Ban processed foods in lieu of nutrient-rich whole foods such as fruits, vegetables, fish and whole grains to elevate your mood.

The food choices you make every day can affect your frame of mind. Research shows that there are many variables associated with diet and mood, including the way in which dietary patterns, specific foods, and nutrients can influence your brain and mood. There is plenty of evidence to suggest that the typical American diet of salty, sugary, and fatty foods may be partly responsible for depressive disorders afflicting an estimated nine percent of the U.S. population, according to the Centers for Disease Control and Prevention.

A growing body of evidence links eating patterns with an increased risk for depression. Boost your mood with these food choices.

-- Whole foods vs. processed foods dietary pattern.

Researchers reported in the British Journal of Psychiatry in 2009 that a processed foods dietary pattern -- one that is rich in processed meat, chocolates, sweet desserts, fried food, refined cereals, and high-fat dairy -- is a risk factor for depression in middle-aged people, compared with a whole foods pattern that is rich in fruits, vegetables and fish. These results match those from a 2010 study also published in British Journal of Psychiatry, which concluded that a dietary pattern characterized by vegetables, fruit, meat, fish and whole grains was associated with lower odds for major depression than the typical Western diet of processed or fried foods, refined grains, and sugary products.

-- Anti-inflammatory eating.

We already know that diets high in processed foods and low in plant foods, which promote chronic, low grade inflammation, are implicated as a contributing factor in heart disease. Now researchers are exploring how this diet also impacts depression. Scientists from the University of Pittsburgh Medical Center reported in the November 2011 Journal of Rheumatology that compelling evidence suggests that inflammation contributes to the development of depression. Many depressed people have higher levels of inflammation in their bodies, which appears to promote depression through many biological pathways. In a 2004 study published in Archives of Internal Medicine, scientists concluded that major depression is strongly associated with c-reactive protein (CRP,) a biomarker of levels of inflammation in the body that is linked to promotion of chronic disease, such as heart disease. This could help to explain the association between cardiovascular disease and depression.

However, any dietary pattern that includes fruits, vegetables and omega-3 fatty acids could protect against both heart disease, depression, and even obesity, cancer, diabetes and other health problems related to inflammation. Adherence to a traditional Mediterranean diet, which includes fruits, vegetables, nuts, cereals, legumes, fish, and olive oil, has also been shown to be protective against depression. This diet provides abundant phytochemicals, omega-3 fatty acids, fiber, B vitamins and antioxidants -- all of which are considered to be anti-inflammatory.

-- "Feel good" brain chemicals boosted with balanced diet.

Research has shown that people who are depressed may have low levels of positive neurotransmitters (brain chemicals) like serotonin and dopamine, which are often referred to as "feel good" brain chemicals. In fact, many medications used to treat depression specifically target raising serotonin.

"Serotonin is the neurotransmitter most directly linked to depression, although other neurotransmitters, like dopamine, can make people feel good. Serotonin is the relaxing and calming neurotransmitter, whereas dopamine is the energetic 'feel good' neurotransmitter," says Elizabeth Somer, M.A., R.D., author of "Food and Mood." It follows that maximizing serotonin levels is a good thing to do.

The brain uses the amino acid tryptophan to make serotonin. Although tryptophan is widely distributed in protein-rich foods, such as meat, poultry and fish, other amino acids in those foods interfere with the entry of tryptophan into the brain which results in the brain's inability to make adequate serotonin.

That's where eating a balanced diet comes in. However, eating carbohydrate foods such as grains, fruits, legumes, and starchy vegetables along with protein foods, enables tryptophan to get into the brain. When you eat carbohydrates, your body digests and absorbs them and blood glucose levels rise. In response, insulin levels rise, which ushers glucose from your blood into your body's tissues, and also moves some of the competing amino acids from the blood into muscle tissue. This mechanism helps open a passage for tryptophan to enter the brain and be converted to serotonin.

As with so many other disease states, it's not about focusing on specific nutrients, it's about focusing on a well-balanced diet of nourishing, whole foods. Drew Ramsey, M.D., co-author of "The Happiness Diet," says, "You don't have to eat just to boost serotonin. A well nourished brain will usually take care of itself."

Susan Kleiner, Ph.D., R.D., author of "The Good Mood Diet," says, "The links between what we don't eat and what we do eat are very strong for depression: nurturing your body with the right fuel can help to heal it. People who never eat well think that's as good as they can feel, until they make the necessary dietary changes and realize how good they can feel."

Best Foods to Beat Depression

Which foods should you eat every day to boost your mood? We spoke with leading nutrition and psychology experts to get the scoop on important brain-fuel foods.

-- Wild salmon, oatmeal, edamame, lentils, chickpeas, spinach, skim milk, ground flaxseeds and blackberries (Joy Bauer, M.S., R.D., author and health and wellness expert for "The Today Show")

-- Shrimp, cherry tomatoes, watermelon, chili peppers, beets, garlic and eggs (Drew Ramsey, M.D., practicing psychiatrist and coauthor of "The Happiness Diet")

-- Green leafy vegetables, whole grains, fruits, vegetables, legumes, nuts and seeds (Susan Biali, M.D., B.Sc., author of "Live the Life You Love")

-- Fat-free milk, eggs, bananas, beans, broccoli, cocoa powder, and olive oil (Susan Kleiner, Ph.D., R.D., author of "The Good Mood Diet")

-- Whole foods, lots of fruits and vegetables, caffeine and alcohol kept to a minimum, and fish at least three times a week (Hyla Cass, M.D., co-author of "Natural High")

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