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Abstract

Gluten-free diets have gained popularity with the public at a rate greater than would be expected based on the prevalence of gluten-related disorders such celiac disease, nonceliac gluten sensitivity, and wheat allergy. This article reviews gluten-related disorders, indications for gluten-free diets, and the possible health benefits of gluten. Despite the health claims for gluten-free eating, no published experimental evidence supports weight-loss with a gluten-free diet or suggests that the general population would benefit from avoiding gluten.
REVIEW ARTICLE
JAAPA Journal of the American Academy of Physician Assistants www.JAAPA.com
Gluten-free diets have gained considerable popularity in
America. According to a 2013 survey by the NPD Group,
30% of American adults were interested in avoiding
gluten or at least reducing the amount of gluten in their
diets.1 The gluten-free food market is now $4.2 billion
per year and is expected to reach $6.6 billion by 2017.2
As of May 18, 2015, Amazon.com listed 16,527 book
entries for “gluten-free,” more than three times the num-
ber in 2012.3 A Google search in May 2015 for “gluten-
free” produced more than 81 million results. A 2013
survey by Mintel indicated that 65% of American adults
say they eat gluten-free products because they think they
are more healthful, and 27% eat gluten-free products to
lose weight.4 Celebrity endorsements also contribute to
the heightened awareness of gluten-free eating, especially
with regard to weight loss.5
Despite the health claims for gluten-free eating, no pub-
lished experimental evidence suggests that the general
population would be better off by excluding gluten from
their diet.3,6 This article is an overview of gluten-related
disorders, the published research on the effects of gluten
and gluten avoidance in otherwise healthy people, and
potential adverse reactions to gluten avoidance in otherwise
healthy people without gluten-related diseases.
GLUTEN-RELATED DISORDERS
Gluten refers to a family of storage proteins (gliadins and
glutenins) found in wheat and related grains such as barley
and rye. Gluten-related disorders are wheat allergy, non-
celiac gluten sensitivity, and celiac disease.7,8
Wheat allergy An IgE-mediated reaction to wheat proteins,
wheat allergy has an estimated prevalence of about 0.1%.7
Wheat allergy is treated with wheat avoidance and is not
as restrictive as a gluten-free diet because patients typically
do not become symptomatic from eating gluten-containing
grains such as rye and barley.7 Although symptoms of
wheat allergy can be similar to celiac disease, wheat allergy
does not cause permanent gastrointestinal (GI) damage as
in celiac disease. Finally, wheat allergy typically develops
during early infancy or toddlerhood, and children typically
outgrow it between ages 3 to 5 years; celiac disease is a
lifelong disorder.7
Nonceliac gluten sensitivity This condition, also called
gluten sensitivity and nonceliac gluten intolerance, is
associated with GI symptoms such as gas, bloating, and
diarrhea, as well as extraintestinal signs and symptoms
such as fatigue, headaches, dizziness, and ataxia. Symp-
toms frequently improve with the adoption of a gluten-free
diet. The prevalence of nonceliac gluten sensitivity is
unknown. One study of 5,896 patients from the Univer-
sity of Maryland Center for Celiac Research reported
prevalence of 6%, which would indicate that about 18
million Americans may have the disorder.8 However, due
to the inherent subjectivity in diagnosis, defi nitive data
on the prevalence of nonceliac gluten sensitivity is diffi cult
to establish.
Celiac disease A complex autoimmune pathology of
the small intestine, celiac disease occurs in genetically
susceptible patients when they eat gluten-containing
grains.9 As recently as 2000, celiac disease was thought
to be rare, occurring in fewer than 1 in 10,000 to 1 in
4,800 people, based on epidemiological studies.10 This
corresponds to 0.01% to 0.02% of the population. The
prevalence is now thought to be much greater, at about
1% worldwide.11,12 Data from the 2009-2010 National
Health and Nutrition Examination Survey indicated that
the overall prevalence of celiac disease in the United States
Navigating the gluten-free boom
Glenn A. Gaesser, PhD; Siddhartha S. Angadi, PhD
Glenn A. Gaesser and Siddhartha S. Angadi practice at the Healthy
Lifestyles Research Center, Exercise Science, and Health Promotion
program in the School of Nutrition and Health Promotion at Arizona
State University in Phoenix, Ariz. Dr. Gaesser discloses that he
receives honoraria as chair of the Scientifi c Advisory Board of the
Grain Foods Foundation and as a member of the Wheat Foods Council
Advisory Board. Dr. Angadi has disclosed no potential confl icts of
interest, fi nancial or otherwise.
