An increased intake of wholegrain-rich foods has been linked to improvements in blood vessel health, says a new study that adds to the heart-health benefits of a diet rich in wholegrains.
The study, published in the American Journal of Clinical Nutrition, looked at the thickness of certain blood vessels as a function of dietary wholegrain consumption among 1178 men and women in a large, ethnically diverse cohort.
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 linking them to a reduced risk of heart disease and certain cancers.
The term wholegrain 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.
Lead author Philip Mellen from the Wake Forest University said that, although the study was not designed to assess the benefits across ethnic groups, "it does suggest that the favourable relation between whole-grain intake and atherosclerosis or cardiovascular disease risk is broadly applicable to individuals of different ethnicities and cardiovascular disease risk profiles."
Atherosclerosis, or hardening of the arteries, is a major risk factor for cardiovascular disease (CVD), which causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy about €169bn ($202bn) per year.
The new study assessed the diet of the subjects (average age 55.2, 56 per cent female) using a semi-quantitative 114-item food-frequency questionnaire (FFQ). The thickness of the carotid artery was measured using carotid ultrasonography at the start of the study and after five years of follow-up.
After adjusting the results for potential confounding nutrients like magnesium, thiamine, vitamin B-6, fiber, and vitamin E, the researchers found that whole-grain consumption was strongly correlated with a lower risk of atherosclerosis as defined by a lower common carotid artery intimal medial thickness (IMT).
"These findings provide further support for the potential beneficial role of whole grains in reducing atherosclerotic cardiovascular disease," they said.
The authors noted limitations with their study, particularly the use of FFQs to measure wholegrain intake. Such questionnaires are reliant on the recall and accuracy of the participants and are therefore subject to some error.
In an accompanying editorial by Vasanti Malik and Frank Hu from Harvard said the study emphasised that whole grains are complex foods with multifactorial effects and stated that further research is needed to explore their actions on atherosclerosis risk.
"An increased consumption of whole grains represents a wholesome and palatable opportunity to reduce the risk of atherosclerosis and cardiovascular disease," they concluded.
Source: American Journal of Clinical Nutrition
Volume 85, Pages 1495-1502
"Whole-grain intake and carotid artery atherosclerosis in a multiethnic cohort: the Insulin Resistance Atherosclerosis Study"
Authors: P.B. Mellen, A.D. Liese, J.A. Tooze, M.Z. Vitolins, L.E. Wagenknecht, D.M. Herrington
Editorial: American Journal of Clinical Nutrition
Volume 85, Pages 1444-1445
"Dietary prevention of atherosclerosis: go with whole grains"
Authors: V.S. Malik, F.B. Hu