Study Looks at the Impact of Gluten Intake and Gluten-Free Diets on Women's Health

Celiac.com 06/01/2023 - The rising popularity of gluten-free diets has captured public attention in recent years. With claims of weight loss, improved digestion, and increased energy, many individuals have jumped on the gluten-free bandwagon. However, it's important to base dietary decisions on scientific evidence, rather than mere trends. To shed some scientific light on the subject, a team of researchers conducted a controlled study to investigate the effects of gluten intake on body weight, body composition, resting energy expenditure, and the changes in nutrient intake caused by gluten-free diets.

Study on Effects of Gluten Intake

The research team included Hirla Karen Fialho Henriques, Luana Moreira Fonseca, Karine Silva de Andrade, Nitin Shivappa, James R. Hébert, Adaliene Versiani Matos Ferreira & Jacqueline Isaura Alvarez Leite. They are variously affiliated with the Department of Biochemistry and Immunology - ICB, Federal University of Minas Gerais, Belo Horizonte, Brazil; the Department of Nutrition, School of Nursing, Federal University of Minas Gerais, Belo Horizonte, Brazil; the Department of Biochemistry and Immunology - ICB, Federal University of Minas Gerais, Belo Horizonte, Brazil; and the Cancer Prevention and Control Program, University of South Carolina, Columbia, South Carolina, USA.

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Their study enrolled twenty-three women, who adhered to a gluten-free diet for a duration of six weeks. During this period, the participants were provided with muffins containing either 20 grams of gluten isolate (known as the gluten period) or gluten-free muffins (the gluten-free period) in a crossover, single-blind, non-randomized trial. The researchers assessed the subjects' habitual diet, including gastrointestinal symptoms, food frequency questionnaires, body composition, resting energy expenditure, and recorded daily food intake for the entire six-week duration.

The Findings - Increase in Fat and Sodium Intake

Surprisingly, the data showed that body weight, body composition, gastrointestinal symptoms, and resting energy expenditure remained similar during both the gluten and gluten-free periods. These results indicate that consuming up to 20 grams of gluten per day does not affect body weight or composition in healthy women without caloric restriction, at least over a relatively short period of three weeks.

However, the team saw some concerning changes when the nutrient composition of the gluten-free period was compared to the participants' habitual diet. The gluten-free diet led to an increase in fat and sodium intake, while reducing the intake of fiber, as well as vitamins B1, B6, B12, and folate. This imbalance in nutrient intake resulted in an elevated dietary inflammatory index, indicating a higher inflammatory potential associated with gluten-free diets.

These findings highlight the importance of considering the overall nutritional quality of a diet, rather than focusing solely on the absence of gluten. 

While a gluten-free diet may be necessary for individuals with specific medical conditions, such as celiac disease, the results suggest that adopting a gluten-free diet without medical necessity may have adverse effects on nutrient intake and potentially contribute to inflammation.

The study offers some potentially valuable insights into the impact of gluten intake and gluten-free diets on health, especially with regards to nutrient intake, but it's important to note that it has certain limitations. The small sample size and the short duration of the trial invite further research with larger populations and longer intervention periods, to validate and expand upon these findings. 

Additionally, the study focused solely on healthy women, so the results may not be generalizable to other populations, or those with specific health conditions. It's also important to note that following a gluten-free diet can lead to imbalances in nutrient intake, particularly a reduction in fiber and essential vitamins, and an increase in dietary inflammation potential, even in non-celiacs.

As with any dietary decision, it's best to consult with a healthcare professional or registered dietitian to ensure a well-rounded and nutritionally adequate diet that suits individual needs.

Read more in the J Am Nutr Assoc. 2022 Nov-Dec;41(8):771-779.