12 March 2012

Happy to be vegetarian: Study shows vegetarians have better moods than omnivores

If you think you’re happier than your non-vegetarian friends, there is new evidence to suggest that you may not be imagining it.

A study conducted by Dr. Bonnie Beezhold, Assistant Professor of Nutrition at Benedictine University, and Dr. Carol Johnston, Professor of Nutrition at Arizona State University School of Nutrition and Health Promotion, suggests that following a vegetarian diet free of meat, fish and poultry may reduce short-term mood disturbance in omnivores.

“I was really interested in the importance of the long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in brain cells,” said Beezhold. “The major source of these fats is fish and seafood so I wanted to look at a population who were not getting a regular supply.”

Beezhold began by surveying grocery store shoppers at specialty grocers that sold fish, asking them to answer questions about mood, and those who said they ate fish had better moods than those who didn’t eat fish. While it was a simple survey and small sample size, Beezhold said it provided the jumping off point for her larger survey of Seventh Day Adventists, which basically found the same results.

Beezhold later added that her initial reason for looking further into the research was that based on previous findings, depressed patients had lower levels of DHA and EPA in their blood.

“Research shows that a low or high intake will be reflected in blood concentrations of these fats,” she said. This led her to the perfect testing group: vegetarians.

Omnivore diets are high in arachidonic acid (AA) compared to vegetarian diets and according to previous research, high intakes of AA have promoted changes in the brain that can disturb mood. However, omnivores who increased their intake of fish also increased their levels of EPA and DHA, fats that reduce the effects of AA in living organisms.

In their new study, published in Nutrition Journal on Feb. 14, Beezhold and Johnston found that despite their lower intakes of EPA and DHA, vegetarians had better mood scores than their omnivore counterparts who also ate fish.

The study consisted of 39 randomly selected omnivores who were assigned to a control group and were instructed to eat either meat, poultry and dairy daily (OMN), 3 to 4 servings of fish weekly (FISH) or no fish, meat, or poultry at all (VEG). Before and after the experiment, participants were asked to complete a food frequency questionnaire, the Profile of Mood States questionnaire and the Depression Anxiety and Stress Scales.

After two weeks, the VEG participants decreased their AA, EPA and DHA intakes while the FISH participants increased their EPA and DHA intakes. Though the moods of the FISH and OMN participants remained unchanged, the VEG participants showed several improvements in mood scores.

“I was very surprised,” said Beezhold, who is not a vegetarian herself. “The fish group did get better, but not significantly, so I began speculating why that would be.”

The DASS-Stress scale, one of the tests given to participants, measures a syndrome of “stress/tension” similar to a Generalized Anxiety Disorder diagnosis on the DSM-IV. After taking the test, declines over the two-week period in the VEG group suggested that eating a vegetarian diet may also help to alleviate mental stress.

“This is another incentive to try vegetarianism,” said Boston University sophomore Jeanine Ilacqua, who tried vegetarianism for a month, but reverted back to an omnivore diet when she wanted chicken parmesan for her birthday. “As a college student, I’m always looking for ways to combat stress and the sometimes depressive moods that I can get into while at school.”

Based on the results of the study, eating a plant-based diet not only makes animals happier, but may also make those who choose not to eat animals happier as well.

“I think you have to be careful not to overstate the results of one or two studies,” Beezhold cautioned. However, the nutrition professor added that the results of the study alleviated her concerns about vegetarians getting enough omega-3 fats to maintain mental health compared to omnivores.

With this new study in mind, it is the perfect time to tell your non-vegetarian friends to replace their hamburger at lunch with a salad. It could just make their day.

Samantha Wood | @bostonu14 | Blog
Boston, MA Samantha is a journalism student at Boston University who hopes to pursue a career in the health magazine field. She is interested in both nutrition and cooking, especially vegan cooking. She became a vegan while in college and has remained that way ever since. She created a blog to document her efforts and it has become a collection of vegan recipes, restaurants and nutrition information. Samantha hopes to develop her photography skills as well so she can take appetizing photos of all her recipes. She loves chocolate (the vegan kind of course) and dogs, as well as California, where she hopes to live someday.

Photo credit:cc:flickr.com/photos/jetheriot