Study suggests foods like oats, barley and fibre supplements may contribute to management of diabetes

By Ana Gajic

Foods like oats, beans and avocados are high in viscous fibre and a new study suggests there are benefits for patients who include viscous fibres in their diets – particularly for patients with diabetes. Dr. Vladimir Vuksan, associate scientist at the Li Ka Shing Knowledge Institute and Elena Jovanovski, clinical research co-ordinator in the Clinical Nutrition and Risk Factor Modification Centre of St. Michael’s led a study that suggests this fibre type may have positive impacts on blood sugar levels and heart health.

We asked the research team about this recent work and what it means for patients.

Q. What did you set out to study?

Dietary fibre can be characterized as non-viscous (also known as cereal fibre type) or viscous (such as oat or psyllium fibre). Based on previous studies, viscous fibre may have metabolic benefits, including the ability to reduce blood sugar levels after meals.

This research study aimed to investigate for the first time if supplementing diets with viscous fibre types, using foods or supplements, may improve markers of blood sugar control and be beneficial in diabetes management. The systematic review and meta-analysis combined the results of all available evidence from randomized controlled trials where a diet rich in viscous fibre was consumed for more than three weeks. It aimed to obtain a comprehensive estimate of viscous fibre’s effect on blood sugar control.

Q. Why were you interested in this topic?

Diabetes markedly elevates the risk for heart disease, and its prevalence is increasing worldwide. Increased intake of fibre has been the cornerstone of major dietary recommendations not only as part of a diet in healthy adults, but also for conditions such as high cholesterol, obesity, elevated blood pressure and in particular diabetes.

Canadians are consuming approximately half of the recommended amount of total fibre with only a fraction of the viscous type, which is believed to have cardio-protective benefits. Since it is difficult to obtain therapeutic amounts of viscous fibre from regular food sources and a typical diet, fibre supplements may be a practical alternative.

Q. What were the key findings of this study?

It was encouraging to observe that supplementation with viscous fibre reduced HbA1c, a major marker of blood sugar control, by a clinically significant reduction of 0.58% assessed in 1,394 individuals with type 2 diabetes. This effect is relevant as dietary interventions often produce modest effects and this reduction is comparable with some conventional add-on diabetes medications. The study findings also showed a reduction in fasting blood glucose and improved insulin sensitivity.

The median dose of viscous fibre supplemented was about one tablespoon a day. It’s important to note that these results were shown in individuals who were mostly already receiving the standard of care for diabetes. This includes diabetes medication and a healthy diet; so the overall effect may be considered to be in addition to, or ‘beyond’, the standard of care.

Q. Why is this important?

Previous research has looked at the effects of fibre in general on diabetes control, demonstrating modest health benefits, but not specifically the viscous type which appears to be more potent. Up until now the American Diabetes Association has reported fibre’s potential for regulating blood sugars as marginal.

It was therefore important to identify the effect of viscous fibre to provide recommendations to the public, in particular to individuals with diabetes. Based on study results it appears that a tablespoon of viscous fibre from foods or supplements would be a fairly easy-to-implement and a convenient strategy to improve blood sugar levels as well as increase overall fibre intake.

Q. What’s next for this research?

This work identified a collective effect of common viscous fibre types at a median dose. It would be of interest to further compare the potency of each fibre for the same dose, given the properties of each (including level of viscosity) that may affect blood sugar levels differently.

Disclosures: Dr. Vuksan holds the Canadian and American patents on the medical use of viscous fibre blend for reducing blood glucose for treatment of diabetes, increasing insulin sensitivity, and reducing systolic blood pressure and blood lipids. Full list of disclosures is in the publication.

These papers are an example of how St. Michael’s Hospital is making Ontario Healthier, Wealthier, Smarter.

About St. Michael’s Hospital

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in more than 29 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the Hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.

About Unity Health Toronto

Unity Health Toronto, comprised of Providence Healthcare, St. Joseph’s Health Centre and St. Michael’s Hospital, works to advance the health of everyone in our urban communities and beyond. Our health network serves patients, residents and clients across the full spectrum of care, spanning primary care, secondary community care, tertiary and quaternary care services to post-acute through rehabilitation, palliative care and long-term care, while investing in world-class research and education. For more information, visit www.unityhealth.to.