The Nurses Health Study II (NHS II) has found that a diet high in ultraprocessed food (UPF), particularly artificial sweeteners, has been linked to increased depression risk. Nurses who consumed more than eight servings daily had about a 50% higher risk of developing depression than those who consumed four or fewer servings daily. However, only artificial sweeteners and artificially sweetened beverages were associated with an increased risk of depression.
Animal studies have shown that artificial sweeteners may trigger the transmission of particular signaling molecules in the brain that are important for mood. Given this potential association between ultraprocessed food and multiple adverse health conditions, wherever possible individuals may wish to limit their intake of such foods. This may be a lifestyle change that could have important benefits, particularly for those who struggle with mental health.
The findings are based on 31,712 mostly non-Hispanic White women who were free of depression at baseline. As part of the NHS II, the women provided information on diet every 4 years using validated food frequency questionnaires. Compared to women with low UPF intake, those with high UPF intake had greater body mass index (BMI), were apt to smoke, have diabetes, hypertension, and dyslipidemia, and were less apt to exercise regularly.
A study has found that a combination of a healthy diet and physical activity can reduce the risk of depression and its impact on quality of life. However, the study has limitations, including the potential for factors like obesity, smoking habits, and less-active lifestyles to influence the results. It is unclear if low mood increases the risk of weight gain or vice versa, and the body mass index (BMI) does not distinguish between excess weight and lean muscle versus fat. The study also relied on participants accurately recalling their eating habits and mental health diagnoses, making it difficult to determine if the findings would apply to other groups.