[Updated May 4, 2018]
You may not expect a mental health practitioner to prescribe a healthy eating plan, but that approach may not be far off. In recent years, scientists have been studying the link between food and mood more closely. They’ve found that there may be a relationship between the risk of common mental health issues – including depression and anxiety – and our diet quality.
“The role of diet in mental health may be particularly important for populations who are vulnerable to nutritional shortfalls, such as infants and the elderly, and those consuming a less-than-optimal diet,” says Robin Kanarek, PhD, a Tufts psychology professor studying the interaction of nutrition and behavior at the Friedman School. Far too many people fall into the latter category. But with a little effort, people generally can improve their eating habits.
Eating Pattern Matters:
When looking at the quality of your diet, consider both foods to eat more of and those to limit. Observational studies show that healthy eating patterns that include plenty of nutrient-rich plant foods, such as vegetables, fruits and whole grains, and omega-3-rich foods, such as salmon and flax seeds, are associated with decreased risk of depression and anxiety.
On the other hand, a Western-style diet – rich in foods high in refined carbohydrates (sugar and white flour), highly processed foods and sugary beverages – is associated with increased risk of depression and anxiety.
Modi-Med Diet for Mood Improvements
Encouraged foods and recommended number of servings*:
Whole grains: 5-8 servings per day
Vegetables: 6 per day
Fruit: 3 per day
Low-fat, unsweetened dairy foods: 2-3 per day
Olive oil: 3 Tbsp per day
Raw unsalted nuts: 1 per day
Legumes: 3-4 per week
Fish: 2 or more per week
Lean red meat: 3-4 per week
Chicken/turkey: 2-3 per week
Eggs: up to 6 per week
Discouraged foods (limit to 3 per week):
Sweets, refined cereals, fried food, fast food, processed meats, sugary drinks and alcohol (red wine in moderation)
*For guidance on serving size, visit ChooseMyPlate.gov.
Testing Eating Patterns:
“While the results of earlier studies suggest a relationship between nutrient intake and mood, research that actually examines the effects of diet on measures of mental health is needed to confirm a causal relationship between food and mood,” Kanarek says. That will require rigorous intervention studies. The first controlled trial explicitly designed to test dietary improvements in people with depression, dubbed the SMILES trial, was recently published in BMC Medicine. It suggests dietary approaches to improving mental health warrant further study.
The three-month trial was led by scientists at Deakin University in Australia. They enrolled 67 adults with relatively poor-quality diets and moderate to severe depression (under medical treatment). They reported a low intake of fruits, vegetables, lean proteins and fiber but a high intake of sweets, processed meats and salty snacks.
Half of the people were asked to follow a modified Mediterranean diet (“Modi-Med Diet,” above) and complete nutrition counseling sessions. The other half (the control group) attended general social support sessions but received no diet advice.
Compared to the control group, those in the diet group had significant improvements in depression and anxiety symptoms. The greatest benefits were seen in those who improved their diet the most. At the end of the trial, 32% of people in the Modi-Med Diet group no longer met criteria for depression. In comparison, only 8% of those in the control group had remission of their depression. These findings are very encouraging but now need to be replicated in larger studies.
Scientists also are taking a closer look at why diet might impact mental health. Some possibilities they’re exploring include diet’s effects on the gut microbiota (bacteria and other microbes), inflammation, oxidative stress (cell damage) and brain plasticity (changing structure, wiring and function).
While scientists work out the details linking diet and mood, don’t wait to adopt a healthy eating pattern. We already know it could benefit your physical health. Its potential to lift your mood may be a bonus.
To learn more: BMC Medicine, January 2017