Latest scientific research still favors grains in diet
Oct. 9, 2013
by Josh Sosland
LAS VEGAS — Even as grain-based foods are subjected to an ever increasing level of scrutiny over alleged connections with chronic disease, research studies on the subject are far more likely to generate favorable findings or messages about grains and carbohydrates than negative conclusions.
The preponderance of positives in scientific research was discovered in an exhaustive literature review conducted by a team led by Glenn Gaesser, chairman of the Scientific Advisory Board of the Grain Foods Foundation. In a presentation Oct. 8 during the International Baking Industry Exposition in Las Vegas, Dr. Gaesser offered a preview of findings in a soon-to-be published literature review.
Additionally, the review into studies exploring the connection between carbohydrates/grain intake and many diseases showed far more favorable conclusions and messages about carbohydrates for every one of the diseases reviewed, Dr. Gaesser said.
Offering background on the project, Dr. Gaesser said it has been nearly 10 years since the Grain Foods Foundation conducted a review of the scientific literature looking at the healthfulness of grain-based foods. Such reviews are useful, he said, in ensuring the messaging of the G.F.F. is consistent with scientific research.
In the review, Dr. Gaesser and a research team looked at peer-reviewed full-length articles published since 2010. In addition to using comprehensive on-line search tools such as PubMed, the group also looked for studies within the top 40 journals in each of 11 different areas of science/medicine, including journals dealing with medicine, cardiology, endocrinology, gastroenterology, geriatrics, immunology, neurology, pediatrics, vascular, nutrition and public health.
“We tried to identify as many potential articles as we could,” he said.
Even more to the point, the literature review looked at the association between grains intake and 13 different diseases/health conditions or other categories:
1) cardiovascular disease
2) diabetes/metabolic syndrome
4) obesity/weight control
5) gastrointestinal health
7) pediatrics/maternal health
8) neurology/cognitive health
10) sports performance
11) miscellaneous health outcomes (other than those above)
12) Celiac disease
13) non-Celiac gluten sensitivity
In the literature review, the team overseen by Dr. Gaesser determined whether the message or findings in the relevant studies were favorable, unfavorable or neutral toward intake of grain-based foods. Dr. Gaesser is a professor at Arizona State University and director of its Exercise and Wellness Program.
The breadth of conditions covered reflects the growing number of “battle fronts” in which grain-based foods have been subjected to criticism. While the connection between cardiovascular disease and grains intake has been studied for decades, interest in issues such as inflammation, cognitive health and metabolic syndrome is more recent. In particular, the recent publication of “Grain Brain,” a book blaming grains intake for a variety of cognitive problems, including Alzheimer’s disease, represents a new challenge for grain-based foods.
All told the literature review yielded 1,227 scientific papers with as many as 200 studies over certain subjects (cardiovascular disease and cancer). At least 20 studies were examined for each of the conditions reviewed.
“What we ended up doing is taking a look at the primary outcome,” Dr. Gaesser said. “So for cardiovascular disease it might be coronary heart disease or peripheral vascular disease or blood pressure or lipids.”
A finding that whole grains are associated with reduced risk of cardiovascular disease would be marked as “favorable.” If intake of grains was associated with heightened risk of a disease, it would be marked as “unfavorable.”
Noting that his draft paper currently is longer than 300 pages, Dr. Gaesser said he was unable to share all his conclusions in a 20-minute presentation. Offering highlights of the findings, Dr. Gaesser said the positive overall results tended to be driven by the words “whole grains” and “fiber.”
The ratio of favorable to unfavorable findings was impressive, Dr. Gaesser said.
“Nearly half of all articles retrieved focused on the major chronic diseases facing our country today — cardiovascular disease, diabetes, and cancer, and the primary findings were uniformly favorable for consumption of ‘carbohydrates, grains, and fiber’ with ‘favorable’ findings in 299 cases (72%) outnumbering ‘unfavorable’ in 50 (12%) findings by six to one.”
In the case of Celiac disease, the scientific studies reviewed affirmed the importance of gluten avoidance for individuals who have been accurately diagnosed with the disease. By contrast, the studies looking at non-Celiac gluten sensitivity in subjects did not find avoiding gluten consistently generated positive health results. Instead, the studies tended to be either neutral to the benefits of gluten avoidance or in other cases challenged whether eliminating gluten was a positive.
“It questioned whether a gluten-free diet was something that needed to be done,” Dr. Gaesser said of several studies. “There have been recent articles suggesting it may not be gluten. People who were self-proclaimed gluten sensitive responded well to a diet to which gluten had been added. So it probably isn’t the gluten for a number of individuals who claim to be gluten sensitive. “
In neurology, 48% of studies exploring the association of neurological conditions and grain-based food intake generated favorable conclusions.
“This is in direct opposition to the claims of the current ‘Grain Brain’ book,” Dr. Gaesser said.
He noted a 27% unfavorable proportion was higher than in most other categories.
“Most of the unfavorable in this and other categories were related to what researchers called refined grains,” Dr. Gaesser said. “There was nothing negative about whole grains, which are criticized in ‘Grain Brain.’”
Still another positive in connection with neurology are recent scientific studies showing a beneficial effect of folic acid on cognitive health in adults. The 60% favorable versus 17% unfavorable is particularly germane in the wake of the publication of “Grain Brain,” Dr. Gaesser said.
More generally, the literature review serves as an indictment of the selective research cited by authors of grain-bashing books, Dr. Gaesser said.
“I should point out that ‘Grain Brain’ was just published. ‘Wheat Belly’ just a couple years ago,” he said. “I looked at their reference lists, and not a single (favorable) article appeared in our literature review, which I find very interesting — how we can have this split. None of them that show a favorable conclusion toward grains or carbohydrates seem to be cited by Perlmutter or Davis in their book.”
Summarizing his findings, Dr. Gaesser said the literature review should allow the G.F.F. to publish data underscoring the importance of grain-based foods in a healthy lifestyle, generate additional opportunities for future research and “inform” future policy efforts, including the Dietary Guidelines for American in 2015 and beyond.