), and it may make little or no difference to CHD events (RR 1.00, 95% CI 0.80 to 1.22, 19,061 participants, 397 CHD events, 4 RCTs, low-quality evidence). However, increased ALA may slightly reduce risk of cardiovascular events (from 4.8% to 4.7%, RR 0.95, 95% CI 0.83 to 1.07, 19,327 participants; 884 CVD events, 5 RCTs, low-quality evidence), and probably reduces risk of CHD mortality (1.1% to 1.0%, RR 0.95, 95% CI 0.72 to 1.26, 18,353 participants; 193 CHD deaths, 3 RCTs), and arrhythmia (3.3% to 2.6%, RR 0.79, 95% CI 0.57 to 1.10, 4,837 participants; 141 events, 1 RCT). Effects on stroke are unclear.Sensitivity analysis retaining only trials at low summary risk of bias moved effect sizes towards the null (RR 1.0) for all LCn3 primary outcomes except arrhythmias, but for most ALA outcomes, effect sizes moved to suggest protection. LCn3 funnel plots suggested that adding in missing studies/results would move effect sizes towards null for most primary outcomes. There were no dose or duration effects in subgrouping or meta-regression.There was no evidence that increasing LCn3 or ALA altered serious adverse events, adiposity or lipids, although LCn3 slightly reduced triglycerides and increased HDL. ALA probably reduces HDL (high- or moderate-quality evidence).

AUTHORS' CONCLUSIONS

This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. Low-quality evidence suggests ALA may slightly reduce CVD event risk, CHD mortality and arrhythmia.

Nutrition practices and knowledge among NCAA Division III football players

Background

Participation in collegiate American football is physically demanding and may have long-term health implications, particularly in relation to cardiovascular and neurological health. National Collegiate Athletic Association (NCAA) Division III (DIII) football players are a relatively unstudied population, particularly in terms of their dietary habits and knowledge. The aim of the present study was to descriptively evaluate the dietary intake of DIII football players including a subset of linemen and assess the nutritional knowledge and sources of information of these athletes.

Methods

The study sample was 88 DIII football players including a subset of nine linemen. All participants completed a food frequency questionnaire, and a nutritional knowledge questionnaire that included a quiz and questions about their main sources of nutrition information. Heights and body masses were also recorded. The linemen submitted written 3-day diet records for assessment of their dietary intake.

Results

Of the 88 participants, >50% reported consuming starches/grains, meat and dairy daily, but <50% reported consuming fruits and vegetables daily. Protein powders were the most commonly used supplements (33% reported daily use). Compared to dietary recommendations, linemen consumed high amounts of total fat, saturated fat, dietary cholesterol, sodium, and potassium, but were low in carbohydrates, fiber, and essential fats. The mean nutrition knowledge quiz score for the 88 participants was 55.2%. Those who had taken a nutrition or health course in college scored significantly higher on the quiz than those who had not. Participants reported relying primarily on coaches, websites, and athletic trainers (ATs) for nutritional guidance; ATs were the most trusted source.

Conclusions

DIII football players had dietary habits that may both mitigate and increase their risk of chronic diseases. These athletes have room to improve their nutrition knowledge. Their reliance on athletic team staff for nutrition guidance highlights the importance of nutrition education for both athletes and staff and the potential role of a registered dietitian nutritionist.

Electronic supplementary material

The online version of this article (doi:10.1186/s12970-017-0170-2) contains supplementary material, which is available to authorized users.

Cognition and Indicators of Dietary Habits in Older Adults from Southern Brazil

OBJECTIVE

To assess the association between unhealthy dietary habits and cognition in older adults from Southern Brazil.

METHODS

This cross-sectional study analyzed data from the second wave of a population- and household-based epidemiological survey (2013-2014) conducted in the city of Florianópolis. A total of 1,197 older adults (778 women) over 60 years old participated in the study. Cognition, the dependent variable, was measured by the Mini-Mental State Examination (MMSE). The independent variables were the following indicators of unhealthy dietary habits: low intake of fruits and vegetables (≤ 4 servings/day); fish (< 1 serving/week); and habitual fatty meat intake (yes/no). Adjustments were made for age, education level, income, smoking status, alcohol intake, leisure-time physical activity, depression symptoms, chronic diseases, and body mass index. Simple and multiple linear regression analyses were performed, considering sampling weights and stratification by gender.

RESULTS

The mean MMSE scores for men and women were 25.15 ± 5.56 and 24.26 ± 5.68, respectively (p = 0.009). After adjustments, in women low fruit and vegetable intake (≤ 4 servings/day) was independently associated with the lowest MMSE scores. No associations were found in men. Additionally, women's mean MMSE scores increased as their daily frequency of fruit and vegetable intake increased (p = 0.001).

