Study: High daily sugar intake increases risk for depression

Key takeaways:

• A dietary sugar increase of 100 g per day was linked to a 28% higher prevalence of depression.
• However, more research is needed to determine causality and underlying mechanisms.

A greater daily intake of sugar in people’s diets was associated with a higher prevalence of depression, according to a study published in BMC Psychiatry.

“Previous studies have linked dietary factors such as caffeine, fish and vegetable intake to the risk of depression,” Lu Zhang, from Shandong University of Traditional Chinese Medicine, in China, and colleagues wrote. “However, only a few studies have examined the relationship between dietary sugar intake and depressive symptoms.”

The researchers analyzed data from 18,439 adults aged 20 years and older who participated in the National Health and Nutrition Examination Survey between 2011 and 2018.

Zhang and colleagues found that, after adjusting for several confounders, a 100 g per day increase in sugar was associated with a 28% higher prevalence of depression (OR = 1.28; 95% CI, 1.17-1.4).

Additionally, compared with participants in the first quartile of daily sugar intake — meaning, those who consumed the least amount of sugar each day — participants in the fourth quartile had an OR of 1.33 (95% CI, 1.1-1.61) for depression.

The researchers highlighted some possible reasons for the association between sugar and depression. For example, a “high-sugar diet can disrupt the gut microbiota, leading to depression,” they wrote.

Zhang and colleagues explained that based on the findings, “emphasis can thus be placed on reducing dietary sugar intake, helping the population to become aware of the link between diet and mental health.”

“Health institutions and government agencies can carry out nutritional education and publicity, formulate relevant policies, and provide guidance for the public to live a healthy lifestyle,” they wrote, although “it is important to note that these applications require further research to support this conclusion... diet needs to be combined with mental health interventions to yield better results.”

Because the study’s design was cross-sectional, Zhang and colleague were unable to establish causality or control for other potential confounders like socioeconomic, genetic or lifestyle factors.

They concluded that more research is needed “to explore the underlying mechanisms and the potential benefits of controlling dietary sugar intake in patients with depression.”