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Living on a private Greek island may be out of the cards for most of us, but that doesn’t mean we can’t eat like we’re on a Mediterranean vacation (without leaving home). Research suggests the Mediterranean diet — consisting primarily of fresh fruits and vegetables, whole grains, beans, nuts and seeds, herbs and spices, and olive oil and supplemented with occasional dairy, poultry, fish, and red wine — doesn’t just promote a healthy body, but can actually make us happier, too. The diet has been touted by organizations like the American Heart Association, the Mayo Clinic, and the Cleveland Clinic as a heart-healthy, cancer-fighting, diabetes-preventing eating plan Mediterranean diet and diabetes prevention: Myth or fact? Kastorini CM, Panagiotakos DB. World Journal of Diabetes. 2010 July 15; 1(3):65-67.. But can it also boost our mood?
The study compares how foods from a traditional Mediterranean diet (specifically vegetables, fruit, olive oil, legumes, and nuts) affect the overall mood when compared to a modern Western diet heavy in sweets, soda, and fast food Intake of Mediterranean foods associated with positive affect and low negative affect. Ford PA, Jaceido-Siegl K, Lee JW, Youngberg W, Tonstad S. Loma Linda University, School of Public Health, Department of Preventive Care, USA. Journal of Pscyhosomatic Research, 2013 February; 74(2): 142-8.. The proof is in the pudding (or the hummus). Participants who ate plenty of fresh fruits and veggies, olive oil, nuts, and legumes were much happier than those who chowed down on desserts, soda, and fast food. Interestingly, eating red meat and fast food put women in a bad mood, but didn’t seem to affect the men. It's worth noting the researchers did not control for grain consumption — whether they white, whole-grain, or gluten-free — so we don't know how the type or amount of grains eaten influenced these results.
Can We Trust It?
Maybe. The researchers recruited about 96,000 subjects from the Adventist church all around the United States to fill out a questionnaire detailing how frequently they ate certain foods over the course of one year. Subjects were recruited and filled out questionnaires between 2002 and 2006 — each person filled out the food frequency questionnaire only once. About 20,000 participants were randomly selected from the group to fill out a Positive and Negative Affect Schedule (PANAS) survey in 2006. Of that number, 9,255 participants returned the survey and were included in study’s final results. Both surveys were self-reported, so there is a possibility that some responses were biased or untruthful. The answers seem fairly black-and-white, but how legitimate are these conclusions?
While the study group was sizeable, it only included a specific group of Americans. The subjects came from all around the country, but the researchers excluded people under age 35, smokers, non-Adventists, and anyone of an ethnicity other than black or white. The results could be different in other countries where food may be of higher or lower quality, or in ethnic or religious communities with different lifestyles. Despite the huge number of people who participated, the study’s main weakness is a lack of diversity.
Regardless of who the researchers included and who they did not, the results show diet definitely affects how we feel. The healthy fats present in the Mediterranean diet may be the key to a good mood. Changes in levels of BNDF, a protein that controls many brain functions, may contribute to mental disorders like schizophrenia and depression. Studies show eating food rich in omega-3 fatty acids — found in fish and some nuts — can help stabilize BNDF levels Dietary omega-3 fatty acids normalize BDNF levels, reduce oxidative damage, and counteract learning disability after traumatic brain injury in rats. Wu A, Ying Z, Gomez-Pinilla F. Department of Pscyhological Science, University of California at Lost Angeles, USA. Journal of Neurotrama, 2004 October; 21(10):1457-67.. Another study tested this theory on humans and found that participants with depression who stuck to a Mediterranean diet had consistently higher levels of BNDF (the participants without a history of depression experienced no change in BNDF levels).
Other studies show that fresh fruits, vegetables, and plenty of greens are good for mental health, too. Polyphenols, compounds found in plant-based foods, can positively affect brain cognition Natural mood foods: the actions of polyphenols against psychiataric and cognitive disorders. Gomez-Pinilla F, Nguyen TTJ. Nutritional Neuroscience. 2012 May; 15(3):127-33.. In a nearly 10-year survey, researchers found that greater fruit and vegetable intake was linked to lower odds of mood disorders like depression, distress, and anxiety The association between fruit and vegetable consumption and mental healthy disorders: Evidence from five waves of a national survey of Canadians. McMartin SE, Jacka FN, Colman I. Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada. Preventive Medicine. 2013 January 4..
The new study has some limitations, but regardless, the results are another good argument in a long history of research advocating a plant-heavy diet. So consider putting down the processed stuff and whipping up some stuffed grape leaves for a healthier, happier lifestyle. (Not into grape leaves? Try one of these meals to boost your mood!)
Would you try a Mediterranean diet? Tell us your take in the comments below or tweet the author @SophBreene.