Research explains the connection between diet, mood, and cognition.

If there’s one concept health researchers have come to agree on it’s this: What you eat matters. Although they don’t always agree on what constitutes a healthy diet, medical experts have long understood that while certain foods can help to improve your physical well-being, others have the opposite effect.

Now, a new collection of evidence clearly demonstrates that what you eat also affects your mental health. A review article published last month in the journal European Neuropsychopharmacology details the emerging evidence on how our diets affect our moods and mental well-being.

It makes sense, the researchers write, because “the composition, structure, and function of the brain are dependent on the availability of appropriate nutrients.” People with specific mental health conditions—including epilepsy, depression, and anxiety—may need to alter their diets in different ways. Here’s what the research has shown to date:

  • Several credible systematic reviews have shown that a diet rich in fresh fruits and vegetables, whole grains and lean proteins can help to improve overall mood and general feelings of happiness; it can also reduce symptoms of depression.
  • Specific diet interventions can help improve the symptoms of some mental health disorders. For example, there is credible evidence that the ketogenic diet, which cuts back on carbohydrates and focuses on calories from protein and fat, reduces the frequency of seizures in children with epilepsy.
  • Not getting enough of a specific nutrient can affect your mental health. For example, a deficiency in vitamin B12 leads to fatigue, lethargy, depression, poor memory, and is associated with mania and psychosis. When pregnant women don’t get enough folic acid, their children can have developmental problems, and those children are more likely to develop depression as adults. And not getting enough niacin can lead to dementia, diarrhea, and itchy skin.
  • There is clear evidence that diet has an effect on cognitive function later in life, the researchers write, even though we still don’t understand how this works in the body. Still, evidence shows that the Mediterranean diet—which focuses on whole foods and lean proteins and cuts out processed foods and sugars—is associated with higher levels of cognitive function later in life. And that diets high in sugar and fat lead to cardiometabolic diseases, which have negative effects on cognition.

The report explains that researchers still have a lot to learn. For example, there have been many studies focused on supplements or elimination diets for people with attention deficit hyperactivity disorder, or ADHD, but the evidence has been inconclusive to date. And even when researchers have found an association between a specific diet and improved mental health, they often don’t understand how foods help support those improvements.

Yet the take-home message is clear: The foods that we eat do affect our moods, feelings and cognitive function. A diet focused on fruits and vegetables, lean proteins and whole grains can help to boost mental health. And specific supplements and diets are proven to help with certain mental health conditions.

SOURCE: The Bronfenbrenner Center for Translational Research (BCTR) at Cornell University