Experts believe the current confusion surrounding whole grains is a hindrance to consumption.

ROCKVILLE, MD. — That the lack of a universally accepted definition for whole grain foods represents a persistent and significant impediment toward the goal of adequate consumer whole grain intake was the conclusion of a group of leading whole grains experts published in a leading nutrition journal.

“Adopting one standard definition for a whole grain food would lead to simplified research, facilitate labeling of whole grain foods and increase consumer understanding of whole grains, helping to ensure a level playing field across all sectors,” the researchers said.

Their conclusions were published in the December 2016 edition of The American Journal of Clinical Nutrition. The report was based on an interdisciplinary roundtable discussing the whole grain definition issue conducted in June 2015 at the Whole Grains Summit in Portland, Ore.

The published paper based on the roundtable was titled “Thinking critically about whole grain definitions: Summary report of an interdisciplinary roundtable discussion at the 2015 Whole Grains Summit.”

The paper featured 12 authors, including a number familiar in the grain-based foods industry, such as Len Marquart and Joanne L. Slavin, both from the Department of Food Science and Nutrition, University of Minnesota, St. Paul; and Cynthia Harriman, Oldways Whole Grains Council.

The discussion was conducted at a time when signs suggest growth in whole grains intake has slowed if not stalled, a situation that has deteriorated further in the intervening 18 months. In the first three quarters of 2016, production of whole wheat flour in the United States was down 7% from the same period in 2015.

“A major opportunity exists if definitions for whole grains and whole grain foods become standard,” the roundtable participants said. “The ultimate goal is for consumers to ingest more whole grain food and nutrients that whole grains provide.”

The group discussed the lack of uniformity in the terms “whole grains” and “whole grain foods,” but said the greater problem rests with confusion over the meaning of whole grain foods.

The roundtable participants cited data indicating that consumers do respond positively when presented with “enhanced market choices,” adding that manufacturers often provide those choices in response to changes in nutrition policy and labeling regulations.”

They said the research shows that food companies, in order to preserve brand reputations, are motivated to reformulate and promote their investments in making products healthier.

“An example of a reformulation effort occurred after the release of the 2005 D.G.A. (Dietary Guidelines for Americans),” the roundtable said. “Under those guidelines, at least half of a person’s daily grain intake should come from whole grains. Manufacturers were quick to respond to the new whole grain recommendations by introducing new whole grain cereals, breads, pastas, etc., to the market.”

The roundtable described “an explosion” of new product introductions in the aftermath of the 2005 D.G.A.

“For example, in 2010, the number of new grain foods marketed as whole grain was nearly 20 times higher than the number introduced in the year  2000,” the authors said.

The group cited U.S.D.A. data indicating that by 2007, whole grain products accounted for 20% of bread purchases, versus only 6% in 2000. Over the same period, the share of whole grain products in the cereals industry rose to 46% from 30%.

A little less impressive were aggregate figures for whole grains intake, climbing to 0.97 whole grain ounce equivalent servings in 2011-12, up from 0.72 in 2001-02. While still far short of the 3.0 servings equivalent minimum target, the authors said the progress showed consumer willingness to respond to calls for higher whole grains intake.

A surge in whole grains intake in Denmark over a similar period offers further encouragement to those who believe whole grains intake targets are achievable, the authors said.

Danes consume 63 grams of whole grains per day, up sharply from 36 grams before the launch of a Danish Whole Grain campaign, the authors said. They noted that 30% of Danes now eat the recommended 75 grams of whole grains per day.

“Improvements in whole grain consumption both in the United States and Denmark indicate that whole grains are acceptable and can be incorporated into a healthy diet,” the authors said. “A focus on standardization of whole grains and whole grain-food definitions and guidelines may help decrease heterogeneity in research findings and further increase whole grain intakes.”

Consumer confusion and a lack of consistency in the approach researchers take when they study whole grains were themes pervading the roundtable report.

“Because whole grain interventions vary, including the types of grains consumed, the amount eaten and the overall diet, it is challenging to find clarity and consistency in study design,” the roundtable said. “On the other hand, evidence from epidemiologic studies has repeatedly demonstrated the benefits of whole grains consumption.”

