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.
Materials provided by University of Florida Institute of Food and Agricultural Sciences. Original written by Brad Buck. Note: Content may be edited for style and length.
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