Boston, MA – Current standards for classifying foods as "whole grain" are inconsistent and, in some cases, misleading, according to a new study by Harvard School of Public Health (HSPH) researchers. One of the most widely used industry standards, the Whole Grain Stamp, actually identified grain products that were higher in both sugars and calories than products without the Stamp. The researchers urge adoption of a consistent, evidence-based standard for labeling whole grain foods to help consumers and organizations make healthy choices. This is the first study to empirically evaluate the healthfulness of whole grain foods based on five commonly used industry and government definitions.
"Given the significant prevalence of refined grains, starches, and sugars in modern diets, identifying a unified criterion to identify higher quality carbohydrates is a key priority in public health," said first author Rebecca Mozaffarian, project manager in the Department of Social and Behavioral Sciences at HSPH.
The study appears in the January 4, 2013 advanced online edition of Public Health Nutrition.
The health benefits of switching from refined to whole grain foods are well established, including lower risk of cardiovascular disease, weight gain, and type 2 diabetes. Based on this evidence, the U.S. Department of Agriculture's (USDA) 2010 Dietary Guidelines recommend that Americans consume at least three servings of whole grain products daily, and the new U.S. national school lunch standards require that at least half of all grains be whole grain-rich. However, no single standard exists for defining any product as a "whole grain."
Mozaffarian and her colleagues assessed five different industry and government guidelines for whole grain products:
From two major U.S. grocers, the researchers identified a total of 545 grain products in eight categories: breads, bagels, English muffins, cereals, crackers, cereal bars, granola bars, and chips. They collected nutrition content, ingredient lists, and the presence or absence of the Whole Grain Stamp on product packages from all of these products.
They found that grain products with the Whole Grain Stamp, one of the most widely-used front-of-package symbols, were higher in fiber and lower in trans fats, but also contained significantly more sugar and calories compared to products without the Stamp. The three USDA recommended criteria also had mixed performance for identifying healthier grain products. Overall, the American Heart Association's standard (a ratio of total carbohydrate to fiber of ≤10:1) proved to be the best indicator of overall healthfulness. Products meeting this ratio were higher in fiber and lower in trans fats, sugar, and sodium, without higher calories than products that did not meet the ratio.
"Our results will help inform national discussions about product labeling, school lunch programs, and guidance for consumers and organizations in their attempts to select whole grain products," said senior author Steven Gortmaker, professor of the practice of health sociology.
Other HSPH authors included researchers Rebekka Lee and Mary Kennedy; Dariush Mozaffarian, associate professor in the Department of Epidemiology; and David Ludwig, professor in the Department of Nutrition.
Support for the study was provided by the Donald and Sue Pritzker Nutrition and Fitness Initiative; the Centers for Disease Control and Prevention (Prevention Research Centers grant U48DP000064, including the Nutrition and Obesity Policy, Research and Evaluation Network); the New Balance Foundation; the National Institute of Diabetes and Digestive and Kidney Diseases (K24082730); and the National Heart, Lung, and Blood Institute, National Institutes of Health (R01 HL085710).
"Identifying whole grain foods: a comparison of different approaches for selecting more healthful whole grain products," Rebecca Mozaffarian, Rebekka Lee, Mary Kennedy, David Ludwig, Dariush Mozaffarian, and Steven Gortmaker, Public Health Nutrition, online January 4, 2013
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