Red X iconGreen tick iconYellow tick icon

We all know whole grains are healthier than refined, but what happens if those grains are processed?

To find out, researchers at the University of Otago are recruiting for a study to determine if eating less processed or more processed wholegrain foods helps improve blood glucose control in those living with type 2 diabetes.

Aysu Shahin image
Aysu Shahin.

The Whole Grains for Health Study, run by PhD candidate and Dietitian Aysu Shahin and Heart Foundation Senior Research Fellow Dr Andrew Reynolds in the Department of Medicine, builds on earlier research showing the benefits of wholegrain foods.

“We already know that eating whole grains, like wholemeal bread, is healthier than eating refined grains, like white bread. What we don't know is if milling whole grains – breaking them into smaller particles – reduces the benefits associated with their intake,” Ms Shahin says.

Previous research by Dr Reynolds suggests that eating less processed whole grains for two weeks can improve blood glucose control for adults with type 2 diabetes. The group wants to extend that research to investigate the benefits of this approach over a 12-week period.

“I’m really pleased about this new trial as it builds on some proof-of-concept studies and smaller trials we started back in 2017. It’s fantastic to see that our idea has evolved into a full clinical trial on whole grains,” Dr Reynolds says.

The researchers are seeking 160 people with type 2 diabetes, living in Otago, Canterbury or Southland, to join the study over the next year.

Participants will receive free fortnightly deliveries of either less-processed wholegrain foods (bread, rice, oats, bulgur) or more processed wholegrain foods (bread, pasta, cous cous, oat flour) for 12 weeks. They will be asked to replace the grain foods they normally eat with the grain foods provided. Enough wholegrain foods will be provided for a household.

As part of the study, blood samples and diet diaries will give a better understanding of how wholegrain processing impacts blood sugar levels.

“A lot of people are talking about ultra processed foods, and the observational evidence looks like they are bad for us, but there is really very little practical evidence underpinning these observations.

“We want to know more about what’s really going on with eating more highly processed foods, and this study is part of that,” Ms Shahin says.

Whole Grains for Health Study

If you are interested in joining this study, or would like more information, visit:

The trial is funded by a Lottery Health Grant and a grant from the Baking Industry Research Trust.

For more information, please contact

Aysu Shahin
PhD candidate
Department of Medicine
University of Otago

Ellie Rowley      
Communications Adviser
University of Otago
Mob + 64 21 278 8200

Back to top