The aim of the study was to prospectively assess the association between micronutrient intake adequacy and risk of depression.
This dynamic cohort study involves Spanish university graduates (SUN Project). Dietary intake was assessed at baseline and after 10 years of follow-up with a semi-quantitative food frequency questionnaire. Micronutrient intake adequacy for vitamins B1, B2, B3, B6, B12, C, A, D, E, folic acid, zinc, iodine, selenium, iron, calcium, potassium, phosphorus, magnesium and chrome was estimated. Inadequate intake for each nutrient was defined when the intake of the nutrient was below the estimated average requirements (EAR) if available or the adequate intake levels, if EARs were not available. We compared participants with inadequate intake for ¿4 nutrients vs. those with one nutrient. Participants were classified as having incident depression if they had no previous history of depression or antidepressants use at baseline, but they reported during follow-up a new clinical diagnosis of depression by a physician, use of antidepressant drugs, or both. Time-dependent multivariable Cox regression models were fitted.
After a median follow-up of 8.5 years, 953 new cases of depression were observed among 13,983 participants. Participants with inadequate intake for ¿4 nutrients showed a significantly higher risk of depression [multivariable hazard ratio (HR) = 1.37; 95% confidence interval (CI) 1.01-1.85]. When the analyses were updated with repeated assessments of intakes, the association was attenuated and it was no longer statistically significant (Multivariable HR = 1.11; 95% CI 0.82-1.51).
Micronutrient inadequacy in four or more micronutrients could exert a moderate role in the development of depression.