The paper included a review of the benefits of whole grains intake, noting both the preponderance of evidence that whole grains are beneficial to health but also areas where studies failed to demonstrate benefits.

For instance, in the case of reducing mortality, the roundtable cited evidence that increasing whole grains intake by 3 servings (90 grams) per day reduced all-cause mortality by 19%, death from cardiovascular disease by 26% and death from cancer by 9%.

At the same time, the roundtable noted, “Conflicting opinions of whether the dose-response relation between whole grain consumption and mortality is linear or nonlinear need resolution.”

Zeroing in on cardiovascular disease, the roundtable said the scientific literature indicates a 21% C.V.D. risk reduction for those at the highest category of whole grains intake, versus those at the lowest.

“But no associations were found between whole grain breads or breakfast cereals and risk of stroke,” the researchers said.

Weight gain over time tends to be less among consumers eating more whole grains, the authors said. Similarly, studies have demonstrated the risk of type 2 diabetes may be reduced by increased intake of whole grains, bran and germ.

Turning to definitions for whole grains, the authors cited several distinct definitions (three for whole grains and five for whole grain foods) but noted that one published in 1999 by AACC International (Whole grains shall consist of the intact, ground, cracked, or flaked caryopsis whole principal components, the starchy endosperm, germ and bran, are present in the same relative proportions as they exist in the intact grain) was generally accepted.

“This definition was adopted with consumer-friendly wording and endorsed by the Whole Grains Council in 2004,” the authors said. A third definition, from the Healthgrain Forum "is different in that it accounts for losses due to processing.”

The roundtable pointed several times to work of the Healthgrain Forum, a Europe-based whole grains consortium with origins dating back more than 10 years, representing 43 participating organizations from 15 countries in Europe.

The roundtable cited the Healthgrain Forum’s objective of establishing a whole grain definition “more comprehensive than current definitions used in Europe. The forum also is looking for a definition that “reflects current industrial flour manufacturing purposes’ and is “useful in the context of nutrition guidelines and for purposes of food labeling.”

“The Healthgrain definition is different from other whole grain definitions in the United States because it accounts for losses due to processing (i.e., losses of less than 2% of the grain and less than 10% of the bran that occur through processing methods consistent with safety and quality), but currently there is no consensus on the desirability of this,” the roundtable participants said.

“Most academic and government sources agree that a whole grain should meet the basic definition established by the AACCI, although more must be done to educate consumers and industry,” the authors said.

Less consensus surrounds a precise definition of whole grain foods, the roundtable noted, adding that the Food and Drug Administration has not yet issued final guidance for the definition of whole grain foods. At present, the AACC International definition has not yet been harmonized with the food industry’s definition.

“The AACCI characterizes whole grain foods as those that contain 8 or more grams of whole grains per 30-gram product without a dietary fiber requirement; whereas, efforts led by the food industry have similar requirements except that the food cannot contain excessive amounts of fat, sugar, sodium, or calories,” the authors said. “In 1999, the F.D.A. allowed food manufacturers to apply a whole grain health claim, but to bear the claim, the food must contain at least 51% whole grain by weight.”

A seemingly minor format difference in the definitions potentially causing serious problems is in units of measure, with some measuring whole grain amounts in grams, others in ounces and still others in percentage, the participants said.

“The variability in units not only confuses consumers who are trying to identify whole grain products, but it also limits researchers who are trying to accurately estimate whole grain intake in observational and intervention studies,” the paper said.

The paper cited a research study calling for a completely different tack — reporting the amount of whole grain consumed (in grams) rather than the absolute amount of the whole grain food product. For example, a serving would be described as “16 grams of whole grain wheat versus a 28 gram whole grain serving of wheat bread.”

Considerably more work is needed toward the establishment of a uniform definition of whole grain foods than is needed for one of whole grains, but the latter issue should not be allowed to languish, the authors said.

“Although there is near-universal agreement on the core definition of a whole grain (‘all of the bran, germ, endosperm in their original proportions’), some final adjustments regarding reconstitution and recombination and processing losses are required before global acceptance can be achieved, and much further effort is needed on a definition of a whole grain food.”