While parents have long worried that too much sugar leads to cavities and weight gain, new research suggests that sugar rush might be followed by a worry crash. 

A study from Bournemouth University in the U.K. has identified a troubling link between high-sugar drinks and increased anxiety symptoms in young people.

Researchers reviewed studies published over the last 25 years, looking for patterns in how a teenager’s diet affects their mind. The beverages analyzed included soda, energy drinks, sweetened juices, flavored milks and even sugary teas and coffees. 

The nine studies, mostly from China and Canada, included more than 73,000 participants.

The results, published in the Journal of Human Nutrition and Dietetics, were consistent: The more sugary drinks a teenager consumed, the more likely they were to report symptoms of anxiety. 

In fact, a meta-analysis of the data linked high sugar intake to 34% higher odds of having an anxiety disorder.

Anxiety is among the most reported mental health conditions for children and young people. 

“With increasing concern about adolescent nutrition, most public health initiatives have emphasized the physical consequences of poor dietary habits, such as obesity and type-2 diabetes,” study co-author Chloe Casey, a lecturer in nutrition at Bournemouth University, said in a news release. “However, the mental health implications of diet have been underexplored by comparison, particularly for drinks that are energy dense but low in nutrients.”

Researchers emphasized that their findings show an association between sugary drinks and anxiety rather than a direct cause-and-effect. This means that while the two are linked, it isn't clear whether the sugar causes the anxiety, or if anxious teens reach for sugary drinks as a way to cope with stress. 

Other factors, like poor sleep or stress, could also play a role in both habits, researchers noted.

Regardless of which comes first, the link was consistent in seven of the nine studies analyzed. 

“Anxiety disorders in adolescence have risen sharply in recent years so it is important to identify lifestyle habits which can be changed to reduce the risk of this trend continuing,” Casey said.