diet and depression

Prowl the perimeter of the grocery store. The foods that comprise a simple, healthy diet are located around the perimeter of most markets.

Put on a happy plate: Fruits, vegetbles and whole foods may lower your risk of depression.

WHAT IT MEANS: A Western diet—packed as it often is with processed or fried foods, refined grains, sugary foods and drinks, and alcohol—seems to be bad news for your mental health as well as your physical wellness. The link between diet and depression is a startling reminder that depression isn't just "all in your head." As for how diet affects mental health, "It's still speculative at this stage," says lead study author Felice Jacka, PhD, a research fellow at the University of Melbourne, "but I believe myriad mechanisms may be behind what we're seeing." Jacka cites these four:

• A poor-quality diet has a detrimental effect on the immune system. Conversely, a good diet (such as the Mediterranean diet) packed with vegetables, whole grains, and legumes supports immune function. And the immune system appears to be involved in the onset of depression.

• Findings from animal studies suggest that a diet high in refined sugars and saturated fats decreases levels of proteins in the brain that are significantly in psychiatric illness.

• There are some data from rat studies to suggest that a diet high in saturated fat activates our innate stress-response system—the fight-or-flight reflex. On the other hand, good-quality fats, such as omega-3 fatty acids, may reduce the stress response.

• There are new studies to suggest that excessive oxidative stress—exposure to damaging chemicals called free radicals—is involved in some psychiatric illnesses. A healthy diet rich in antioxidants could help the body's natural defence systems.

Future research by Jacka and colleagues will test for a similar phenomenon among men, and help clarify whether it's depression that affects diet, instead of the other way around. "There's no doubt that depression and anxiety can lead to changes in diet," says Jacka. "But those changes are often temporary and, just as importantly, seem to also work the other way." In other words, she says, some people who are feeling depressed try to make themselves feel better by eating a healthier diet. This study suggests that's a pretty good idea.

In the meantime, here's how you can eat for excellent health—both physical and mental:

• Eat simply. "There is no magic diet," says Jacka. But as a rule of thumb, she suggests eating food that been processed as little as possible, as often as possible. "Eating fruit, vegetables, whole grains, low-fat dairy, fish, and lean meat, and treating more processed foods as 'sometimes foods' will support your physical health, and possibly your mental health, as well," she says.

• Prowl the perimeter of the grocery store. It's an effective trick. The fresh fruits and veggies, seafood, meat, and dairy that comprise a simple, healthful diet are located around the perimeter of most markets. Spend the majority of your shopping time there for the makings of a mood-boosting diet. You'll find the healthiest food, and avoid the packaged foods full of sugar, salt, and fat.

• Be careful on the weekends. A new study found that people tend to eat extra calories on weekends without realizing it, thanks to the change in schedule.

• Throw a healthy eating party. Get together with friends for a potluck dinner, with each person bringing something healthy and tasty. It's a chance to try new foods, build healthy eating habits, and spend time with friends—which can make you happier, too.