The influence of plant-based nutrition and level of oestrogen on life satisfaction

Previous studies have shown that people benefit more from vegetarian or vegan diets than from an omnivorous diet, not only in physical but also in mental health. Studies have also reported substantial evidence that particular disorders can be triggered by preferred food choices. For example, consumption of animal products increases the intake of arachidonic acid which can induce depressive moods. On the other hand, nutrition can have positive effects, e.g. polyunsaturated N-3 fatty acids have several somatic health benefits not only on cardiovascular diseases, but also on depression. Similarly, a diet with a high content of tryptophan (a serotonin predecessor) can change mood by altering the synthesis of different neurotransmitters. In this pilot study, (i) omnivores (n=45), (ii) vegetarians (n=13) and (iii) vegans (n=7) were compared for their levels of satisfaction in everyday life, as measured on the Oxford Happiness Scale. The effect of oestrogen was analysed as a confounding variable. Between the three styles of nutrition, only small differences were found. All groups achieved an average of more than 4 points on a 6-stage Likert-scale (1=not happy, 6 = very happy), which lies in the range of moderately happy. The mean score of all three groups was 4.30 ±0.84. The difference between the omnivore, (4.23 ±0.69) and the vegetarian groups, (4.29 ±1.24) was very small, but the vegan group achieved a score well above 5, (5.20 ±0.17). In an ANCOVA, the effect of nutrition style on happiness was close to being significant, [p=0.066]. In addition, estimated oestrogen level had significant effects on satisfaction in everyday life, [p=0.047]. Conclusion: Further research on a larger sample is justified to determine if life satisfaction is influenced by nutrition style when controlled for oestrogen levels.