It’s no surprise that downing an entire sleeve of cookies in one sitting can make you feel less than fantastic, but can certain foods actually make you clinically depressed? It’s starting to look that way, according to a comprehensive new study published in the journal Brain, Behavior, and Immunity.
For 12 years, researchers tracked the diet habits and health outcomes of more than 43,000 women—none of whom had depression at the start of the study period. Here’s what they found: Women who sipped soft drinks, ate fatty red meat, or consumed refined grains (like pasta, white bread, crackers, or chips) daily were 29 to 41% more likely to be diagnosed or treated for depression than those who stuck to a healthier diet. Blood tests revealed that women who ate the above foods also tested significantly higher for three biomarkers of inflammation.
Although healthy amounts of inflammation are necessary to help your body fight off disease and bounce back from injury, dozens of recent studies have linked out-of-control inflammation to ailments ranging from heart disease and stroke to diabetes and cancer. This new study isn’t the first to link certain diet choices to inflammation and depression, but it is one of the most complete to date.
It’s not clear exactly how inflammation and depression are linked, says study coauthor Michel Lucas, PhD, of the Harvard School of Public Health. He says the physiological and cognitive underpinnings of the mood disorder remain elusive. But evidence is mounting that certain foods increase both inflammation and depression risk, while others appear to have the opposite effect.
For example, Dr. Lucas’ research found foods like coffee, olive oil, wine, and vegetables including carrots, sweet potatoes, and leafy greens—if consumed daily—can help reduce inflammation and depression. A Mediterranean-style diet heavy in olive oil as well as fish and vegetables has also been linked to lower rates of the mood disorder.
More from Prevention: 5 Ways to Reduce Inflammation