High-Sugar, High-Saturated-Fat Dietary Patterns Are Not Associated with Depressive Symptoms in Middle-Aged Adults in a Prospective Study

Testing the causal relationship of fat and sugar intake with depression and cortisol: a Mendelian Randomisation study

Unhealthy diets high in fat and sugar content may have an impact on psychological health and increase the risk of Major Depressive Disorder (MDD) and stress levels. On the other hand, MDD and stress might be related to food choices and intake. However, it is not clear whether diet, and specifically fat and sugar intake, is causally related to stress and MDD, and whether this relationship may be bi-directional. This study utilised Mendelian Randomisation (MR) to investigate the causal nature of the relationship of fat and sugar intake with MDD and cortisol (as a proxy of stress), and to shed light on the direction of this relationship. Summary-level data for all exposure and outcome variables were obtained from large-scale, non-overlapping GWASs in individuals of European ancestry. Bidirectional analyses were performed: one with macronutrients as exposures and one with MDD/cortisol as exposures. Random-effects inverse-variance weighted regression was used as the primary analytic method for genetic instruments with at least two single nucleotide polymorphisms (SNPs) available (and individual Wald ratio was used when only one SNP was available). Higher levels of genetically predicted relative sugar intake were causally associated with lower MDD risk, for both genome-wide significant p-value threshold of p < 1 × 10-8, (OR = 0.553, 95% CI: 0.395-0.775) and relaxed p-value threshold of p < 1 × 10-6 (OR = 0.786, 95% CI: 0.630-0.981). No reverse causality was detected in the opposite direction as MDD was not associated with sugar consumption. The associations observed for all the other pairs of variables were weak and imprecise. A number of limitations was present in the study, such as low-SNP based heritability for some exposures, inability to prove whether variants were correlated with unmeasured confounders and self-reporting of MDD data. Lifestyle and/or pharmacological interventions targeting sugar-related physiological mechanisms may help to reduce depressive symptoms. However, more research is necessary on short- and long-term effects of sugar on the risk of MDD. Additionally, future studies should investigate whether the amount and type of sugar consumed may underlie the impact of sugar on mood and stress levels.

The associations of dietary patterns with depressive and anxiety symptoms: a prospective study

BACKGROUND

Diet is increasingly recognized as an important risk factor for mental health. However, evidence regarding the association between diet pattern and depressive and anxiety symptoms is limited. We aimed to investigate the associations of dietary patterns characterized by a set of nutrients of interest with depressive and anxiety symptoms.

METHODS

The analyses included a total of 126,819 participants in the UK Biobank who had completed at least two dietary questionnaires. Dietary data were obtained through 24-h dietary assessment at baseline between 2006 and 2010 and four rounds of online follow-ups between 2011 and 2012. Reduced rank regression was applied to derive dietary patterns (DPs) explaining variability in energy density, free sugars, saturated fat, and fiber intakes. Depressive and anxiety symptoms were measured by the Patient Health Questionnaire-9 and General Anxiety Disorder-7 between 2016 and 2017, respectively. Logistic regression models were performed to investigate the associations between dietary patterns and depressive and anxiety symptoms.

RESULTS

During a mean follow-up of 7.6 years, 2746 cases of depressive symptoms and 2202 cases of anxiety symptoms were recorded. Three major DPs were derived, explaining 74% of the variation in nutrients hypothesized to be related to depressive and anxiety symptoms. DP1 was characterized by high intakes of chocolate, confectionery, butter, and low vegetable/fruit intakes. Compared to the lowest quintile of DP1, the odds ratio (95% confidence interval) of depressive symptoms for Q2-Q5 was 0.82 (0.72-0.93), 0.86 (0.76-0.98), 1.02 (0.90-1.15), and 1.17 (1.03-1.32), respectively. Compared to the lowest quintile of DP1, the odds ratio (95% CI) of anxiety symptoms for Q2-Q5 was 0.84 (0.73-0.97), 0.91 (0.79-1.05), 1.01 (0.88-1.15), and 1.18 (1.03-1.35), respectively. DP2 featured high intakes of sugar-sweetened beverages, added sugars, and low intakes of butter/cheese but showed no significant links to depressive or anxiety symptoms. DP3 was characterized by high butter and milk desserts and low alcohol/bread intakes. Compared to the lowest quintile of DP3, the odds ratio (95% CI) of depressive symptoms for Q2-Q5 was 0.90 (0.79-1.01), 1.00 (0.88-1.13), 1.06 (0.94-1.20), and 1.17 (1.03-1.32), respectively. Compared to the lowest quintile of DP3, the odds ratio (95% CI) of anxiety symptoms for Q2-Q5 was 0.90 (0.78-1.04), 1.05 (0.91-1.20), 1.02 (0.89-1.17), and 1.21 (1.05-1.38), respectively.

