BackgroundThe physical health status of vegetarians has been extensively reported, but there is limited research regarding the mental health status of vegetarians, particularly with regard to mood. Vegetarian diets exclude fish, the major dietary source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), critical regulators of brain cell structure and function. Omnivorous diets low in EPA and DHA are linked to impaired mood states in observational and experimental studies.MethodsWe examined associations between mood state and polyunsaturated fatty acid intake as a result of adherence to a vegetarian or omnivorous diet in a cross-sectional study of 138 healthy Seventh Day Adventist men and women residing in the Southwest. Participants completed a quantitative food frequency questionnaire, Depression Anxiety Stress Scale (DASS), and Profile of Mood States (POMS) questionnaires.ResultsVegetarians (VEG:n = 60) reported significantly less negative emotion than omnivores (OMN:n = 78) as measured by both mean total DASS and POMS scores (8.32 ± 0.88 vs 17.51 ± 1.88, p = .000 and 0.10 ± 1.99 vs 15.33 ± 3.10, p = .007, respectively). VEG reported significantly lower mean intakes of EPA (p < .001), DHA (p < .001), as well as the omega-6 fatty acid, arachidonic acid (AA; p < .001), and reported higher mean intakes of shorter-chain α-linolenic acid (p < .001) and linoleic acid (p < .001) than OMN. Mean total DASS and POMS scores were positively related to mean intakes of EPA (p < 0.05), DHA (p < 0.05), and AA (p < 0.05), and inversely related to intakes of ALA (p < 0.05), and LA (p < 0.05), indicating that participants with low intakes of EPA, DHA, and AA and high intakes of ALA and LA had better mood.ConclusionsThe vegetarian diet profile does not appear to adversely affect mood despite low intake of long-chain omega-3 fatty acids.

Considering the low eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) status widely reported for vegetarians, and the evidence that EPA+DHA promotes mental health, we examined the relationship between dietary EPA+DHA and depression in healthy vegetarian (VEG) and omnivore (OMN) adults from Seventh‐Day Adventist populations in the Southwest. Participants (60 VEG; 78 OMN) completed a survey including a food frequency questionnaire and Depression Anxiety Stress (DASS) and Profile of Mood States (POMS) scales. VEG consumed less EPA+DHA and arachidonic acid (AA), but significantly more a‐linoleic acid and linoleic acid, compared to OMN. VEG reported significantly less negative emotion than OMN as assessed by DASS scores (8.3±0.9 and 17.5±1.9, p=.003, adjusted for the confounding variable, physical activity). VEG tended to report less mood disturbance than OMN as assessed by POMS scores (0.1±2.0 and 15.3±3.1, p=.083, adjusted for age and physical activity); however, VEG females reported significantly less mood disturbance than OMN females (1.6±2.9 vs 22.2±4.6, p=.006). Moreover, dietary AA, but not EPA+DHA, was significantly related to mood disturbance among omnivores (r=.256, p=.024). We conclude that VEG reported less negative emotion than OMN due perhaps to lower intakes of AA which may alter brain eicosanoid profile and inflammatory potential. This research was supported by the ASU Nutrition Research Fund.