DOI: 10.1097/01.JAA.0000469434.67572.a4
Copyright © 2015 American Academy of Physician Assistants
ABSTRACT
Gluten-free diets have gained popularity with the public
at a rate greater than would be expected based on the
prevalence of gluten-related disorders such celiac disease,
nonceliac gluten sensitivity, and wheat allergy. This article
reviews gluten-related disorders, indications for gluten-free
diets, and the possible health benefi ts of gluten. Despite the
health claims for gluten-free eating, no published experi-
mental evidence supports weight-loss with a gluten-free
diet or suggests that the general population would benefi t
from avoiding gluten.
Keywords: gluten, celiac disease, nonceliac gluten sensitivity,
wheat allergy, microbiota, autoimmunity
Copyright © 2015 American Academy of Physician Assistants
REVIEW ARTICLE
www.JAAPA.com Volume 28 • Number 8 • August 2015
was 0.7%, with a 1% prevalence among non-Hispanic
whites, suggesting that celiac disease is much less common
among minorities.13 Reasons for the increased reported
prevalence in celiac disease are speculative. International
trends indicate increased wheat consumption, and the
rising prevalence of celiac disease also is consistent with
trends for other autoimmune diseases.14 Another possibil-
ity is that the increased prevalence of celiac disease
reported in recent studies is due in part to reliance on
serologic testing alone rather than confi rmation with
small-bowel biopsy.15
Celiac disease is a unique model of autoimmunity in which
some of the genes involved, the target autoantigen, and the
environmental trigger (gluten) are known. The genetic
predisposition observed in patients with celiac disease is
related to human leukocyte antigen (HLA) class II genes,
namely, HLA-DQ2 and HLA-DQ8. These genes explain
about 40% of the disease heritability.11,12 Because celiac
disease prevalence increases with age, genes and gluten
probably are not the only things responsible for the disease.
GLUTEN-FREE DIET IN OTHER DISORDERS
A gluten-free diet has been shown to improve GI and/or
systemic symptoms in patients with dermatitis herpetifor-
mis, irritable bowel syndrome, rheumatoid arthritis, type
1 diabetes, HIV-associated enteropathy, systemic lupus
erythematosus, thyroiditis, psoriasis, and neurologic dis-
orders such as gluten ataxia and multiple sclerosis.16,17
Clinical research evidence for a benefi t of a gluten-free diet
is strongest for dermatitis herpetiformis, irritable bowel
syndrome, gluten ataxia, and type 1 diabetes.17 Although
gluten-free diets have been used to treat autism spectrum
disorders, results are inconsistent, and the American Acad-
emy of Pediatrics does not support the use of gluten-free
diets as a primary treatment for patients with autism spec-
trum disorders.8,18-20
DIAGNOSIS OF GLUTEN-RELATED DISORDERS
Algorithms have been proposed for diagnosis of the
spectrum of gluten-related disorders (Figure 1).8,21 Diag-
nosis of celiac disease is primarily carried out through
serologic testing for antigliadin, antiendomysium, and
antitransglutaminase antibodies. These serologic tests are
coupled with a small-bowel biopsy for histopathological
assessment of the gut, the gold standard for diagnosing
celiac disease. Immunoglobulin A (IgA) antitissue trans-
glutaminase (TTG) antibody is the preferred serologic
test for detecting celiac disease in patients over age 2
years.22 For patients under age 2 years, the IgA TTG test
should be combined with the immunoglobulin G (IgG)
deamidated gliadin peptides (DGP) test. IgG TTG and
DGP are also recommended for patients over age 2 years
if low IgA or selective IgA defi ciency is suspected. If the
index of suspicion is high, an intestinal biopsy can be
pursued despite negative serology. All testing should be
done while patients are on a diet containing gluten in
order to avoid a false-negative biopsy (the duodenal
mucosa will heal in the absence of gluten). Lifelong adher-
ence to a strict gluten-free diet is the principle treatment
for managing celiac disease.9,11,12
Although diagnostic criteria for celiac disease and wheat
allergy have been established, clinical diagnosis of nonce-
liac gluten sensitivity is generally based on response to a
gluten-free diet. A double-blind, placebo-controlled gluten
rechallenge test is considered to have the highest diagnos-
tic accuracy, but the reliability of this test has been ques-
tioned recently because of inconsistent results in patients
with self-reported nonceliac gluten sensitivity.23,24 The main
diffi culty with this test is that it is expensive and time-
consuming. Single-blind testing, in which the patient but
not the physician is blinded, or open testing (neither patient
nor physician is blinded) are less desirable, but may be
easier alternatives.23
A CONFOUNDING FACTOR?
