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Improving wheat to remove coeliac epitopes but retain functionality

by luciano

An interesting study that explores the possibilities of obtaining low toxicity grains by investigating the quality, quantity and distribution of the toxic fractions (for celiacs) of whea

“…..omissis. Wheat gluten proteins are traditionally classified into two groups based on their solubility. The gliadins are readily extracted from flour with alcohol:water mixtures, such as 60% (v/v) ethanol or 50% (v/v) propan-1- ol, while the glutenins were traditionally extracted with dilute acid or alkali. However, these fractions contain related proteins and the differences in solubility are determined by their presence as monomers or polymers. Thus, the gliadin fraction comprises mainly proteins which are present as monomers, with small amounts of polymeric components, while the glutenins comprise “subunits” assembled into high molecular mass polymers stabilized principally by inter-chain disulphide bonds. When these disulphide bonds are reduced the monomeric glutenin subunits resemble the gliadins in being soluble in alcohol: water mixtures. Hence, the protein subunits present in both fractions correspond to alcohol-soluble prolamin proteins as defined in the classic studies of Osborne (1924). more in full text”. Improving wheat to remove coeliac epitopes but retain functionality. Peter R. Shewry and Arthur S. Tatham. Journal of Cereal Science 2016 Jan

Extract from the study:
1.2. Wheat gluten protein
1.3. Wheat gluten protein genes and expressed proteins
2.2. Identification of coeliac disease epitopes
2.3. Distribution of coeliac disease epitopes
3.1. Genetic diversity of wheat
3.2. Exploiting genetic diversity in gluten proteins to reduce coeliac toxicity
3.3. Developing coeliac-safe wheat

Wheat genotypes containing minimally harmful gluten sequences

by luciano

“Previous studies have documented that landraces and older wheat varieties contain more diverse gene combinations for prolamins (wheat proteins) in comparison to modern varieties (10, 11). Literature shows variations for specific gene sequences mainly in the epitopic regions of Glia-α9, Glia-α2, Glia-α20, and Glia-α in older landraces (9). In the last decade in the context of CD, the immunogenicity of T-cell specific epitopes has been bought to the forefront (9, 12). The immunogenic potential amongst different hexaploid wheat varieties is variable; hence it is possible that there are breeding-induced differences in the presence and expression of T-cell stimulatory epitopes in modern varieties of wheat (13, 14). This raises the question of, whether there is any specific variety of wheat which is less immunogenic and can be used in breeding programs for developing a wheat genotype completely safe for consumption by patients suffering from CD”.

Highlights:
• The identification of less/non-immunogenic wheat species is an important milestone that could help patients or even prevent CD.
• With the use of gluten-specific T-cells and PBMCs, wheat genotypes containing minimally harmful gluten sequences can be selected.

Adverse Reactions to Wheat or Wheat Components.

by luciano

The research we present is an excellent compendium of current knowledge on non-celiac gluten sensitivity

“Abstract: Wheat is an important staple food globally, providing a significant contribution to daily energy, fiber, and micronutrient intake. Observational evidence for health impacts of consuming more whole grains, among which wheat is a major contributor, points to significant risk reduction for diabetes, cardiovascular disease, and colon cancer. However, specific wheat components may also elicit adverse physical reactions in susceptible individuals such as celiac disease (CD) and wheat allergy (WA). Recently, broad coverage in the popular and social media has suggested that wheat consumption leads to a wide range of adverse health effects. This has motivated many consumers to avoid or reduce their consumption of foods that contain wheat/gluten, despite the absence of diagnosed CD or WA, raising questions about underlying mechanisms and possible nocebo effects. However, recent studies did show that some individuals may suffer from adverse reactions in absence of CD and WA. This condition is called non-celiac gluten sensitivity (NCGS) or non-celiac wheat sensitivity (NCWS). In addition to gluten, wheat and derived products contain many other components which may trigger symptoms, including inhibitors of α-amylase and trypsin (ATIs), lectins, and rapidly fermentable carbohydrates (FODMAPs). Furthermore, the way in which foods are being processed, such as the use of yeast or sourdough fermentation, fermentation time and baking conditions, may also affect the presence and bioactivity of these components. The present review systematically describes the characteristics of wheat-related intolerances, including their etiology, prevalence, the components responsible, diagnosis, and strategies to reduce adverse reactions.

Extract from the study:

Non-Celiac Gluten/Wheat Sensitivity
During recent years a third group of people has been classified who experience symptoms after eating wheat products, but have been diagnosed not to suffer from either WA or CD. Mostly these individuals are self diagnosed wheat intolerant/sensitive. In these individuals, irritable bowel syndrome (IBS)-like gastrointestinal symptoms and extra-intestinal complaints occur, which improve on a gluten-free diet. This group of patients is referred to as “non-celiac gluten sensitivity” (NCGS), or the more recently, “non-celiac wheat sensitivity” (NCWS). Di Sabatino emphasizes that NCWS is not a homogeneous disease syndrome (such as CD and WA), but rather a heterogeneous syndrome (Di Sabatino & Corazza, 2012). It is probable that the underlying causes and mechanisms are not the same for all people with NCWS and that reactions may be caused by different components of wheat or grain (products) and involving different host factors. Ludvigsson et al. (2013) defined NCGS as follows: one or more of a variety of immunological, morphological, or symptomatic manifestations that are precipitated by the ingestion of gluten in individuals in whom CD has been excluded. However, despite the word “gluten” in the currently most cited definition “NCGS,” it is far from certain that the gluten is the (main) cause of the symptoms observed. The more recent term “NCWS” was adopted since it was noted that gluten (NCGS) may not be the real cause (Biesiekierski, Peters, et al., 2013; Skodje et al., 2018). For that reason, we will use the term NCWS as most appropriate in the remainder of this article.

Antinutrients

by luciano

What are antinutrients?
“Antinutritional or antinutrient compounds are natural or synthetic substances that interfere with the metabolism and absorption of nutrients. They are present both in plant organisms, where they perform structural, reserve or defense functions against any predators, and in animal organisms (e.g. toxins and biological amines present in molluscs or fish, in milk derivatives and in wine). They can also form from degradation, cooking (e.g. heterocyclic amines of cooked meats) or food preservation processes, or be present as environmental, microbial, fungal or xenobiotic contaminants (agrochemicals, hormones, etc.).
Gli antinutrienti possono essere classificati in base all’azione che svolgono:
• riducono la digestione proteica e l’utilizzazione delle proteine (es. inibitori della tripsina e della chimotripsina, lectine o emoagglutinine, composti fenolici, saponine);
• interferiscono con la digestione dei carboidrati (es. inibitori dell’amilasi, composti polifenolici, fattori di flautolenza);
• disturbano la digestione e l’azione dei sali minerali (glicosinolati, acido ossalico, acido fitico, gossipolo);
• inattivano le vitamine o causano un incremento del loro fabbisogno (antivitamine);
• producono un effetto tossico ( es. afla-tosine, nitrati);
• stimolano il sistema immunitario (istamina, antigeni).