You have probably noticed it too. When it comes to young people’s mental well-being and, more specifically, the decline of it, there is almost always a clear explanation somewhere. Social media, smartphones, parents, school pressure, the spirit of the times… Pick one, and you have a story that sounds convincing and is easy to remember.

Only, that story is rarely entirely correct. In this post, a new piece of the puzzle.

In an earlier blog post, I tried to describe why young people today seem to feel worse. Not to find the cause, but rather to show that there probably isn’t just one. The increase in mental health problems started before COVID. It was reinforced by the pandemic. And all of this takes place against a backdrop of broader societal changes. Think of uncertainty about the future, stress that also affects parents and carries over, changes in social interactions, and yes, also technology, but in a much less straightforward way than is often suggested.

Anyone who looks at the whole picture does not see a simple story, but rather an accumulation of factors that influence one another. And it is precisely within such a complex whole that new possible explanations occasionally appear. Not a major breakthrough, not a “this is it”, but rather small pieces that may add something to the overall picture.

A recent example is a systematic review and meta-analysis by Karim Khaled and colleagues on the relationship between sugar-sweetened beverages and anxiety symptoms in adolescents. And yes, I am a well-known soft drink consumer. But I will try not to let that influence the rest of this blog.

What this study does is actually quite simple: it brings together a number of existing studies and looks for a pattern. And that pattern is there, albeit modestly. Young people who consume more sugar-sweetened beverages report, on average, slightly more anxiety symptoms. In the meta-analysis, this comes down to an odds ratio of 1.34, which you can interpret as a small increase in likelihood.

But as so often, the meaning of such a result lies not in the number itself, but in everything surrounding it.

The researchers have to work with the evidence that exists, and that comes with limitations. To begin with, the research is almost entirely observational. That means we do not know what the cause is and what the effect is. It may be that higher consumption of soft drinks contributes to anxiety symptoms. But it may just as well be that young people who feel worse are more likely to reach for those drinks. Or that both are related to other factors such as sleep, stress, lifestyle, or the broader context in which young people grow up.

In addition, the effects are small. Statistically detectable, certainly, but not of a magnitude that allows you to explain a large part of the problem. This is also visible in the few longitudinal studies, where the effects are present but limited.

There are also methodological limitations. Most studies rely on self-report, both for consumption and for anxiety, and use different definitions and measurement instruments. This makes it harder to interpret the results precisely, let alone to draw strong conclusions.

And perhaps, even more importantly, this factor never exists in isolation, as I wrote in the introduction. Young people who consume more sugar-sweetened beverages often differ in other ways as well. Diet, physical activity, screen use, sleep, and socio-economic background are variables that play a role and are often interconnected. That makes it almost impossible to isolate one element and present it as the explanation.

Still, it is interesting research. Not because it provides the explanation, but because it adds an extra piece to an already complex puzzle. It suggests that diet, and perhaps even something specific like sugar-sweetened beverages, may play a small role in the broader story of young people’s mental health.

But “small” is the keyword here.

Anyone who concludes from this that drinking less soft drinks will solve the problem of anxiety in young people is oversimplifying things. Just as anyone who thinks one other factor can do so. This kind of research mainly shows how tempting it remains to seek simple explanations for complex phenomena.

And how important it is not to go along with that.

Image: https://commons.wikimedia.org/wiki/File:Coca_Cola_Flasche_-_Original_Taste.jpg