Americans are eating more whole-grain foods, but determining how much more is tricky because of the lack of a consistent definition of the term “whole-grain.” A new study highlights the need to standardize the definition so consumers know what to buy and researchers can track Americans’ intake accuratey.

The increase in consumption of whole-grain foods over the past 20 years could be 40 percent or it could be 60 percent, depending on which definition of "whole-grain food" is used to make that determination. Even so, the Friedman School of Nutrition Science and Policy at Tufts University reports that average consumption is much below the recommended intake and is confounded by which definition of “whole-grain food” is used.

Smart consumers will ignore front-of-the-package marketing claims about the grain content of foods, turn the package over and go straight to the ingredient list.

Researchers at Tufts University compared the definitions of whole-grain foods from the Dietary Guidelines for Americans, the U.S. Food and Drug Administration (FDA), the American Heart Association (AHA), the American Association of Cereal Chemists International and The Whole-grains Council. The various definitions were applied to the dietary intake of nearly 40,000 adults as reported to the National Health and Nutrition Examination Survey from 2003 to 2018.

“We found that each definition captured very different types of grain- or flour-containing foods as whole-grain foods, resulting in differences in the average consumption of whole-grain foods and the associated trends,” said one of the study authors, Mengxi Du, in a statement.

Currently, there is no standard definition of what classifies a food as whole-grain. Under all definitions, Americans’ consumption of whole-grain bread has increased, but an unexpected finding was how foods eaten by some racial/ethnic populations were classified depending on which definition of whole-grain foods was used.

The American Heart Association recognizes corn-based foods, such as tortillas, as whole-grain, so under the AHA’s definition of whole-grain foods, Hispanic people ate the most whole-grain foods.

There are some similarities among the definitions of different categories of whole-grain foods, but more differences exist. The FDA has the strictest definition of whole-grain foods, while the Whole Grains Council, an industry led organization, is more lenient.

The findings from the study highlight the need for there to be a consensus on the definition of whole-grain, starting with an assessment of the nutrient profiles of each of the current definitions and how they correlate with health outcomes.

The nutritional value of whole grains is not in dispute. Whole-grain foods are high in fiber, and they can reduce the chance of developing some health conditions, like certain types of cancer. Whole grains can also help people manage chronic diseases like diabetes. The Dietary Guidelines for Americans recommend that we should eat a minimum of three ounces of whole-grain foods daily, and that half of our grain intake each day should come from whole-grains.

Du, a PhD candidate in Nutrition Epidemiology and Data Science, explained that she has experienced difficulties identifying whole-grain food from package labeling herself, so it’s not surprising that nearly half of American consumers have similar problems.

Smart consumers will ignore front-of-the-package marketing claims about the grain content of foods, turn the package over and go straight to the ingredient list. If a whole grain is listed within the first three ingredients, you can feel certain you are choosing a food that is good for your health.

The study was published in The American Journal of Clinical Nutrition.