depression, pessimism
© Luke MacGregor / Reuters
Vegetarians are almost twice as likely to suffer from depression as those who consume a conventional balanced diet, according to a new study.

The new Bristol University study of almost 10,000 from southwestern England found that vegetarians were more likely to develop depression due to vitamin and mineral deficiencies that can negatively impact their mental health.

The 350 committed vegetarians who participated in the study had a higher average depression score when compared to the meat-eaters, according to the study, which was published in the Journal of Affective Disorders.

The vegetarians' diet tended to feature lower vitamin B12 consumption, as well as greater intake of nuts that contain omega-6 fatty acids, which have been linked with an increased risk of mental health problems.

Slightly more than 50 percent of vegans and 7 percent of vegetarians have a vitamin B12 deficiency, the researchers said. Vitamin B12 can be found in red meat, and plays an important role in affecting an individual's mood.

"Other potential factors include high blood levels of phytoestrogens - consequent mainly on diets rich in vegetables and soya," the report says. "Another potential contributing factor is that lower intakes of seafood are thought to be associated with greater risk of depressive symptoms."

The lack of a balanced diet can influence the development of depression, and the research findings can also be attributed partially to iron deficiencies, the study says. Participants who had been consuming a vegetarian diet for longer periods of time had higher depression scores throughout.

But the researchers did not rule out the possibility that the vegetarians' decisions to adopt their diet could have been a symptom of depression from the start.