The condition seems to be linked to the Glycaemic Index (GI), an indicator of the foods that quickly raise blood-sugar levels. These are the 'white' and processed foods and drinks. The higher the food on the GI scale, the more likely it is to cause depression, say researchers at the Columbia University Medical Centre.
Conversely, people who ate low-GI foods, such as whole grains, vegetables and fruit, were less likely to suffer depression. The researchers analysed data from the Women's Health Initiative, which had recruited more than 70,000 post-menopausal women and tracked their lifestyle, diet and health.
They suspect that fast, processed foods could also cause sudden mood swings, fatigue and other symptoms associated with depression.
(Source: American Journal of Clinical Nutrition, 2015; 102: 454-63)