Scientists identify simple saliva test to detect hidden diabetes risk

Researchers at the University of British Columbia’s Okanagan campus have developed a simple, needle-free test that measures insulin in saliva to help identify people at risk of diabetes.

The scientists say saliva testing can mirror insulin patterns linked to metabolic health, offering a painless alternative to blood tests for both research and routine screening.

High levels of insulin in the blood—known as hyperinsulinemia—can signal metabolic problems long before noticeable symptoms appear. It is already considered an early warning sign for several conditions, including Type 2 diabetes, obesity, and heart disease.

Dr Jonathan Little, a professor in UBC Okanagan’s School of Health and Exercise Sciences, said the method could do more than replace traditional blood tests. It may also help detect early metabolic changes associated with obesity and related health risks at a stage when blood sugar levels still appear normal.

The study, published in Applied Physiology, Nutrition, and Metabolism, involved 94 healthy participants with different body sizes. After fasting, participants consumed a standardised meal replacement shake. Researchers then collected saliva samples and measured blood glucose using a finger-prick test.

According to Dr Little, participants living with obesity had significantly higher insulin levels in their saliva compared with those who were slightly overweight or had lower body weight, even though their blood sugar levels were similar.

“This suggests saliva testing could be a simple, non-invasive way to identify people at risk of Type 2 diabetes before symptoms develop,” he said. “If hyperinsulinemia can be detected before blood glucose levels begin to rise, individuals at risk could be identified earlier, allowing lifestyle changes and treatments to start well before glucose levels increase.”

Early intervention is crucial because hyperinsulinemia is linked to a higher risk of several chronic conditions, including Type 2 diabetes, hypertension, cardiovascular disease, stroke, and certain cancers. Recent research has also connected the condition to obesity.

Co-author Dr Hossein Rafiei said the study aimed to explore the potential for a practical, non-invasive test to detect hyperinsulinemia. During the research, the team also noticed an interesting pattern after participants consumed the meal replacement drink.

Some participants with lower body weight showed large increases in saliva insulin levels after the meal, suggesting they might also face an elevated risk of Type 2 diabetes, even though they were not overweight and had normal blood glucose levels.

“The finding that some lean individuals have high insulin levels is intriguing,” Dr Rafiei said. “It suggests that measuring insulin in saliva may be more informative than relying only on weight or waist size to assess diabetes risk.”