A recent study suggested a link between vegetarian and vegan diets and depression, but experts have questioned the findings
Experts have hit back at a recent study suggesting there is a link between meat-free diets and depression.
The paper, titled Association between meatless diet and depressive episodes: A cross-sectional analysis of baseline data from the longitudinal study of adult health, was published in the Journal of Affective Disorders.
Some 14,216 people in Brazil took part, between the ages of 35 and 74. Participants filled out a food frequency questionnaire so researchers could determine whether they followed a vegetarian, vegan or omnivorous diet.
Meanwhile, whether participants had episodes of depression was ascertained using a diagnostic tool called the Clinical Interview Schedule-Revised (CIS-R).
The survey found that those who ate a meat-free diet suffered from depressive episodes twice as often as meat-eaters, with researchers noting that the association was ‘independent of socioeconomic, lifestyle factors and nutrient deficiencies’.
Diet and depression
Speaking to Healthline, registered dietitian Mary Mosquera-Cochran, at The Ohio State University Wexner Medical Center, noted several points about the study’s design, which she said make it impossible to conclude that a meat-free diet causes depression.
Firstly, she noted that rather than carrying out a controlled experiment, researchers simply analysed data. Additionally, the proportion of vegetarians in the study (a total of 82 people out of some 14,000) was very small.
Mary, who was not a part of the study, added: “The researchers found that diet quality was somewhat associated with higher rates of depression, but it did not fully explain the association.”
The researchers themselves also noted that any link between meatless diets and depression is unclear, saying: “The nature of the association remains unclear, and longitudinal data are needed to clarify causal relationship.”
They also clarified that ‘nutrient deficiencies do not explain this association’.
A meat-free diet does not make you depressed
Writing on his public Facebook page, renowned plant-based medic Dr Garth Davis also discussed the limitations of the study.
He said: “This was one cross sectional study that does not follow patients or differentiate how long they have been on the diet. It also ignores the actual nutritional quality of the diet.
“Multiple studies have actual shown that healthy plant-based diets are associated with less depression. A different study in Brazil showed that the longer people are on a plant-based diet the less depression they have, and other studies have shown meat increases depression.”
He also pointed out that people who opt to eschew animal products may be more likely to suffer from depression because of their empathy towards animals who are killed for food.
Dr Davis explained: “Vegans tend to choose the diet because they are empathetic to the suffering of animals. I have had times where I struggled to fall asleep with images of the billions of tortured animals locked up in feeding operations. Yes, that can depress you.
“But a whole food plant-based diet does not make you depressed, and has all the nutrients to make you happy and healthy. And you can sleep peacefully knowing you are minimising your effect on the animals and the environment.”