CONCLUSION

Women with low fruit and vegetable intake according to the World Health Organization (WHO) have lower cognition scores. Regular intake of fruits, vegetables, and fish in exchange of fatty meats may be a viable public policy strategy to preserve cognition in aging.

Intakes of fish and polyunsaturated fatty acids and mild-to-severe cognitive impairment risks: a dose-response meta-analysis of 21 cohort studies

BACKGROUND

The intake of fish and polyunsaturated fatty acids (PUFAs) may benefit cognitive function. However, optimal intake recommendations for protection are unknown.

OBJECTIVE

We systematically investigated associations between fish and PUFA intake and mild-to-severe cognitive impairment risk.

DESIGN

Studies that reported risk estimates for mild cognitive impairment (MCI), cognitive decline, dementia, Alzheimer disease (AD), or Parkinson disease (PD) from fish, total PUFAs, total n-3 (ω-3) PUFAs, or at least one n-3 PUFA were included. Study characteristics and outcomes were extracted. The pooled RR was estimated with the use of a random-effects model meta-analysis. A dose-response analysis was conducted with the use of the 2-stage generalized least-squares trend program.

RESULTS

We included 21 studies (181,580 participants) with 4438 cases identified during follow-up periods (2.1-21 y). A 1-serving/wk increment of dietary fish was associated with lower risks of dementia (RR: 0.95; 95% CI: 0.90, 0.99; P = 0.042, I(2) = 63.4%) and AD (RR: 0.93; 95% CI: 0.90, 0.95; P = 0.003, I(2) = 74.8%). Pooled RRs of MCI and PD were 0.71 (95% CI: 0.59, 0.82; P = 0.733, I(2) = 0%) and 0.90 (95% CI: 0.80, 0.99; P = 0.221, I(2) = 33.7%), respectively, for an 8-g/d increment of PUFA intake. As an important source of marine n-3 PUFAs, a 0.1-g/d increment of dietary docosahexaenoic acid (DHA) intake was associated with lower risks of dementia (RR: 0.86; 95% CI: 0.76, 0.96; P < 0.001, I(2) = 92.7%) and AD (RR: 0.63; 95% CI: 0.51, 0.76; P < 0.001, I(2) = 94.5%). Significant curvilinear relations between fish consumption and risk of AD and between total PUFAs and risk of MCI (both P-nonlinearity < 0.001) were observed.

CONCLUSIONS

Fishery products are recommended as dietary sources and are associated with lower risk of cognitive impairment. Marine-derived DHA was associated with lower risk of dementia and AD but without a linear dose-response relation.

Understanding the gastrointestinal tract of the elderly to develop dietary solutions that prevent malnutrition

Although the prevalence of malnutrition in the old age is increasing worldwide a synthetic understanding of the impact of aging on the intake, digestion, and absorption of nutrients is still lacking. This review article aims at filling the gap in knowledge between the functional decline of the aging gastrointestinal tract (GIT) and the consequences of malnutrition on the health status of elderly. Changes in the aging GIT include the mechanical disintegration of food, gastrointestinal motor function, food transit, chemical food digestion, and functionality of the intestinal wall. These alterations progressively decrease the ability of the GIT to provide the aging organism with adequate levels of nutrients, what contributes to the development of malnutrition. Malnutrition, in turn, increases the risks for the development of a range of pathologies associated with most organ systems, in particular the nervous-, muscoskeletal-, cardiovascular-, immune-, and skin systems. In addition to psychological, economics, and societal factors, dietary solutions preventing malnutrition should thus propose dietary guidelines and food products that integrate knowledge on the functionality of the aging GIT and the nutritional status of the elderly. Achieving this goal will request the identification, validation, and correlative analysis of biomarkers of food intake, nutrient bioavailability, and malnutrition.

Docosahexaenoic acid and adult memory: a systematic review and meta-analysis

Introduction

Subjective memory complaints are common with aging. Docosahexaenoic acid (DHA; 22:6 n-3) is a long-chain polyunsaturated fatty acid (LCPUFA) and an integral part of neural membrane phospholipids that impacts brain structure and function. Past research demonstrates a positive association between DHA plasma status/dietary intake and cognitive function.

Objectives

The current meta-analysis was designed to determine the effect of DHA intake, alone or combined with eicosapentaenoic acid (EPA; 20:5 n-3), on specific memory domains: episodic, working, and semantic in healthy adults aged 18 years and older. A secondary objective was to systematically review/summarize the related observational epidemiologic literature.

