"The take home message is that higher consumption of whole grain should be promoted based on research on whole grain and lower risk of type 2 diabetes as well as other chronic diseases," lead researcher Dr. Rob van Dam told NutraIngredients.com.
Wholegrains have received considerable attention in the last year, especially in the US where the FDA permits foods containing at least 51 percent whole grains by weight and are low in total fat, saturated fat, and cholesterol to carry a health claim, which links them to a reduced risk of heart disease and certain cancers.
The researchers, from Harvard School of Public Health, the Vrije Universiteit Amsterdam, and Boston University, said that it was not clear however if the results would also be observed and applicable to magnesium supplements.
These comments are based on results of the Black Women's Health Study, a prospective cohort that, for this study, involved 41,186 African American women with an average age of 39 years. Dietary assessment was performed using 68-item food frequency questionnaires, while incidence of diabetes was assessed every two years by questionnaire.
After eight years of follow-up 1,964 newly diagnosed cases of type 2 diabetes were documented by Dr. van Dam and his wo-workers.
Taking into account possible confounding factors like smoking status, BMI, alcohol consumption, age, parental history of diabetes, soft drink consumption, calcium intake, and several others, the researchers found that women with the highest intake of magnesium (average 244 mg per day) had a 35 per cent lower risk of type-2 diabetes than those with the lowest intake (about 115 mg per day).
Similar protective effects were also observed for wholegrain consumption, with women with the highest intake (one or more servings a day) associated with a 31 per cent lower risk of diabetes that women who ate less than one serving a week.
"These findings indicate that higher consumption of magnesium-rich foods, particularly wholegrain products, is associated with a lower risk of type-2 diabetes in African-American women," wrote the researchers in the October issue of Diabetes Care (Vol. 29, pp. 2238-2243).
The potential mechanism of protection afforded by the magnesium-rich food, suggested the researchers, in on glucose control since magnesium can act as a co-factor for enzymes involved in the metabolism of glucose, or possibly on insulin secretion.
But while the evidence appears to point towards the benefits of magnesium, Dr. van Dam told this website: "Further well-conducted intervention studies are needed to elucidate whether magnesium per se can improve glucose homeostasis."
Dr. van Dam confirmed that the researchers are continuing to look into the area of wholegrain consumption and diabetes. "We are evaluating intake of whole grain and its components in relation to risk of type 2 diabetes in other population as well as summarizing the evidence from all research conducted on this topic," he said.
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.