Is Gluten? Gluten is the protein found in wheat. Similar
proteins which are harmful to Coeliacs are present in rye, barley
and possibly oats. Wheat, rye and barley are therefore excluded
from the gluten-free diet. Oats may be allowed for some patients,
under careful medical and dietetic supervision.
DISEASE : Coeliac Disease is a life-long inflammatory condition
of the gastro-intestinal tract that affects the small intestine
in genetically susceptible individuals. Gluten
damages the lining of the small intestine, reducing its ability
to absorb adequate nutrients from food, resulting in illness which
may resemble malnutrition, The treatment for Coeliac Disease is
a strict gluten-free diet for life.
cannot tolerate a protein called "gliadin", which is found
in wheat, rye, barley, oats, and spelt. When people with celiac
disease eat foods containing gluten, their immune system responds
by damaging the villi – the tiny, fingerlike protrusions coating
the inside of the small intestine. The villi allow nutrients from
food to be absorbed into the bloodstream. Without functioning villi,
a person can become malnourished. Individuals with Celiac Disease,
gluten intolerance and other food allergies and intolerances require
high quality, good tasting, and gluten-free foods to live a quality
HERPETIFORMIS : Dermatitis Herpetiformis is an itchy blistering
skin eruption, due to gluten sensitivity. This sensitivity also
affects the small intestine in the majority of patients, giving
rise to a mild form of Coeliac Disease. The gluten-free diet eventually
cures the skin rash as well as being the treatment for Coeliac Disease
- ft should therefore be continued for life. For more information
on Dermatitis Herpetiformis click here
IS NATURALLY GLUTEN-FREE? : Many foods are naturally gluten-free
as they do not contain any wheat, rye, barley or oats. For example,
all fresh meat, fish, cheese, eggs, milk, fruit and vegetables are
gluten-free. However, once such foods are processed or used as ingredients
in other foods, great care must be taken to ensure that wheat or
other gluten-containing cereals have not been added in the manufacture.
DIETARY SOURCES OF GLUTEN : Wheat is usually milled into
flour and therefore any food made from four, such as ordinary bread,
biscuits, cakes, pastries, puddings and pies, will contain gluten.
SOURCES OF GLUTEN : Gluten is also contained in manufactured
and processed foods where wheat flour is commonly used as a processing
aid, a binder, a filler or as a carrier for favourings and spices.
Contamination with wheat or wheat flour can also occur during cereal
production, storage, processing or manufacture.
IS WHEAT STARCH : Wheat starch is produced from wheat four
by removing the proteins including gluten. Years ago it was believed
that all the protein could be removed, It is now recognised that
it is technically impossible to remove all traces of protein and
a small amount remains.
are two types of wheat starch : Commercial wheat starch
which is not pure enough to be suitable for Coeliacs. Specially-manufactured
wheat starch which complies with the lntemational Gluten-free Standard
(Codex Ahmentarius) and can safely be included in the gluten-free
diet. Wheat starch of this purity is expensive and it is most commonly
used in products specially-manufactured for Coeliacs, to provide
palatable and acceptable bread and flour substitutes.
FREE, GLUTEN-FREE DIETS : These may be preferable for a
few Coeliacs who appear to be intolerant to wheat starch. This diet
contains breads and flours made from naturally gluten-free foods
such as maize, potato, rice and soya rather than wheat starch.
: There are a few super-sensitive Coeliacs who do not respond fully
to a strict traditional gluten-free diet, Such people may therefore
be advised to limit their diets further - not only by omitting wheat
starch on the gluten-free, wheat free diet, but also by restricting
malt extract and malt extract flavorings. Sensitive Coeliacs should
additionally avoid oats and oat products. However, further restrictions
should not be undertaken lightly and the Society therefore recommends
that highly sensitive Coeliacs should discuss their diets carefully
with their Consultant Gastroenterologist and Dietitian.
