Eating This Type of Fruit Every Day May Lower the Risk of Depression up to 20%

There's no singular superfood that can wipe away years of lifestyle discretions or prevent a host of illnesses. However, new research suggests there's one variety of fruits that can have a remarkably profound impact on the brain.

As it turns out, eating citrus fruits, like oranges, once a day can lower the risk of depression by up to 20 percent, according to new research published in Microbiome.

To gain some insight into the connection between food and mood, researchers analyzed data from more than 32,000 middle-aged women between 2003 and 2017. During this time, forms were sent to participants every two years asking about their diet, mood, medication use, lifestyle, and overall health.

"We found that eating one medium orange a day may lower the risk of developing depression by about 20 percent," said Raaj Mehta, MD, MPH, an instructor in medicine at Harvard Medical School and lead author of the study, in a press release. "And the effect seems to be specific to citrus. When we look at people’s total fruit or vegetable consumption or at other individual fruits such as apples or bananas, we don’t see any relationship between intake and risk of depression."

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Per the study, there was a lower amount of F. prausnitzii—a type of bacteria found in the gut that some researchers believe may play a role in mood—in participants who experienced symptoms of depression.

"Consuming a lot of citrus was also associated with high levels of F. prausnitzii," Mehta says. "So, we think this bacterium may link citrus consumption with good mental health."

Although the initial study only included women, Mehta and his team wanted to see if the results were similar for men. To do so, they turned to a similar study called the Men’s Lifestyle Validation Study. Surprisingly, they found that increasing levels of F. prausnitzii were inversely correlated with depression risk scores.

So how might oranges reduce depression symptoms? 

"One answer, we think, might be that these bacteria use a metabolic pathway known as the S-adenosyl-L-methionine cycle I pathway to influence levels of two neurotransmitters—serotonin and dopamine—produced by human cells in the gut," Metha said. "These neurotransmitters regulate how food passes through the digestive tract, but they can also travel to the brain, where they elevate mood."

While Mehta doesn't suggest skipping out on your current treatment plan for depression, he would love to see more research proving it can help.

"There’s such a huge unmet need for depression treatments, and eating citrus doesn’t really have any major side effects, so it would be great to see how much this simple treatment can help," he said.