Genetic and environmental influences on fruit and vegetable consumption and depression in older adults.

BACKGROUND: Prior work suggests that higher fruit and vegetable consumption may protect against depression in older adults. Better understanding of the influence of genetic and environmental factors on fruit and vegetable intakes may lead to the design of more effective dietary strategies to increase intakes. In turn this may reduce the occurrence of depression in older adults. OBJECTIVES: The primary aim of this study is to estimate the genetic and environmental influences on the consumption of fruit and vegetables in older adults. The secondary aim is an exploratory analysis into possible shared genetic influences on fruit and vegetable intakes and depression. METHODS: Analysis of observational data from 374 twins (67.1% female; 208 monozygotic (MZ); 166 dizygotic (DZ)) aged ≥ 65 years drawn from the Older Australian Twins Study. Dietary data were obtained using a validated food frequency questionnaire and depressive symptoms were measured using the 15-item short form Geriatric Depression Scale. The contribution of genetic and environmental influences on fruit and vegetable intake were estimated by comparing MZ and DZ twin intakes using structural equation modelling. A tri-variate twin model was used to estimate the genetic and environmental correlation between total fruit and vegetable intakes and depression. RESULTS: In this study, vegetable intake was moderately influenced by genetics (0.39 95%CI 0.22, 0.54). Heritability was highest for brassica vegetables (0.40 95%CI 0.24, 0.54). Overall fruit intake was not significantly heritable. No significant genetic correlations were detected between fruit and vegetable intake and depressive symptoms. CONCLUSIONS: Vegetable consumption, particularly bitter tasting brassica vegetables, was significantly influenced by genetics, although environmental influences were also apparent. Consumption of fruit was only influenced by the environment, with no genetic influence detected, suggesting strategies targeting the food environment may be particularly effective for encouraging fruit consumption.

Association between dietary protein intake and changes in health-related quality of life in older adults: findings from the AusDiab 12-year prospective study.

BACKGROUND: Adequate dietary protein intake is recommended for older adults to optimise muscle health and function, and support recovery from illness, however, its effect on health-related quality of life (HRQoL) is unclear. The aim of this study was to examine the association between total protein intake and different sources of dietary protein and HRQoL in Australians aged 60 years and older over a 12-year period. METHODS: This study used data from the Australian Diabetes, Obesity and Lifestyle study (AusDiab), a 12-year population-based prospective study. The sample included 752 (386 females) adults aged 60 years and older. Protein intake was estimated at baseline (1999/2000) from a 74-item Food Frequency Questionnaire, and HRQoL using the 36-item Short-form Health Survey assessed at baseline (1999/2000) and after 12 years (2011/12). The association between protein intake and change in HRQoL was evaluated using multivariate regression analysis adjusted for relevant confounders. The difference in change in HRQoL between participants with total protein intakes of < 1.0 g/kg/day, intakes of between 1.0-1.2 g/kg/day and intakes of > 1.2 g/kg/day were assessed using one-way ANCOVA. RESULTS: Total protein intake at baseline was not associated with 12-year changes in physical component summary (PCS) or mental component summary (MCS) scores of HRQoL. Higher animal, red meat and processed animal protein intakes were associated with deteriorations in PCS scores after adjusting for relevant confounders (ß = - 0.04; 95% CI: - 0.07, -0.01 ; p = 0.009; ß = - 0.05; 95% CI: - 0.08, - 0.01; p = 0.018; ß = - 0.17; 95% CI: - 0.31, - 0.02; p = 0.027 respectively). Higher red meat protein intake was associated with deteriorations in MCS scores after adjusting for relevant confounders (ß = - 0.04; 95% CI: - 0.08, - 0.01; p = 0.011). There was no difference in 12-year changes in PCS or MCS between participants consuming total protein of < 1.0 g/kg/day, 1.0-1.2 g/kg/day and intakes of > 1.2 g/kg/day. CONCLUSION: There was no relationship between total dietary protein intake and HRQoL, but higher protein intakes from animal, red meat and processed animal sources were associated with a deterioration in HRQoL scores over 12 years. Due to the number of associations examined and high drop out of older less healthy participants, further research is required to confirm the associations detected in healthy and less healthy participants, with a view to making protein intake recommendations for older adults.

Associations between fruit and vegetable intakes and incident depression in middle-aged and older adults from 10 diverse international longitudinal cohorts.

BACKGROUND: Emerging observational evidence supports a role for higher fruit and vegetable intake in protecting against the development of depression. However, there is a scarcity of research in older adults or in low- to middle-income countries (LMICs). METHODS: Participants were 7801 community-based adults (mean age 68.6 ± 8.0 years, 55.8 % female) without depression, from 10 diverse cohorts, including four cohorts from LMICs. Fruit and vegetable intake was self-reported via comprehensive food frequency questionnaire, short food questionnaire or diet history. Depressive symptoms were assessed using validated measures, and depression defined applying validated cut-offs. The associations between baseline fruit and vegetable intakes and incident depression over a follow-up period of three to nine years were examined using Cox regression. Analyses were performed by cohort with results meta-analysed. RESULTS: There were 1630 cases of incident depression (21 % of participants) over 40,258 person-years of follow-up. Higher intake of fruit was associated with a lower risk of incident depression (HR 0.87, 95%CI [0.77, 0.99], I2 = 4 %). No association was found between vegetable intake and incident depression (HR 0.93, 95%CI [0.84, 1.04], I2 = 0 %). LIMITATIONS: Diverse measures used across the different cohorts and the modest sample size of our study compared with prior studies may have prevented an association being detected for vegetable intake. CONCLUSIONS: Our study supports a role for fruit, but not vegetable intake in protecting against depression. Research investigating different types of fruits and vegetables using standardised measures in larger cohorts of older adults from low- and middle-income countries is warranted.

Associations between nutrition and the incidence of depression in middle-aged and older adults: A systematic review and meta-analysis of prospective observational population-based studies.

AIM: To systematically examine the longitudinal observational evidence between diet and the incidence of depression in adults aged 45 years and older. METHOD: Three electronic databases were searched for cohort studies published up to December 2020 that investigated the association between baseline dietary intake and incidence of depression in community-dwelling adults aged 45+years. Combined odds ratios (OR) and 95% confidence intervals (95%CI) were calculated. Random-effects models were used. RESULTS: In total 33 articles were included, with 21 combined in meta-analyses. Both the Dietary Inflammatory Index and the Western diet were associated with an increased odds of incident depression (Dietary Inflammatory Index: OR 1.33; 95%CI 1.04, 1.70; P = 0.02; Western: OR 1.15 95%CI 1.04, 1.26; P = 0.005). Higher fruit and vegetable intakes were associated with a reduced risk of incident depression (vegetables: OR 0.91; 95%CI 0.87, 0.96; P < 0.001; fruit: OR 0.85; 95%CI 0.81, 0.90; P < 0.001). No association was observed between the Mediterranean diet, "healthy" diet, fish intake and incident depression. CONCLUSIONS: Results suggest an association between higher consumption of pro-inflammatory diets and Western diets and increased incidence of depression, while higher intake of fruit and vegetables was associated with decreased incidence of depression. These results are limited by the observational nature of the evidence (results may reflect residual confounding) and the limited number of studies. More high-quality intervention and cohort studies are needed to confirm these associations and to extend this work to other food groups and dietary patterns.