A review of the literature suggests a favorable relationship between plant-rich diets – particularly the Mediterranean diet – and a lower risk of depression. Excess sugars, processed foods or saturated fats would have the opposite effect.
This study, conducted by the University College of London, scanned the scientific literature to assess the impact of diet on the risk of depression. 41 observational studies were considered eligible for analysis: 21 longitudinal studies (which follow individuals over time) and 20 cross-sectional studies (which take a snapshot and assess potential associations). Four of the longitudinal studies focused on depression, in a population of 36,556 adults following a traditional Mediterranean diet.
A diet rich in plants reduces the risk of depression by 35%
Analysis of the pooled data revealed that following a plant-rich diet was globally associated with a 35% lower risk of depression, compared to following a low-vegetable diet. The most compelling evidence has been observed for the traditional Mediterranean diet. As a reminder, this is characterized by the abundant consumption of plants such as fruits, vegetables, legumes, cereals, aromatic herbs and olive oil, a moderate consumption of dairy products, eggs and wine. , a limited consumption of fish and a low consumption of meat.
The study finds a 33% reduction in the combined relative risk of depression incidence in the highest category of adherence to the Mediterranean diet, compared to the lowest adherence to the diet.
Sugar and Saturated Fat: A Pro-Depression Diet
Using data from five of the longitudinal studies, the researchers also found that following a “pro-inflammatory diet,” defined by the researchers as a diet that typically contains high amounts of sugars, processed foods, and saturated fat, was linked to a higher risk of depression. The data came from a total of 32,908 adults living in Australia, France, Spain, the UK and the US. Avoiding such a diet lowered the risk by 24%.
The researchers conclude that adopting a healthy diet rich in plants, in particular a traditional Mediterranean diet, seems to confer some protection against depression in observational studies, without however being able to establish a causal link. Remember also that plants are part of the TOP 10 nutritional priorities.
Lassale C et al. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studiesMol Psychiatry. doi: 10.1038/s41380-018-0237-8.