Research on nutraceutical and dietary interventions in psychiatry has grown substantially, but progress is hindered by methodological inconsistencies and limited reporting standards. To address this, the International Society for Nutritional Psychiatry Research presents the first guidelines on clinical trial design, conduct, and reporting for future clinical trials in this area. Recommendations were developed using a Delphi process including eighteen researchers with considerable clinical trial expertise and experience in either methodology, nutraceutical, or dietary interventions in psychiatry. These guidelines provide forty-nine recommendations for clinical trial design and outcomes, five for trial reporting, and seven for future research priorities. The recommendations included in these guidelines are designed to inform both nutraceutical and dietary clinical trial interventions in Nutritional Psychiatry. Common themes include an emphasis on the importance of a multidisciplinary research team and integration of co-design processes into the conduct and design of clinical research, methods to improve transparency and replicability of trial outcomes, and measures to address common biases in nutrition trials. Furthermore, we provide recommendations for future research including examining a greater variety of nutraceutical and dietary interventions, scalable delivery models, effectiveness and implementation studies, and the need to investigate these interventions in the prevention and management of less studied psychiatric conditions (e.g. schizophrenia and bipolar disorder). Recommendations included within these guidelines are intended to improve the rigor and clinical relevance of ongoing and future clinical trials in Nutritional Psychiatry.

Reduced appetite with ageing is a key factor that may increase risk of undernutrition. The objective of this study is to determine the impact of innovative plant protein fibre (PPF) products within a personalised optimised diet (PD), a physical activity (PA) programme, and their combination on appetite, and other nutritional, functional and clinical outcomes in community-dwelling older adults in a multi-country randomised controlled intervention trial. One hundred and eighty community-dwelling adults (approximately sixty per trial centre in Germany, Ireland and Italy) aged 65 years and over will be recruited to participate in a 12-week, parallel-group, controlled trial. Participants will be randomised into one of four groups: 1, PD (incorporating two PPF products): 2, PA; 3, PD + PA; and 4, no intervention (control). The primary outcome is appetite measured by visual analogue scales and energy intake from an ad libitum test meal. Secondary outcomes include fasting and postprandial appetite-related gut hormones, Simplified Nutritional Appetite Questionnaire score, body composition, cardiorespiratory fitness, muscle strength, physical function and PA. In addition, self-efficacy, cognitive status, dietary restraint, depressive symptoms and compliance and acceptability of the intervention will be assessed. Metabolomic profiles, RMR, muscle motor unit properties and gut microbiome will also be assessed to explore potential underlying mechanisms. This multi-centre randomised controlled trial will advance knowledge on how PD (incorporating PPF products), PA and their combination influence appetite, nutritional status and related health outcomes in community-dwelling older adults and contribute to the prevention of undernutrition. Trial registration: Clinical Trials.gov Registry NCT05608707 (registered on 2 November 2022). Protocol Version: NCT05608707 Version 4 (registered on 29 September 2023).

In this cohort profile article we describe the lifetime major depressive disorder (MDD) database that has been established as part of the BIObanks Netherlands Internet Collaboration (BIONIC). Across the Netherlands we collected data on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) lifetime MDD diagnosis in 132,850 Dutch individuals. Currently, N = 66,684 of these also have genomewide single nucleotide polymorphism (SNP) data. We initiated this project because the complex genetic basis of MDD requires large population-wide studies with uniform in-depth phenotyping. For standardized phenotyping we developed the LIDAS (LIfetime Depression Assessment Survey), which then was used to measure MDD in 11 Dutch cohorts. Data from these cohorts were combined with diagnostic interview depression data from 5 clinical cohorts to create a dataset of N = 29,650 lifetime MDD cases (22%) meeting DSM-5 criteria and 94,300 screened controls. In addition, genomewide genotype data from the cohorts were assembled into a genomewide association study (GWAS) dataset of N = 66,684 Dutch individuals (25.3% cases). Phenotype data include DSM-5-based MDD diagnoses, sociodemographic variables, information on lifestyle and BMI, characteristics of depressive symptoms and episodes, and psychiatric diagnosis and treatment history. We describe the establishment and harmonization of the BIONIC phenotype and GWAS datasets and provide an overview of the available information and sample characteristics. Our next step is the GWAS of lifetime MDD in the Netherlands, with future plans including fine-grained genetic analyses of depression characteristics, international collaborations and multi-omics studies.

