Grains are responsible for less than 15% of calories, says C.D.C.

ATLANTA — A study published in August in the scientific journal Nutrients shows that less than 15% of Americans’ total calories come from grain-based foods such as bread, rolls and tortillas. However, this quantity is providing its eaters with nutrient content necessary to maintain health.

In the study, more than 10,000 surveys completed by adults over the age of 19 were compiled by the National Center for Health Statistics of the Centers for Disease Control and Prevention (C.D.C.). Participants were asked to disclose their eating behaviors for the most recent 24-hour period. The data for both men and women was analyzed, looking for both the consumption level of grains and related subcategories and the contribution of those grains to dietary vitamins, minerals and fiber. Specifically, the study focused on how grains contribute to shortfall nutrients such as folate, magnesium, calcium and iron.

“All grain foods, collectively — in addition to specific grain food groups — are meaningful contributors of nutrient density and provide sources for several shortfall nutrients and nutrients of public health concern as identified by the 2015-2020 Dietary Guidelines for Americans (D.G.A.),” the study said. “Certain grain foods, as part of healthy dietary patterns that include a selection of enriched and fortified grains, may improve overall nutrient intakes and minimize gaps in shortfall nutrient intakes.”

According to the study, grains supply 14.6% of daily sodium, 14.2% energy, 7.9% total sugar, 7.2% total fat, and 5.4% saturated fat in American diets. Comparatively, they provide 22.9% of daily fiber, 33.6% folate, 29.7% iron, 10.6% vitamin A, 13.9% magnesium and 13.2% of calcium, all identified as shortfall nutrients in the most recent D.G.A.

According to the study, grains supply 14.6% daily sodium, 14.2% energy, 7.9% total sugar, 7.2% total fat, and 5.4% saturated fat in American diets. Comparatively, they provide 22.9% of daily fiber, 33.6% folate, 29.7% iron, 10.6% vitamin A, 13.9% magnesium and 13.2% of calcium, all identified as shortfall nutrients in the most recent D.G.A.

The study also found that eliminating whole and enriched grains from a diet can have a negative impact on public health initiatives and health outcomes, particularly if foods substituted into the diet lack nutrient density and promote excess calories.

“These data show that grain foods are the foods we love that love us back,” said study co-author, Yanni Papanikolaou, vice-president at Nutritional Strategies, Inc. “Finally, we can enjoy bread again. The nutrient contribution of all whole and refined grain food products, including breads, rolls and tortillas and ready-to-eat cereals, can play a key role in helping American adults meet recommendations for under-consumed nutrients and nutrients of public health concern.”