Nearly one in five adults lives with a mental illness such as depression or anxiety, which are among the leading causes of morbidity, disability and mortality, according to the National Institute of Mental Health. At the same time, consumption of ultra-processed foods has reached record levels in the US.
Researchers at Florida Atlantic University’s Schmidt College of Medicine set out to determine whether there was a direct link between UPF consumption and adverse psychiatric symptoms.
“Eating patterns can affect mental health. For example, poor dietary patterns that lack essential nutrients, have a high glycemic index and are high in added sugars can lead to adverse mental health symptoms.”researchers claim in the study, published in the journalNutrition for public health.
“Although there is some evidence regarding UPF consumption and depressiondata are scarce regarding other adverse mental symptoms, including anxiety and mentally unhealthy days.
“More than 70% of packaged foods in the U.S. are classified as ultra-processed foods and account for about 60% of all calories consumed by Americans. “Given the extent of exposure and the effects of consuming ultra-processed foods, our study has significant clinical and public health implications.” said study author Eric Hecht, MD, PhD, and associate professor at FAU’s Schmidt College of Medicine.
According to recent research, UPF accounted for over half (57%) of the calories consumed by US adults in 2017-2018, down from 53.5% in 2001-2002. In contrast, consumption of whole foods decreased from 32, 7% (in 2001-2002) to 27.4% in 2017-2018.
What are ultra-processed foods?
Researchers define ultra-processed foods as “industrial formulas of processed nutrients (oils, fats, sugars, starches, protein isolates) that contain little or no whole food and typically include flavors, colors, emulsifiers, and other cosmetic additives.”
For the purpose of the study, the researchers used the NOVA food classification, a system recently adopted by the Food and Agriculture Organization of the United Nations. NOVA looks at the nature, extent, and purpose of food processing to categorize foods and beverages into four groups: unprocessed or minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods.
“Ultra-processed food reduces its nutritional value and also increases the calorie count because ultra-processed foods are high in added sugar, saturated fat and salt, while low in protein, fibre, vitamins, minerals and phytochemicals.” Hecht added.
UPF consumption and self-reported “mentally unhealthy” and “anxious” days
Researchers surveyed a nationally representative sample of the US population (10,359 adults aged 18 and older from the US National Health and Nutrition Examination Survey) and measured three mental health symptoms: mild depression (as determined by a 9-item Personal Health Questionnaire ), number of mentally unhealthy days and number of anxious days.
The number of mentally unhealthy days was obtained by answering the question: “In the past 30 days, how many days was your mental health not good?’ The number of anxious days is obtained from the answer to the question: ‘In the past 30 days, how many days have you felt worried, tense or anxious?’.
Research results showed that people who consumed the most ultra-processed foods compared to those who consumed the least amount were more likely to report adverse mental symptoms of mild depression, “mentally unhealthy days”,and “anxious days”.They also had significantly lower rates of zero reporting “mentally unhealthy days”and zero “anxious days”.
A growing body of research examining the relationship between diet and mental health
These results are consistent with other studies examining the relationship between diet and mental health, researchers noted. For example in one A 2014 meta-analysisof twenty observational studies, people who followed diets that included higher intakes of fruits, vegetables, fish, and whole grains had a lower risk of depression.
In another randomized trial, which the researchers say provides the strongest evidence of small to moderate effects, those who were assigned to a three-month healthy dietary intervention (consisting of higher intakes of fruits and vegetables, fish, and whole grains) reported a significant reduction of moderate to severe depression.
“Data from this study add important and relevant information to the growing body of evidence regarding the adverse effects of ultra-processed consumption on mental health symptoms,”said Charles H. Hennekens, MD, PhD, PH, co-author, first Sir Richard Dole Professor of Medicine and Senior Academic Advisor, FAU Schmidt College of Medicine.
source: Public health and nutrition
A cross-sectional study of ultra-processed food consumption and adverse psychiatric symptoms
Authors: Eric M Hecht, et al.