Saturday, Nov 01, 2014
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Unfounded beliefs abound with gluten-free diets, study finds


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– While necessary for some, many people eat gluten-free diets because they believe they’ll gain certain health benefits, but these beliefs are not all supported by research, a University of Florida nutrition expert says.

Those with celiac disease, or about 1 percent of the U.S. population, must follow a gluten-free diet because it’s the only treatment for their condition, said Karla Shelnutt, a UF assistant professor in family, youth and community sciences. But gluten-free diets can lack essential nutrients if a person does not eat a balanced diet and/or take a multivitamin supplement.

Unlike their conventional counterparts, refined gluten-free foods, for the most part, are not enriched or fortified with essential vitamins and minerals.

“If I’m a college student, and I want to lose weight, and I read on the Internet that a gluten-free diet is the way to go, I may start avoiding products that contain essential nutrients such as those found in cereal grains fortified with folic acid,” Shelnutt said. “The problem is you have a lot of healthy women who choose a gluten-free diet because they believe it is healthier for them and can help them lose weight and give them healthier skin.”

The $10.5-billion gluten-free food and beverage industry has grown 44 percent from 2011-13 as the rate of celiac disease diagnoses increases, along with awareness of gluten-free foods, according to Mintel, a market research company. Mintel estimates sales will top $15 billion in 2016.

One of Shelnutt’s doctoral students, Caroline Dunn, wanted to know if gluten-free labeling has any impact on how consumers perceive the foods’ taste and nutrition.

In a one-day experiment on the UF campus in Gainesville in February, 97 people ate cookies and chips, all gluten-free. Half were labeled “gluten-free”; the other half labeled “conventional.”

Participants then rated each food on a nine-point scale for how much they liked the flavor and texture. They also filled out a questionnaire, said Shelnutt, a faculty member with UF’s Institute of Food and Agricultural Sciences.

About a third of participants said they believed gluten-free foods to be healthier than those labeled “conventional,” a figure she thought would be much lower. While avoiding gluten-containing foods can reduce carbohydrate intake, thus helping some lose weight, many health experts say a gluten-free diet is no healthier than a conventional diet except for those with celiac disease.

Although such a small sample cannot be generalized to the public, Shelnutt said the experiment gives researchers insight into how the public views gluten-free foods.

For example, 57 percent of participants believed gluten-free diets can be used to alleviate medical conditions, and 32 percent said doctors prescribe them for weight loss. Thirty-one percent believed gluten-free diets improve overall health, 35 percent believed them to improve digestive health and 32 percent felt that eating them would improve their diet.

Gluten, a protein, is found in grains such as wheat, barley, rye and triticale, a cross between wheat and rye. A gluten-free diet is prescribed for those with celiac disease, a condition that can damage the lining of the small intestine.

The experiment’s results are published in the current edition of the Journal of Nutrition Education and Behavior.

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