A new study adds to the mounting evidence that an unhealthy diet is tied to poor mental health, regardless of personal characteristics such as gender, education, age, marital status and income level.
The findings, published in the International Journal of Food Sciences and Nutrition, show that California adults who consumed a large amount of unhealthy food were more likely to report symptoms of either moderate or severe psychological distress compared to those who ate a healthier diet.
Lead author Jim E. Banta, PhD, MPH, associate professor at Loma Linda University School of Public Health, says the findings are similar to those of other studies around the world revealing a link between mental illness and unhealthy diet choices.
Increased sugar consumption has been shown to be linked to bipolar disorder, for example, while fried foods or foods that contain high amounts of sugar and processed grains have been linked with depression.
“This and other studies like it could have big implications for treatments in behavorial medicine,” Banta said. “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.”
Banta warns that the study does not prove a causal link between unhealthy food and poor mental health. Still, he said the findings build upon previous work and could impact future research and treatment approaches.
In the study, the research team looked at data from more than 240,000 telephone surveys conducted between 2005 and 2015 as part of the multi-year California Health Interview Survey (CHIS).
The CHIS dataset includes extensive information about socio-demographics, health status and health behaviors and was developed to provide statewide approximations for regions within California and for various ethnic groups. The findings show that nearly 17 percent of California adults are likely to suffer from mental illness: 13.2 percent with moderate psychological distress and 3.7 percent with severe psychological distress.
The paper states that the team’s findings provide “additional evidence that public policy and clinical practice should more explicitly aim to improve diet quality among those struggling with mental health.”
It also stated that “dietary interventions for people with mental illness should especially target young adults, those with less than 12 years of education, and obese individuals.”