WHOLEGRAINS AND RISK OF DIABETES
A new study published in the British Medical Journal has found that a higher intake of wholegrains is associated with a lower risk of developing type 2 diabetes.
Researchers combined the findings from three large prospective cohort studies – the Nurses’ Health Study, The Nurses’ Health Study 2 and the Health Professionals Follow-Up Study. Together, they included 158,259 women and 36,525 men who did not have type 2 diabetes, cardiovascular disease, or cancer when the studies began. Participants completed a dietary questionnaire at the start of the study and every four years, and another questionnaire to identify newly diagnosed type 2 diabetes and other health conditions every two years. The average follow-up period was 24 years.
In this study, the researchers looked specifically at intake of total and individual whole grain foods and the risk of type 2 diabetes.
After adjusting for other lifestyle and dietary factors which might affect diabetes risk, participants with the highest intakes of wholegrains had a 29% lower risk of type 2 diabetes compared to those with the lowest intakes.
The researchers also looked at specific wholegrains including wholegrain breakfast cereals, wholegrain breads, oatmeal and brown rice. People who ate 1-2 serves of wholegrain cereal or breads per day had around a 20% lower risk of developing diabetes compared to those who ate these foods less than once per month. And those who ate oatmeal or brown rice once or twice per week had a 21% and 12% lower risk, respectively, than those who ate these foods less than once per month. Physical activity, family history of diabetes and smoking status didn’t affect the findings but the association between wholegrain intake and diabetes risk was stronger in those who were lean compared to those carrying excess weight.
These findings are consistent with previous studies showing a lower risk of type 2 diabetes associated with wholegrain, but not refined grain, intake. When it comes to rice, previous research has found that higher intakes of white rice were associated with an increased risk of type 2 diabetes and it was estimated that replacing 50g (uncooked) per day of white rice with brown rice could reduce diabetes risk by 16%.
- Hu Y, and colleagues. Intake of whole grain foods and risk of type 2 diabetes: results from three prospective cohort studies. BMJ. 2020.
- Sun Q, and colleagues. White rice, brown rice, and risk of type 2 diabetes in US men and women. Arch Intern Med. 2010.
- Aune D, and colleagues Whole grain and refined grain consumption and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of cohort studies. Eur J Epidemiol. 2013.
Kate Marsh is an is an Advanced Accredited Practising Dietitian, Credentialled Diabetes Educator and health and medical writer with a particular interest in plant-based eating and the dietary management of diabetes and polycystic ovary syndrome (PCOS).
Contact: Via her website www.drkatemarsh.com.au.