Can eating meat be detrimental for your mood and mental health? Is there a reason that your vegetarian friend is so energetic and cheerful all the time? The latest nutrition research suggests there may be scientific validity to these observations.
According to a recent study published this February by Bonnie Beezhold in Nutrition Journal, a randomized group of omnivores reported improved mood states after only two weeks of eliminating meat, fish and poultry from their diets.
The study consisted of three groups. The omnivores were randomly assigned to either a control group, which included consuming meat, fish and poultry daily, a second group assigned to consuming fish 3-4 times a week but avoiding meat and poultry, and a third group that avoided meat, fish, and poultry altogether. At baseline and at the end of the two weeks, the participants completed a food frequency questionnaire, a "Profile of Mood States" questionnaire, and a "Depression Anxiety and Stress Scale." According to the self-reported results, both the omnivore's and the fish eater's moods remained unchanged, while the vegetarian group showed significant improvements in their mood scores at the end of the two week trial. (1) This and other studies conducted by Beezhold suggest that vegetarianism is associated with overall healthier mood status.
So what is it about meat and poultry that may have adverse affects on our mood? Omnivorous diets are high in arachidonic acid (omega-6) in comparison to vegetarian diets. Past research has shown that high intakes of arachidonic acid, found mainly in red meat, poultry, and some fish, promotes changes in the brain that can negatively disturb our mood. High blood levels of arachidonic acid, in relationship to eicosapentaenoic acid (omega-3), have been linked to clinical symptoms of depression. (2) While omega-3s, especially fish oil, have become the poster child for brain function and lowering oxidative stress, the high levels of omega-6 in our modern omnivorous diets may be doing us more harm than good. A possible solution to this imbalance of omegas in your diet could be the addition of several amazing plant sources of omega-3s such as walnuts and flaxseed, that provide the benefits of omega-3s with lower levels of omega-6s.
These findings challenge what we have come to learn about the beneficial effects of fish our brain and, according to Beezhold, suggest an unrecognized benefit of vegetarian diets that are naturally lower in omega fatty acids. While vegetarians typically have lower levels of both omega fatty acids, they also have much higher circulating concentrations of antioxidants due to their increased plant consumption. (3) Vegetarians therefore may not need as many omega fatty acids to protect them from oxidative stress.
While there is still debate about the ideal diet for optimum brain function, this field of research certainly raises another interesting argument that points to how cutting down on our meat and poultry consumption can have beneficial impacts on our overall health and well-being.
(1) Beezhold and Johnston: Restriction of meat, fish, and poultry in omnivores improves mood: A pilot randomized controlled trial. Nutrition Journal 2012 11:9 (http://www.nutritionj.com/content/pdf/1475-2891-11-9.pdf)
(2) Adams, Peter B., Sheryl Lawson, Andrew Sanigorski, and Andrew J. Sinclair. "Arachidonic Acid to Eicosapentaenoic Acid Ratio in Blood Correlates Positively with Clinical Symptoms of Depression." Lipids 31.1 (1996): S157-161. Print. (http://www.springerlink.com/content/u028h00453272554/about/)
(3) Beezhold et al., Vegetarian diets are associated with healthy mood states: a cross-sectional study in Seventh Day Adventist adults Nutrition Journal 2010, 9:26 (http://www.biomedcentral.com/content/pdf/1475-2891-9-26.pdf)
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