Fructose metabolism and its links to metabolic disease, cancer and dementia
What it found
Fructose drives fat production, raises blood fats and uric acid, and is linked to fatty liver, insulin resistance, cancer and dementia in people and animals.
The body can also make fructose from glucose.
What they found
Studies in people
Insulin resistance in people
Liver insulin resistance appeared in people after two to three weeks of drinking fructose beverages but not glucose beverages. Overweight men drinking 200 g of fructose daily developed higher fasting insulin and blood pressure within two weeks.
Uric acid rises quickly
Blood uric acid levels rise within 15 to 60 minutes after taking in fructose in people. Long-term fructose intake keeps both fasting and after-meal uric acid levels elevated.
Animal and lab studies
Cancer growth signals
In lab and animal studies, fructose supports tumor growth, spread and survival across several cancers including breast, lung and liver. Tumor cells can also make their own fructose from glucose to fuel growth.
Studies in people and animals
Fat production and blood fats
Fructose strongly stimulates new fat creation in the liver compared with glucose. In a 10-week trial, overweight or obese people drinking fructose-sweetened beverages had higher blood fats and more belly fat than those drinking glucose drinks.
Fatty liver and liver disease
Sugar-sweetened drinks are strongly linked to fatty liver in people, and cutting back on fructose lowers liver fat. In mice, blocking the enzyme that breaks down fructose largely prevents fatty liver even on high-sugar diets.
Brain changes and dementia risk
Rats fed fructose long term developed memory problems, brain inflammation and protein clumps seen in Alzheimer's disease. Autopsy studies found five to six times more fructose and sorbitol in the brains of people with Alzheimer's disease.
What the authors conclude
- They conclude that fructose triggers ancient survival signals meant to store fat for times of food scarcity.
- They note that under modern conditions of constant food abundance, these same signals promote insulin resistance, high blood fats, fatty liver and raised blood pressure.
- They call for more research into how internally produced fructose contributes to disease and whether blocking fructose-metabolizing enzymes could help treat metabolic conditions.
How it was done
Added sugar intake has risen sharply over recent centuries alongside obesity and diabetes. The authors wanted to explain how fructose differs from glucose in the body and why excess fructose may drive disease.
The authors gathered and examined biochemical, animal and human research on fructose and glucose metabolism. They looked at how the body processes fructose from food and how it makes fructose internally from glucose. They reviewed studies ranging from cell experiments to clinical trials in people.
What it can’t tell you
- This is a review that gathers many different studies, so it cannot prove on its own that fructose directly causes disease in people.
- Some findings come from animals given very large amounts of fructose, which may not match what happens when people consume typical amounts.
- Observational links between sugary drinks and disease in people show an association but cannot confirm cause and effect.
Who paid
- Funding
- Funded by NCI NIH HHS; NIDDK NIH HHS; NIAAA NIH HHS (from the PubMed record).
- Conflicts
- Competing interests: R.J.J., M.A.L., D.R.T. and J.D.R. have equity with Colorado Research Partners, which is developing KHK inhibitors. R.J.J. also consults for Amgen, Dynamicure, Soba Pharmaceuticals and Kibow and is on the Scientific Board of Blue Oak Nutraceuticals, Santa Barbara Nutrients and RxSugar. M.D.G. holds equity in Faeth Therapeutics and Skye Biosciences; reports consulting or advisory roles with Almac Discovery, Genentech, Faeth Therapeutics, Scorpion Therapeutics and Skye Biosciences; patents, royalties and other intellectual property with Weill Cornell Medicine and Faeth Therapeutics. J.D.R. is a member of the Rutgers Cancer Institute (RCI) and the University of Pennsylvania Diabetes Research Center (U Penn DRC); director of the U Penn DRC-Princeton inter-institutional metabolomics core and RCI metabolomics core; advisor and stockholder in Bantam Pharmaceuticals, Rafael Pharmaceuticals and Empress Therapeutics; a founder, director and stockholder of Farber Partners and Raze Therapeutics; a founder, advisor and stockholder in Marea Therapeutics and Fargo Biotechnologies; and inventor of patents held by Princeton University. S.S., K.L.S., L.G.S-L. and M.A.H. declare no competing interests.
- Authors work at
- University of Colorado Anschutz Medical Center, USA; Boston University, USA; NYU Grossman School of Medicine, USA
The paper
- Title
- Fructose: metabolic signal and modern hazard
- 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
- Johnson RJ, Lanaspa MA, Tolan DR, et al (2026). Fructose: metabolic signal and modern hazard. Nature metabolism. doi:10.1038/s42255-026-01506-yFree full textPubMed 41998215DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error