WASHINGTON — The amount of fiber in breakfast cereal from two major manufacturers, The Kellogg Co. and General Mills, Inc., increased 32% in the United States between 2005 and 2011 while the amounts of sugar and sodium decreased 10% and 14%, respectively, according to U.S. Department of Agriculture research. The study “Recent trends in ready-to-eat breakfast cereals in the U.S.” appears in the June issue of Procedia Food Science.

The study involved data from the U.S.D.A. National Nutrient Database for Standard Reference (SR). The brands from The Kellogg Co., Battle Creek, Mich., and General Mills, Inc., Minneapolis, represented 62% of the U.S. ready-to-eat (R.T.E.) cereal market from August 2010 to August 2011. The brands included Kashi, which Kellogg owns. Researchers calculated mean values for total sugar, total dietary fiber and sodium.

Fiber levels per 100 grams of cereal increased to 9.4 grams in 2011 from 7.1 grams in 2005. Overall U.S. adult fiber intakes are 40% to 50% below recommended levels, according to the study.

Sugar levels per 100 grams of cereal fell to 24.8 grams from 27.5 grams. While the 10% decline in sugar levels between 2005 and 2011 was not significant, a decline of 12% between 2006 and 2011 was significant, according to the U.S.D.A. Sodium levels per 100 grams of cereal fell to 438 mg per 100 grams in 2011 from 511 mg in 2005. The Dietary Guidelines for Americans 2010 recommend people cut back on foods high in added sugars and salt.

Nutrient comparisons were made on a subset of 83 products, which excluded cereals that had been added or dropped between 2005 and 2011. In the subset, sugar levels decreased 7.6% and sodium levels decreased 11.2%. Fiber levels in the subset increased 13.4% between 2005 and 2011.

The study involved researchers from the Nutrient Data Laboratory at the U.S.D.A’s Beltsville Human Nutrition Research Center in Beltsville, Md., as well as researchers from General Mills and The Kellogg Co.

“According to the U.S. Dietary Guidelines Advisory Committee, less than 1 in 10 Americans get the recommended amount of fiber in their diet,” said Kevin Miller, Ph.D., a senior nutrition scientist at The Kellogg Co. and a contributing author to the U.S.D.A. study. “The reductions in sodium and sugar also reflect the commitment of food companies to improve the nutrient profile of cereals.

“However, it is important to remember that ready-to-eat cereal is a small contributor of sugar and sodium in the diet. The Dietary Guidelines for Americans notes that cereals provide less than 4% of total sugar and only 2% of sodium in the diet.”

In the U.S.D.A. study, whole grain ingredients were found in at least two-thirds of the cereals in 2011. The U.S.D.A. currently does not track the amount of whole grain in foods in its Standard Reference, which precluded accumulation of consistent quantitative data on the whole grain level in R.T.E. cereals.

Ingredient sources of fiber in the U.S.D.A. study other than whole grain included oat fiber, corn bran, inulin or chicory root fiber, and soluble corn fiber. Other potential benefits of consuming whole grains are lower body weight and protection against cardiovascular disease. The Dietary Guidelines for Americans recommend people make half their grain intake whole grain, but whole grain intake is falling short of those recommendations.

“The 2010 Dietary Guidelines for Americans recommend making half your grains whole, which for most people is at least 48 grams of whole grain every day,” said Kathy Wiemer, fellow/director, General Mills Bell Institute of Health and Nutrition. “Ninety-five per cent of Americans continue to fall short of the recommendations. What they may not realize is that beginning your day with a bowl of cereal can be one of the best ways to help meet whole grain recommendations.”

As of January 2012, all Big G cereals from General Mills have more whole grain than any other single ingredient, providing 10 grams of whole grain or more per serving.