Higher dietary protein, alone or in combination with physical activity (PA), may slow the loss of age-related muscle strength in older adults. We investigated the longitudinal relationship between protein intake and grip strength, and the interaction between protein intake and PA, using four longitudinal ageing cohorts. Individual participant data from 5584 older adults (52 % women; median: 75 years, IQR: 71·6, 79·0) followed for up to 8·5 years (mean: 4·9 years, SD: 2·3) from the Health ABC, NuAge, LASA and Newcastle 85+ cohorts were pooled. Baseline protein intake was assessed with food frequency questionnaires and 24-h recalls and categorized into < 0·8, 0·8–<1·0, 1·0–<1·2 and ≥ 1·2 g/kg adjusted body weight (aBW)/d. The prospective association between protein intake, its interaction with PA, and grip strength (sex- and cohort-specific) was determined using joint models (hierarchical linear mixed effects and a link function for Cox proportional hazards models). Grip strength declined on average by 0·018 SD (95 % CI: –0·026, –0·006) every year. No associations were found between protein intake, measured at baseline, and grip strength, measured prospectively, or rate of decline of grip strength in models adjusted for sociodemographic, anthropometric, lifestyle and health variables (e.g., protein intake ≥ 1·2 v· < 0·8 g/kg aBW/d: β = –0·003, 95 % CI: –0·014, 0·005 SD per year). There also was no evidence of an interaction between protein intake and PA. We failed to find evidence in this study to support the hypothesis that higher protein intake, alone or in combination with higher PA, slowed the rate of grip strength decline in older adults.

A lower dietary protein intake has been associated with muscle mass loss, a decline in physical performance and more mobility limitations over time in old age. Current guidelines for protein intake advise ≥ 0.8 g/kg body weight (BW)/d, while experts propose a higher intake for older adults (1.0–1.2 g/kg BW/d), irrespective of sex. It is unknown whether the association between protein intake and loss of muscle mass is different for men and women, and whether there is an optimal protein intake to prevent this loss. Therefore, we investigated the shape of the association between protein intake and change in appendicular lean mass (aLM) over 3 years in community-dwelling older adults, separately for men and women. Data of men (n = 935) and women (n = 1061) aged 70–81 years and participating in the Health, Aging and Body Composition study were used. Dietary protein intake, measured in 1998/1999 using a food frequency questionnaire, was expressed in daily grams of protein per kg adjusted BW (g/kg aBW/d) by using healthy instead of actual BW. aLM was assessed by dual-energy X-ray absorptiometry at baseline and after 3 years. Restricted cubic spline functions with 3 knots in linear regression models were used as well as linear regression analyses. The fit of both models was compared using the likelihood ratio test. All analyses were stratified by sex and adjusted for demographics, lifestyle factors, chronic conditions, height and baseline aLM. Mean (SD) protein intake was 70.8 (26.2) g in men and 61.0 (22.5) g in women, or 0.93 (0.36) and 0.95 (0.36) g/kg aBW/d, respectively. Over 3 years, mean loss of aLM was 0.61 (1.16) kg in men and 0.35 (0.95) kg in women. In both men and women, the likelihood ratio was not significant (P = 0.57 and 0.67, respectively), indicating that the spline regression model did not fit the data better than the linear regression model. In men, the linear model showed no association between protein intake and change in aLM (adjusted B per 0.1 g/kg aBW/d = 18.1, P = 0.34). In women, a higher protein intake was associated with a smaller loss of aLM (adjusted B per 0.1 g/kg aBW/d = 34.5, P = 0.017). This study suggests a linear association between protein intake and 3-year loss of aLM in older women; however, no association was found in older men. Future studies into sex differences in associations with other physical outcomes are needed. For both sexes, an optimal protein intake could not be detected.

This study investigated bidirectional associations between intake of food groups and depressive symptoms in 1058 Italian participants (aged 20–102 years) of the Invecchiare in Chianti study. Dietary intake, assessed with a validated FFQ, and depressive symptoms, measured with the Center for Epidemiologic Studies Depression scale (CES-D), were assessed at baseline and after 3, 6 and 9 years. Associations of repeated measurements of intakes of thirteen food groups with 3-year changes in depressive symptoms, and vice versa, were analysed using linear mixed models and logistic generalised estimating equations. Fish intake was inversely (quartile (Q)4 v. Q1, B=–0·97, 95 % CI –1·74, –0·21) and sweet food intake positively (Q4 v. Q1, B=1·03, 95 % CI 0·25, 1·81) associated with subsequent CES-D score. In the other direction, higher CES-D scores were associated with decreases in intakes of vegetables (ratio: 0·995, 95 % CI 0·990, 0·999) and red and processed meat (B=–0·006, 95 % CI –0·010, –0·001), an increase in dairy product intake (ratio: 1·008, 95 % CI 1·004, 1·013), and increasing odds of eating savoury snacks (OR: 1·012, 95 % CI 1·000, 1·024). Fruit, nuts and legumes, potatoes, wholegrain bread, olive oil, sugar-sweetened beverages, and coffee and tea were not significantly associated in either direction. Our study confirmed bidirectional associations between food group intakes and depressive symptoms. Fish and sweet food intakes were associated with 3-year improvement and deterioration in depressive symptoms, respectively. Depressive symptoms were associated with 3-year changes in vegetable, meat, dairy product and savoury snack intakes. Trials are necessary to examine the causal associations between food groups and depression.