Methods

A systematic literature search of clinical trials and observational studies that examined the relationship between n-3 LCPUFA on memory outcomes in healthy adults was conducted in Ovid MEDLINE and EMBASE databases. Studies of subjects free of neurologic disease at baseline, with or without mild memory complaints (MMC), were included. Random effects meta-analyses were conducted to generate weighted group mean differences, standardized weighted group mean differences (Hedge’s g), z-scores, and p-values for heterogeneity comparing DHA/EPA to a placebo. A priori sub-group analyses were conducted to evaluate the effect of age at enrollment, dose level, and memory type tested.

Results

Episodic memory outcomes of adults with MMC were significantly (P<.004) improved with DHA/EPA supplementation. Regardless of cognitive status at baseline, > 1 g/day DHA/EPA improved episodic memory (P<.04). Semantic and working memory changes from baseline were significant with DHA but no between group differences were detected. Observational studies support a beneficial association between intake/blood levels of DHA/EPA and memory function in older adults.

Conclusion

DHA, alone or combined with EPA, contributes to improved memory function in older adults with mild memory complaints.

Reduced anxiety in forensic inpatients after a long-term intervention with Atlantic salmon

The aim of the present study was to investigate the effects of Atlantic salmon consumption on underlying biological mechanisms associated with anxiety such as heart rate variability (HRV) and heart rate (HR) as well as a measure of self-reported anxiety. Moreover, these biological and self-reported outcome measures were investigated in relation to specific nutrients; vitamin D status, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Ninety-five male forensic inpatients were randomly assigned into a Fish (Atlantic salmon three times per week from September to February) or a Control group (alternative meal, e.g., chicken, pork, or beef three times per week during the same period). HRV measured as the root mean square of successive differences (rMSSD), HR, state- and trait-anxiety (STAI), were assessed before (pre-test) and at the end of the 23 weeks dietary intervention period (post-test). The Fish group showed significant improvements in both rMSSD and HR. The Fish group also showed significant decreases in state-anxiety. Finally, there was a positive relationship between rMSSD and vitamin D status. The findings suggest that Atlantic salmon consumption may have an impact on mental health related variables such as underlying mechanisms playing a key role in emotion-regulation and state-anxiety.

Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis

Background

Cognitive impairment, including dementia, is a major health concern with the increasing aging population. Preventive measures to delay cognitive decline are of utmost importance. Alzheimer’s disease (AD) is the most frequent cause of dementia, increasing in prevalence from <1% below the age of 60 years to >40% above 85 years of age.

Methods

We systematically reviewed selected modifiable factors such as education, smoking, alcohol, physical activity, caffeine, antioxidants, homocysteine (Hcy), n-3 fatty acids that were studied in relation to various cognitive health outcomes, including incident AD. We searched MEDLINE for published literature (January 1990 through October 2012), including cross-sectional and cohort studies (sample sizes > 300). Analyses compared study finding consistency across factors, study designs and study-level characteristics. Selecting studies of incident AD, our meta-analysis estimated pooled risk ratios (RR), population attributable risk percent (PAR%) and assessed publication bias.

Results

In total, 247 studies were retrieved for systematic review. Consistency analysis for each risk factor suggested positive findings ranging from ~38.9% for caffeine to ~89% for physical activity. Education also had a significantly higher propensity for “a positive finding” compared to caffeine, smoking and antioxidant-related studies. Meta-analysis of 31 studies with incident AD yielded pooled RR for low education (RR = 1.99; 95% CI: 1.30-3.04), high Hcy (RR = 1.93; 95% CI: 1.50-2.49), and current/ever smoking status (RR = 1.37; 95% CI: 1.23-1.52) while indicating protective effects of higher physical activity and n-3 fatty acids. Estimated PAR% were particularly high for physical activity (PAR% = 31.9; 95% CI: 22.7-41.2) and smoking (PAR%=31.09%; 95% CI: 17.9-44.3). Overall, no significant publication bias was found.

Conclusions

Higher Hcy levels, lower educational attainment, and decreased physical activity were particularly strong predictors of incident AD. Further studies are needed to support other potential modifiable protective factors, such as caffeine.

