As people become more aware of the environmental impact of the meat industry, it is likely that more people will consider cutting some meat out of their diets. Further, there is some evidence suggesting that there are mental health benefits to reducing meat in one’s diet. For example, one study examined the effect of restricting meat consumption on mood (Beezhold & Johnston, 2012). This article will briefly review that study.
Methods
The participants in this study consisted of 39 men and women who ate meat/poultry at least once a day. To begin, all participants completed a general health history at baseline. Then, participants were randomly assigned into an omnivore group (OMN), a fish group (FISH), or a vegetarian group (VEG):
- The OMN group was instructed to not change their diets and continue eating meat/poultry at least once a day.
- The FISH group was instructed to avoid meat/poultry but eat seafood at least three to four times a week.
- The VEG group was instructed to avoid all animal products.
The study continued for two weeks. The following measures were taken at baseline and upon completion of the two-week study period:
- Dietary fatty acid intake was assessed through a validated food frequency questionnaire.
- Mood was assessed using the following:
- The Depression Anxiety Stress Scales (DASS), which measure depression (DASS-D), anxiety (DASS-A), and stress (DASS-S).
- The Profile of Mood States questionnaire (POMS), which measures tension-anxiety (POMS-T), depression-dejection (POMS-D), and anger-hostility (POMS-A), fatigue-inertia (POMS-F), confusion-bewilderment (POMS-C), and vigor-activity (POMS-V).
Participants were given written instructions regarding their diets, were contacted at least twice during the study to encourage compliance, and took a survey upon completion of the study to record compliance and any physical side effects.
Results
The following results were obtained:
- Regarding fatty acid intake:
- In the VEG group, dietary EPA, DHA, and AA “fell to negligible amounts”, ALA fell, and n-6 to n-3 ratio rose substantially.
- In the FISH group, dietary EPA and DHA increased by around 100%.
- In the OMN group, there were no significant fatty acid changes.
- Regarding mood:
- The VEG group showed a significantly greater reduction in DASS-S score and POMS-C score than the other two groups.
In other words, the fatty acid levels of the participants were significantly changed by the intervention. The VEG group showed a significantly reduced DASS-S score, indicating increased resilience to stress. Finally, the VEG group showed a significantly reduced POMS-C score, indicating reduced confusion/bewilderment.
Wrapping up
The results in this study suggest that switching to a vegetarian diet can lead to certain improvements in mood. Of course, more research is needed to further explore these relationships, and anyone switching to a vegetarian diet likely needs to take action to increase their EPA and DHA levels. Still, it is noteworthy that this study indicates that switching to a vegetarian diet may have psychological benefits along with environmental benefits.
References
Beezhold, B.L., Johnston, C.S. (2012). Restriction of Meat, Fish, and Poultry in Omnivores Improves Mood: A Pilot Randomized Controlled Trial. Nutrition Journal, 11(1), 9. doi: 10.1186/1475-2891-11-9.
