Perspective: Advancing Dietary Guidance for Cognitive Health-Focus On Solutions to Harmonize Test Selection, Implementation, and Evaluation.

This perspective article is a product of a workshop of experts convened by the Institute for the Advancement of Food and Nutrition Sciences (IAFNS), a nonprofit organization that brings together scientists from government, academia, and industry to catalyze science relevant to food and nutrition for public benefit. An expert group was convened in March 2022 to discuss the current issues surrounding cognitive task selection in nutrition research, with a focus on solutions toward informing dietary guidance for cognitive health, to address a gap identified in the 2020 United States Dietary Guidelines Advisory Committee report, specifically the "considerable variation in testing methods used, [and] inconsistent validity and reliability of cognitive testing methods." To address this issue, we first undertook an umbrella review of relevant reviews already undertaken; these indicate agreement on some of the issues that affect heterogeneity in task selection, and on many of the fundamental principles underlying the selection of cognitive outcome measures. However, resolving the points of disagreement is critical to ensuring a meaningful impact on the issue of heterogeneity in task selection; these issues hamper the evaluation of existing data for informing dietary guidance. This summary of the literature is therefore followed by the expert group's perspective in the form of a discussion of potential solutions to these challenges, with the aim of building on the work of previous reviews in the area and advancing dietary guidance for cognitive health. Registered on PROSPERO: CRD42022348106. Data described in the manuscript, code book, and analytic code will be made publicly and freely available without restriction at doi.org/10.17605/OSF.IO/XRZCK.

Multinutrients for the Treatment of Psychiatric Symptoms in Clinical Samples: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

This systematic review and meta-analysis focused on randomized controlled trials (RCT) of multinutrients consisting of at least four vitamins and/or minerals as interventions for participants with psychiatric symptoms. A systematic search identified 16 RCTs that fit the inclusion criteria (n = 1719 participants) in six psychiatric categories: depression, post-disaster stress, antisocial behavior, behavioral deficits in dementia, attention-deficit/hyperactivity disorder, and autism. Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to rate the evidence base. Significant clinical benefit was assessed using minimal clinically important differences (MIDs). Due to heterogeneity in participants, multinutrient formulas, outcome measures, and absence of complete data, only the Attention-Deficit/Hyperactivity Disorder (ADHD) category was eligible for meta-analyses. In ADHD populations, statistically and clinically significant improvements were found in global functioning, Mean Difference (MD) -3.3, p = 0.001, MID -3.26; Standardized Mean Difference (SMD) -0.49 p = 0.001 MD -0.5), clinician ratings of global improvement (MD -0.58, p = 0.001, MID -0.5) and ADHD improvement (MD -0.54, p = 0.002, MID -0.5), and clinician (but not observer) measures of ADHD inattentive symptoms (MD -1.53, p = 0.05, MID -0.5). Narrative synthesis also revealed a pattern of benefit for global measures of improvement, for example: in autism, and in participants with behavioral deficits in dementia. Post-natural disaster anxiety and the number of violent incidents in prison populations also improved. Broad-spectrum formulas (vitamins + minerals) demonstrated more robust effects than formulas with fewer ingredients. This review highlights the need for robust methodology-RCTs that report full data, including means and standard deviations for all outcomes-in order to further elucidate the effects of multinutrients for psychiatric symptoms.

A double-blind, randomized, placebo-controlled trial of Lactobacillus helveticus and Bifidobacterium longum for the symptoms of depression.

OBJECTIVES: This trial investigated whether probiotics improved mood, stress and anxiety in a sample selected for low mood. We also tested whether the presence or severity of irritable bowel syndrome symptoms, and levels of proinflammatory cytokines, brain-derived neurotrophic factor and other blood markers, would predict or impact treatment response. METHOD: Seventy-nine participants (10 dropouts) not currently taking psychotropic medications with at least moderate scores on self-report mood measures were randomly allocated to receive either a probiotic preparation (containing Lactobacillus helveticus and Bifidobacterium longum) or a matched placebo, in a double-blind trial for 8 weeks. Data were analysed as intent-to-treat. RESULTS: No significant difference was found between the probiotic and placebo groups on any psychological outcome measure (Cohen's d range = 0.07-0.16) or any blood-based biomarker. At end-point, 9 (23%) of those in the probiotic group showed a ⩾60% change on the Montgomery-Åsberg Depression Rating Scale (responders), compared to 10 (26%) of those in the placebo group ([Formula: see text], p = ns). Baseline vitamin D level was found to moderate treatment effect on several outcome measures. Dry mouth and sleep disruption were reported more frequently in the placebo group. CONCLUSIONS: This study found no evidence that the probiotic formulation is effective in treating low mood, or in moderating the levels of inflammatory and other biomarkers. The lack of observed effect on mood symptoms may be due to the severity, chronicity or treatment resistance of the sample; recruiting an antidepressant-naive sample experiencing mild, acute symptoms of low mood, may well yield a different result. Future studies taking a preventative approach or using probiotics as an adjuvant treatment may also be more effective. Vitamin D levels should be monitored in future studies in the area. The results of this trial are preliminary; future studies in the area should not be discouraged.

Systematic review of evidence to support the theory of psychobiotics.

CONTEXT: The theory that supplemented probiotic bacteria could affect psychological outcomes has recently been outlined in narrative reviews; to date, however, this area of research has not been systematically reviewed. OBJECTIVE: The objective of this review was to compare the effects of probiotics with those of placebo on psychological outcomes and symptoms of psychiatric disorders. DATA SOURCES: The Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PubMed, PsycINFO, and PsycARTICLES databases were searched electronically for studies published up to July 17, 2014. Reference lists of relevant articles were searched manually. STUDY SELECTION: Only double-blind, randomized, placebo-controlled human trials that used a standardized, validated scale to assess the effects of probiotic interventions compared with placebo on psychological outcomes or symptoms of psychiatric disorders were included. DATA EXTRACTION: Two researchers independently assessed trials and evaluated them for methodological quality. Data were extracted from the included studies using a data extraction form. DATA SYNTHESIS: Ten trials met the inclusion criteria. Overall, there is very limited evidence for the efficacy of probiotic interventions in psychological outcomes. The evidence base is incomplete and lacks applicability. CONCLUSIONS: More trials are necessary before any inferences can be made about the efficacy of probiotics in mental health applications.

A randomised trial of nutrient supplements to minimise psychological stress after a natural disaster.

After devastating flooding in southern Alberta in June 2013, we attempted to replicate a New Zealand randomised trial that showed that micronutrient (minerals, vitamins) consumption after the earthquakes of 2010-11 resulted in improved mental health. Residents of southern Alberta were invited to participate in a study on the potential benefit of nutrient supplements following a natural disaster. Fifty-six adults aged 23-66 were randomised to receive a single nutrient (vitamin D, n=17), a few-nutrients formula (B-Complex, n=21), or a broad-spectrum mineral/vitamin formula (BSMV, n=18). Self-reported changes in depression, anxiety and stress were monitored for six weeks. Although all groups showed substantial decreases on all measures, those consuming the B-Complex and the BSMV formulas showed significantly greater improvement in stress and anxiety compared with those consuming the single nutrient, with large effect sizes (Cohen's d range 0.76-1.08). There were no group differences between those consuming the B-Complex and BSMV. The use of nutrient formulas with multiple minerals and/or vitamins to minimise stress associated with natural disasters is now supported by three studies. Further research should be carried out to evaluate the potential population benefit that might accrue if such formulas were distributed as a post-disaster public health measure.