Diet + exercise cuts depression

Depression prevention usually gets sold as one habit at a time: eat better, or move more. New data out of South Korea says the bigger effect shows up when those two habits travel together, not separately. (en.sedaily.com) The study came from Seoul National University Hospital, where Professor Park Min-sun’s team looked at 17,737 adults in the Korea National Health and Nutrition Examination Survey across 2014, 2016, 2018, and 2020. They removed people who already had depression, then compared diet quality, weekly physical activity, and later depression-screen scores. (en.sedaily.com) To measure depression, the researchers used the Patient Health Questionnaire, a nine-question checklist doctors use to flag likely depression. In this dataset, a score of 10 or higher counted as moderate depressive symptoms. (en.sedaily.com) They split people into four groups: low diet quality plus low activity, high diet quality only, high activity only, and both together. Only 4.6 percent of all participants screened positive, but the differences between those four groups were large. (en.sedaily.com) People who had both a healthier diet and higher physical activity had about a 45 percent lower risk of depressive symptoms than people who had neither. People with higher activity alone saw a 26 percent reduction, while better diet alone was not statistically significant in this analysis. (en.sedaily.com) The pattern was even stronger in some groups. Women who combined both habits had a 52 percent lower risk, and adults ages 45 to 65 and 65 and older saw reductions of about 58 to 59 percent, while men and adults under 45 did not show a clear association in this sample. (en.sedaily.com) That result fits a bigger shift in mental-health research away from single fixes and toward stacked routines. A 2023 Nature Mental Health briefing described a 287,282-person cohort study in which a “favorable lifestyle” with multiple healthy factors was linked to lower depression risk even in people with higher genetic susceptibility. (nature.com) Exercise already has unusually strong evidence on its own for treating depression after it appears. A 2024 British Medical Journal review of 218 randomized trials with 14,170 participants found moderate reductions in depression from walking or jogging, yoga, strength training, and mixed aerobic exercise. (bmj.com) Diet is the messier part of the science, because food studies are harder to randomize and people misreport what they eat. A 2022 systematic review in Cureus found observational evidence that diets with more vegetables and fruits, and less fast food and other pro-inflammatory patterns, were linked to lower depression risk, while also calling for stronger prospective and randomized studies. (pmc.ncbi.nlm.nih.gov) So this South Korean result does not mean one salad and three gym visits will “prevent” depression. It means the body seems to respond more like a system than a checklist, where food quality and regular movement reinforce each other more than either one does alone. (en.sedaily.com)