Neuropsychological disorders, including anxiety, depression, and dementia, are significant public health problems among older adults. While psychotropics are effective treatments, long-term treatment often has adverse side effects(1). Many patients often seek healthy food consumption as an alternative preventive strategy. Dietary fibre has been suggested for many health benefits, including cardiometabolic health and anti-inflammation, which may influence neurological health through the gut-brain axis(2). However, fibre’s role in neuropsychological health outcomes in older people is unclear. This study examined the potential role of dietary fibre intake and consumption of fibre-rich foods in neurological health outcomes in older Australians. We utilised data from the Ageing Study (MAS) of 1,037 participants aged 70–90(3). At baseline, dietary fibre, whole grains, fresh fruit, vegetables, and nuts and legumes consumption was estimated using the Cancer Council of Victoria food frequency questionnaire. The intake amount was further derived into tertiles (T), with T1 in the lower 33rd%tile and T3 in the upper 33rd%tile. Depressive symptoms (Geriatric Depression Scale), anxiety symptoms (Goldberg Anxiety Scale), and psychological distress (Kessler Psychological Distress Scale) were assessed. Linear regression models were used to estimate beta coefficients for the associations cross-sectionally. Incident dementia was defined using diagnostic criteria, clinical assessments, and a consensus panel review. Nine hundred and sixty-three participants were followed up from the baseline (2005) until wave 4 (2011) [median: 5.8 (IQR: 3.1–5.9) years; 97 incident cases). Incident depression was defined as diagnoses by healthcare professionals and treatments for depression. Eight hundred and nine participants were followed up from the baseline (2005) until wave 3 (2009) [median: 3.9 (IQR: 1.9–4.0) years; 109 incident cases). Cox proportional hazard models were used to estimate hazard ratios (95% CIs). All models were adjusted for demographic characteristics, lifestyle factors, and health history. Among 963 participants (mean age: 78.5; 5.8% females) in the cross-sectional analysis, compared with T1, higher vegetable intake was associated with fewer depressive symptoms (T2: β = 0.52; T3: β= −0.53; both p < 0.05), psychological distress (T2: β = −0.59; T3: β = −1.13; both p < 0.05), and anxiety symptoms (T3: β = −0.37; p = 0.03). Combined intake of vegetables and fruit was inversely associated with fewer psychological distress symptoms (T2: β = −0.55; p = 0.06; T3: β = −1.3; p < 0.05). In the highest tertile, dietary fibre was associated with fewer depressive symptoms (T3: β = −0.47; p = 0.04). In the longitudinal analysis, dietary fibre intake was associated with a 43–56% lower risk of incident dementia (T2 vs T1: adj.HR = 0.57; 95% CI: 0.31–1.03; T3 vs T1: adj.HR = 0.44; 95% CI: 0.19–1.01). Intakes of whole grains, fruit, nuts and legumes were not associated with the outcomes assessed. In a cohort of older Australians, dietary fibre intake appeared to be protective in reducing depressive symptoms cross-sectionally and the risk of incident dementia longitudinally. Additionally, vegetable consumption was associated with fewer symptoms related to depression, anxiety, and distress cross-sectionally.

Depression and dementia represent significant public health issues, affecting approximately 1 in 10 and 1 in 12 older Australians, respectively. While current pharmacological treatments are effective in relieving symptoms, they often entail undesirable adverse effects, including gastrointestinal issues and bradycardia(1,2). This highlights the need for primary preventative measures, including food- and nutrition-based approaches. Chronic brain inflammation is believed to interfere with the gut–brain axis(3). Consumption of fermented dairy products rich in beneficial gut microbes may attenuate this inflammation and offer protective health benefits. This study aimed to examine whether fermented dairy intake could mitigate the risk of incident depression and dementia. Utilising data from the Sydney Memory and Ageing Study I of 1037 participants 70–90 years, 816 participants (mean age: 76.7) were followed from 2005 until 2012 for incident depression, and 974 participants (mean age: 80.7) were followed up from 2005 until 2014 for incident dementia. Fermented dairy intake was assessed using the Dietary Questionnaire for Epidemiological Studies version 2 and categorised yoghurt and regular cheese into quartiles (Q) and low-fat cheese into consumers/non-consumers, with no consumption as the reference group. Depression diagnoses were assessed via self-reported physician-diagnosed history, medication use, service utilisation, and heavy alcohol use. Dementia diagnoses followed the criteria in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders. Cox proportional hazards models examined the associations between fermented dairy intake and the risk of incident depression/dementia. Additionally, linear regression models were applied to assess for depressive symptoms score (measured by the Geriatric Depression Scale-15) and psychological distress score (measured by the Kessler Psychological Distress Scale-10). All models were adjusted for sociodemographic, lifestyle factors, and medical histories. Over a median follow-up of 3.9 and 5.8 years, 120 incident depression and 100 incident dementia cases occurred, respectively. Those who consumed high yoghurt (Q4: 145.8–437.4 g/day) and low-fat cheese (consumers: 0.4–103.1g/day) intakes were associated with a lower risk of incident depression, both compared to non-consumers (yoghurt: adj.HR: 0.38, 95% CI: 0.19–0.77; low-fat cheese: adj.HR: 0.50; 95% CI: 0.29–0.86). They were also associated with lower depressive symptom scores (yoghurt: adj.β = −0.46; 95% CI: −0.84, −0.07; low-fat cheese: adj.β = −0.42; 95% CI: −0.73, −0.11). However, those who consumed a higher intake of regular cheese (Q4: 14.7–86.1 g/day) had an elevated risk of incident depression (adj.HR: 1.88; 95% CI: 1.02, 3.47), and those in Q2 (0.1–7.2 g/day) had significantly higher depressive symptom scores (adj.β = 0.42; 95% CI: 0.05, 0.78). No significant findings were found for psychological distress scores or incident dementia. Our findings of a cohort of older Australians suggest that higher yoghurt and low-fat cheese intakes may reduce incident depression and depressive symptoms, while a higher intake of regular cheese may increase these risks.

