By: Agata Blaszczak Boxe
Published: 09/18/2015 10:31 AM EDT on LiveScience
Following a diet rich in produce and low in processed meats — even if you don't do it perfectly — may be helpful in preventing depression, according to a large new study.
To lower the risk of depression, "People can eat everything, but everything in moderation," as long as they try to eat lots of vegetables, fruits, nuts and fish, and avoid fast food and processed meats, said study author Almudena Sanchez-Villegas of the University of Las Palmas de Gran Canaria.
At the start of the study, researchers asked 15,000 Spanish university graduates who had never had depression what they normally ate. Then they asked them again, 10 years later.
The researchers looked at how closely the participants' everyday diets adhered to three healthy diet patterns that involved consuming high amounts of fruits, vegetables, legumes, nuts and fish, and avoiding processed meats. These principles are part of the Mediterranean diet and other healthy diets.
After 8.5 years, 1,550 people in the study reported being diagnosed with depression or using antidepressant drugs.
The researchers found that the people in the study who stuck to the healthy patterns to a moderate or a high extent had a lower risk of depression than those who did not follow these diets at all, or who adhered to them to a low degree.
For example, the risk of depression over the study period for the people who moderately adhered to the Mediterranean diet was about 25 to 30 percent lower than for those who did not adhere to the diet at all, or who adhered to it only to a very small extent, the researchers found. [7 Ways to Recognize Depression in 20-Somethings]
"Even a moderate adherence to these healthy dietary patterns … was associated with an important reduction in the risk of developing depression," Sanchez-Villegas told Live Science.
Moreover, the researchers saw no extra benefit for depression risk when participants followed the diets very closely, compared with moderate adherence, she said.
The researchers don't know for sure what may explain the link between these dietary patterns and people's risk of depression. However, one potential mechanism is that people who follow these patterns may have a lower risk of depression because they get adequate levels of some micronutrients, such as B vitamins, folate or zinc — all of which areessential to brain health, Sanchez-Villegas said.
Conversely, the people who don’t follow these patterns may have a higher risk of depression because of their nutrient deficits, she said.
Sanchez-Villegas' previous research, published in 2006 and 2009, also showed a link between following a Mediterranean diet and a lower risk of depression.
The new study was published today (Sept. 16) in the journal BMC Medicine.
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Leafy Greens
Any genuinely healthy eating plan is going to be heavy on veggies. The MIND diet places a special emphasis on leafy greens, for good reason: Two large-scale studies of older adults found that eating more than two servings of veggies a day was associated with slower cognitive decline overall, with leafy greens having the strongest effect. Participants in one of the studies who consumed more than two servings of vegetables daily appeared to have a level of brain function equivalent to that of people five years younger. Leafy greens generally contain more vitamin E than other vegetables, and the nutrient is a powerful antioxidant that may help keep neurons healthy. For an extra boost, drizzle some olive oil on your salad. Its healthy fats increase absorption of vitamin E.
Berries
If you like to add fruit to your cereal or yogurt, go for blueberries and strawberries -- they're clear winners. A study of roughly 16,000 women age 70 and older revealed that eating at least one serving of blueberries or two servings of strawberries a week delayed cognitive aging by up to two and a half years compared with those who ate less of either fruit. The antiaging effects may be attributed to anthocyanins, antioxidants that may help protect neurons in regions of the brain related to learning and memory.
Fish
The Mediterranean diet can include a whopping six servings of fish a week, but if that's too much for you, don't stress: The scientists behind the MIND diet found that eating fish even once a week can help lower the risk of Alzheimer's. And according to a recent study in the American Journal of Preventive Medicine, consuming baked or broiled fish at least once a week may increase gray matter, a type of brain tissue that diminishes with the disease.
Wine
Multiple studies have found that drinking vino in moderation may help your heart, but the good news doesn't stop there. New research suggests it may also help prevent cognitive decline. A 2014 British Journal of Nutrition study, which followed healthy subjects ages 43 to 70 for five years, discovered that red wine drinkers who consumed about one and a half glasses per day experienced the least memory loss compared with those who drank less. Cheers!
Your Brain-Boosting Grocery List
The MIND diet includes ten brain-healthy food groups, but you don't need to eat each daily.
Every day:
□ Whole grains (three or more servings)
□ Leafy greens (one serving)
□ Other veggies (one or more servings)
□ Glass of wine (opt for red)
Most days:
□ Nuts (like almonds and walnuts)
□ Olive oil (as main cooking oil)
Every other day:
□ Beans
Twice a week or more:
□ Blueberries or strawberries
□ Poultry
At least once a week:
□ Fish
Limit these foods:
Butter (less than one tablespoon per day)
Fast food and fried food (less than one serving per week)
Full-fat cheese (less than one serving per week)
Red meat (less than four times per week)
Pastries and sweets (less than five servings per week)