Smart move: The healthy fats in olive oil are good for your brain as well as your heart.

RODALE NEWS, LENOX, MA—If someone asked you the difference between omega-3 fats and trans fats, would you scratch your head? That could mean you need more of the former, and less of the latter.

The food you eat can have a powerful effect on your mood. You don't have to be addicted to sugar to experienced a sugar crash after a big hot fudge sundae. Most of us can relate to getting jitters after one too many cups of double espresso, or feeling fatigue and a brain fog after polishing off a giant bowl of pasta. Those reactions tend to be rapid and noticeable, and are related to sugar, caffeine, and carbs. But more subtle and gradual are the effects that different fats can have. Healthy fats can enhance your mood, guard you against depression, and maybe even keep your brain in good working order as you age.

THE DETAILS: For the first time, a large population-based study has demonstrated a link between the type of fats we consume and our risk for depression. The multi-year study was conducted in Spain, and was published last month in the online journal PLoS One. The research looked at more than 12,000 Spaniards over several years. Study participants who ate the highest levels of trans fats had a 48 percent greater risk of depression, compared to those with the lowest trans fat consumption levels. The researchers also looked at consumption of other fats. They found that people who consumed the most monounsaturated fats (MUFAs), polyunsaturated fats (PUFAs), and olive oil—all healthy fats—were less likely to become depressed.

The food industry likes to use trans fats because of their extended shelf life and flavor stability. But these fats also raise serum levels of LDL cholesterol (that's the "bad" cholesterol), reduce levels of HDL cholesterol (the "good" kind), and promote inflammation that can damage arteries. The link between trans fat consumption and elevated risk for obesity, diabetes, and cardiovascular disease has already led to bans on their use in restaurants in major American cities like New York and Chicago. Food manufacturers have also begun responding to pressure to reduce or remove trans fats from their products. The new study’s link between trans fats and depression provides even more reason to eliminate these synthetically formulated fats from our food supply.

WHAT IT MEANS: There are healthy fats out there, but it can take a little effort to make sure they're on the menu. Here in America, the impact of trans fats on mood may be even greater than what the Spanish study found. In Spain, the consumption of trans fats is low (0.6 percent of total caloric intake). In the U.S., it’s much higher, about 2.5 percent, and the study authors speculate that the depressing impact of trans fats on Americans is even greater.