Another dilemma in the diagnosis of nonceliac gluten
sensitivity is that the symptoms produced by consumption
of gluten-containing foods may not be attributable to
gluten. Evidence suggests that GI symptoms in patients
with nonceliac gluten sensitivity may be due to the con-
sumption of fermentable, oligo-, di-, monosaccharides,
and polyols (fodmaps). In a recent double-blind crossover
trial of 37 women and men with nonceliac gluten sensitiv-
ity and irritable bowel syndrome, GI symptoms consistently
improved when subjects consumed a diet low in fodmaps,
but gluten-specifi c effects were observed in only 3 (8%)
of the subjects.25 Subjects who consumed a low-fodmap
diet that was high in gluten had the same symptom profi le
as when they consumed the same diet with low gluten
content. These results suggest that in patients with non-
celiac gluten sensitivity and/or irritable bowel syndrome,
symptoms widely attributed to gluten may be due to
Key points
Gluten-free diets have gained popularity with the public
at a rate greater than would be expected based on the
prevalence of gluten-related disorders.
Patients with celiac disease and nonceliac gluten sensitivity
should adhere to a gluten-free diet and work with their
primary care provider and a registered dietitian.
Wheat is the most widely consumed grain in the United
States, and contains fructan-type resistant starches that
help create healthy gut bacteria. Eliminating wheat from
the diet without an established medical reason may have
unintended consequences.
Despite the health claims for gluten-free eating, no
published experimental evidence supports a weight loss
claim for a gluten-free diet or suggests that the general
population would be better off by avoiding gluten.
Copyright © 2015 American Academy of Physician Assistants
Navigating the gluten-free boom
JAAPA Journal of the American Academy of Physician Assistants www.JAAPA.com
fodmaps. In a follow-up study by the same researchers
on 22 of the 37 subjects in the initial cohort, gluten-specifi c
GI symptoms were absent in response to a 3-day double-
blinded gluten rechallenge.26 Recent fi ndings by others
have confirmed the improvement in GI symptoms in
patients with irritable bowel syndrome following a low-
fodmap diet.27,28 To improve treatment strategies for
nonceliac gluten sensitivity, the results of these studies on
patients with nonceliac gluten sensitivity and/or irritable
bowel syndrome need to be replicated. Further research
also is necessary to determine the extent of symptomology
due to gluten and fodmaps. In healthy adults, inulin, a
fodmap prevalent in wheat, was reported to cause few
GI symptoms.29
DEBUNKING WEIGHT-LOSS CLAIMS
A gluten-free diet has demonstrated effectiveness for treat-
ing gluten-related disorders and the conditions mentioned
above. But evidence-based research fails to support a
gluten-free diet as a more healthful option for the general
population. Although an estimated 27% of American
adults consume gluten-free products for weight loss, no
published studies have found that a gluten-free diet produces
weight loss in patients without celiac disease or nonceliac
gluten sensitivity.4 Data on weight change in patients with
celiac disease who follow a gluten-free diet are mixed.30-33
Patients who are underweight frequently gain weight after
starting a gluten-free diet; those who are initially overweight
or obese may lose weight.30 However, a gluten-free diet
NO
YES YES
YES
YES
NO
NO
NO
O
N
N
YES
YE
S
N
YES
YE
S
N
History and physical – initial evaluation —
consider differential diagnosis
Celiac disease or
nonceliac gluten sensitivity
TTG and/or
dAGA+
Esophagogastroduodenoscopy
with biopsies
Biopsy
positive
Celiac disease
diagnosis conrmed
Gluten
challenge +
Nonceliac gluten
sensitivity conrmed
Nonceliac gluten
sensitivity ruled out.
