The study found the odds of depression over a six-year period were 11 percent lower among the people who most closely followed the DASH diet compared with people whose diets were the least like the DASH diet. An estimated 5 percent of people age 50 and older have major depression, according to the 2016 National Survey on Drug Use and Health. The DASH diet — known formally as Dietary Approaches to Stop Hypertension — was created to help people with high blood pressure manage the condition. The diet limits intake of salt, red meat, sugars, and butter or margarine. It emphasizes intake of whole grains, vegetables, and fruit and recommends only fat-free or low-fat dairy. The diet is widely recommended because studies show it also facilitates weight loss and improves overall cardiovascular health. The study is another indication that food affects all organs of the body, including brain function, says the lead author of the research, Laurel Cherian, MD, of Rush University Medical Center in Chicago. “The idea that food can have a positive impact on health is not a new one,” Dr. Cherian says, referencing the long-lived proverb, often attributed to Hippocrates, “Let food be thy medicine and medicine be thy food.” But depression in the modern age is usually treated with medications. “The focus has been on the pharmacology intervention,” Cherian says. “Those are wonder drugs that are very important for our patients. But shouldn’t we use diet and lifestyle as a way to augment treatment?”
The DASH Diet Trumped the Western and Mediterrean Diet for Depression
For their study, Cherian and her colleagues explored whether diet could be used to lower the risk of depression. They utilized data from the Memory and Aging Project at Rush University that follows older Americans without dementia as they age to explore the onset of the condition and factors that may influence dementia. The study included 964 people with an average age of 81 who were followed for more than six years. The participants were monitored for symptoms of depression and completed questionnaires about food intake. Based on the food-intake questionnaires, the researchers classified the participants into groups based on how closely they followed either the DASH diet, the Mediterranean diet, the MIND diet or the traditional Western diet. The Mediterranean diet features plant-based foods, replacing butter with olive or canola oil, limiting red meat and eating fish or poultry. The MIND Diet (Mediterranean-DASH Intervention for Neurodegenerative Delay) is a hybrid of the DASH and Mediterranean diet that emphasizes nutrients that are thought to promote brain health, such as green leafy vegetables, nuts, berries, olive oil and a low- to moderate intake of alcohol. The traditional Western diet, Cherian says, “is classically higher in red meat, salt and saturated fats, like butter, and lower in fruits and vegetables. It has more highly refined and processed foods, such as white bread, snack items, and sugar.” The study found that people who followed the DASH diet were the least likely to develop depression, while those who followed the traditional Western diet had the highest risk for developing depression. The study only links the DASH diet with a reduced risk for depression — it does not show that it causes this effect. But, Cherian, notes, the researchers controlled for other factors that may cause depression in order to try to isolate the impact of diet.
How Does the DASH Diet Affect Mood?
The same mechanisms of the DASH diet that promote cardiovascular health may also promote good brain health, Cherian says. “We know a healthy diet reduces your risk for insulin resistance and metabolic syndrome,” conditions that are caused by inflammation in the cells, she explains. Cherian, a vascular neurologist, advises people to introduce aspects of the diet gradually in order to better adjust and stick with it over time. “What’s interesting about our results is it shows that it doesn’t have to be all or none,” she says. “If you incorporate this diet gradually, you may still see a benefit.” It also helps to make an overall commitment to a healthier lifestyle that involves the entire family and includes exercise. “We live in a culture that makes eating poorly very easy and makes eating healthy very challenging,” Cherian says. “A lot of this is about getting the whole family on board and changing your lifestyle.”