GLUTEN-FREE FOODS : Many specially-manufactured branded
gluten-free and wheat free products are now produced. For people
medically-diagnosed as having Coeliac Disease or Dermatitis Herpetiformis,
basic foods such as breads, flours, mixes, biscuits, crackers and
pasta are available on a doctor’s prescription, A complete
up to date list of Prescribable Items is always available from the
Coeliac Society Office. Gluten-free luxury items such as cakes,
chocolate and fancy biscuits and seasonal foods like mince pies
are not prescribable, but can be bought over the counter, at pharmacies
and some health food stores. They may have to be specially ordered
and they can be expensive.
labelling : Unfortunately, food labels do not tell consumers
everything. A label will reveal the obvious presence of wheat or
wheat flour, but where flour is used as a processing aid or as
a small percentage of a compound ingredient, it does not have to
be declared on a label.
labeling legislation is continually improving, Coeliacs are still
advised to use the Coeliac Society’s Food List rather than
rely totally on information given on a label. If a product is not
in the Society’s Food List then it should be avoided. Each
year the Coeliac Society produces an extensive List of Gluten-free
Manufactured Products which is sent to all its members. This list
is constantly updated throughout the year using information from
the major food manufacturers and supermarket chains. Only a current
Food List should be used, and it is essential that this is regularly
updated throughout the year with information available from the
there Gluten in Sprouted Grains?
Revealed from Dr Vikki Petersen
sprouted or germinated grains contain gluten?
am gluten sensitive and want to know if they can affect my health.”
very glad this question was asked. I address it one on one with
patients frequently and there definitely seems to be some false
information out on the internet that is likely propagating the confusion.
here you go; the definitive answer:
Sprouted glutinous grains (wheat, rye, barley and contaminated oats)
still have the protein gluten present. I believe the confusion comes
from the fact that the act of sprouting begins some enzymatic breakdown
of the protein and for those who are not gluten intolerant but merely
have difficulty digesting certain grains, sprouting can make that
process of digestion easier. These people notice that they don’t
have the same symptoms from eating sprouted bread as they do from
eating non-sprouted regular bread.
in NO WAY does sprouting eliminate gluten from the grain and these
sprouted grains are NOT SAFE for anyone with gluten intolerance
– celiac nor gluten sensitivity.
realize that one of the major problems associated with gluten intolerance
is the “silent”, insidious nature of it. While many
people notice immediate symptoms when eating gluten, about 75% notice
no digestive symptoms, and some notice very little symptoms at all.
Unfortunately that doesn’t lessen your chances of developing
autoimmune diseases, nervous system damage and intestinal cancer,
to name a few. Some of these serious conditions do develop silently
and your first knowledge of the damage comes with the diagnosis
of a disease.
not trying to scare you but the theme of early diagnosis rings out
in much of the scientific research being performed during the last
decade. We know the association with gluten and autoimmune disease.
What’s the recommendation? Diagnose the problem with gluten
early in life so as to prevent its development.
know the association between gluten and depression in children and
adults. What’s the recommendation? Diagnose the problem with
gluten early in life so as to prevent the needless suffering and
use of dangerous anti-depressants.
you see the theme? It goes on and on. From osteoporosis to infertility,
from psoriasis to obesity - the list of symptoms is very long and
the recommendations are always the same. So please do not fall into
the trap of eating gluten (even in a slightly predigested fashion)
and thinking it’s okay because it doesn’t initiate certain
symptoms. If you’ve already determined that you are gluten
intolerant then don’t play Russian roulette with your health.
lastly, not to confuse the matter, but the grass of the grain is
gluten-free for approximately the first 10-14 days of growth. Beyond
that point “jointing” occurs which is the development
process whereby the grain forms and gluten becomes present. This
means that if you drank wheat juice made from the grass only (and
it was less than 10 days old – pre-jointing phase) it would
be a gluten-free product. But I must emphasize that would be consuming
the grass only, NOT the grass PLUS the rest of the grain such as
what is used in sprouted breads.
would recommend that if you do choose to ingest a greens drink that
you ensure that the company tests their products thoroughly to ensure
that they are gluten-free."
and Gluten measurement
Relationship to food toxicity for celiac disease patients from Diane
The gluten analysis of foods has long had limitations, which have
precluded food standards authorities from issuing standards for
gluten-free foods based on final gluten content. The Codex Alimentarius
and the Food and Drug Administration have taken steps towards
such standards in which they favour the R5-enzyme-linked immunosorbent
assay for gluten analysis. If this method is to be widely employed,
its limitations should be recognised. Above all, it should be
noted the ability of R5-enzyme-linked immunosorbent assay, and
other methods, to measure gluten's toxicity toward celiac disease
patients is not validated clinically. Gluten is a complex mixture
of proteins and its toxicity is not fully understood. Analytical
methods are a valuable tool in the definition of gluten-free foods,
but they should be employed with appropriate caveats in ensuring
the safety of the foods.
