In a new study published in the European Heart Journal, researchers pooled information on the eating habits of 147,642 people from 21 countries and created a newly developed diet score (called the PURE healthy diet score) that captured intakes of fruits, vegetables, legumes, nuts, fish, and full-fat dairy. Using this score, the authors observed that people who most closely adhered to this diet were less likely to develop cardiovascular disease and had a lower risk of mortality. When one serving of whole grains per day were then added to their analysis, the risk of cardiovascular disease and mortality did not change, leading the study authors to conclude that “including a moderate amount of whole grains is optional for a healthy diet.”  The authors went on to define one serving per day as a moderate amount of whole grain, but a closer look at the science reveals why this recommendation is completely misleading.

One serving of whole grains per day is far lower than the amount recommended in dietary guidelines around the globe, and is far lower than the optimal amount suggested by the body of nutrition research, so it is not surprising that the contribution of amounts as small as one serving per day did not have a significant impact on CVD risk.                                   

Further, when you take a closer look at what the study authors define as a serving of whole grains, their conclusion about whole grains is revealed to be even more misleading. Foods counted towards the whole grains category in this study include semolina (durum wheat that is more often refined than whole), polenta (a corn porridge that is often refined rather than whole grain) and cooked rice, specifically noting that the rice was mainly white rice. By grouping whole grains and refined grains together in their analysis, and by limiting “whole grain” contributions to only 1 serving per day, it is not possible for the authors to be able to deduce that whole grains are optional for a healthy diet.

Declaring that whole grains are optional for a healthy diet “is very irresponsible in light of the vast amount of evidence to the contrary,” says Dr. David Jacobs, Whole Grains Council Scientific Advisor and Mayo Professor of Public Health in Epidemiology and Community Health at the University of Minnesota School of Public Health. The misleading takeaway in this new study flies in the face of the prevailing evidence, including evidence from the Global Burden of Diseases study in which insufficient whole grain intake was found to be a leading cause of disability adjusted life years and mortality. “In my studies of whole grain food intake, whole grain was highly correlated with the individual’s perception of healthy diet and lifestyle generally,” says Dr. Jacobs, who emphasizes that, “it is protective to include a large and varied amount of nutritionally-rich plant food in the diet and whole grain foods are good examples of such foods.”

Additionally, Dr. Nicola McKeown, Whole Grains Council Scientific Advisor and Research Professor at Sargent College of Health and Rehabilitation Sciences at Boston University, pointed out that the estimation of whole-grain intake in research is challenging because of variation in dietary assessment methods, lack of consensus on whole-grain foods, and misclassification of foods as ‘whole’ grains when in fact they are refined grains (such as semolina). Dr. McKeown and other experts in this field are aware of the caveats and understand the complexity in accurately capturing grain intake. However, given the diversity of grain intake across the countries in this new analysis, particular attention needs to be given to how each country captured whole-grain intake and how the grain foods were classified (or misclassified).

Even in the materials accompanying the study, reviewers analyzing the study did not conclude that whole grains are optional, nor did they conclude that red meat is beneficial. For example, in Dr. Dariush Mozaffarian’s editorial accompanying the new PURE study, he writes that “this new report from the PURE study provides valuable confirmatory evidence from diverse nations on the importance of health-protecting foods such as fruits, whole grains, vegetables, legumes, nuts/seeds, and dairy” and that “present findings provide no support for major health benefits of inclusion or ‘variety and moderation’ of other ‘natural foods’ such as red meat, poultry, or butter.”

Given the wide geographic scope of this study, it is also important to be as representative as possible of the whole grains that are available in these communities. However, when looking at the grain list in the Appendix, the study authors do not appear to include heritage whole grains like teff, millet, and sorghum, which are often served in their whole grain form throughout the African continent and in some other countries in Southeast Asia. “There are many ways to achieve a healthy diet, and this is done in different cultural and geographic contexts in different ways,” says Dr. Jacobs. “The pattern is what really matters, in my view.”  (Kelly)

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