Fructose, sugar and the development of fatty liver disease
What it found
Diets high in fructose and sugar are linked to fat building up in the liver in people and animals.
Early human studies suggest cutting sugary drinks may lower liver fat.
What they found
Studies in people
Sugary drinks in people
People with fatty liver disease drank two to three times more fructose from sweet beverages than matched controls. Giving people sugary drinks for six months raised their liver fat. Cutting fructose for nine days lowered liver fat in children.
Uric acid and liver fat
Fructose raises uric acid levels in the blood within minutes. A combined analysis of 55,573 patients found higher uric acid was tied to more fatty liver disease. In a small trial of 17 people, a drug that lowers uric acid improved liver test results after three months.
Animal and lab studies
Liver fat in animals
Rats and monkeys fed high fructose diets developed fatty livers. In rats it usually took 8 to 24 weeks. Monkeys showed liver scarring after seven years of fructose feeding.
Gut changes in animals
In mice, fructose metabolism in the small intestine weakened the gut lining. This let bacterial toxins enter the blood and reach the liver, which triggered fat buildup. Mice bred without fructokinase did not show these gut changes.
Studies in people and animals
How fructose makes fat
Fructose is broken down by an enzyme called fructokinase C in the liver. This process uses up cell energy and creates uric acid. These changes tell the liver to build new fat while stopping it from burning existing fat.
What the authors conclude
- They conclude that fructose plays a major role in causing fatty liver disease by changing how the liver handles fat.
- They advise that cutting back on sugar and high fructose corn syrup could significantly reduce liver fat accumulation.
- They call for larger clinical trials to test whether lowering sugar intake or blocking uric acid production can help treat fatty liver disease.
How it was done
Fatty liver disease is becoming more common alongside rising obesity and diabetes. The authors wanted to gather evidence on whether sugar and fructose play a role in this trend.
The authors gathered and examined laboratory, animal and human research on how fructose affects the liver. They looked at studies ranging from short trials lasting days to animal work spanning seven years. They also reviewed population surveys tracking added sugar intake over several decades.
What it can’t tell you
- This is a review of many different studies rather than a single controlled trial. It cannot prove on its own that fructose directly causes fatty liver disease in every person.
- Some of the detailed mechanisms were shown only in mice or lab cells. Scientists do not yet know if those exact processes happen the same way in people.
- A few short human trials found no link between fructose and liver problems. The authors note these trials may have been too short to see changes that take months to develop.
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 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error