The dietary habits of over 64,000 women were assessed and correlated with the development of type-2 diabetes over about five years, and a high intake of all legumes was associated with a 38 per cent reduction in risk of developing the disease, report researchers in this month's American Journal of Clinical Nutrition. An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030. In the US, there are over 20 million people with diabetes, equal to seven per cent of the population. The total costs are thought to be as much as $132 bn, with $92 bn being direct costs from medication, according to 2002 American Diabetes Association figures. According to background information in the study, it has been suggested previously that a high intake of these foods can have benefits against the development of type-2 diabetes, although data is limited for this link.
Researchers from Vanderbilt University Medical Center and the Shanghai Cancer Institute set about filling in these gaps, and recruited 64,227 middle-aged Chinese women with no previous history of diabetes, cardiovascular disease or cancer, and followed then for an average of 4.6 years. The authors, led by Raquel Villegas, used food-frequency questionnaires to assess the dietary intakes of the subjects, and reported an inverse association between the intake of legumes and the incidence of type-2 diabetes. Indeed, for a high intake of all legumes, the researchers reported a 38 per cent reduction in risk, while a high intake of soybeans was associated with a 47 per cent reduction in risk. Interestingly, no relationship was observed for the consumption of soy products and soy protein with diabetes risk.
The study does have several limitations, including the use of food frequency questionnaires to measure dietary intakes, which are subject to recall errors, and being focused on Chinese women, which prevents generalization of the results to other populations. Late last year, researchers from the University of Massachusetts Amherst reported that soy yoghurts could play an important role in the management of type-2 diabetes and high blood pressure. The Massachusetts researchers reported that phenol-rich soy yogurts could inhibit about 92 per cent of the activity of the angiotensin-I converting enzyme (ACE-I), which plays a role in the constriction of blood vessels. Source: American Journal of Clinical Nutrition January 2008, Volume 87, Number 1, Pages 162-167
"Legume and soy food intake and the incidence of type 2 diabetes in the Shanghai Women's Health Study"
Authors: R. Villegas, Y.-T. Gao, G. Yang, H.-L. Li, T.A. Elasy, W. Zheng and X.O. Shu