Sugar, fructose and fatty liver disease
What it found
Diets high in sugar, especially fructose from sugary drinks, are strongly linked to fat building up in the liver.
The evidence comes from animal experiments and from studies in people.
What they found
Studies in people
Sugary drinks in people
People with fatty liver disease drank 2 to 3 times more fructose from sugary drinks than matched controls. The link with liver scarring followed a dose pattern in children, adolescents and adults.
Cutting fructose in children
Restricting fructose for 9 days in children who usually took in a lot reduced liver fat and new fat production, compared with children on a similar-calorie diet. Some also saw better blood pressure, blood fats and insulin resistance.
Animal and lab studies
Sugar and liver fat
In animal experiments, diets high in fructose, sucrose or high fructose corn syrup tended to cause fatty liver, usually after at least 8 to 24 weeks. The liver changes got worse with longer exposure.
Fructose in monkeys
In one study, cynomolgus monkeys given fructose developed more liver fat and liver scarring after seven years. The amount of scarring tracked with how long they had been exposed.
How fructose is metabolised
Fructose is broken down quickly by an enzyme called fructokinase C, which uses up ATP and phosphate and produces uric acid. This is different from how glucose is handled and is thought to drive fat build-up.
Studies in people and animals
Uric acid and liver fat
In mice, blocking uric acid production with drugs like allopurinol reduced fatty liver from fructose and other causes. In people, higher blood uric acid was linked with more fatty liver and with the more serious form, NASH.
What the authors conclude
“Reducing sugar or HFCS intake may have a major benefit on NAFLD.”
Also in their conclusions
- They say the fructose part of sugar and high fructose corn syrup appears to play a major role in causing fatty liver.
- They advise that cutting sugar or high fructose corn syrup intake may have a major benefit for fatty liver disease.
- They call for larger, more definitive trials, including studies on lowering uric acid.
How it was done
Fatty liver disease has become more common alongside rising obesity and diabetes. The authors wanted to review whether sugar, and fructose in particular, plays a major role.
They pulled together laboratory experiments in animals and cells, and clinical and population studies in people, looking at how fructose is handled by the body and how it relates to liver fat.
What it can’t tell you
- Many of the experiments were in animals or cells, so they cannot show exactly what happens in people.
- Most clinical studies followed people over time or compared groups, so they can show a link but not prove that sugar causes fatty liver.
- Large, long trials in people are still lacking, and short trials may miss effects that take months to appear.
Who paid
- Funding
- Funded by NIDDK NIH HHS (from the PubMed record).
- Authors work at
- University of Colorado Anschutz Medical Campus, United States; Duke University, United States; Nara Medical University, Japan
The paper
- Title
- Fructose and sugar: A major mediator of non-alcoholic fatty liver disease
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Jensen T, Abdelmalek MF, Sullivan S, et al (2018). Fructose and sugar: A major mediator of non-alcoholic fatty liver disease. Journal of hepatology. doi:10.1016/j.jhep.2018.01.019Free full textPubMed 29408694DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error