Celiac disease (CD) is chronic gastrointestinal inflammation caused
by an aberrant immune response to dietary gluten . It is treated
by life-long adherence to a gluten-free (GF) diet. Speciality
GF foods cater for CD patients. ELISA assays have long been used
to monitor these foods, but the methods have had limitations which,
until recently, have prevented them gaining acceptance as the
basis for official GF standards . The analysis of gluten is challenging
because gluten is a mixture of water-insoluble proteins, derived
from wheat, barley or rye grain, which in commercial foods, is
within a range of matrices and is modified variously by heat and
methods of gluten analysis are based on the ELISA, employing an
initial extraction step to solubilise gluten from food samples.
The limitations and efficiencies of these methods for the testing
of GF foods were reviewed previously. New improved gluten ELISAs
have since appeared on the market and others are in development.
The commercial R-ELISA has been deemed sufficiently reliable and
sensitive to support standards for GF foods based on final gluten
content . If the method is to be widely employed, its limitations
should be recognised so the method is used correctly.
I critically examine the basis of the R5-ELISA and other recent
ELISA methods of gluten analysis.
Gluten is a scientifically imprecise term and its definition varies,
even when GF foods are concerned. Herein, the current Codex definition
of gluten is employed, which is 'a protein fraction from wheat,
rye, barley, oats or their crossbred varieties and derivatives
thereof, to which some people are intolerant and that is insoluble
in water and 0.5 M NaCl'; This definition is similar to that recently
proposed by the FDA, 'the proteins that naturally occur in a prohibited
grain and that may cause adverse health effects in persons in
celiac disease' .
gluten is sometimes defined by its solubility only, a feature
which derives from the high proline and glutamine content of the
native gluten proteins. For example, 'a protein fraction of wheat,
rye or barley insoluble in water or a solution of 0.5 M NaCl'.
Such a definition is not used here because it does not support
meaningful discussions concerning food safety. (Some food processing
procedures increase gluten's solubility, but do not necessarily
diminish the protein fraction's harmful effect).
Demonstrating intolerance to gluten is a complex endeavour. The
toxicity of gluten in CD stems from an immune response involving
both innate and adaptive systems . No model is available to replicate
the response, although rhesus macaques were recently proposed
. The demonstration of gluten intolerance depends on in vivo challenge
has a highly variable presentation and symptoms are considered
unreliable as an indicator of active disease. The defining indicator
of gluten-induced damage in CD is histopathology of the mucosa
of the small intestine . It only develops in response to ongoing
gluten exposure, which means the investigation of gluten intolerance
faces design and ethical hurdles. Other factors associated with
CD hinder representative studies. They include the heterogeneous
presentation of disease, a high rate of under-diagnosis and the
lifestyle challenges of a truly GF diet .
In many circles, a zero tolerance approach to gluten in GF foods
is considered impractical. With derivatives of wheat, and to a
lesser extent barley, used widely in mainstream food channels,
GF foods are susceptible to contamination, even when produced
in dedicated facilities. Some GF foods in Europe are even based
on wheat-starch which, though processed to remove gluten, contains
gluten residues. However, many GF foods are entirely free of gluten-containing
grains and they are available throughout Europe. Preventative
measures to minimise contamination are employed by GF manufacturers
which, in some cases, are very strict. For example, a core group
of manufacturers not only exclude all gluten-containing grains
from their foods and use dedicated facilities, they also heed
the provenance of all their ingredients.
efforts to reach a universal definition of GF foods, studies have
aimed to define safe threshold gluten for CD patients through
in vivo challenge studies. While it remains limited, the evidence
base in this area has strengthened in recent years . It appears
the extent to which gluten must be excluded from the diet varies
between CD individuals with highly sensitive individuals difficult
to study. They do not tolerate, and are possibly deterred by,
an extended gluten challenge.
