Posted: Thursday, September 20, 2012 12:00 PM
Sean Ellis/Capital Press
A wheat field in southwest Idaho is shown in this photo taken in early August. Idaho wheat exports to Mexico soared during the first half of 2012 compared with the same period in 2011.
'Much of that is based on conjecture; it's nonsense,' researcher says
A researcher says there's no sound science indicating that a gluten-free diet will help otherwise healthy people lose weight.
Consumers buy gluten-free products because of the perception they are more healthful than products containing gluten, said Glenn Gaesser, director of the Healthy Lifestyles Research Center at Arizona State University in Phoenix.
But the research doesn't support that perception, he found.
"There's the lingering perception there that carbs are somehow bad, grains in particular," he said. "Much of that is based on conjecture; it's nonsense. It claims that wheat is the cause of all our problems, that it stimulates appetite, but that's just not true."
Gluten is a protein typically found in foods made from wheat, barley and rye.
Gaesser believes programs like William Davis' "Wheat Belly" diet are lingering effects of low-carb diets promoted by authors in the 1990s and early 2000s. The market for gluten-free products is expected to reach $2.6 billion this year.
Judi Adams, president of the Wheat Foods Council, said the average per-capita consumption of wheat flour dropped from 133 pounds in 2010 to 131 pounds in 2011.
"It's a huge drop," she said. "We don't want it to drop at all, we want to see an increase, and two pounds is very significant."
Adams attributes part of the drop to the adoption of gluten-free diets.
"Instead of for the 7 percent who actually need it, it looks like there may be as many as 30 percent looking for gluten-free items," she said. People with celiac disease or who have been shown to have a gluten sensitivity avoid eating foods that contain gluten.
The lowest per-capita annual consumption of wheat was 110 pounds in 1972 and the highest was 147 pounds in 1997.
Earlier drops could be attributed to bakeries using products with extended shelf lives, but Adams thinks the later drops can be attributed to misinformation and the Atkins low-carbohydrate diet and the gluten-free diets.
As the gluten-free market "exploded" in recent years, Gaesser said he looked for science to support the popular claim that going gluten-free leads to better health and weight loss.
"There was nothing in the literature that indicated going on a gluten-free diet would lead to weight loss in people who are otherwise healthy," he said, noting the health necessity of gluten-free diets for celiac patients. For that population, some lose or gain weight, he said, while others show no change at all.
Gluten is important for gastrointestinal health, Gaesser said, pointing to a study in which going gluten-free for a month decreased the amount of beneficial bacteria in the digestive track and raised the amount of potentially harmful bacteria.
"This suggests going gluten-free might have some negative consequences for people who do not need to avoid gluten," he said.
Kara Rowe, director of outreach for the Washington Association of Wheat Growers, said Gaesser's research supports the industry's position that gluten alone does not cause obesity.
Rowe expects to see more studies like Gaesser's. She cautions the public to take a serious look at the motives of the authors of gluten-free theories.
"As skeptical as some of these theories have been on wheat, I would hope consumers look with the same skepticism at the people producing these other reports," she said.
As an exercise physiologist and nutrition researcher, Gaesser does not have plans to further pursue the gluten-free issue.
"I think the onus is on people advocating gluten-free diets to do the studies to show otherwise," he said. "There's really nothing there."
Arizona State University Healthy Lifestyles Research Center: http://healthpromotion.asu.edu/healthy-lifestyle
Grain Foods Foundation: www.gowiththegrain.org
Wheat Foods Council: http://wheatfoods.org