Nutritional intakes of food bank recipients and consequently their health status largely rely on the availability and quality of donated food in provided food parcels. In this cross-sectional study, the nutritional quality of ninety-six individual food parcels was assessed and compared with the Dutch nutritional guidelines for a healthy diet. Furthermore, we assessed how food bank recipients use the contents of the food parcel. Therefore, 251 Dutch food bank recipients from eleven food banks throughout the Netherlands filled out a general questionnaire. The provided amounts of energy (19 849 (sd 162 615) kJ (4744 (sd 38 866) kcal)), protein (14·6 energy percentages (en%)) and SFA (12·9 en%) in a single-person food parcel for one single day were higher than the nutritional guidelines, whereas the provided amounts of fruits (97 (sd 1441) g) and fish (23 (sd 640) g) were lower. The number of days for which macronutrients, fruits, vegetables and fish were provided for a single-person food parcel ranged from 1·2 (fruits) to 11·3 (protein) d. Of the participants, only 9·5 % bought fruits and 4·6 % bought fish to supplement the food parcel, 39·4 % used all foods provided and 75·7 % were (very) satisfied with the contents of the food parcel. Our study shows that the nutritional content of food parcels provided by Dutch food banks is not in line with the nutritional guidelines. Improving the quality of the parcels is likely to positively impact the dietary intake of this vulnerable population subgroup.

This study aimed to identify dietary patterns using reduced rank regression (RRR) and to explore their associations with depressive symptoms over 9 years in the Invecchiare in Chianti study. At baseline, 1362 participants (55·4 % women) aged 18–102 years (mean age 68 (sd 15·5) years) were included in the study. Baseline data collection started in 1998 and was repeated after 3, 6 and 9 years. Dietary intake information was obtained using a country-specific, validated FFQ with 188 food items. For baseline diet, dietary pattern scores in quartiles (Q) were derived using RRR with the nutrients EPA+DHA, folate, Mg and Zn as response variables. Continuous depression scores from the Centre for Epidemiologic Studies Depression (CES-D) scale were used for assessing depressive symptoms. The derived dietary pattern was rich in vegetables, olive oil, grains, fruit, fish and moderate in wine and red and processed meat, and was labelled as ‘typical Tuscan dietary pattern’. After full adjustment, an inverse association was observed between this dietary pattern and depressive symptoms at baseline (Q1 v. Q4, B −2·77; 95 % CI −4·55, −0·98). When examining the relationship between the above-mentioned dietary pattern at baseline and depressive symptoms over 9 years, a similar association was found after full adjustment for confounding factors (Q1 v. Q4, B −1·78; 95 % CI −3·17, −0·38). A diet rich in vegetables, olive oil, grains, fruits, fish and moderate in wine and red and processed meat was consistently associated with lower CES-D scores over a 9-year period in the Tuscan population.

Undernutrition may be an important modifiable risk factor for poor clinical outcomes in older individuals. To achieve earlier detection or prevention of undernutrition, more information is needed about risk factors for the development of undernutrition in community-dwelling older individuals. The objective was to identify early determinants of incident undernutrition in a prospective population-based study. Baseline data (1992–3) on socio-economic, psychological, medical, functional, lifestyle and social factors of 1120 participants aged 65–85 years of the Longitudinal Aging Study Amsterdam were used. Undernutrition, defined as a BMI < 20 kg/m2 or self-reported involuntary weight loss ≥  5 % in the last 6 months, was assessed every 3 years during a 9-year follow-up period. Cox proportional-hazards regression analysis was used to investigate the association between early determinants at baseline and incident undernutrition. In 9 years, 156 participants (13·9 %) developed undernutrition. In univariate analyses, female sex, depressive symptoms, anxiety symptoms, multiple chronic diseases, high medication use (women), poor appetite, no alcohol use v. light alcohol use, loneliness, not having a partner, limitations in performing normal activities due to a health problem, low physical performance (participants aged < 75 years) and reporting difficulties walking stairs (participants aged < 75 years) were statistically significantly associated with incident undernutrition. In a multivariate model, poor appetite and reporting difficulties walking stairs (participants aged < 75 years) remained early determinants. The results of the present study can be used to identify subgroups of older individuals with increased risk of undernutrition and to identify modifiable determinants for the purpose of prevention of undernutrition.

The prevalence of obesity is high in older persons and recent trends show a rapid increase in this prevalence. Results from observational and intervention studies (i.e. weight loss studies) show the strong negative impact of obesity on functional status in old age. There are different potential pathways through which obesity may lead to functional decline in older persons. Furthermore, the presence of overweight and obesity during the life course and trends in medical care are likely to influence the impact of obesity on disability. The concepts sarcopenia (age-related loss of muscle mass) and dynapenia (age-related loss of muscle strength) receive a lot of research attention as potential determinants of functional decline in old age. There is no consensus on the definitions of these concepts. Recent studies conducted in large cohort studies of mainly community-dwelling older persons show that poor muscle strength is strongly associated with functional decline compared to low muscle mass. In several studies, no association between muscle mass and functional status was observed. Current research on the combination of obesity with poor muscle strength (dynapenic-obesity) suggests a potential additive effect of both components on poor functional status in old age which seems independent of the level of physical activity.