By Panagiota Kaisari
A Gluten-Free Diet seems to be the latest ‘’trend’’, promoted by celebrities. A multitude of books been published and countless numbers of articles have appeared in the press about the supposed benefits of following a gluten-free diet. Searching the Internet for information on ‘’gluten-free diet and weight loss’’ returns over 25.000.000 results. Along with this surge of media attention, the number of gluten-free products on the market is expanding rapidly and the gluten-free products gain more and more space in the selves of the supermarkets.
According to statistics presented at last year’s Food and Drink Innovation Network’s free-from conference (http://www.fdin.org.uk/) the UK gluten-free market, which was forecast to grow by 46% to £561M by 2017, has already seen double-digit growth since 2008. Research by an independent market analyst has found the UK’s gluten-free market will be worth the most in Europe at $374.2 million– growing at rate, second only to Germany. In addition, the DS-gluten free, a subsidiary of Dr Schar UK, plans to extend its range and launch 15 new gluten-free products this year following its success in 2013.
But what drives people to buy gluten-free food products? Interestingly, according to the most recent report from the United States the number one motivation for buying gluten-free products is that they are considered healthier than their conventional counterparts. In the UK particularly, as Mark Whalley, consumer analyst at Datamonitor comments: ‘’Celebrities have also helped to make gluten-free high profile’’ (http://www.fdin.org.uk/2011/06/gluten-free-market-set-to-experiences-large-scale-growth/).
Numerous possible health benefits, including weight loss are attributed to gluten avoidance.
But is there evidence to support the claim that gluten-free diet should be used for weight loss? Before answering, let’s start from scratch…
What is gluten?
Gluten is a protein composite consisting of gliadinns and glutenins. Gluten is found in foods processed from wheat and related grains such as barley and rye. It is present in a part of the grain called the endosperm (Fig. 1). Gluten gives elasticity to dough, helping it rise and keep its shape and often gives the final product a chewy texture.Figure 1. The structure of a grain of wheat
Yes, it is true that a gluten-free diet is considered the best treatment for people who suffer from celiac disease.
Celiac disease is a digestive and autoimmune disorder that affects the small intestine after ingestion of gluten-containing grains, including wheat, rye and barley in genetically susceptible people (Schuppan, Junker, & Barisani, 2009). The consumption of gluten in individuals with celiac disease triggers an immune response, a reaction that over time produces inflammation that damages the small intestine and prevents absorption of certain nutrients (malabsorption).
Lifelong adherence to a strict gluten-free diet, devoid of proteins from wheat, rye, barley, and related cereals, remains the gold standard of treatment in celiac disease (Rubio-Tapia, Hill, Kelly, Calderwood, & Murray, 2013). A gluten-free diet lowers the incidence of diseases often related to celiac disease, such as gastrointestinal cancers (Briani, Samaroo, & Alaedini, 2008; Haines, Anderson, & Gibson, 2008; Niewinski, 2008). In addition, common symptoms of gluten intolerance, such as bloating, diarrhoea, nausea, wind, constipation, tiredness, headaches, sudden or unexpected weight loss (but not in all cases), hair loss and anaemia all are improved as a result of adoption of a gluten-free diet, leading to a significantly better quality of life of people who suffer from the disease (Theethira, Dennis, & Leffler, 2014). However, it is worth noting that the estimated prevalence of celiac disease is approximately 1 % (1 in 100 people).
A gluten-free diet can also be effective for treating gluten sensitivity (also referred as non-celiac gluten intolerance) and wheat allergy. Common symptoms of gluten sensitivity, such as fatigue and headaches, and gastrointestinal distress, are frequently improved with the adoption of a gluten-free diet (Gaesser & Angadi, 2012). Wheat allergy is an adverse immunological reaction specific to wheat proteins (Pietzak, 2012). Because that allergy can be treated with wheat avoidance, a wheat-free diet may be more permissive than a strict-gluten free diet. However, the prevalence of wheat allergy, it is estimated at only 0.1% of individuals in Westernized countries (Pietzak, 2012).
Following a gluten-free diet can ameliorate gastrointestinal and/or systematic symptoms in individuals with systematic lupus erythematosus, dermatitis herpetiformis, irritable bowel syndrome, rheumatoid arthritis, type 1 diabetes, thyroiditis and psoriasis (El-Chammas & Danner, 2011; Green, 2009). Gluten-free diets have also been used by patients with autism spectrum disorders (ASD) (Buie et al., 2010; Sapone et al., 2012). However, the American Academy of Paediatrics does not support the use of gluten-free diets as primary treatment for individuals with ASD (Buie, 2013; Buie et al., 2010).
Gluten-free diet and Weight Loss: Where is the evidence?
