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Enjoying that soda? New research can reveal how much you drink

A ҹɫ���� scientist has shown that a chemical marker in the body can reliably reveal how much added sugar and how many sugar-sweetened drinks a person consumes. The marker works in people of different ages, sexes, races and diets.

“We now have an objective way to measure a person’s intake of added sugar or sugar-sweetened beverages,” said postdoctoral researcher Jessica Johnson at the UAF Institute of Arctic Biology’s Center for Alaska Native Health Research.

That information can then be associated with rates of obesity and chronic disease to improve research.

“This is important because we know people misreport their diet for a variety of reasons, especially their sugar intake, and that can really complicate studies of diet and health,” she said.

The findings were published in in late 2025. Johnson is the research paper’s lead author.

Johnson analyzed data on the ratio between different carbon types in one of the body’s amino acids. The ratio reveals a person’s added sugar consumption, her work confirmed.

“Added sugar” means sugar introduced by food companies during processing or consumers at the table. Most of it comes from corn and sugarcane.

The isotope carbon-12 makes up about 99% of carbon on the planet, but a small amount is carbon-13. Corn and sugarcane contain more carbon-13 than other plants.

When people consume glucose from corn and sugarcane, some ends up in an amino acid called alanine. The ratio of carbon-12 to carbon-13 in a person’s alanine reveals how much added sugar and sugary drinks they’ve consumed.

“The reason we use carbon isotope ratios to tell us anything about diet comes down to the types of plants that make up the base of our diet’s food web,” Johnson said.

Johnson analyzed data from four previous U.S. studies that looked at the carbon isotope ratio of alanine as a sugar biomarker. The studies used different methods and produced varying results. The first study occurred in Southwest Alaska. Scientists at the Center for Alaska Native Health Research conducted it with support from the Yukon-Kuskokwim Health Corp.

To test whether alanine could reliably show sugar intake, Johnson had to make the data sets comparable.

“They were more consistent with each other than you would expect from just having read the conclusions of each of the papers,” she said. “And that was very encouraging."

Foods such as meat, fish and eggs also contain alanine, which created another research challenge. Johnson and her team developed a way to adjust for this and improve the accuracy of sugar intake estimates.

Alanine’s carbon isotope ratio can’t be used in a clinical setting such as a doctor’s office yet, Johnson said.

“For now it can be used to study how chronic diseases such as cancer, Type 2 diabetes and cardiovascular disease relate to diet,” she said. “We can determine what proportion of that disease distribution can be attributed to what people are eating.”

Dietary biomarker research has traditionally focused on molecules in the body that reflect what someone has eaten recently. Isotope analysis, by contrast, can provide a longer-term view. 

“UAF is one of few institutions in the world leading in this emerging field that has great potential to improve the science behind dietary recommendations,” said Diane O’Brien, director of the Institute of Arctic Biology.

O'Brien is a research paper co-author, one of 14 from eight institutions, including the National Institutes of Health.

Other UAF co-authors are postdoctoral fellow Sambit Ghosh at the Institute of Northern Engineering’s Alaska Stable Isotope Facility; former CANHR Director Bert Boyer, now an affiliated researcher; and affiliated researcher Scarlett Hopkins. 

Former UAF doctoral student Sarah Nash, who is another co-author, did extensive data collection for the Southwest Alaska study. Nash is co-director of the New Mexico Tumor Registry and an associate professor at the University of New Mexico School of Medicine.

ADDITIONAL CONTACTS: Jessica Johnson, jjjohnson20@alaska.edu; Diane O’Brien, dmobrien@alaska.edu

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