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Too Much Added Sugar May Increase Risk of Fatty Liver Disease in Kids

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Key Takeaways

  • High consumption of added sugar, particularly fructose, can make children more likely to develop fat in the liver, a recent study suggests.
  • This type of fatty liver disease used to affect only adults, but is increasingly seen in kids.
  • There are two major lifestyle changes that can help, and provide other health benefits along the way.

Excessive consumption of added sugar could make children more likely to develop chronic liver disease, according to a research review published in the journal Pediatric Obesity.?? Looking at more than 20 studies, researchers found a connection between non-alcoholic fatty liver disease (NAFLD) and the type of sugars added in manufacturing processes—rather than naturally occurring sugars found in fruits, whole grains, and dairy.

Particularly detrimental is high consumption of fructose, says the review’s senior author, Johanna DiStefano, PhD, head of the Diabetes and Fibrotic Disease Unit for the Translational Genomics Research Institute.

That’s because fructose needs to be converted by the liver into glucose before it can be used as an energy source, says DiStefano, and previous research has suggested this process can change cell function and gene expression. Over time, that can have a serious impact on the liver, which is why NAFLD seemed to affect mainly adults. But with higher consumption of sugars among kids, the condition is turning into a growing problem for children.

“This is similar to type 2 diabetes, which used to be a condition that affected mainly adults, and that’s why it was called adult-onset diabetes,” she says. “But just as that’s no longer true, NAFLD is escalating in children.”

What Happens With Fatty Liver Disease

Also called metabolic-associated fatty liver disease, this condition involves a buildup of fat in the liver, which can affect:

  • Blood clotting
  • Digestion
  • Inflammation
  • Higher risk of heart disease
  • Development of diabetes

The initial stage is called NAFL, or non-alcoholic fatty liver, which may then progress into a more serious condition known as NASH, or non-alcoholic steatohepatitis. If left untreated, the liver damage can become severe, and may lead to life-threatening conditions like cirrhosis, liver failure, and liver cancer.

Although the recent study highlighted concerns for children, the problem affects adults as well, and is growing in prevalence.

In the U.S., it’s estimated that fatty liver disease not related to alcohol consumption affects up to 9% of the population, and is higher in certain groups. For example, over 80% of people with obesity have the condition. Globally, prevalence is even higher, estimated at 25%. NAFLD is the leading cause of chronic liver disease in the world.??

Next Steps

For both population health and individuals, DiStefano says it’s important to address the high consumption rates of added sugars, for both kids and adults. Working on lowering processed foods and adding more fruits and vegetables into daily meals can be helpful, for example.

Another big step is reducing the amount of sedentary time, which brings benefits not just for NAFLD, but for a wide range of health outcomes, such as:

  • Improved mental health
  • Better cardiovascular function
  • More mobility
  • Higher muscle mass and bone density
  • Better cognitive function
  • Deeper and more restorative sleep

A small study in Alimentary Pharmacology and Therapeutics employed a 12-week aerobic exercise intervention in 24 people with the liver condition and found those in the exercise group had significantly improved inflammation and liver health markers compared to a control group.??

Although the sample size was modest, the results are promising, according to first author Philip O'Gorman, PhD, who did the research while at the School of Physiotherapy at the Royal College of Surgeons in Ireland. One of the most striking aspects of the results is that liver markers improved even without weight loss. That’s notable, he says, because the most common advice for improving liver disease is to lose weight.

"The important message here is that exercise training can improve liver-related outcomes, and that's not strictly limited to the liver," he said. "You can also improve cardiovascular risk, which again, may be more important that weight loss."

Liver Health as a Lifestyle

Another key lesson from the exercise study, adds O’Gorman, is that during a follow-up on participants a year later, researchers found that those who stopped exercising went back to having problematic liver disease indicators. Those who maintained their fitness after that study continued to have improved liver health.

"That tells us that continued engagement is needed for the benefits of exercise to be sustained," he said.

The same is likely true for added sugar consumption, says DiStefano. Resolving the issue through better eating habits shouldn’t be seen as a short-term fix to boost liver health. Instead, given the many other benefits of lowering added sugars, this should be a long-term lifestyle change that helps people well into adulthood.

What This Means For You

For both children and adults, high consumption of processed sugars and low rates of activity can contribute to creating more fat in the liver. This significantly raises health risks, but the good news is that it can sometimes be controlled or reversed with lifestyle changes.

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  1. DiStefano JK, Shaibi GQ. The relationship between excessive dietary fructose consumption and paediatric fatty liver disease. Pediatr Obes. Published online December 11, 2020. doi:10.1111/ijpo.12759

  2. Younossi ZM, Koenig AB, Abdelatif D, Fazel Y, Henry L, Wymer M. Global epidemiology of nonalcoholic fatty liver disease—meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology. 2016 Jul;64(1):73-84. doi:10.1002/hep.28431

  3. O’Gorman, P,?Naimimohasses, S,?Monaghan, A, et al.?Improvement in histological endpoints of MAFLD following a 12‐week aerobic exercise intervention. Aliment Pharmacol Ther. 2020;52:1387–1398. doi:10.1111/apt.15989