CONCLUSIONS

A DP characterized by high intakes of chocolate and confectionery, butter, high-fat cheese, added sugars, along with low intakes of fresh fruit and vegetables, is associated with a higher risk of depressive and anxiety symptoms.

Dietary Restrictions and Depressive Symptoms: Longitudinal Results from the Constances Cohort

Cross-sectional results have suggested a linear association between the number of dietary exclusions and depressive symptoms. This longitudinal study aimed to examine the direction of this association. Methods: In the population-based Constances cohort, depressive symptoms were defined by a score ≥19 on the Centre of Epidemiologic Studies-Depression (CES-D) scale. Diet was measured with a 24-item qualitative food frequency questionnaire (FFQ). Both variables were available at inclusion (from 2012 to 2014) and on follow-up (2015 for the CES-D and 2017 for diet). Food exclusion was categorized into five different groups: No exclusion, exclusion of one, two, three, or ≥4 food groups according to the self-reported number of food groups rarely or never consumed. Logistic regressions were conducted, either taking depressive symptoms as the outcome on follow-up with dietary exclusions at baseline as predictor or with the opposite, adjusting for age, sex, education, income, alcohol intake, smoking, physical activity, and anemia. The path analysis included outcomes and covariates in one model. Results: The median follow-up was three years. A total of 29,337 participants (53.4% women, 48.15 ± 12.9 y.o.) had complete CES-D data and 25,356 (53.56% women, 49.05 ± 12.8 y.o.) FFQ data. Dietary exclusion at inclusion predicted depressive symptoms at follow-up (odds ratio [95% confidence interval]: 2.35 [1.62–3.40] for ≥4 excluded items compared to no exclusions). Depressive symptoms at inclusion predicted dietary exclusions at follow-up (3.45 [1.93–6.16] for ≥4 excluded items). In the path analysis, the standardized estimate of the association between dietary exclusions at inclusion and depressive symptoms at follow-up was by far higher than the opposite (0.1863 and 0.00189, respectively, both p < 0.05). Conclusions: The association of dietary exclusion with subsequent depression is stronger than the opposite association.

Associations of depressive symptoms and history with three a priori diet quality indices in middle-aged and older adults

BACKGROUND

Evidence for the diet-depression link is growing but longitudinal studies on the reverse association are scarce. We investigated associations of (1) current depressive symptoms, (2) short-term changes in and (3) long-term history of depressive symptoms with three a priori diet quality indices.

METHODS

Data were from participants (≥ 55 years) of the Longitudinal Aging Study Amsterdam (LASA). The Mediterranean Diet Score (MDS), Alternative Healthy Eating Index (AHEI-2010) and Dietary Approaches to Stop Hypertension diet (DASH) were derived in 2014/2015. Depressive symptoms (Center for Epidemiologic Studies Depression scale; CES-D) were assessed in 2014/2015 and at five regular 3-yearly cycles from 2001-2003 to 2015/2016. Associations between three depression determinants and the diet indices were analysed by multivariable linear regression models.

RESULTS

Cross-sectionally (n = 1312), current depressive symptoms (CES-D ≥ 16) were associated with lower MDS (adjusted B = -1.21, 95%CI = -2.41, -0.023) and AHEI (B = -2.72, 95%CI = -5.24, -0.20) scores in men only. Chronic/recurrent depressive symptoms (CES-D ≥ 16 in both 2011-2013 and 2015/2016) were associated with lower MDS scores (n = 1233; B = -2.22, 95%CI = -3.40, -1.04) and a trend for lower AHEI scores (B = -2.37, 95%CI = -4.92, 0.18), compared to no depressive symptoms (twice CES-D < 16). History of depressive symptoms (ever CES-D ≥ 16 from 2001-2003 to 2011-2013; n = 687) was associated with lower MDS (B = -1.87, 95%CI = -3.47, -0.27) and AHEI (B = -4.33, 95%CI = -7.54, -1.13) scores in men only. No associations were found with the DASH score.

LIMITATIONS

Single dietary data collection impeded investigation of prospective depression-diet associations.

CONCLUSIONS

Our study in middle-aged and older adults suggests that current and past depressive symptoms are associated with poorer diet quality, particularly in men.