A number of food ingredients can cause or aggravate depression, but one of the most significant is sugar, particularly refined sugar and processed fructose. For example, in one study, men consuming more than 67 grams of sugar per day were 23 percent more likely to develop anxiety or depression over the course of five years compared to those whose sugar consumption was less than 40 grams per day (which is still far higher than the 25 grams per day recommended for optimal health).
This held true even after accounting for other contributing factors, such as socioeconomic status, exercise, alcohol use, smoking, other eating habits, body weight and general physical health. Lead author Anika Knüppel, a research student in the department of epidemiology and public health at University College London, commented on the findings, saying:
“Sweet food has been found to induce positive feelings in the short-term. People experiencing low mood may eat sugary foods in the hope of alleviating negative feelings. Our study suggests a high intake of sugary foods is more likely to have the opposite effect on mental health in the long-term.”
Research published in 2002, which correlated per capita consumption of sugar with prevalence of major depression in six countries, also found “a highly significant correlation between sugar consumption and the annual rate of depression.” A Spanish study published in 2011 linked depression specifically to consumption of baked goods.
Those who ate the most baked goods had a 38 percent higher risk of depression than those who ate the least. This makes sense when you consider baked goods contain both processed grains and added sugars.