Consider other
diagnoses
Suspected nonceliac
gluten sensitivity
• TTG IgA +/- EMA + total IgA
• Deamidated antigliadin antibodies IgA
• Antigliadin antibodies
Wheat allergy
• Specic skin prick tests
• Wheat-specic serum IgE
• Gluten challenge
Tests +
Challenge +
Wheat allergy
diagnosis conrmed
Wheat allergy
ruled out
Potential
celiac disease
FIGURE 1. Proposed algorithm for the differential diagnosis of gluten-related disorders, including celiac disease, nonceliac gluten
sensitivity, and wheat allergy. All testing on patients suspected of celiac disease or nonceliac gluten sensitivity needs to be carried
out while patients are on a diet containing gluten in order to avoid a false-negative biopsy.8
Copyright © 2015 American Academy of Physician Assistants
REVIEW ARTICLE
www.JAAPA.com Volume 28 • Number 8 • August 2015
may increase body weight in a signifi cant number of over-
weight patients.30-33
In two studies of a total of 740 adults with celiac disease,
22 of 81 (27%) initially overweight subjects in one study
and 55 of 67 (82%) initially overweight subjects in another
study gained weight after following a gluten-free diet for
at least 2 years.30,31 Similar results have been documented
in children.32,33 In one study of 149 children with celiac
disease who followed a gluten-free diet for at least 1 year,
the percentage of overweight children increased from 11%
to 21%.32 Among 679 children with celiac disease who
followed a gluten-free diet, body mass index (BMI)
increased by an average of 2 BMI units during a mean
follow-up of 39.5 months.33 The change in BMI was cor-
related with the duration of follow-up. In this study, 15.8%
of children moved from a normal BMI into an overweight
BMI class, and 22% of initially overweight children gained
weight. The authors concluded that weight maintenance
counseling should be a key component of dietary educa-
tion in these patients. The increased body weight observed
in a signifi cant percentage of patients with celiac disease
who adhere to a gluten-free diet is likely due to enhanced
absorption of nutrients corresponding to healing of intes-
tinal lining.
No published data support a weight-loss claim following
adherence to a gluten-free diet in otherwise healthy people
without gluten-related disorders. This may be because
gluten-free foods are not necessarily low-calorie and may
in fact contain more calories than the gluten-containing
foods they are designed to replace.6 A gluten-free diet may
also result in lower intake of whole grains and dietary fi ber,
which are reported to be inversely correlated with BMI.6,34
DOWNSIDE TO ELIMINATING WHEAT?
Wheat is the most widely consumed grain in the United
States and is by far the most important source of fructan-
type resistant starches such as oligofructose and inulin.35,36
These substances have a prebiotic action that helps create
a healthy composition of gut bacteria and may reduce risk
of some cancers, infl ammatory conditions, and cardio-
vascular disease.37-44 Eliminating wheat from the diet
without an established medical reason may have unin-
tended consequences.
Because intense attention to gluten as a potential health
issue is a recent phenomenon, very little published research
exists on the effects of gluten-free diets in otherwise healthy
people. Some evidence suggests that following a gluten-free
diet reduces concentrations of benefi cial gut bacteria.45 Ten
healthy subjects followed a gluten-free diet for 1 month
by exchanging all gluten-containing foods with products
certifi ed to be gluten-free. Fecal samples of the subjects
revealed reduced concentrations of benefi cial bacteria,
including Bifi dobacterium, Lactobacillus, Faecalibacterium
prausnitzii (which have been shown to be protective in
animal models of inflammatory bowel disease) and
Clostridium lituseburense, and increased levels of patho-
genic Enterobacteriaceae and Escherichia coli.45,46 Although
conclusions from this study must be viewed with caution,
they do suggest that following a gluten-free diet without
a valid medical reason may adversely affect composition
of gut bacteria.
On the other hand, a gluten-rich diet may boost the
numbers of benefi cial gut bacteria.47 While maintaining
their habitual diet, 31 healthy adults consumed either 48
g/day of 100% whole-grain wheat breakfast cereal or 48
g/day of wheat-bran cereal for 3 weeks. The addition of
48 g/day of 100% whole-grain wheat breakfast cereal
increased numbers of fecal Bifi dobacterium by about 10%;
wheat bran had no effect. The numbers of Lactobacilli in
fecal samples were increased by 7.4% after the 100%
whole-grain wheat consumption, which was statistically
signifi cantly greater than the 5% improvement after the
wheat-bran consumption. A prebiotic effect of whole-grain
wheat breakfast cereal may be one of the mechanisms by
which whole-grain foods confer health benefi ts, which is
consistent with the reduced cardiovascular disease risk
associated with whole-grain food intake.37-44
UNRECOGNIZED HEALTH BENEFITS OF GLUTEN?
