Study Shows Vegetarian Diet May Improve Mood


Vegan diet improves mood – When Bonnie Beezhold of the University of Arizona set off to study vegetarianism and mood, she hypothesized that people on a plant-based diet would have poorer mood than meat eaters.  Her reasoning was that vegetarians don’t get as much of the Omega 3 fatty acids EPA or DHA.  These fatty acids are crucial for brain cell function. Since omnivores diets low in EPA and DHA are linked to impaired mood, her theory had some grounds. To her surprise, Beezhold found that she was wrong.  Vegetarians not only didn’t suffer from impaired mood, but they actually had better moods than the meat eaters.

First Study Shows Vegetarians Have Better Mood

Beezhold’s first study (get the PDF here), which was published in Nutrition Journal, took subjects from a group of Seventh Day Adventists.  60 of them were vegetarian and 78 of them were omnivores.  Beezhold, along with her research partners, carefully recorded the diets of the participants to account for their intake of fatty acids.  They gauged the mood of the participants by having them complete psychometric tests.

As Beezhold expected, the vegetarian group did have significantly lower levels of fatty acids.  Despite this, the vegetarians still scored much better on their mood tests.

When I first read about this study, I didn’t think much of it.  It seemed logical that vegetarians would have better moods.  Extensive research and surveys show that vegetarians are more educated than their peers, have lower rates of obesity, and lower rates of heart disease and some other diseases.  Of course they would be happier!

But Beezhold’s next study shows that there is a lot more to the vegetarian-happiness connection than just demographics or body weight.

Second Study Shows Switching to Vegan Diet Improves Mood

In this more recent study, which was also published in Nutrition Journal last March, Beezhold didn’t just compare mood levels in vegetarians and omnivores.  She got a group of omnivores and randomly assigned them to one of three groups:

  • Control group which ate meat, fish, and poultry daily
  • A group which ate fish 3-4 times weekly but did not eat meat or poultry
  • A vegetarian group which ate no meat, fish, or poultry

The study lasted two weeks and the subjects had their moods assessed using psychometric tests and also had a cognitive test performed.

Based on all the hype that fish oil supplements have gotten in recent years, you’d expect the fish group to come out with the best mood.  But, once again, it was the vegetarian group that had the best mood.

How Vegetarianism Improves Mood

The findings from these studies are hardly complete, but we can draw some conclusions from them as to why the vegetarian diet improves mood.

The typical omnivore diet is much higher in arachidonic acid (better known as Omega 6) than the typical vegetarian diet.   Studies have found that Omega 6 causes changes to the brain which impair mood.  By contrast, Omega 3s are shown to have a positive impact on mood.  Thus, health experts recommend balancing out Omega 6 to Omega 3 ratios, such as by consuming Omega 3 rich fish.  The theory is that the Omega 3 will counter the negative effects of Omega 6.

While studies have shown benefits of taking Omega 3, such as reducing symptoms of depression in patients, it seems that this isn’t enough.  Several studies show that simply increasing Omega 3 consumption does NOT combat the negative effects of Omega 6.    In other words, you can’t keep gorging on Omega 6 foods (like from refined oils and red meat), pop a fish oil pill, and expect everything to be alright.   So, even though vegetarians may have lower intake levels of Omega 3, they still have better moods because of their lower Omega 6 intake.

Beezhold also theorizes that there could be some other reasons for the better mood in vegetarians.   She writes that vegetarian diets are typically rich in antioxidants, which could provide mood protection by reducing oxidative stress.  Thus, vegetarians may not need as much Omega 3 as their meat-eating counterparts.

Vegetarians Still Need Omega 3!

This study doesn’t mean that vegetarians shouldn’t be worried about Omega 3.  To make sure they are keeping their brain cells happy and healthy, vegetarians (and everyone else for that matter) should be loading up on foods with a low Omega 6 to Omega 3 ratio.  Some good ones are flax, chia seeds, hemp seeds, mustard oil, spirulina, beans, and winter squash.  Check out this post for the top 14 sources of omega 3 for vegans.  Or you can look at our recommendations for vegan Omega 3 supplements.


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Diane Vukovic

Diane Vukovic is a vegan mom, health nut, and kitchen diva. When she's not deducing veggie nutritional facts, she's probably dancing crazily with her daughter or traveling somewhere in Europe.