Intake of high-fat yogurt, but not of low-fat yogurt or prebiotics, is related to lower risk of depression in women of the SUN cohort study

Background: Yogurt and prebiotic consumption has been linked to better health. However, to our knowledge, no longitudinalstudy has assessed the association of yogurt and prebiotic consumption with depression risk.Objective: We longitudinally evaluated the association of yogurt and prebiotic consumption with depression risk in aMediterranean cohort.Methods: The SUN (Seguimiento Universidad de Navarra) Project is a dynamic, prospective cohort of Spanish universitygraduates. A total of 14,539 men and women (mean age: 37 y) initially free of depression were assessed during a medianfollow-up period of 9.3 y. Validated food-frequency questionnaires at baseline and after a 10-y follow-up were used toassess prebiotic (fructans and galacto-oligosaccharide) intake and yogurt consumption (<0.5, ≥0.5 to <3, ≥3 to<7, and ≥7 servings/wk). Participants were classified as incident cases of depression when they reported a new clinicaldiagnosis of depression by a physician (previously validated). Multivariable Cox proportional hazards models were used tocalculate HRs and 95% CIs.Results: We identified 727 incident cases of depression during follow-up. Whole-fat yogurt intake was associatedwith reduced depression risk: HR for the highest [≥7 servings/wk (1 serving = 125 g)] compared with the lowest (<0.5servings/wk) consumption: 0.78 (95% CI: 0.63, 0.98; P-trend = 0.020). When stratified by sex, this association wassignificant only in women (HR: 0.66; 95% CI: 0.50, 0.87; P-trend = 0.004). Low-fat yogurt consumption was associatedwith a higher incidence of depression (HR: 1.32; 95% CI: 1.06, 1.65; P-trend = 0.001), although this association lostsignificance after the exclusion of early incident cases, suggesting possible reverse causation bias. Prebiotic consumptionwas not significantly associated with depression risk.Conclusions: Our study suggests that high consumption of whole-fat yogurt was related to a lower risk of depression inwomen of the SUN cohort. No association was observed for prebiotics. Further studies are needed to clarify why theyogurt-depression association may differ by fat content of the yogurt.