An analysis of previously carried out study reviews on the association between whole grain foods and type 2 diabetes risk appears to have backed the theory that such foods may reduce the likelihood of developing the disease, especially in people who consume a diet high in unrefined grains.
The authors have, however, warned that more research is necessary before scientists can confirm a causal relationship.
At the moment, because there is only weak evidence, no definite conclusion can be drawn concerning the protective effect of whole grain foods for the development of type 2 diabetes, said lead review author Marion Priebe, a nutritionist and epidemiologist at the Center for Medical Biomics, University Medical Center Groningen in the Netherlands.
A decrease in consumption of whole grain cereals over the last decade, occurring at the same time as an increase in type 2 diabetes, has given rise to the theory that there is a connection between the two.
The researchers reviewed 12 studies that examined relationships between whole grain intake and type 2 diabetes, which consisted of a single randomized controlled clinical trial and 11 prospective studies.
In the prospective studies, groups of people without diabetes were followed over long periods to see whether those who consumed more whole grain foods were less likely to get the disease than other participants were.
The review appearing in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration, suggests that these studies consistently showed a reduction of risk for the disease in those with a high intake of whole grain foods or cereal fibre.