I’ve been surrounded by vegetarians my whole life. I lived with two vegetarians for two years, and was the sole meat eater in the house. My best friend in college fluctuated between a slim-jim eating omnivore to a strict vegan who ordered celery sticks and hummus at sports bars known for wings and mozzarella sticks. And my most recent roommate recently made the switch to vegetarianism after reading an inspirational book that encouraged her to make some life changes.

My roomie’s switch, combined with the fact that I work in the health and nutrition field, nudged me in the direction of research. Why become a vegetarian? Andof course, I dove deep into the gaping hole we call the Internet. But, I did come away with some key takeaways and pros for living the meatless life. Of course there’s the obvious – save the animals, the meat industry treats animals terribly, the carbon footprint of red meat, etc. However, in the least selfish way possible, I wanted to know how is being a vegetarian going to benefit ME? The most compelling (for me, at least) answer I found, was the vegetarians may be happier than their meat eating friends.

Let’s starts with arachidonic acid. Arachidonic acid (which I will refer to as AA from now on) is an omega-6 fatty acid. This is a close relative of the ever popular omega-3 fatty acids, found in the fish oil you take daily, and known to prevent things like heart disease and arthritis [1] .

Omega-6 fatty acids, like AA, is found throughout your body. You need it for the proper function of almost all of your organs, including the brain, and it does a bunch of different jobs. And because AA is high in chicken, eggs, and most meat, meat eaters have more of it flowing through their system [1]. One study showed that omnivores had nine times the amount of AA in their system [2].

In the brain, AA can cause a ‘cascade of neuroinflammation’ or basically cause inflammation in your brain. This can have some negative effects on mental health [3].

There are a plethora of studies that connect depression to arachidonic acid, and connect improved mood to vegetarianism. One study concluded that omega-6 fatty acids can even increase the risk of suicide and depression [4]. In another two week trial, “meat eating adults placed on a two week vegetarian diet reported significantly greater improvements in mood compared to participants who continued to eat meat, fish, or poultry” [5].

Not buying the whole two-week improvement thing? In another study, researchers measured the effects of a vegan nutrition program for the workplace over 22 weeks. The control group followed their normal diet, meat included. The other group was given vegan diet restrictions. They were not, however, giving caloric, carb, or portion restriction. The study found that “participants following a vegan diet had greater diet satisfaction compared with the control participants with no diet restrictions at all.” The participants following a vegan diet reported that they had improved digestion, increased energy, and better sleep (all of which I could definitely improve). The vegan group also reported increase in physical functioning and mental health over the 22 weeks [6].

A group of researchers from Israel accidently discovered a link between arachidonic acid and depression when researching a link between omega-3 (not 6, like AA) fatty acids and depression. And while they didn’t find any difference in omega-3 fatty acid levels, they did find that brains from rats with depression had higher concentrations of arachidonic acid [1].

So, less arachidonic acid, happier person. That simple right? A lack of arachidonic acid isn’t the only reason that vegetarians are shown to be happier. Vegetarians are often physically healthy, and mental health could be associated with this. Fruits and veggies, turns out, may also be a natural antidepressant [7].

To understand how, we need to understand how depression works. One theory is the monoamine theory of depression – the theory that depression is caused by a chemical imbalance in the brain. For our nerves in our brain to communicate, the send out neurotransmitters – dopamine, serotonin, and norepinephrine. These neurotransmitters are sucked up by the nerve to be used again. At the same time, we’re constantly making new neurotransmitters. So, to make sure that these remain balanced, an enzyme called monoamine oxidase chews up some of the neurotransmitters. Depressed people have an elevated level of these enzymes, so their neurotransmitter levels are lower than they probably should be [8].

Of course, modern medicine has developed antidepressants that stop our nerves from ‘sucking up’ dopamine, serotonin, and norepinephrine so that they stick around longer. There are also monoamine oxidase inhibitors, which seems like the most logical solution. But these drugs have crazy side effects, and are considered an absolute last resort [9].

Okay enough of the technical stuff, what does this have to do with being a vegetarian? Some foods have naturally occurring monoamine oxidase inhibitors – which means they stop those enzymes from chewing up your neurotransmitters and help the chemical balance in your brain. Some spices, for example, have a lot of them, but we do not consume enough for it to be really impactful. Another naturally occurring antidepressant – tobacco! But tobacco increases your risk of developing cancer, so again probably not your best bet. However, you can find this inhibitor in apples, berries, grapes, onions, and green tea. They may affect the chemical balance in your brain enough to improve your mood [10].

References

[1] American Society For Biochemistry And Molecular Biology. “Study Links Brain Fatty Acid Levels To Depression.” ScienceDaily. ScienceDaily, 25 May 2005. <>.

[2] http://nutritionfacts.org/video/improving-mood-through-diet/

[3] http://nutritionfacts.org/video/plant-based-diet-mood/

[4] J S Vaz, G Kac, A E Nardi, J R Hibbein. Omega-6 fatty acids and greater likelihood of suicide risk and major depression in early pregnancy. J Affect Disord. 2014 Jan;152-154:76-82.

[5] Beezhold BL, Johnston CS, Daigle DR. Preliminary evidence that vegetarian diet improves mood. American Public Health Association annual conference, November 7-11, 2009. Philadelphia, PA.

[6] U Agarwal, S Mishra, J Xu, S Levin, J Gonzales, N D Barnard. A multicenter randomized controlled trial of a nutrition intervention program in a multiethnic adult population in the corporate setting reduces depression and anxiety and improves quality of life: the GEICO study. Am J Health Promot. 2015 Mar-Apr;29(4):245-54.

[7] http://nutritionfacts.org/video/fighting-the-blues-with-greens-mao-inhibitors-in-plants/

[8]J. H. Meyer, N. Ginovart, A. Boovariwala, S. Sagrati, D. Hussey, A. Garcia, T. Young, N. Praschak-Rieder, A. A. Wilson, S. Houle. Elevated monoamine oxidase a levels in the brain: An explanation for the monoamine imbalance of major depression. Arch. Gen. Psychiatry 2006 63(11):1209 – 1216

[9] F. López-Muñoz, C. Alamo. Monoaminergic neurotransmission: the history of the discovery of antidepressants from 1950s until today. Curr Pharm Des. 2009 15(14):1563-1586.

[10] A. C. Tsai, T.-L. Chang, S.-H. Chi. Frequent consumption of vegetables predicts lower risk of depression in older Taiwanese – results of a prospective population-based study. Public Health Nutr. 2011 15(6):1087-1092