for specialty GF foods vary between regulatory authorities. The
FDA recently proposed draft GF standards for the first time, which
are based on final gluten content. Codex is in the final stages
of approving similar standards. The draft standards permit trace
gluten in GF foods, but aim to keep total dietary gluten well
below levels generally accepted as safe for CD patients. They
allow ingredients derived from gluten-containing grains in the
foods, providing the ingredients have been processed to remove
gluten and prescribed limits are met.
addition, Codex has had standards since 1981, which define GF
foods according to the nitrogen content of raw ingredients . These
standards are only applicable to GF foods with ingredients derived
from wheat, barley or rye. The Codex has endorsed the R5-ELISA
as a means of upholding GF standards based on final gluten content
. The FDA has tentatively endorsed the method and acknowledges
that future methods including other ELISAs, may prove useful in
the area . In light of such significant endorsement, it is important
to consider the remaining limitations of gluten analysis by ELISA.
basis for gluten's toxicity
In vitro, and to a lesser extent, in vivo methods have been useful
in dissecting the basis for gluten's immunotoxicity. Activation
of CD4(+) T cells in the small intestinal mucosa by gluten peptides
released by digestive enzymes is a key event in CD . A direct
effect from other gluten peptides on the intestinal epithelium
has a role in inflammation . Autoantibodies are associated with
active CD and their role in pathogenesis is currently an active
area of research.
peptides are implicated in T cell stimulation, present in both
major fractions of gluten (in wheat these fractions are the gliadins
and glutenins) . A single peptide located within a region resistant
to digestive enzymes is the immunodominant portion of the gluten
subfraction, a-gliadin, at least in adult patients . The full
potency of this peptide, and that of others, is dependent on its
modification by a tissue transglutaminase within the intestinal
mucosa. The enzyme introduces a negative charge into the peptide,
which enhances class II MHC binding on antigen-presenting cells.
crucial role of T cell activation in disease pathogenesis is evident
from the association of CD with class II MHC genotype. Over 90%
of patients are positive for the HLA DQ2 heterodimer with the
remainder positive for HLA DQ8 . The peptides stimulatory to T
cells in HLA DQ8 individuals appear to be distinct from those
of the HLA DQ2 model.
bases of recent gluten ELISAs
The commercial R5-ELISA is hailed as a significant advance in
the area of gluten detection . Nonetheless, developments in the
area continue. The bases of the R5-ELISA and other recent methods
are examined here. Earlier gluten ELISAs are not included because
they are already appraised in detail.
R5-ELISA and subsequent methods are based on monoclonal antibodies
which target sequences characteristic of peptides stimulatory
to T cells. The latest methods have highest specificity for gliadin
peptides of known immunodominance in HLA DQ2 patients, in particular
the well-characterised a-gliadin peptide. One method also has
demonstrated cross-reactivity with a gliadin peptide which invokes
an innate immune response .
strategy of targeting immunogenic peptides with a gluten ELISA
aims for an analytical method, which acts as an indicator of food
toxicity to CD patients. It contrasts with the strategy of an
earlier, but widely-used gluten ELISA which targets the most heat-stable
subfraction of gliadin, the ?-gliadins.
should be noted the gluten proteins are not necessarily intact
when present in food. The original version of the R5-ELISA and
the anti-gliadin ELISA employ a sandwich format, which is unable
detect small gluten fragments. The latest R5-ELISA, together with
other recent methods, employs a competitive format, which enables
detection of gluten peptides containing single epitopes and therefore
is suitable against highly degraded protein. At least in sandwich
form, the R5-ELISA is considered more sensitive than the anti-?-gliadin
ELISA and better at detecting barley gluten . An inability to
detect barley and rye sequences is a weakness of another recently-developed
commercial gluten ELISA .
commercially available, the competitive R5-ELISA is not yet trialled
as extensively as the sandwich R5-ELISA. The abilities of the
sandwich R5-ELISA and the anti-gliadin to detect the gluten proteins
in food were reviewed recently, and the merits of the competitive
R5-ELISA considered. All gluten ELISAs use a standard of native
gliadin . The contribution of the glutenins toward gluten measurements
is estimated, based on the assumption that both fractions of gluten
are present in equal amounts.
