Gluten-free diets and specialist products – challenges, myths and progress

  1. Dr. Schär Institute
  2. News
  3. Gluten-related Disorders
  4. Gluten-free diets and specialist products – challenges, myths and progress

We are pleased to report the publication of our most recent Forum journal, a special issue dedicated to the nutritional quality and safety of manufactured gluten-free foods and implications for health and disease.

This 27 page document delves ‘behind the scenes’ at Dr Schar, Europe’s leading gluten-free food manufacturer and examines the many processes and procedures involved in the safe production of specialist gluten-free products. The importance and function of specific ingredients is discussed, with comparison to wheat-based equivalents and other gluten-free brands. In addition, the studies and reviews that have fuelled recent concerns regarding the nutritional quality and health implications of gluten-free diets are considered in greater depth.

A strict, life-long gluten-free (GF) diet is essential for the management of coeliac disease and dermatitis herpetiformis. Furthermore, the GF diet also has application in the management of non-coeliac gluten sensitivity [1] and, more recently, diarrhoea predominant IBS [2]. However, a GF diet is not recommended for the general population and there is no evidence that it may be beneficial for individuals without symptoms attributable to gluten consumption.
 
The production of GF bakery products presents a significant technical challenge for manufacturers. Gluten is a protein complex that provides important visco-elastic properties, responsible for conferring palatability, optimal texture and structural integrity in baked goods. No one ingredient alone can replace gluten in this context, instead the manufacture of GF foods requires the addition of several ingredients, including hydrocolloids, starches, fats and proteins in order to maximise palatability and ensure adequate shelf-life.
 
Over the past 10 years, many studies have been conducted aiming to evaluate the nutritional quality of the GF diet, many with conflicting and limited results. To date, studies have indicated higher fat and lower protein and fibre levels within GF product samples, alongside suboptimal micronutrient intake amongst long-term followers of the diet [3-4]. However, some researchers acknowledge that a paucity of data regarding the nutritional content of GF products may hinder accurate analysis for this population group5. More recent studies have suggested significantly higher fibre content amongst GF foods samples versus wheat-containing counterparts, alongside much larger variation in macronutrient levels between different brands [6], making it hard to evaluate the overall nutritional adequacy of an ‘average’ GF diet. Recent data from paediatric coeliac patients also indicates that intakes of sugar and fat in excess of national guidelines are commonplace amongst children consuming regular and GF diets, with no difference or worsening affect reported as a result of following a GF diet [7]. Furthermore, there is evidence to suggest that poor nutrient intake whilst following a GF diet is a result of inappropriate dietary balance and reliance on energy-dense, high fat and protein foods and a reduced intake of starchy carbohydrate [8]. 

The growing public and scientific interest in GF diets and the nutritional quality of manufactured GF products shows no sign in abating. Indeed, since publication of the aforementioned Forum journal, two further studies considering this topic have been published in peer reviewed medical press. The first, a nutritional comparison of GF food versus regular food sold in Italy9 examined the macronutrient profile of 235 GFproducts and 349 regular products across 7 food categories. Few significant differences in nutrient content between GF and regular samples were recorded. Average energy, protein and total carbohydrate content were all significantly lower for GF bread samples versus regular products, whereas the fibre content of GF breads was significantly higher. For biscuit products, higher average saturated fat and total carbohydrate levels were recorded for the GF samples, however there was no significant difference in terms of sugar or energy content.

A further study published in the American journal Pediatrics early this month10, reported on the nutritional quality of GF products specifically marketed to children in Canada and compared these to equivalent products aimed at children but without bearing a GF claim. A total of 374 child-targeted products were included in the analysis, of which 66 products (18%) carried a specific GF claim. Overall, products with a GF claim had lower levels of protein, sodium, total fat and saturated fat compared to those without a GF claim. Free sugar levels were similar for child-targeted GF products and regular products aimed at children and there was no difference in sugar accounting for the percentage of calories. Disappointingly, 80.3% of child-targeted GF products and 80.8% of child-targeted regular products were found to contain high sugar levels (>10% sugar/ free sugar). Whilst 88% of GF child-targeted products were classified as having poor nutritional quality (determined using the Pan American Health Organisation Nutrient Profile Model), 97% of child-targeted regular products also fell in to this category (P<0.001). When 43 GF products in the data set were matched with comparable products, the caloric content, fat and protein levels were found to be similar per 100g. However, GF products had higher levels of free sugars and lower levels of sodium when compared with their matched controls. These findings taken in combination do not support the possible public perception that GF foods are ‘healthier’ alternatives to regular food products, however neither do they substantiate reports that foods bearing GF claims are nutritionally inferior to regular foods.
 

Click to read the Forum journal: Gluten-free diets and specialist products – challenges, myths and progress
 

References

  1. Catassi C, Elli L et al. Diagnosis of Non-Celiac Gluten Sensitivity (NCGS): The Salerno Experts' Criteria. Nutrients. 2015 Jun 18;7(6):4966-77
  2. Aziz I, Trott N et al. Effi cacy of a Gluten-Free Diet in Subjects With Irritable Bowel Syndrome-Diarrhoea Unaware of Their HLA-DQ2/8 Genotype. Clin Gastroenterol Hepatol. 2016;14(5):696-703.e691
  3. Kinsey L, Burden ST, Bannerman E. A dietary survey to determine if patients with coeliac disease are meeting current healthy eating guidelines and how their diet compares to that of the British general population. Eur J Clin Nutr 2008; 62(11):1333-42.
  4. Thompson T, Dennis M et al. Gluten-free diet survey: are Americans with coeliac disease consuming recommended amounts of fibre, iron, calcium and grain foods? J Hum Nutr Diet 2005; 18(3):163-9.
  5. Zucotti G, Fabiano V et al. Intakes of nutrients in Italian children with celiac disease and the role of commercially available gluten-free products. J Hum Nutr Diet 2013; 26(5):436-44.
  6. Fry L, Madden AM, Fallaize R. An investigation into the nutritional composition and cost of gluten-free versus regular food products in the UK. J Hum Nutr Diet 2018;31(1):108-120.
  7. Sue A, Dehlsen K, Ooi CY. Paediatric patients with coeliac disease on a gluten-free diet: Nutritional adequacy and macro- and micronutrient imbalances. Curr Gastro Rep 2018; 22;20(1):2.
  8. Babio N, Alcazar M et al. Patients with celiac disease reported higher consumption of added sugar and total fat than healthy controls. J Pediatr Gastoenterol Nutr 2017;64(1):63-69.
  9. Elliott C. The Nutritional Quality of Gluten0free Products for Children. Pediatrics 2018: 142 (2):e20180525
  10. Cornicelli M et al. Nutritional composition of gluten-free food versus regular food sold in the Italian market. Dig Liver Dis 2018, https:doi.org/10.1016/j.dld.2018.04.028