Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: a systematic review and meta-analysis of randomised trials

Background There is strong public belief that polyunsaturated fats protect against and ameliorate depression and anxiety. Aims To assess effects of increasing omega-3, omega-6 or total polyunsaturated fat on prevention and treatment of depression and anxiety symptoms. Method We searched widely (Central, Medline and EMBASE to April 2017, trial registers to September 2016, ongoing trials updated to August 2019), including trials of adults with or without depression or anxiety, randomised to increased omega-3, omega-6 or total polyunsaturated fat for ≥24 weeks, excluding multifactorial interventions. Inclusion, data extraction and risk of bias were assessed independently in duplicate, and authors contacted for further data. We used random-effects meta-analysis, sensitivity analyses, subgrouping and Grading of Recommendations, Assessment, Development and Evaluations (GRADE) assessment. Results We included 31 trials assessing effects of long-chain omega-3 (n = 41 470), one of alpha-linolenic acid (n = 4837), one of total polyunsaturated fat (n = 4997) and none of omega-6. Meta-analysis suggested that increasing long-chain omega-3 probably has little or no effect on risk of depression symptoms (risk ratio 1.01, 95% CI 0.92-1.10, I2 = 0%, median dose 0.95 g/d, duration 12 months) or anxiety symptoms (standardised mean difference 0.15, 95% CI 0.05-0.26, I2 = 0%, median dose 1.1 g/d, duration 6 months; both moderate-quality evidence). Evidence of effects on depression severity and remission in existing depression were unclear (very-low-quality evidence). Results did not differ by risk of bias, omega-3 dose, duration or nutrients replaced. Increasing alpha-linolenic acid by 2 g/d may increase risk of depression symptoms very slightly over 40 months (number needed to harm, 1000). Conclusions Long-chain omega-3 supplementation probably has little or no effect in preventing depression or anxiety symptoms. Declaration of interest L.H. and A.A. were funded to attend the World Health Organization Nutrition Guidance Expert Advisory Group (NUGAG) Subgroup on Diet and Health meetings and present review results. The authors report no other conflicts of interest

Social prescribing programmes to prevent or delay frailty in community-dwelling older adults

The increasing incidence of frailty is a health and social care challenge. Social prescription is advocated as an important approach to allow health professionals to link patients with sources of support in the community. This study aimed to determine the current evidence on the effectiveness of social prescribing programmes to delay or reduce frailty in frail older adults living in the community. A systematic literature review of published (DARE, Cochrane Database of Systematic Reviews, MEDLINE, EMBASE, CINAHL, NICE and SCIE, NHS Economic Evaluation Database) and unpublished databases (OpenGrey; WHO Clinical Trial Registry; ClinicalTrials.gov) were searched to July 2019. Studies were eligible if they reported health, social or economic outcomes on social prescribing, community referral, referral schemes, wellbeing programmes or interventions when a non-health link worker was the intervention provider to people who are frail living in the community. 1079 unique studies were screened for eligibility. No papers were eligible. There is therefore a paucity of evidence reporting the effectiveness of social prescribing programmes for frail older adults living in the community. Given that frailty is a clinical priority and social prescribing is considered a key future direction in the provision of community care, this is a major limitation

Omega-3, omega-6 and polyunsaturated fat for cognition: systematic review & meta-analysis of randomised trials

Objectives: Neurocognitive function may be influenced by polyunsaturated fat intake. Many older adults consume omega-3 supplements hoping to prevent cognitive decline. We assessed effects of increasing omega-3, omega-6, or total polyunsaturated fats on new neurocognitive illness and cognition. Design and inclusion criteria: We carried out a systematic review and meta-analysis of randomized controlled trials (RCTs) in adults, with duration ≥24 weeks, assessing effects of higher vs lower omega-3, omega-6, or total polyunsaturated fats and outcomes: new neurocognitive illness, newly impaired cognition, and/or continuous measures of cognition.  Methods: We searched MEDLINE, Embase, Cochrane CENTRAL, and trials registers (final update of ongoing trials December 2018). We duplicated screening, data extraction, and risk of bias assessment. Neurocognitive measures were grouped to enable random effects meta-analysis. GRADE assessment, sensitivity analyses, and subgrouping by dose, duration, type of intervention, and replacement were used to interrogate our findings.  Results: Searches generated 37,810 hits, from which we included 38 RCTs (41 comparisons, 49,757 participants). Meta-analysis suggested no or very little effect of long-chain omega-3 on new neurocognitive illness [risk ratio (RR) 0.98, 95% confidence interval (CI) 0.87-1.10, 6 RCTs, 33,496 participants, I 2 36%), new cognitive impairment (RR 0.99, 95% CI 0.92-1.06, 5 RCTs, 33,296 participants, I 2 0%) or global cognition assessed using the Mini-Mental State Examination (MD 0.10, 95% CI 0.03-0.16, 13 RCTs, 14,851 participants, I 2 0%), all moderate-quality evidence. Effects did not differ with sensitivity analyses, and we found no differential effects by dose, duration, intervention type, or replacement. Effects of increasing α-linolenic acid, omega-6, or total PUFA were unclear.  Conclusions: This extensive trial data set enabled assessment of effects on neurocognitive illness and cognitive decline not previously adequately assessed. Long-chain omega-3 probably has little or no effect on new neurocognitive outcomes or cognitive impairment. Implications: Long-chain omega-3 supplements do not help older adults protect against cognitive decline