relationship between gluten measurements and the toxicity of food
to CD patients
It should be noted that the relationship between ELISA measurements
of gluten in food and the toxicity of the foods toward CD patients
is not directly investigated. No gluten ELISA has been evaluated
through clinical trials. The relationship has been explored to
a limited extent with a bioassay employing T cells isolated from
CD patients .
the capabilities of ELISA methods to ensure the GF status of foods
are assumed, combining analytical estimations of gluten in food
with knowledge on daily safe threshold levels of gluten and current
understanding of its toxicity toward CD patients.
limitations of gluten ELISAs
Notwithstanding the advantages of recent methods, the assessment
of the safety of GF foods for CD patients based on gluten analysis
by ELISA is not clearcut. The multiple challenges associated with
the testing of GF foods are not completely surmounted by the methods.
Uncertainties remain regarding the quantitative measurement of
gluten in foods and analytical-based predictions of food toxicity
to CD patients.
the most intractable aspect of gluten analysis is the accurate
standardisation of measurements. The most soluble half of wheat
gluten, gliadin, has been deemed the best standard for gluten
measurements, however it may not accurately represent gluten in
food in every instance.
precise composition varies between species and cereal variety.
In addition, the food industry uses technological procedures in
the preparation of ingredients and foods, which modify gluten
physically, chemically or enzymatically. These modifications,
as well as matrix effects associated with food ingredients, may
affect gluten's solubility, its intermolecular associations, not
to mention the availability, and even the sequence, of its epitopes.
These factors conceivably impact on gluten analysis by ELISA protocols,
during extraction and/or immunodetection. To illustrate the vagaries
associated with the standardisation of gluten measurements, gliadin
is no longer considered ideal as a standard for measuring barley-derived
gluten with the R5-ELISA .
is practically impossible to analyse the gluten of commercial
foods in a controlled fashion because the foods are so various
and their exact composition is unknown. In trials of the R5-ELISA
, thousands of commercial GF foods were analysed, their gluten
content estimated against a pure native gliadin standard. The
validity of this approach in establishing the method's reliability
can be challenged because the approach does show whether gluten
in the foods evades detection in some instances. Nor is it able
to reveal whether non-specific antibody interactions are occurring
and leading to a skewing of ELISA values. Controlled experiments
were included in the trials , however they involved relatively
simple foods spiked with native gliadin only, which, arguably,
do not reflect the diversity of commercial foods.
a subsequent study suggests that the R5-ELISA fails to detect
some forms of gluten, at least when employed in the sandwich format.
The sandwich R5-ELISA yielded lower gluten values on beer samples
than the competitive R5-ELISA. This difference was attributed
to an inability of the sandwich R5-ELISA to detect hydrolysed
gluten, however the experiments were insufficiently controlled
to show that the competitive R5-ELISA reliably detected all gluten
in the commercial samples tested.
use of a gliadin standard for gluten measurements may also be
challenged on the basis it overlooks the glutenin fraction of
gluten. Formerly, the contribution of this less soluble fraction
to gluten toxicity was unclear , however glutenin peptides are
now known to be involved in T cell activation in CD patients .
Being highly insoluble, the glutenins may persist throughout processing
procedures, which eliminate the gliadins . Thus, it is debatable
whether a gluten detection method is capable of indicating food
toxicity, using a gliadin standard only.
weaknesses can be found in the theory behind gluten ELISAs. Gluten's
toxicity is related to its quality as well as its quantity. The
immunogenicity of gluten proteins varies according to influences
such as cereal variety and food processing procedures . Most notably,
deamidation has implications for food safety. Deamidated gluten
is detected inefficiently by the R5-ELISA , yet may have heightened
toxicity in some instances.
Gluten ELISAs are able to detect gluten contamination in foods
in many instances and are a valuable tool in the analysis of GF
foods. However, they are not clinically validated as an indicator
of food toxicity toward CD patients and analytical-based predictions
of food toxicity are not straightforward. The methods cannot on
their own ensure the safety of GF foods, but must be employed
with appropriate caveats. False reliance on the methods is to
be avoided, if official standards for GF foods based on final
gluten content are widely adopted.