Dr. Felice N. Jacka, at the University of Melbourne, Australia, and colleagues report mood disorders were more common among women 20 to 93 years old who, over 10 years, ate primarily processed, refined, high-fat foods.

"There's no magic diet," Jacka commented in an email to Reuters Health. But eating a diet mainly of vegetables, fruit, whole grain foods, low fat dairy products, and lean meat, and reserving processed and sweet treats to "sometimes foods," will aid physical health and may also support mental well-being, she said.

Jacka's team assessed diet and psychiatric evaluations gathered over 10 years from 1,046 women representative of the general Australian population. A total of 925 women were free of mood disorders, whereas 121 had depressive and/or anxiety disorders, the researchers report in the American Journal of Psychiatry.

When they assessed how diet might relate to mood disorders, they found that a "Western" diet -- eating primarily hamburgers, white bread, pizza, chips, flavored milk drinks, beer, and sugar-laden foods -- was associated with more than a 50 percent greater likelihood for depressive disorders.

By contrast, both depression and anxiety disorders appeared about 30 percent less likely among women eating a more "traditional" Australian diet --- mostly of vegetables, fruit, beef, lamb, fish, and whole-grain foods.

These associations remained when the research team allowed for a variety of factors including age, body weight, social and economic status, education, physical activity, smoking, and alcohol drinking habits. But similar "adjusted" analyses in women mainly consuming fruits, salads, fish, tofu, beans, nuts, yogurt, and red wine showed no similar associations.

Taken together, the findings highlight the need for additional investigations to determine whether unhealthy eating leads to declining mental health or vice versa, the researchers say.

Given that diet is modifiable, finding evidence of a causal tie between diet and mental health seems worthy of pursuit, the researchers conclude.

Reuters