Over the past decade, the California Walnut Commission (CWC) has been conducting research on walnuts and various aspects of cognitive health. A new epidemiological study from Dr. Lenore Arab of UCLA, is the first time the CWC has looked at symptoms of depression, and suggests consuming walnuts may be associated with a lower prevalence and frequency of depression symptoms among American adults1. Researchers examined data from the National Health and Nutrition Examination Survey (NHANES), which draws from a large sampling of the U.S. population. After evaluating study participants for depression, researchers found that depression scores were 26% lower for walnut consumers and 8% percent lower for consumers of other nuts, compared to those who did not consume nuts at all.
More than 26,000 American adults were asked about their dietary intake over the course of one to two days as well as depression symptoms over the past two weeks. Using a widely accepted questionnaire, participants ranked how often they experienced factors such as little interest in doing things, trouble sleeping or sleeping too much, feeling tired or having little energy, and trouble concentrating. According to the findings, walnut consumers were more likely to have greater interest in activities, higher energy levels, less hopelessness (for women), better concentration, and greater optimism.
“According to the CDC, one out of every six adults will have depression at some time in their life. It is important to find low-cost interventions, such as dietary changes, that are easy to implement and may help reduce the incidence of depression,” says lead investigator, Dr. Lenore Arab of the David Geffen School of Medicine at The University of California, Los Angeles.
“Walnuts have previously been investigated for their potential role in cardiovascular and cognitive health, and now we see an association with depression symptoms – providing another reason to include them in a healthy eating plan.”
As with any scientific research, some study limitations should be considered. Due to the cross-sectional observational nature of the study, the findings cannot prove causality and are subject to the risk of diet changing after a diagnosis occurs in response to the condition. Depression may also change typical appetite and eating behaviors resulting in apparent associations that are not causal. In addition, participants were asked about their dietary choices over the course of one to two days, which may not be representative of usual consumption patterns.