Keep recommendation for six servings of grain per day

Offering a science-based underpinning for each of its recommendations, the group said maintaining from the 2010 Guidelines the six servings of grains daily, three each of whole grains and enriched grains, was justified based on the category’s important position as a source of micronutrients.

“As a category, grain foods contribute vital, and often underconsumed, nutrients to the American diet,” the group said, citing grains’ important position as a source of fiber, folic acid and iron.

Much of the discussion in the letter defended the role of enriched grains in the diet.

“While whole grains have a well-established link to reduced obesity risk, the 2015 D.G.A.C. has overstated the evidence against refined (enriched) grains,” the groups said.

Specifically, the letter cited a literature review showing scant relationship between refined grains intake and body mass index, a 2012 review showing no clear consistent trends linking refined grains to body weight, a study showing no association between refined grains intake and body fat distribution and a study showing an inverse relationship between waist circumference and refined grains intake in adolescents.

Regarding weight loss, the group cited 2014 and 2008 reports showing enriched grain foods and whole grain foods equally effective in facilitating weight loss.

The group chided the committee for a selective citation of studies linking refined grains with chronic diseases.

“The 2015 D.G.A.C. report cited a 2014 meta-analysis in the Journal of Human Nutrition and Dietetics that indicated a positive relationship between refined (enriched) grain intake and risk of type 2 diabetes,” the letter said. “However, refined grains were not analyzed separately, but only as part of a dietary pattern. Surprisingly, the 2015 D.G.A.C. report did not cite a 2013 meta-analysis published in the European Journal of Epidemiology that showed no relationship between refined (enriched) grain intake and diabetes risk.”

The group said this lack of association held up even among subjects who consumed as many as seven grain servings per day.

Another study with 28,000 subjects found no association between enriched grains intake and the risk of hypertension.

The group also cited recently presented data from the Grain Foods Foundation and presented at the Experimental Biology meeting. The research looked at subjects following 10 different grain food patterns, versus the U.S.D.A. ideal food pattern, based on data from What We Eat in America – 2005-10.

“All patterns were compared to the U.S.D.A. ideal and U.S.D.A. typical food patterns,” the group said. “All 10 models examined provided less energy in comparison to the U.S.D.A. typical food pattern.”

The researchers also found that individuals who avoided grains did not demonstrate significant differences from those who consume grains as measured by body mass index or fasting blood concentrations of glucose, insulin, total cholesterol, LDL-cholesterol and triglycerides.

Cost of nutrients analysis showed grains to be a “nutrition bargain,” for American consumers, the researcher said.