Recent research shows the dangers of sugary drinks for kids

Sugar-sweetened beverages consumed early in life may impact not only weight but also brain and liver health

Casey Means, MD

Medical Reviewer

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As any parent will attest, developing healthy eating habits in your kids is a game of whack-a-mole: just when you find a vegetable they like, their palette changes. Maybe you eliminate soda at home, only to find they’re getting Coke at camp. 

And even though we want to encourage our kids to make positive food choices, we also need always to be conscious that we’re not planting the seeds of diet anxiety or body shame. As with all things parenting, it’s a fine balance.

So in this roundup, we narrow our focus to recent research around sugar-sweetened beverages and some potential physiological implications. According to the Centers for Disease Control and Prevention (CDC), between 2011 and 2014, 63% of people 19 and under in the United States drank a sugar-sweetened beverage (SSB) on a given day. And as of 2019, almost a third of kids 10-17 are obese or overweight.  Even more frightening, two separate research projects just found significant increases—more than doubling in one data set—in the rates of diabetes among kids during the pandemic, as well the proportion of Type 2 diabetes versus Type 1. 

Consuming Excess Sugar Early in Life May Impact Long-Term Brain Health 

The Study: Gut microbial taxa elevated by dietary sugar disrupt memory function (March 2021)

What it Says: This research from the University of Georgia examined the neurological effects of early life sugar consumption in rats. When the animals were in the adolescent stage, researchers fed the animals a solution that mimicked the sugar content of a soda. Then, they gave them memory tests as adults, including object recognition and context-specific tasks. They also examined the rats’ brains and their microbiomes. 

The results: Rats who consumed sugar when they were young performed worse on tests that required upper hippocampal function (a key part of the brain involved in learning and memory), reducing the ability to recognize an object as novel in a specific context. Researchers also found these rats had impaired glucose tolerance on a fasted glucose test as adults, even though they didn’t show changes in body composition from the control group.

The researchers then sampled the gut microbiota of the rats and found that the sugar group had elevated levels of a kind of bacteria called Parabacteroides. To make the connection with the neurological results, they implanted that bacteria into the GI tract of a separate group of rats and found those rats then developed similarly impaired hippocampal processing, suggesting that the microbiome alteration impacted the neurologic outcomes. 

Levels Take: Although this is an animal model, it’s an important demonstration of the multi-pronged effects of diet. It reminds us that there are more profound consequences to excess sugar than just the immediate spike and crash or even the more direct long-term risks of insulin resistance and diabetes. Excess glucose (like processed foods in general) disrupts our microbiome, and this can affect us in all sorts of unexpected ways. That these effects can take place in adolescence and have lasting effects has been shown in other studies as well.

This study builds on earlier research by the same group, in which adolescent rats were given a similar sugar solution and neurological testing. However, in that study, the sugar was taken away from the rats at the end of adolescence. They found the same kind of hippocampal and glucose impairment. The study demonstrates how critical early habits can be. As the authors say, “These findings reveal that the juvenile/adolescent period is one of high vulnerability to long-lasting cognitive impairments from habitual sugar consumption.” 

Kids Who Drink Sugary Beverages with Meals at Home Have a Greater Risk of Obesity

The Study: Young Children’s Sugar-Sweetened Beverage Consumption and 5-Year Change in BMI: Lessons Learned from the Timing of Consumption (August 2020)

What it Says: This study out of the Netherlands used a cohort of an extensive data set of children to examine the effects of SSBs on young kids’ health over a five-year period (from around 5 to 10). It also looked more granularly at what times of day the kids consumed the drinks, and whether that had any correlation with health outcomes.

The researchers identified a group of around 1,200 5- to 6-year-olds and, using a parental questionnaire, noted when they drank SSBs: in the morning, afternoon or evening, and with breakfast, lunch at school or lunch at home, and dinner. They sorted the results into four quartiles based on overall SSB consumption, with the lowest quartile drinking SSBs 1.9 times per day and the highest quartile drinking SSBs 4.9 times per day. They found that all the kids were drinking SSBs in the morning and afternoon at pretty similar levels. What separated the highest consumers is that they drank SSBs with meals at home: breakfast, lunch, and dinner, as well as in the evenings. 

Researchers also compared the BMI of the kids at age 5-6 and in a five-year follow-up. The group that drank the most SSBs at 5-6 were three times more likely to develop overweight by age 10-11 than the group that consumed the fewest. 

Levels Take: Not only does this study confirm several other studies showing the link between childhood SSB consumption and obesity, but it gives us a deeper window into the behaviors around how kids form these habits. To be more specific, it reveals how important the home environment is in shaping what kids eat and drink. Understanding these patterns helps us design better educational programs and interventions.

For example, a thorough review of programs designed to reduce SSB consumption among kids, spanning several categories, found that home-based interventions, such as delivering alternatives to SSBs to parents, were more successful than some school-based and public health programs in cutting SSBs and reducing weight. 

Helping Families Drink Fewer Sugary Drinks Reduces the Risk of Fatty Liver Disease in Kids

The Study: The Effect of a Family-Based Lifestyle Education Program on Dietary Habits, Hepatic Fat and Adiposity Markers in 8–12-Year-Old Children with Overweight/Obesity (May 2020)

What it Says: This study in Spain asked whether a 22-week nutrition education program for families who have children with overweight/obesity could a) improve dietary habits; and b) if those improvements would affect the children’s health, in particular, fat around the belly and fat in the liver. All 81 kids went through the educational program, but half of them also exercised three times per week. 

The study found that nutrition habits improved across both groups after the educational program. The kids cut their total calorie intake, their consumption of added sugars, and total fat. The control group (education, but no exercise), reduced their carbohydrate consumption, and the exercise group reduced their simple sugar and cholesterol intake. There was a 43% reduction in consumption of SSBs, although this was not statistically significant.  The kids skipped breakfast less, ate better quality breakfast, and moved towards a more Mediterranean-style diet. 

Only two changes in body stats were significant: kids in the exercise group lost weight, and kids in the control group (no exercise) who drank fewer SSBs lowered their liver fat.

Levels Take: Given what we see in the previous two studies (and others) about the lasting health consequences of drinking SSBs at a young age and how sticky the habit of drinking them can be, it’s encouraging to see evidence that interventions can lead to healthier choices. But it’s challenging: a meta-analysis found that only about half of intervention programs worked to reduce kids’ SSB consumption. 

The other unique and vital aspect of this study is its focus on liver fat. Non-alcoholic fatty liver disease (NAFLD) is a blanket term for liver conditions not caused by excessive alcohol, and it’s one of the main drivers of liver disease worldwide. What’s frightening is how prevalent it is in children: as high as 70-80% in kids with obesity. NAFLD in children is associated with higher incidences of metabolic syndrome and a six-fold increase in the risk of atherosclerosis, or build-up of fatty deposits in arteries.

Fructose, the primary sweetener in SSBs, causes the liver to store more fat. This, in turn, can spur insulin resistance in the liver and uric acid build-up and inflammation. Interestingly, in the group that did not have an exercise intervention, there was a reduction in liver fat associated with reduced SSB consumption, corroborating prior research showing that SSBs are a driver of fatty liver.

Related article: Why fructose is bad for metabolic health