At this time there is no scientific evidence that supports the alleged benefit that a gluten-free diet will promote weight loss (Gaesser & Angadi, 2012; Marcason, 2011). According to the American Dietetic Association (2011) there is nothing special about a gluten-free diet that can help a person lose weight. Most recently, the British Dietetic Association revealed that a gluten-free diet belongs among the 5 Worst Celebrity Diets to follow in 2014
I am sure you are wondering why not go gluten-free?
- Gluten-free diet does not necessarily mean low-energy and/or low-fat (Marcason, 2011), and some gluten free products actually have a greater energy and fat value than corresponding gluten containing foods. For example, a slice (29g) of white bread provides 70 calories and 1 gram of fat and a slice (29g) of gluten free bread manufactured by the same company contains 80 calories and 2.4 grams of fat (more than twice the fat content of the corresponding non gluten-free bread!).
- Some research has confirmed weight gain in celiac patients when they start a gluten-free diet (Cheng, Brar, Lee, & Green, 2010; Kabbani et al., 2012). This could be due to improved gastrointestinal absorption, consuming a diet with higher portions of fat and proteins, or consuming some of the new (higher calorie) gluten-free products (Valletta et al., 2010). It is therefore suggested that weight maintenance counselling should be an integral part ofceliac dietary education.
- A gluten-free diet may be deficient in whole grains and fiber (Marcason, 2011), both of which have been shown to be inversely associated with BMI (Karl & Saltzman, 2012; O’Neil, Zanovec, Cho, & Nicklas, 2010; van de Vijver, van den Bosch, van den Brandt, & Goldbohm, 2009).
- Also, research shows that a gluten-free diet may actually result in a diet that is low in thiamine (B1), rivoflavin (B2), iron, folate, niasin and zinc (Shepherd & Gibson, 2013). Therefore, individuals for whom gluten avoidance is essential should be aware of this nutritional deficiencies that are associated with a gluten-free diet and read the food labels of the gluten-free products in order to make an ‘’informed’’ choice.
- Gluten-free diet may adversely affect gut health in those without celiac disease or gluten sensitivity. There is evidence that gluten-rich grains, especially wheat, may protect the gut from some cancers, inflammatory conditions, and cardiovascular disease by creating a healthy composition of colon bacteria (Rastall et al., 2005). In addition, gluten and one of its component proteins gliadin, may contribute to blood pressure control and immune function (Thewissen, Pauly, Celus, Brijs, & Delcour, 2011).
- Gluten-free foods are considerably more expensive than their gluten-containing counterpart. For example, while 400gr of whole wheat sliced bread cost £0.75, 400g of wheat, gluten free sliced bread manufactured by the same company cost £2.48. This means that a gluten-free diet can be more than 3 times more expensive than a gluten-containing diet.
- A Gluten-free diet is a very strict diet (Verrill, Zhang, & Kane, 2013). Gluten is ‘’hidden’’ in many foods that you wouldn’t normally expect to find gluten such as: pasta, barbecue and dipping sauces, salad dressings, flavoured potato chips, soups (and the list goes on…). Therefore, people who try to lose weight through the adoption of a gluten-free diet can find it very difficult to follow such a diet, something that can lead to a negative evaluation of themselves (‘’I am not able to follow the diet’’, ‘’I do not have self-control’’) and undermine their efforts to lose weight.
In conclusion, there is no evidence to suggest that following a gluten-free diet has any significant effects on weight-loss for the general population. Randomised-control trials are necessary to establish the effect of a gluten-free diet on weight loss in overweight and obese individuals for whom a gluten-free diet is not medically indicated. A gluten-free diet may be a well-balanced diet if care is taken in choosing whole-grain products, including more legumes, and selecting foods with lower energy density. This does not imply that a gluten-free diet, per se, is a healthier diet.
Take Home Message
The need for weight loss seems sometimes ‘’urgent’’ for a number of people, especially for those who have unsuccessfully tried to lose weight in the past. This need, can lead these individuals to try anything that sounds ‘’magic’’ in order to achieve their goal (=the weight loss). Unfortunately, the media usually present ‘’magic’’ diets that can act instantly and gluten-free diet seems to be the new trend. However, eating is a very complex behaviour that is affected by numerous factors and although the goal of ‘’immediate’’ weight loss sometimes is achievable, what is more challenging is the maintenance of the lost weight. As health scientists, it is our responsibility to inform individuals that what is most important is the adoption of a healthy lifestyle, which includes a balanced, nutritious diet and a physically active way of living, and not the body weight reduction per se. Individuals should be educated about healthy eating and with experts’ help they should try to identify their own ‘’problematic’’ behaviours that act as barriers to their effort to achieve and maintain a healthy body weight.
‘’Take care of your body.
It’s the only place you have to live.’’
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