A scientific paper by researchers in the US could change the way that we think about what constitutes a healthy diet.

Published in the journal Critical Reviews in Food Science and Nutrition, the work highlighted that people who don’t eat meat are at higher risk of depression, anxiety and self-harm.

As part of the study the researchers reviewed existing data from 18 studies, with over 160,000 participants across Europe, Asia, North America, and Oceania. Of these, 8,584 people abstained from eating meat.

Included in the US review paper was a study of over 90,000 French adults which showed that 28.4% of those who didn’t eat meat had symptoms of depression, compared to only 16.2% of meat consumers.

Similar to that was an Australian study from 2007 of over 9,000 females, which found that the use of prescription medication for depression was nearly twice that among women who didn’t eat meat compared to those who did. It also showed that the prevalence of deliberate self-harm was over three times greater in meat-abstainers than meat consumers.

In their conclusions, the US researchers note that the avoidance of meat may be a behavioural marker that signifies poorer mental health, but what is not clear is whether meat consumption per se has psychological benefits.

For example, the review points out that it is well-established that vegetarianism may be used as a strategy to mask an eating disorder, especially among females.

“Our study does not support avoiding meat consumption for overall psychological health benefits,” states the review.