Depression is a huge global health problem
Depression accounts for a substantial fraction of disability worldwide and creates more medical burden than any other form of mental illness. In addition to the damage depression causes, it predicts increased risk of cardiovascular disease, the most common cause of death.
The growing prevalence of chronic diseases, including depression, may reflect an evolutionary mismatch between ancestral human environments and modern living. Key features, such as declining social capital, greater inequality, and loneliness, may account for the increasing prevalence of depression. Modern humans in Western countries trend toward being overfed, undernourished, sedentary, sunlight-limited, sleep deprived, and socially isolated.
Healthy lifestyle choices, including physical activity, diet, and not smoking, have received considerable attention for preventing non-communicable diseases. However, these lifestyle choices have received little attention with respect to the mental disorders of depression and anxiety. Accumulating evidence suggests that adopting the healthy lifestyle choices of Keep Moving and Eat Better, plus not smoking, predicts lower risk of developing depression. Mental disorders should be included under the umbrella of non-communicable diseases along with a primary prevention strategy that features healthy lifestyle choices.
Lifestyle choices matter
According to psychologist Roger Walsh at the University of California, Irvine, mental health professionals underestimate the importance of lifestyle factors as contributors to various psychopathologies and as promoters of individual and social mental health and well-being. Walsh identifies exercise, nutrition, time in nature, relationships, recreation, and stress management, religious and spiritual involvement, and contribution and service to others as key factors. Exercise compares favorably with medication as a therapy for depression, but Walsh notes that only 10 percent of health professionals recommend exercise. This in spite of the fact that such professionals probably exercise themselves and probably understand the benefits of exercise.
Foods to be emphasized include fish, vegetables, and probably fruit, with animal fats de-emphasized. Recreation and contemplation in natural settings can enhance aspects of both physical and mental health including greater cognitive, attentional, emotional, and spiritual subjective well-being, as well as stress management. Good relationships with other people predict greater happiness, quality of life, resilience, and cognitive capacity. In our digital age of electronic gadgetry that connects us, the number and intimacy of relationships seems to be declining. Service to others can provide greater benefits to the giver than the receiver, including greater purpose in life. Religious and spiritual involvement can foster service and contribution to others, greater life purpose, and better health behaviors. Sadly, too many people have little social support, don’t understand the power of healthy lifestyle choices, and have a passive belief that healing arises from an outside authority or from medication—as opposed to one’s daily lifestyle choices. Unfortunately, doctors often fail to promote healthy lifestyle choices to their patients. Given the huge health and well-being cost of a typical American lifestyle, embracing healthy lifestyle choices needs to be a centerpiece of personal and public health initiatives.
While many studies show that physical activity predicts lower risk of depression, it’s less clear that physical activity decreases the onset of depression. A new review and meta-analysis of 111 reports involving over 3 million adults found that physical activity predicted 21 and 22 percent lower odds the odds of developing depression or increasing subclinical depressive symptoms, respectively, after adjusting for confounding factors. The odds of either depressive outcome declined by 27 percent for moderate or high physical activity compared to 23 percent to low physical activity, and by 31 percent when participants increased their level of physical activity during follow-up compared to 19 percent for participants with a single measure of physical activity at baseline. The beneficial effect of physical activity on sub-clinical depressive symptoms suggests that persons with such symptoms might be able to avoid full-blown depression if they were to increase their level of physical activity.
Abundant research shows that increased physical activity predicts reduced risk of depression. Yet, the shape of the relationship between increased physical activity and the rate of decline in risk of depression remains unknown. Researchers in the UK conducted a systematic review and meta-analysis of 15 published studies that investigated at least three levels of physical activity in relation to risk of depression and depressive symptoms. Analyses showed a declining risk of major depression as physical activity increased to about 22 minutes of brisk walking per day, after which additional physical activity did not predict further benefit. Here’s good news: Even participants who got the equivalent of 11 minutes of brisk walking per day had 18 percent lower risk of major depression. Similarly, risk of increased depressive symptoms declined as physical activity increased to about 22 minutes of brisk walking per day, after which further decrease in risk slowed considerably. Participants who got the equivalent of 22 minutes of brisk walking per day had 25 percent lower risk of major depression compared to participants who reported no physical activity. This study reprises many other studies that show significant health benefits of increased physical activity. Can’t you find 22 minutes each day for a brisk walk to reduce your risk of depression, not to mention many other health benefits?
Recent research has identified factors that underlie the development of both depression and cardiovascular disease. Thus, healthy lifestyle choices that predict lower risk of cardiovascular disease might also reduce the risk of depression. This means that widely accepted healthy lifestyle choices, such as increased physical activity and a better diet, which help you avoid cardiovascular disease, might also help you avoid depression. A team of Spanish researchers noted that substantial evidence links the Mediterranean diet with lower risk of depression. Key dietary factors include lots of vegetables, fruits, whole grains, nuts, olive oil, and oily fish; low consumption of meat (especially processed red meat), dairy products, sugary drinks, and refined flour in its many guises; and moderate amounts of red wine. Thus, the advice that you’ve heard many times to Eat Better may benefit you more that you previously thought by reducing your risk of depression.