Approximately 16.1 million Americans aged 18 or older experience at least one major depressive episode each year, according to the latest estimates from the National Institute of Mental Health. For many of these people, symptoms of depression, such as sadness, fatigue, hopelessness, feelings of worthlessness, loss of pleasure, and disturbances in sleep and appetite, are eased with medications and/or talk therapy. Now a small preliminary study dubbed SMILES has suggested that dietary changes may also help lift mood.
WHAT YOU CAN DO
These suggestions may help you avoid mood problems associated with your diet:
- Keep a food journal noting the relationship between your mood and what you’ve eaten.
- Consider taking a multivitamin or supplements if you know your diet is lacking in specific nutrients. For example, if you don’t usually eat fish, fish oil supplements may help ensure you get adequate amounts of brain-healthy omega-3 fatty acids.
- Consult with a mental health professional if mood symptoms last two weeks or longer or if they affect your daily functioning.
The research found that adults with major depression who participated in a 12-week program of nutritional counseling and dietary support experienced significantly greater improvements in mood than a similar group who received 12 weeks of social support. Psychological tests administered before and after the study revealed that 32 percent of the diet participants—who were advised to increase their levels of healthful foods such as fruits and vegetables, fish, and whole grains—achieved remission from depression, while only 8 percent of the social-support group did so, according to a Jan. 30, 2017 report in BMC Medicine.
“This study is one of very few published randomized, controlled studies assessing the association between diet and mood in humans,” says MGH psychiatrist Uma Naidoo, MD, an Instructor in Psychiatry at Harvard Medical School. “Although the study was small—involving only 67 participants—and will need to be replicated in larger trials, it offers valuable insights into the important role of the foods we consume in affecting how we feel.
“The hopeful message suggested by this research is that if we pay attention to what and how we eat, we might be able to improve a depressed mood, or even avoid depression altogether.”
The BMC Medicine study encouraged participants to adhere to the Mod/MedDiet, which was based on the Dietary Guidelines for Adults in Greece. The eating plan was similar to the well-known Mediterranean diet, which has been associated with numerous benefits for physical and mental health.
The ingredients are easily obtainable and involve a large variety of healthful foods and beverages, making adherence to the regimen easy and relatively inexpensive for most people.
How It Works
The study authors suggested several possible ways a better diet might help reduce depression. They included positive effects on levels of inflammation and oxidative stress in the brain; promotion of brain plasticity, which is linked with improvements in mood; positive effects on microbes in the gut that improve brain health; and the benefits of activities such as planning meals, shopping, and cooking that may have a therapeutic affect.
On Your Own
“This nutritional plan addresses many of the dietary factors that have been linked in earlier studies to greater risk for depression,” Dr. Naidoo points out. “And the good news is that people can improve their diet on their own, provided that they take certain basic precautions, such as checking with their physician before significantly changing their diet.
“Also, read food labels to be sure that foods do not contain hidden ingredients, such as added sugar, that might cancel out the health benefits associated with that food. And be sure to stay hydrated. Dehydration, especially in older adults, can result in effects such as irritability, fatigue, and confusion.”
The following outline indicates the 12 key food groups diet participants were encouraged to consume, and the number of servings recommended:
- Whole grains: 5-8 servings per day
- Vegetables: 6 servings per day
- Fruit: 3 servings per day
- Legumes: 3-4 servings per week
- Low-fat and unsweetened dairy foods: 2-3 servings per day
- Raw, unsalted nuts: 1 serving per day
- Fish: 2 servings per week
- Lean red meats: 3-4 servings per week
- Chicken: 2-3 servings per week
- Eggs: Up to 6 servings per week
- Olive oil: 3 tablespoons per day
- Red wine (white is less desirable): 2 drinks a day with meals
Foods that were limited to no more than 3 servings per week included:
- Refined cereals
- Fried food
- Fast food
- Processed meats
- Sugary drinks
- Beer and spirits
By percentage of total energy supplied, the Mod/MedDiet was: 18 percent protein; 40 percent fat; 38 percent carbohydrates; 2 percent alcohol, and 3 percent fiber/other.