Effect of reducing total fat intake on body weight: a review of the evidence

A variety of mechanisms and genetic associations suggest that total dietary fat intake may influence body weight and risk of being overweight. Long-term RCTs suggest that reducing total fat intake (in people of normal body weight and without any intention to reduce body weight) causes a small reduction in body weight. Meta-analysis suggests that the effect of eating less than 30% of energy from fat, compared with higher fat intake, is a mean weight reduction of 1.4 kg (95% confidence interval (CI) 1.7 to 1.1 kg, in 53 875 participants from 26 RCTs, I2¼75%). Greater fat reduction results in greater weight loss. Similar effects were seen on BMI, waist circumference and body fatness, and small improvements in lipids and blood pressure were also seen. This relationship between dietary fat and weight was confirmed in a 6-month isocaloric controlled feeding trial from China. The three trials of low-fat interventions in children suggest small reductions in BMI with a lower fat diet, but data quality was low. On the other hand, in overweight or obese adults trying to lose weight, macronutrient composition appears fairly unimportant, and weight loss depends on adherence to calorie restriction

Protecting and empowering adults with capacity-affecting conditions to take part in health and health-related research

Health research is essential if people are to enjoy the highest attainable standard of health and healthcare. Yet, persons with capacity-affecting conditions are routinely excluded from research, as they are often judged to lack the capacity to give consent. Focusing on the Mental Capacity Act England and Wales 2005 (MCA), which regulates research involving adults judged to lack capacity, we outline the provision of the MCA and then describe the process of ethical review designed to ensure compliance with these provisions; 2) present findings from interviews with members of the committees responsible for ethical review and with researchers, who have experience of working with the MCA; 3) discuss the implications of these findings for the inclusion of adults lacking capacity in research as well as drawing conclusions about the effectiveness of the MCA

Inclusion of adults with conditions that have the potential to affect capacity and/or communication in research: triangulation from a mixed methods study of current practice and values across multiple stakeholders

Objectives: We aimed to: (a) describe researcher decision-making when including or excluding adults with conditions that have the potential to affect capacity and/or communication in research, and (b) explore the underlying values and reasoning of stakeholders in research which falls under the provisions of the Mental Capacity Act, 2005. Design: The mixed methods design included semi-structured interviews with adults with conditions that have the potential to affect capacity and/or communication, supporters, researchers, Research Ethics Committee members and an online survey with researchers. Triangulation was used to integrate the data and examine the complementarity of the findings. Setting: England and Wales. Participants: There were 61 participants who took part in semi-structured interviews, of which 39 were adults with conditions with potential to affect capacity and/or communication, 6 were in support roles for adults with conditions with potential to affect capacity and/or communication (including family members and professionals in advocacy organisations), 8 were members of Research Ethics Committees flagged under the Mental Capacity Act to review research where there could be issues of mental capacity and 8 were researchers with experience of working with adults with conditions that have the potential to affect capacity and/or communication. The online survey had 128 participants, researchers with experience of working with adults with conditions that have the potential to affect capacity and/or communication. Results: All stakeholders were supportive of the genuine inclusion of adults with conditions that have the potential to affect capacity and/or communication in research, and exclusion was seen as a form of discrimination. Many researchers were daunted by meeting the threshold within the legislation for including participants who may lack capacity. Conclusion: Further training, expertise, and resource is required to promote the successful inclusion in research of adults with conditions that have the potential to affect capacity and/or communication

Inclusion of adults with conditions that have the potential to affect capacity and or communication in research: triangulation from a mixed-methods study of current practice and values across multiple stakeholders

Objectives We aimed to: (A) describe researcher decision-making when including or excluding adults with conditions that have the potential to affect capacity and/or communication in research and (B) explore the underlying values and reasoning of stakeholders in research which falls under the provisions of the Mental Capacity Act, 2005.Design The mixed-methods design included semistructured interviews with adults with conditions that have the potential to affect capacity and/or communication, supporters, researchers, research ethics committee members and an online survey with researchers. Triangulation was used to integrate the data and examine the complementarity of the findings.Setting England and Wales.Participants There were 61 participants who took part in semistructured interviews, of which 39 were adults with conditions with potential to affect capacity and/or communication, 6 were in support roles for adults with conditions with potential to affect capacity and/or communication (including family members and professionals in advocacy organisations), 8 were members of research ethics committees flagged under the Mental Capacity Act to review research where there could be issues of mental capacity and 8 were researchers with experience of working with adults with conditions that have the potential to affect capacity and/or communication. The online survey had 128 participants, researchers with experience of working with adults with conditions that have the potential to affect capacity and/or communication.Results All stakeholders were supportive of the genuine inclusion of adults with conditions that have the potential to affect capacity and/or communication in research, and exclusion was seen as a form of discrimination. Many researchers were daunted by meeting the threshold within the legislation for including participants who may lack capacity.Conclusion Further training, expertise and resources are required to promote the successful inclusion in research of adults with conditions that have the potential to affect capacity and/or communication