Current evidence and future perspectives on n-3 PUFAs

The family of polyunsaturated fatty acids (PUFAs), which can be found in most lipid classes, includes n-3 PUFAs essential for mammals and whose deficiency is associated with multiple diseases. Because of their multiple physiological actions, n-3 PUFAs play a crucial role in normal human metabolism as well as maintenance of a healthy status, with clinical effects that are not limited to the cardiovascular system but also include maternal and offspring health, growth and development, immune system disorders, cancer, cognitive function and psychological status. Multiple health organisations and scientific societies recommend increasing food-derived n-3 PUFA intake and also suggest that patients with documented coronary heart disease receive a minimum of 1000 mg/day of eicosapentaenoic acid and docosahexaenoic acid. The preventive and therapeutic effects of n-3 PUFAs appear to be largely dependent on the dosages employed and the characteristics of selected patients. So, in the era of personalised medicine, the time has come to move from generic advice to increase n-3 PUFA intake to a more evidence-based approach characterised by tailored indications to n-3 PUFA dietary or supplement consumption. This approach will require evaluation on a case-to-case basis the potential usefulness of n-3 PUFAs, taking into consideration their 'pleiotropic effects', the optimal dose for any given indication in relation to international guidelines, potential interactions with background therapy, possible side effects, differences in genetics and dietary response to supplementation, and the cost:benefit ratio, which is likely to vary as a function of differences in the range of fish intake in the diet.

Subjective cognitive impairment

PURPOSE OF REVIEW

To describe the recent (2011-2012) literature relevant to subjective cognitive impairment (SCI), focusing principally on studies of this symptom in older age groups. This is an issue of growing importance: although the symptom itself is controversial in older people because of variable associations with objective cognitive impairment, it remains one of the few presenting complaints which may identify people experiencing early cognitive decline.

RECENT FINDINGS

Several neuroimaging studies confirm earlier reports of associations between SCI and underlying abnormalities whereas those between subjective and objective cognitive function remain heterogeneous. Several studies now highlight the fact that, regardless of underlying associations, SCI as a symptom is associated with significant concern but is something for which older people rarely seek help.

SUMMARY

Neuroimaging findings suggest that older people may be more aware of underlying brain changes than was previously apparent or than can be detected using conventional neuropsychological assessments. However, not all of these brain changes are necessarily progressive or neurodegenerative. At least some attention should be paid to interventions for what is a common, often distressing, but underreported symptom.

Omega 3 fatty acids and cognitive health in older people

Oily fish and other sources of long-chain n-3 polyunsaturated fatty acids (n-3 LCPs) have been proposed as protective against dementia and age related cognitive impairment. The basic mechanisms underlying these proposed benefits have been postulated and experimental studies supporting the plausibility of the putative effects have been published. Observational epidemiological and case control studies also largely support a protective role of fish consumption on cognitive function with advancing age, albeit with important unexplained heterogeneity in findings. In this review we report the findings of the latest Cochrane review on the benefits of n-3 LCP supplementation on cognitive function among cognitively healthy older people and expand the review by including trials conducted with individuals with prevalent poor cognitive function or dementia. We identified seven relevant trials, four among cognitively healthy older people, and three among individuals with pre-existing cognitive decline or dementia, and overall conclude that there is no evidence to support the routine use of n-3 LCPs supplements for the prevention, or amelioration, of cognitive decline in later life. We identified several challenges in the design of intervention studies for the prevention of dementia and cognitive decline in older people that require careful consideration especially in recruitment and retention in long-term trials. Whether the lack of agreement in findings from mechanistic and observational data and from intervention studies reflects a real absence of benefit on cognitive function from n-3 LCP supplementation, or whether it reflects intrinsic limitations in the design of published studies remains open to question.

Polyunsaturated fatty acids as putative cognitive enhancers

Polyunsaturated essential fatty acids (PUFAs) play a pivotal role in mediating cognitive, learning, and memory functions. We propose that PUFAs directly affect the neuronal membrane. PUFAs serve to stabilize and protect the structure and functions of the neuronal membrane. PUFAs exert many effects on the brain with respect to physiology, brain biochemistry, and disorders of the central nervous system. Many of these functions have effects at the cognitive level. This summary demonstrates that a deficiency in brain PUFAs will lead to cognitive deficits, while supplementation of PUFAs can rehabilitate cognitive deficits, as manifested in attention deficit hyperactivity disorder, stress/anxiety, and aging.