Although limited in numbers, several studies suggest gluten
itself may have health benefi ts in addition to its energy
value as a protein. For example, serum triglycerides were
reduced 13% in 24 adults with hyperlipidemia who con-
sumed an additional 60 g/day of gluten over a 2-week
period.48 In the same subjects, a diet with increased amounts
of wheat fi ber or wheat bran had no effect on triglycerides.
In another study by the same researchers, men and women
with hyperlipidemia consumed either a control diet or a
diet in which 11% of the carbohydrates were replaced
with wheat gluten.49 Over the 4-week study period, the
increased gluten intake (78 g/day) reduced serum triglyc-
erides by 19.2%, uric acid by 12.7%, and low-density
lipoprotein (LDL) oxidation by 10.6%. The researchers
noted that the observed effects of added wheat gluten on
serum triglycerides and oxidized LDL are comparable to
those of monounsaturated fat and soy protein.
Gluten also may have a positive effect on BP. Various
peptide fragments of gliadin extracted from wheat gluten
have been shown to inhibit angiotensin-converting enzyme,
which could help lower BP.50 Whole-grain diets have been
shown to reduce BP in adults with mild hypercholesterol-
emia, with wheat having a specifi c effect.51,52 In addition
Gluten in whole grains
may have a positive effect
on BP.
Copyright © 2015 American Academy of Physician Assistants
Navigating the gluten-free boom
JAAPA Journal of the American Academy of Physician Assistants www.JAAPA.com
to the contribution of the dietary fi ber component of whole
grains in BP regulation, gluten (via its constituent protein
gliadin) also may play a role.50,53
GLUTEN-FREE OPTIONS
With the explosion of interest in gluten-free foods, more
options are available, including gluten-free grains, seeds,
ours, and starches that can help patients obtain adequate
dietary fi ber normally found in whole grains.2,54 These
safe options are listed in Table 1 and may enable patients
on a gluten-free diet to avoid some of the nutritional
defi ciencies, such as low intakes of thiamin, ribofl avin,
niacin, folate, and iron, that are associated with gluten
avoidance.12,54 Gluten-free products also may have lower
protein content than the gluten-containing foods they
are designed to replace.55 By choosing foods that are
nutrient-dense, patients on gluten-free diets can have
well-balanced diets. This does not, however, mean that
a gluten-free diet is a more healthful diet, as is commonly
believed.4 Patients who require a gluten-free diet should
consult with a registered dietitian with expertise in celiac
disease.
Guidelines established by the FDA should help patients
who require a gluten-free diet be able to determine whether
a product really is gluten-free. To be labeled gluten-free,
without gluten, free of gluten, or no gluten, the product
must have fewer than 20 parts per million of gluten. This
level corresponds to the lower limit that can be consistently
detected with available analytical tools, and is in agreement
with recommendations in the scientifi c literature.56
Along with the growing numbers of people avoiding
gluten, Internet sites catering to the demand for gluten-
free products also have increased. More than 93% of
patients with digestive diseases seek Web-based health
information.57 However, nearly one-half of 98 Internet
sites that provided information on celiac disease had
information that was judged to be less than 95% accu-
rate.57 Furthermore, 20% of commercial, nonprofi t, and
professional websites provided information that was
less than 90% accurate. Inaccuracies included informa-
tion about the defi nition and prevalence of celiac disease,
proper diagnosis of the disease, and various aspects of
a gluten-free diet. Fifty-two percent of websites contained
less than 50% of the core information that is considered
essential information about celiac disease. This reinforces
our recommendation that patients with celiac disease
or documented nonceliac gluten sensitivity work with
their primary care provider and a registered dietitian
with expertise in celiac disease and gluten-free dieting.
