Daily consumption of wholegrains, a rich source of magnesium, previously reported to lower the risk of diabetes in white women, could also cut the risk in black women by about 30 percent, says new research from Harvard.
“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.
The research study
These comments are based on results of the Black Women’s Health Study, a prospective cohort that, for this study, involved 41 186 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 co-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 244mg per day) had a 35 percent lower risk of type-2 diabetes than those with the lowest intake (about 115mg 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 percent 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).
Mechanism of protection
The potential mechanism of protection afforded by the magnesium-rich food, suggested the researchers, involves 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 populations as well as summarising the evidence from all research conducted on this topic,” he said. - (Decision News Media, October 2006)
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