Diet is healthy when it contributes to protecting against malnutrition and overnutrition, according to the World Health Organization (WHO). In food intolerances, allergies and some diseases, it is necessary to apply "special diets" to protect the health of individuals. Gluten-free diet is one of them. A gluten-free diet should be followed under three conditions: wheat allergy, gluten sensitivity, and celiac disease (1).
Gluten; It consists of a protein network that contributes to flexibility and extensibility in crops containing wheat, rye or barley (2). American market research found that 44% of people buy gluten-free food even though they have no problem consuming gluten, and 65% believe gluten-free products are healthier. This trend pushed the worldwide gluten-free industry from $ 1.7 billion in 2011 to $ 4.7 billion in 2020 (2).
HOW DOES THE GLUTEN-FREE DIET BECOME A TREND?
The possibility that gluten may also cause problems in individuals without celiac disease was first suggested in a small study in the 1980s in 8 patients with chronic diarrhea and abdominal pain.
Later, a major cultural change occurred with the publication of "Wheat Belly" by cardiologist William Davis and "Grain Brain" by neurologist David Perlmutter. The denigration of wheat and gluten in these books created an empire based on the premise that gluten is poison.
Although there is no strong scientific evidence in either book, simple nutritional solutions to many health problems are promised. The common theme in these books is to limit processed foods and refined sugary products. Therefore, it is unclear whether the benefit provided by this diet is due to a reduction in processed foods or a gluten-free diet (2).
IS A GLUTEN-FREE DIET EFFECTIVE ON WEIGHT LOSS?
It is scientifically uncertain whether the gluten-free diet will be effective in weight loss, although individuals aiming for weight loss turn to gluten-free diet, with the public's interest in the media and famous individuals. Because, the gluten removed from the diet means consuming less wheat products. If a person does not consume products such as bread, cookies and cakes containing wheat and substitutes more vegetables and fruits for these products, weight loss may occur due to less carbohydrate consumption. However, this is not because gluten is removed from the diet, but rather the reduction of carbohydrate-containing products.
A healthy person can also lose weight with an adequate-balanced diet containing gluten. Contrary to popular belief, there is currently insufficient justification to confirm that gluten elimination causes weight loss (3).
DOES GLUTEN-FREE DIET IMPROVE EXERCİSE PERFORMANCE?
The gluten-free diet has also become popular among athletes. In a survey participated by 910 athletes, it was determined that 41% of the athletes were on gluten-free diet. The most important example of this situation can be shown as the writing of a book by Tennis player Novak Djokovic called "The 14-Day Gluten-Free Plan for Physical and Mental Perfection" (4).
In a scientific study with a high level of evidence examining the effect of a gluten-free diet on exercise performance, 13 cyclists first followed a gluten-containing diet and then a gluten-free diet for 10 days, and at the end of the study, no difference was found in athletes' performance and digestive system health (5).
HOW DOES GLUTEN-FREE DIET AFFECT OUR HEALTH?
In a study with a high level of evidence on healthy individuals, Croall et al. divided 30 healthy individuals into 2 groups and applied a gluten-containing diet to 1 group for 2 weeks and a gluten-free diet to the other group. As a result of the study, it was found that following a gluten-free diet in healthy individuals does not provide any extra health benefits. If it is harmful for an individual to consume gluten, this situation can be noticed within a maximum of 1 week. Therefore, the duration of this study is sufficient to show that it is not necessary to follow a gluten-free diet in healthy individuals (6).
Also, gluten-free products generally contain lower protein and fiber. The glycemic index of gluten-free products varies according to the type and quality of ingredients used and the food processing procedures performed to produce them. For example, "gluten-free flours" obtained when gluten is extracted from wheat are flours based on starch. Therefore, they raise blood sugar faster when consumed (3).
In addition, gluten-free products are generally lower in vitamin and mineral content (eg; iron, calcium, zinc, vitamin B12, vitamin D and folate, niacin, thiamine, and riboflavin). It may contain more sugar and saturated fat (4).
Although there is no link between gluten consumption and heart disease risk, there is a reduction in the intake of whole grain foods that are beneficial for our heart health while avoiding gluten-containing products (4).
WHAT IS THE EFFECT ON OUR MICROBIOTA?
Diet plays a crucial role in the composition and function of the gut microbiota, which affects the health of individuals in multiple ways. The large variety of bacteria in our gut microbiota improves our health. The gut microbiota varies from the moment we are born to adulthood. It is generally stable in adults; however, differences may occur as a result of dietary change, gastrointestinal disease, and antibiotic treatment (1).
De Palma et al. found that healthy individuals had a decrease in the number of good bacteria in their microbiota after 1 month of gluten-free diet (7).
In conclusion, in addition to the nutrient deficiencies seen in the gluten-free diet, our microbiota is also negatively affected, showing that healthy individuals' gluten-free diet does more harm than good.
Note: This article discusses the effects of the gluten-free diet in “HEALTHY INDIVIDUALS”. Individuals with celiac disease, gluten intolerance or wheat allergy should follow a gluten-free diet under the control of a physician and dietician.
RESOURCES:
1. Melini V (2019), Gluten-Free Diet: Gaps and Needs for a Healthier Diet, Nutrients 2019, 11, 170; doi:10.3390/nu11010170
2. Pearlman M. (2019), Who Should Be Gluten-Free? A Review for the General Practitioner, Med Clin N Am 103 (2019) 89–99.
3. El Khoury D (2018), A Review on the Gluten-Free Diet: Technological and Nutritional Challenges, Nutrients 2018, 10, 1410; doi:10.3390/nu10101410
4. Lerner B. (2019), Going Against the Grains: Gluten‐Free Diets in Patients Without Celiac Disease—Worthwhile or Not? Digestive Diseases and Sciences (2019) 64:1740–1747
5. Lis D (2015), No effects of a short-term gluten-free diet on performance in nonceliac athletes. Med Sci Sports Exerc. 2015; 47: 2563–2570.
6. Croall ID (2019), Gluten does not induce gastrointestinal symptoms in healthy volunteers: A double-blind randomized placebo trial, Gastroenterology 2019;157:881–883.
7.De Palma (2009), Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects. Br. J. Nutr. 2009, 102, 1154–1160.