SUMMARY AND RECOMMENDATIONS
Gluten-free diets are clearly indicated for patients with
celiac disease. Notwithstanding the recent evidence sug-
gesting that fodmaps may be the underlying cause of
symptoms in many patients with nonceliac gluten sensitiv-
ity, gluten-free diets appear to be indicated for these patients
as well.24-28 A gluten-free diet also may be benefi cial for
patients with other chronic autoimmune conditions.16,17
Despite recent surveys showing that most adults in
the United States think gluten-free products are more
healthful, and that more than one-quarter of adults are
avoiding gluten for purposes of weight control, no
published medical evidence supports health or weight-
loss claims for the general population.3,4,6 Furthermore,
despite an extensive review of the literature, the authors
failed to fi nd any evidence to suggest that a gluten-free
diet may have any purported health benefi ts in people
without gluten-related disorders. Moreover, because
whole-grain intake is associated with numerous health
benefi ts, and because wheat is the most widely consumed
grain in America, going gluten-free may not only be
unnecessary but may be a less healthful alternative if
people do not pay careful attention to the nutritional
quality of gluten-free replacements.41,42 Gluten-free baked
goods, for example, can be high in fat and total calories
Gluten-free grains, seeds, fl ours, and starches
• Amaranth
• Arrowroot
• Buckwheat
• Flax
• Legume fl ours
• Mesquite fl our
• Millet
• Montina (Indian rice grass)
• Nut fl ours
• Oats*
• Potato starch and fl our
• Quinoa
• Rice (white, wild, brown, black, glutinous/sweet)
• Rice bran
• Sorghum
• Soy
• Sweet potato fl our
• Tapioca
• Teff
Grains and ingredients to avoid
Wheat and wheat varieties/products (bulgur, couscous,
einkorn, emmer, durum, farro, kamut, semolina, spelt,
wheat bran, wheat germ, wheat starch)
Barley, and barley-derived malt extract, malt fl avoring, and
malt vinegar)
• Rye
• Triticale (a hybrid of wheat and rye)
• Oats*
*Oats are naturally gluten-free, but are frequently contaminated with wheat
during growing or processing, so proceed cautiously. Some companies certify
their oats products as gluten-free. Certifi ed gluten-free oats products should
be safe for patients with celiac disease or nonceliac gluten sensitivity.
TABLE 1. Safe grains and those to avoid for patients
requiring a gluten-free diet
Copyright © 2015 American Academy of Physician Assistants
REVIEW ARTICLE
www.JAAPA.com Volume 28 • Number 8 • August 2015
and lower in protein.12,55 Gluten-free products also may
be much more expensive (76% to 512%) than their
gluten-containing counterparts.58,59 More research on
the health effects of gluten is needed, including the
conceivable unintended consequences of gluten avoid-
ance, especially in otherwise healthy people. JAAPA
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Supplementary resource (1)

... Cependant, il y a peu d'études scientifiques qui évaluent objectivement ces croyances. [3] Pour mieux appréhender la provenance de ces pensées, il serait intéressant de mieux interpréter les effets du gluten sur le corps humain. ...
... Le blé, et plus particulièrement sa fraction gliadine oméga-5, est l'allergène le plus fréquemment impliqué dans l'anaphylaxie alimentaire à l'effort et celui-ci implique des anticorps immunoglobuline (Ig) E. [10] L'allergie au blé n'est pas directement liée au gluten car les patients atteints de cette allergie peuvent tout à fait manger d'autre aliment contenant du gluten comme le seigle, l'orge... Bien que ces symptômes soient fortement similaires à la maladie coeliaque, cette allergie ne provoque pas de lésion gastro-intestinale. La prévalence de l'allergie au blé à médiation IgE varie de 0,33 % à 1,17 %. [3,11] La maladie coeliaque est une maladie auto-immune qui provoque des lésions intestinales. Elle n'est pas uniquement caractérisée par des symptômes gastrointestinaux mais par des signes qui peuvent être également extra-intestinaux comme la dermatite herpétiforme, l'ataxie au gluten ou l'ostéoporose. ...
... Ces gènes expliquent environ 40 % de son hérédité. [3,11] Le peptide intestinal zonuline, impliqué dans la régulation des jonctions serrées présentes entre les entérocytes intestinaux, semble être en partie responsable de l'augmentation de la perméabilité de l'intestin lors de l'absorption du gluten. Par conséquent, les peptides dérivés du gluten atteignent la muqueuse par transport transcellulaire ou paracellulaire où ils sont modifiés par la transglutaminase tissulaire (tTG) en gluten désamidé ce qui les rend toxiques et immunogènes chez les patients présentant la molécule DQ2 ou DQ8. ...