Depression is the largest global contributor to non-fatal disease burden(1). A growing body of evidence suggests that dietary behaviours, such as higher fruit and vegetable intake, may be protective against the risk of depression(2). However, this evidence is primarily from high-income countries, despite over 80% of the burden of depression being experienced in low- and middle-income countries(1). There are also limited studies to date focusing on older adults. The aim of this study was to prospectively examine the associations between baseline fruit and vegetable intake and incidence of depression in adults aged 45-years and older from 10 cohorts across six continents, including four cohorts from low and middle-income countries. The association between baseline fruit and vegetable intake and incident depression over a 3–6-year follow-up period was examined using Cox proportional hazard regression after controlling for a range of potential confounders. Participants were 7771 community-based adults aged 45+ years from 10 diverse cohorts. All cohorts were members of the Cohort Studies of Memory in an International Consortium collaboration(3). Fruit intake (excluding juice) and vegetable intake was collected using either a comprehensive food frequency questionnaire, short food questionnaire or diet history. Depressive symptoms were assessed using validated depression measures, and depression was defined as a score greater than or equal to a validated cut-off. Prior to analysis all data were harmonised. Analysis was performed by cohort and then cohort results were combined using meta-analysis. Subgroup analysis was performed by sex, age (45 – 64 versus 65+ years) and income level of country (high income countries versus low- and middle-income countries). There were 1537 incident cases of depression over 32,420 person-years of follow-up. Mean daily intakes of fruit were 1.7 ± 1.5 serves and vegetables 1.9 ± 1.4. serves. We found no association between fruit and vegetable intakes and risk of incident depression in any of the analyses, and this was consistent across the subgroup analyses. The low intake of fruit and vegetables of participants, diverse measures used across the different cohorts, and modest sample size of our study compared with prior studies in the literature, may have prevented an association being detected. Further investigation using standardised measures in larger cohorts of older adults from low- to middle-income countries is needed. Future research should consider the potential relationship between different types of fruits and vegetables and depression.

The present study was conducted to appraise the ontogenic radio-sensitivity of a serious tropical pest, Spodoptera litura (Fabr.). The molecular responses pertaining to the phenoloxidase (PO) pathway and an anti-oxidant defense mechanism were evaluated in order to understand its implication in pest control at pre-harvest and post-harvest intervals. Irradiation exhibited an inverse relationship with age with respect to impact on developmental and transcriptional responses. Transcript abundance of PO cascade enzymes, prophenoloxidase (slppo-2), its activating enzyme (slppae-1) and free-radical scavenging enzymes, superoxide dismutase (slsod) and catalase (slcat) was evaluated upon gamma irradiation alone and the dual-stress of radiation plus microbial challenge. The slppo-2, slppae-1, slsod and slcat transcripts were significantly up-regulated in F1 L6 larvae (6th-instar) resulting from 100 Gy sub-sterilized male adults and unirradiated female moths. The extent of upregulation was relatively higher in comparison with L6 survivors (6th-instar larvae) developed from irradiated neonates (L1) treated with 100 Gy. Upon Photorhabdus challenge, the transcripts were down-regulated in irradiated L1 suggesting increased larval susceptibility to bacterial infections. Radioresistance increased with the age of the insect, and molecular responses (transcript abundance) of insect defense mechanism were less influenced when older age (F1 progeny) were irradiated. These findings will help to optimize the gamma dose to be employed in inherited sterility technique for (pre-harvest) pest suppression and (post-harvest) phytosanitation and quarantine, and suggest compatible integration of biorational tactics including nuclear technology.