The observational study, the first to look at the relationship between wholegrain consumption in an exclusively older population, was started in 1981 and has up to 14 years of mortality follow-up.
Although the results of the new study confirm the 2005 Dietary Guidelines to Americans recommendation to consume at least three wholegrain servings per day, studies have shown that MetS is on the rise in the US and Europe.
MetS is a condition characterised by central obesity, hypertension, and disturbed glucose and insulin metabolism. The syndrome has been linked to increased risks of both type 2 diabetes and CVD.
Fifteen per cent of adult Europeans are estimated to be affected by MetS, while the US statistic is estimated to be a whopping 32 per cent.
Lead author of the new study, Nadine Sahyoun from the University of Maryland, told NutraIngredients.com: "Our results do confirm that the association between whole grains and metabolic syndrome can still be seen among an older population who may have different metabolic characteristics than a younger population."
The study, published in the January issue of the American Journal of Clinical Nutrition (Vol. 83, pp. 124-131), required 535 healthy volunteers with an average age of 72 to complete three-day food records and undergo blood tests for metabolic risk factors.
Volunteers in the highest wholegrain intake group (3 servings per day) were statistically half as likely to develop MetS as those who consumed less than half a serving per day.
The benefits of wholegrain are proposed to be due to its favourable effect on total blood cholesterol, thereby improving lipid profiles. Other possible explanations included improved endothelial function, fibrinolysis, and coagulation.
The study also highlighted an important difference between wholegrain and refined grain intake.
"We observed in our older population that higher intake of refined grains was associated with higher prevalence of the metabolic syndrome. This was not consistently found among younger populations in other studies," said Sahyoun.
"This is probably due to the fact that this was an older population and, therefore, more susceptible to impaired glucose tolerance," she said.
Cathy Ross, medical spokesperson for the British Heart Foundation (BHF), gave a note of caution. She said that the mortality statistics could have been affected by the lipid-lowering medication and high blood pressure treatment of some of the subjects.
Ross told NutraIngredients.com: "The results are however positive and reinforce the BHF message that healthy eating along with regular exercise and stopping smoking reduces the risks of coronary artery disease."
The European Union has already announced steps to halt the rise of MetS among member state populations. The €16 million Healthgrain Integrated Project aims to examine the effects of bioactive compounds in wheat and rye on human metabolism.