How sweet it is – clinical trial putting fructose to the test

Jun 16 2014

Professor Manohar Garg

With opinion divided on whether an apple a day really keeps the doctor away, HMRI nutrition researcher Professor Manohar Garg is conducting a new clinical trial to determine the cardio-metabolic health impacts of fructose.

A member of the University of Newcastle’s Centre for Physical Activity and Nutrition, Professor Garg believes fruit sugar has minimal affect in its natural, complex form – not so the fructose found in sweeteners such as corn syrup, honey, maple syrup, table sugar and soft drinks including fruit juices.

“Whenever you mention fructose there is controversy,” Professor Garg said. “Not all fruits are rich in fructose, of course, and they contain many other nutrients that are important; what we’re talking about is fructose consumed in isolation.

“There are biochemical aspects which differentiate fructose from glucose sugars that we consume. Fructose induces minimal insulin response, and insulin is one of the satiety hormones – that means people remain hungry and tend to consume more calories.”

Professor Garg believes the sweetener is a prime culprit when it comes to obesity and associated health issues such as diabetes and heart disease because it’s converted into harmful fat in the body.

For his four-week randomised trial he will give volunteers a daily serve of either 50 grams of fructose or glucose, which they can sprinkle on their breakfast cereal or beverages. The two sugars look alike and participants won’t know which they’re receiving.

The research team is aiming to recruit 40 people for the study, aged 18-60, in a normal weight range and with no symptoms of diabetes or cardiovascular problems. Blood samples will be used to assess the level of lipids, satiety hormones, inflammatory biomarkers and insulin resistance.

“It may sound like a lot of sugar but it’s not – people often consume over 100 grams a day,” Professor Garg said. “We are not expecting to see weight gain in the four week intervention, but we hope to distinguish between fructose and glucose and anticipate seeing elevated blood lipids levels with fructose.

“Obesity is such a problem that we must sort out whether we can have alternatives to sugars that will satisfy the cravings for sweet foods without the ill effects on our health.”

Those interested in this trial can contact Faizan Jameel via email at or phone 4921 5638.