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Gluten is the name given to the protein in wheat, rye, barley and oats that affect people with coeliac disease. It is a composite name representing
- Gliadin in Wheat
- Hordein in Barley
- Secalin in Rye
- Avenin in Oats
The current tests for gluten can measure gliadin, hordein, and secalin but not avenin as it is a slightly different protein. Accordingly it is prohibited under the Food Standards Code to use oats in foods labelled or advertised as gluten free. When people discuss gluten free oats (and laboratories advise that oats are gluten free) what should be said is that they are free from wheat (and rye, barley) gliadin i.e. there is no measurable contamination.
Avenin is an essential part of oats (as gliadin is with wheat). Oats will never be gluten (i.e. avenin) free [even if they are described as gluten (i.e. gliadin) free]. As mentioned in The Australian Coeliac magazine on several occasions, Dr Robert Anderson has found that approximately 1:5 people with coeliac disease react to pure uncontaminated oats i.e. they react to oat avenin.
Since we cannot determine who is the 1:5 and we know that damage can occur in the absence of symptoms, Dr Anderson’s advice (and Coeliac Australia’s) is that oats should not be consumed without a biopsy prior to and during consumption.
Graham Price OAM BSc (Hons)
Technical Officer, Coeliac Australia
Vaccine for coeliac disease
An experimental vaccine designed to treat people with coeliac disease is under development in Melbourne at the Walter and Eliza Hall Institute. The goal of the vaccine is to “switch-off” the damaging immune response to gluten seen in people with coeliac disease, in the hope that, one day, people with coeliac disease may better tolerate gluten.
However, the vaccine has only just entered clinical trials to assess the vaccine’s safety, tolerability, efficacy, and dosing schedules. The trials will take at least 5 years to complete, ultimately involving thousands of volunteers around the world. The vaccine will only become available to the general public if it is shown to be at least as safe and effective as the current treatment for coeliac disease - the gluten free diet. Right now, and for the foreseeable future, a strict gluten free diet remains the best and only treatment for proven coeliac disease.
Dr Gregor Brown / Gastroenterologist and Head of Endoscopy, The Alfred Hospital
Dr Brown is the Principal Investigator of the Phase 1 clinical study investigating the safety, tolerability and bioactivity of ‘NexVax2’ in volunteers with coeliac disease, mentioned above.
Spelt - is it gluten free?
To answer this question we have reprinted an article which appeared in the December 2004 edition of this magazine -
There is no doubt that spelt wheat contains gluten and should be avoided by those diagnosed with coeliac disease. In the abstract to an article in the journal ‘Cereal Chemistry’ the following comment is made – “The comparison showed only minor differences in amino acid sequences between the α-type gliadin from bread wheat and the α-type gliadin from spelt1. The two sequences had an identity of 98%. Larger differences can be found between different α-type gliadin amino acid sequences from common bread wheat. Because all the different classes of gliadins, α, β, γ, and ω, appear to be active in coeliac disease, it is reasonably certain that the spelta gliadin is also toxic. We conclude that spelta is not a safe grain for people with coeliac disease, contrary to the implications in labelling a bread made from spelta as “an alternative to wheat”.
As well in a letter to a bread manufacturer from the Bread Research Institute of Australia Inc the following information was given - “For your information Spelt flour is milled from Spelt Wheat, contains gluten and tests positive to gluten immunoassay analysis.”
1 Donald D. Kasarda and Renato D’Ovidio 1999. Deduced Amino Acid Sequence of an α-Gliadin Gene from Spelt Wheat (Spelta) Includes Sequences Active in Coeliac Disease. Cereal Chem 76(4):548-551
Gene test positive - What does this mean?
The gene test referred to is a test that looks at two HLA markers: HLA DQ2 and DQ8. The HLA proteins are proteins on the outside of certain cells in the body. Different patterns of the HLA proteins influence how our body responds to certain stimuli. HLA patterns are inherited and passed through families. DQ2 and DQ8 are present in almost everyone with coeliac disease. However, in the Australian community around 30% of people are HLA DQ2 or DQ8 positive, but it is thought that around 1% of people in Australia have coeliac disease.
So, if someone has a positive gene test, this means that they are at greater risk of coeliac disease, but it does NOT mean that they have coeliac disease. The risk could be expressed as a change in risk from 1 in a 100, to 1 in 30. Also, a negative gene test essentially means that a person is not at risk of coeliac disease.
In regards to your daughter, because of your history, she is certainly at greater risk of also developing coeliac disease. However, her HLA test only tells you about her risk of coeliac disease: it does not mean that she has coeliac disease. The positive test should NOT be a reason to change to a gluten-free diet. If she has symptoms suggestive of coeliac disease, or you have any concerns about her health or growth, she should have further tests, including antibody tests. If the initial tests are concerning, then she should be referred to a Paediatric Gastroenterologist for a small bowel biopsy to prove conclusively whether she does or doesn’t have coeliac disease. Only if she has biopsy-proven coeliac disease should she be started on a gluten-free diet.
Associate Professor Andrew Day
Paediatric Gastroenterologist; Member, Clinical Advisory Committee
Grain-fed beef & chicken
All fresh meat and eggs will be gluten free regardless of what diet the animal had in life. All food eaten by an animal is broken down by the digestive process into smaller components (for instance protein is broken down into amino acids). These basic building blocks are then reassembled to make body tissue such as muscle or egg protein. Therefore any cereal protein eaten by the animal (whether it contains gluten or not) will be broken down by digestion, and gluten will not become incorporated into the animal's tissue, whether it be beef meat or chicken egg. The nutritional value of the meat may differ depending on whether the animal's diet was predominantly grain or grass, but in both cases the meat is gluten free. To label eggs as gluten free is correct, but can cause some confusion as it implies some eggs could be gluten containing, and this is not the case.
Processing of meat or eggs, the use of gluten-containing sauces or contamination during preparation are far more relevant issues that could cause these foods to be gluten containing and therefore unsafe to people with coeliac disease. Consideration of these factors when maintaining a gluten free diet is therefore most important.
Dr Jason Tye-Din
The Royal Melbourne Hospital
NHMRC Postgraduate Research Fellow
The Walter and Eliza Hall Institute