The relationship between diet and health is well-established. According to the World Health Organization, consuming a healthy diet not only protects against malnutrition in all its forms, but also against noncommunicable diseases, cardiovascular diseases, and different types of cancer.

According to the WHO, unhealthy dietary practices are a leading risk to global health. Urbanization, changing lifestyles, and the increased production of processed foods have led the vast majority of the world population to consume foods high in sugar, fats, and energy. Healthy foods, such as vegetables, whole grains, and dietary fiber, have been largely replaced by unhealthy, processed foods.

Although dietary guidelines have changed over the years, It has been the scientific consensus for decades that a balanced diet is the foundation of physical health.

The link between diet quality and mental health has not been thoroughly researched, however.

A new study by the Loma Linda University School of Public Health explores the relationship between food and psychological well-being, diet, and mental health.

Published in the International Journal of Food Sciences and Nutrition, and authored by Jim E. Banta, Gina Segovia-Siapco, Christine Betty Crocker, Danielle Montoya, and Noara Alhusseini, “Mental health status and dietary intake among California adults: a population-based survey” is an analysis of 245,891 surveys representing 27.7 million adults annually.

For the study, Loma Linda University School of Public Health researchers used data from the California Health Interview Survey (the largest health survey in the United States) conducted between 2005 and 2015.

The dataset included extensive information about health behaviors (consumption of fruits, vegetables, fast food, soda, sugar), health status (e.g. Body Mass Index), and socio-demographics (race, gender, education, martial status, poverty, geography etc.) of respondents.

The results showed that nearly 17 percent of California adults are likely to suffer from mental illness. More than 13 percent are likely to experience moderate psychological distress, and nearly 4 percent are likely to experience severe psychological distress. The researchers note that previous research has linked, for instance, high intake of sugar and processed foods with depression and bipolar disorder.

In a press release, lead author Jim E. Banta stated the following.

“This and other studies like it could have big implications for treatments in behavioral medicine. Perhaps the time has come for us to take a closer look at the role of diet in mental health, because it could be that healthy diet choices contribute to mental health. More research is needed before we can answer definitively, but the evidence seems to be pointing in that direction.”

The researchers concluded that their findings provide additional evidence for policymakers and guidance for clinical practice, which should “more explicitly aim to improve diet quality among those struggling with mental health.”