The consistent evidence linking the consumption of whole grain to significant decreases in the risk of heart disease should push policy makers to redouble their efforts to get the public eating more of the grains, scientists behind a new meta-analysis have said.
The meta-analysis - a combination of seven prospective studies containing 149 000 participants in total - revealed that consumption of at least 2,5g of whole grains every day was associated with a 21 percent reduction in the risk of cardiovascular events, compared to consumption of 0,2g per day.
"There is a consistent, inverse association between dietary whole grains and incident cardiovascular disease in epidemiological cohort studies," wrote lead author Philip Mellen in the journal Nutrition, Metabolism & Cardiovascular Diseases.
Efforts should be redoubled
"In light of this evidence, policy makers, scientists, and clinicians should redouble their efforts to incorporate clear messages on the beneficial effects of whole grains into public health and clinical practice endeavours," he said.
Whole grains 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 term 'whole grain' is considered to be more consumer friendly than the term 'fibre', which leads some manufacturers to favour it on product packaging since it is likely to strike more of a chord of recognition for its healthy benefits.
The research study
The reviewers behind the new meta-analysis, from Wake Forest University in the US, identified seven cohorts with quantitative whole grain estimates and clinical cardiovascular event rates. The pooled average intake of participants with the highest intake of whole grain was 2,5g per day, and the lowest average was 0,2g per day.
Mellen and co-workers calculated that consumption of at least 2,5g per day was associated with a 21 percent decrease in the risk of cardiovascular events such as coronary heart disease and stroke, compared to consumption of 0,2g per day.
Similar findings were observed when calculated on a sex-specific basis, with women associated with a 21 percent risk reduction from whole-grain consumption and men with an 18 percent reduction.
No difference in cardiovascular disease risk was observed when Mellen and co-workers considered refined grains.
Refining removes important agents
They note that refining grains removes many biologically active agents from the grain, including fibre, vitamins, minerals, lignans, phytosterols and other plant compounds.
"These biological agents influence cardiovascular risk through effects on glucose homeostasis, lipids and lipoproteins, endothelial function, and other mechanisms, potentially accounting for much of the observed benefit of high intake of whole grains," wrote the authors.
The authors also note that, despite a wealth of evidence supporting the benefits of whole-grain consumption, intake among the general population remains relatively low. Indeed, the US-based National Health and Nutrition Examination Survey revealed that only eight percent of American adults consumed three or more servings of whole grains every day.
"Many consumers and health professionals are unaware of the health benefits of whole grains," they added.
The authors concluded that efforts should be redoubled in order to make an impact on cardiovascular disease risk. - (Decision News Media, April 2007)
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