Nutrient intake linked to depression risk

By Mark Cowen, Senior medwireNews Reporter

Increased intakes of zinc, magnesium, and folate are associated with a reduced risk for depression in women, results from an Australian study show.

In a study of more than 1000 women, the team found that each standard deviation increase in the intake of zinc, magnesium, and folate was associated with a respective 48%, 40%, and 34% reduction in the risk for depression/dysthymia, after accounting for total energy intake.

Furthermore, increased intake of magnesium and zinc was associated with better mental health scores on the General Health Questionnaire 12 (GHQ-12).

However, the team found no significant association between nutrient intake and risk for anxiety.

"Promoting an increased consumption of nutrient-dense foods may be a useful strategy in the prevention and treatment of depression in the community," comment Felice Jacka (Deakin University, Geelong) and team.

The researchers analyzed data from the Geelong Osteoporosis Study - an ongoing population-based study of 1494 women, aged 20 to 94 years, who were recruited in 1994 to 1997.

The participants' habitual diets were assessed at regular intervals using the Cancer Council Victoria dietary questionnaire, which assesses consumption of 74 foods and six alcoholic beverages over the preceding 12 months using a 10-point frequency scale. From this, nutrient intakes were calculated.

Psychiatric assessments were undertaken at the 10-year follow up using the Structured Clinical Interview for DSM-IV-Text Revision Research Version, Non-patient edition, and psychiatric symptoms were measured using the self-reported GHQ-12, with higher scores equating to poorer mental health.

In total, 118 women out of 1046 for whom data were available tested positive for depression/dysthymia or anxiety.

Median intakes of zinc, magnesium, and folate were 9.6 mg/day, 240.9 mg/day, and 261.6 µ/day.

Although 70% of women met or exceeded the recommended daily intake (RDI) for zinc (8 mg/day), only 26% met or exceeded the RDI for magnesium (320 mg/day), and just 8% met or exceeded the RDI for folate (400 µ/day), the team notes.

Jacka et al conclude in the Journal of Affective Disorders: "The results of this study support the contention that the consumption of nutrient-dense foods plays a role in depression, but not anxiety."

However, they add that "reverse causality and/or confounding cannot be ruled out as explanations."

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