Long term adequate n-3 polyunsaturated fatty acid diet protects from depressive-like behavior but not from working memory disruption and brain cytokine expression in aged mice

Converging epidemiological studies suggest that dietary essential n-3 polyunsaturated fatty acid (PUFA) are likely to be involved in the pathogenesis of mood and cognitive disorders linked to aging. The question arises as to whether the decreased prevalence of these symptoms in the elderly with high n-3 PUFA consumption is also associated with improved central inflammation, i.e. cytokine activation, in the brain. To answer this, we measured memory performance and emotional behavior as well as cytokine synthesis and PUFA level in the spleen and the cortex of adult and aged mice submitted to a diet with an adequate supply of n-3 PUFA in form of α-linolenic acid (α-LNA) or a n-3 deficient diet. Our results show that docosahexaenoic acid (DHA), the main n-3 PUFA in the brain, was higher in the spleen and cortex of n-3 adequate mice relative to n-3 deficient mice and this difference was maintained throughout life. Interestingly, high level of brain DHA was associated with a decrease in depressive-like symptoms throughout aging. On the opposite, spatial memory was maintained in adult but not in aged n-3 adequate mice relative to n-3 deficient mice. Furthermore, increased interleukin-6 (IL-6) and decreased IL-10 expression were found in the cortex of aged mice independently of the diets. All together, our results suggest that n-3 PUFA dietary supply in the form of α-LNA is sufficient to protect from deficits in emotional behavior but not from memory disruption and brain proinflammatory cytokine expression linked to age.

Identifying built environmental patterns using cluster analysis and GIS: relationships with walking, cycling and body mass index in French adults

Background

Socio-ecological models suggest that both individual and neighborhood characteristics contribute to facilitating health-enhancing behaviors such as physical activity. Few European studies have explored relationships between local built environmental characteristics, recreational walking and cycling and weight status in adults. The aim of this study was to identify built environmental patterns in a French urban context and to assess associations with recreational walking and cycling behaviors as performed by middle-aged adult residents.

Methods

We used a two-step procedure based on cluster analysis to identify built environmental patterns in the region surrounding Paris, France, using measures derived from Geographic Information Systems databases on green spaces, proximity facilities (destinations) and cycle paths. Individual data were obtained from participants in the SU.VI.MAX cohort; 1,309 participants residing in the Ile-de-France in 2007 were included in this analysis. Associations between built environment patterns, leisure walking/cycling data (h/week) and measured weight status were assessed using multinomial logistic regression with adjustment for individual and neighborhood characteristics.

Results

Based on accessibility to green spaces, proximity facilities and availability of cycle paths, seven built environmental patterns were identified. The geographic distribution of built environmental patterns in the Ile-de-France showed that a pattern characterized by poor spatial accessibility to green spaces and proximity facilities and an absence of cycle paths was found only in neighborhoods in the outer suburbs, whereas patterns characterized by better spatial accessibility to green spaces, proximity facilities and cycle paths were more evenly distributed across the region. Compared to the reference pattern (poor accessibility to green areas and facilities, absence of cycle paths), subjects residing in neighborhoods characterized by high accessibility to green areas and local facilities and by a high density of cycle paths were more likely to walk/cycle, after adjustment for individual and neighborhood sociodemographic characteristics (OR = 2.5 95%CI 1.4-4.6). Body mass index did not differ across patterns.

Conclusions

Built environmental patterns were associated with walking and cycling among French adults. These analyses may be useful in determining urban and public health policies aimed at promoting a healthy lifestyle.

Omega 3 fatty acids in the elderly

Population ageing affects the entire world population. Also at world level one can observe a sharp increase in the proportion of older people. The challenge posed by population ageing translates into ensuring that the extra years of life will be as good as possible, free from high-cost dependency. Omega-3 fatty acids are now generally recognized as potential key nutrients to prevent the pathological conditions associated to the aging process. Ageing physiological process, its association with quality of life and the impact of omega-3 fatty acids intake and/or status is the focus of the present review. This report deals with the effects of omega-3 fatty acids on normal aging of older adults ( ≥  65 years) mainly on the effects such as nutritional status itself, cognition, bone health, muscle tonus, and general health status. The preliminary broad search of the literature on the effects of omega-3 fatty acids on normal aging yielded 685 citations. Forty two full text papers were checked for inclusion and thirty six studies were finally included in this review. It may be concluded that paradoxically even though the elderly population is the largest one, the number of studies and the methodology employed clearly lacks of sufficient evidence to establish definite conclusions on the effects of omega-3 fatty acids on aging metabolism without pathological conditions and on quality of life.

Supplementation with DHA and the psychological functioning of young adults

The grey matter of the brain contains high levels of the essential nutrient DHA. Although the role of DHA in the developing brain and in dementia has attracted attention, its influence on the brain of the healthy adult has been little considered. A total of 285 young adult females took 400 mg of DHA, in a double-blind, placebo-controlled trial, for 50 d. After 50 d, recently acquired information was more likely to be forgotten by those who had consumed DHA. No significant differences in mood, reaction times, vigilance or visual acuity were found.