The study, published in the American Journal of Clinical Nutrition (vol. 83, pp. 275-283), adds to the number of observational studies linking whole grains to lower risks of the diseases - news that has already been grasped by cereal makers as the number of wholegrain products look set to rise.
Sales of whole grains products in the US have increased following recommendations of the health benefits in the USDA's new Dietary Guidelines for Americans.
In Europe, the Healthgrain Integrated Project was recently launched to identify new sources of nutritionally enhanced grain, as well as to develop methods to make cereal products more appealing to consumers.
The joint Danish-American cross-sectional study analysed diet records, assessed by a 131-item food frequency questionnaire, and took blood analyses of 468 men and 473 women.
The researchers measured intake of whole grains, bran and germ to markers of glycemic control, blood lipids, cholesterol, and inflammation.
"Compared with participants in the bottom quintile [lowest intake group], participants in the highest quintile had 17, 14, 14 and 11 per cent lower concentrations of homocysteine, insulin, C-peptide, and leptin, respectively," wrote lead author Majken Jensen from Aarhus University Hospital and Harvard School of Public Health.
"Inverse associations were also observed with total cholesterol, HDL (good) cholesterol, and LDL (bad) cholesterol," reported Jensen.
No link was observed between the intake of whole grains and markers of inflammation, however.
Although, the limitations of using food frequency questionnaires have been well noted, the researchers are confident with their conclusions: "The results suggest a lower risk of diabetes and heart disease in persons who consume diets high in whole grains."
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 billion, according to 2002 American Diabetes Association figures.
CVD causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy an estimated €169 billion ($202 billion) per year. According to the American Heart Association, 34.2 percent of Americans (70.1 million people) suffered from some form of cardiovascular disease (CVD) in 2002.