Thesis
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Objectif : Le but de notre revue narrative est de brasser l'ensemble de la littérature actuelle sur les liens existant entre le gluten et des pathologies inflammatoires comme la polyarthrite rhumatoïde et la fibromyalgie ainsi qu'un lien possible avec l'inflammation induit par l'exercices intense chez les sportifs de haut niveau. Dans un second temps, nous avons cherché à savoir si un régime sans gluten peut réellement avoir un impact positif sur ces différentes populations. Méthode : La recherche documentaire s'est effectuée à travers différentes bases de données : Pubmed, Sciences direct, Embase, Cochran, Scopus. Les articles non-retenus pour cette étude étaient ceux concernant la maladie coeliaque et les pathologies juvéniles. Résultats : D'après cette recherche, il semble exister des liens entre le gluten et la polyarthrite rhumatoïde ainsi que la fibromyalgie, et davantage lorsque ces patients présentes une sensibilité au gluten non céliaque. Concernant les athlètes, le régime sans gluten semble ne montrer que peu d'évidences scientifiques claires. Cependant, cliniquement, beaucoup de sportifs ayant essayé ce régime l'adoptent définitivement. Conclusion : Les résultats montrent des avis mitigés à l'adoption d'un régime sans gluten pour diminuer l'inflammation chez des personnes atteints de polyarthrite rhumatoïde et de fibromyalgie. Il pourrait cependant s'agir d'un moyen de développer une approche plus globale et complète au traitement conventionnel. Certains sportifs manifestent un intérêt croissant à l.
... Food regulations allow for, but do not require, the fortification of GF foods for special dietary use in Canada [2]. Although interest in gluten-free (GF) products has expanded [4], concerns for nutrient inadequacy and diet quality of this restrictive diet remain [5,6]. Historically, GF grain products have relied on starches (e.g., corn, rice, tapioca) as the main ingredients, resulting in foods lower in protein, fibre, and minerals but higher in glycemic index [7]. ...
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Country-specific food composition data are needed for gluten-free (GF) food products to assess nutritional adequacy and diet quality. This research aimed to develop a comprehensive GF food composition database for key GF foods consumed in Canada. Average nutrient data from 167 products were estimated from Nutrition Fact Panel labels and the commercial ingredient list, using an iterative and systematic approach. The database reports mean values for energy and 29 nutrients per 100 g for 33 GF commercial grain-based foods. Nutrient values were evaluated with Health Canada’s nutrient content claims per standard reference serving. On average, GF products were, at minimum, a source of thiamin (73%), riboflavin (70%), niacin (58%), iron (58%), fibre (55%), magnesium (48%), folate (36%), zinc (19%), and calcium (15%). Most GF products were low in saturated fat (85%) and cholesterol (64%) but only 15% were low in total fat and 6% were free of sugar. Micronutrient enrichment and the use of nutrient-dense whole grain flours, legume flours, oil seed husks, and functional fibre ingredients varied within and between categories and brands but appeared to contribute to nutrient content. This database provides a new tool to enhance GF diet assessment in individuals or populations in Canada.
... Since celiac disease is triggered by the consumption of food containing gluten (Elli et al., 2015), the only treatment currently available for celiac disease is to follow a strict lifelong gluten-free diet (Hill et al., 2016). Today, large numbers of individuals without celiac disease avoid gluten in the belief that a gluten-free diet is associated with health benefits, potentially resulting in the unnecessary consumption of gluten-free foods (Gaesser and Angadi, 2015). ...
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Autism spectrum disorder (ASD) is a set of heterogeneous neurodevelopmental conditions, characterized by early-onset difficulties in social communication as well as repetitive and unusually restricted behaviors and interests. The treatment of ASD is based primarily on psychoeducational and behavioral interventions. Since the effectiveness of available treatments for ASD is limited, many families search for alternative therapies, such as the gluten-free and casein-free (GFCF) diet. Despite the popularity of the GFCF diet as a supplementary treatment in children with ASD, several rigorous evaluations have failed to confirm its effectiveness. The majority of the available studies examining the efficacy of the GFCF diet are seriously flawed and allow no firm conclusions. The available evidence regarding the effectiveness of the GFCF diet in the treatment of childhood ASD is very weak and cannot be considered promising. The GFCF diet should be used only if an allergy or intolerance to nutritional gluten or casein has been established. The identification of a hypothetical diet-related ASD phenotype may help in selecting children who could benefit from a GFCF dietary intervention. An important consideration is that potentially ineffective therapies may imply considerable opportunity costs, with other possibly more effective treatment approaches remaining unutilized.
... Considering offers by OFSP, this crop holds great potential to be utilised into various food forms in various market segments. Sweet potato can be utilised to make a healthy juice, while the flesh/pulp can be used to make flour for bread and pastries which can cater to celiac disease patients (non-gluten tolerance) (Gaesser & Angadi, 2015). Detailed exploration and processing of sweet potato are needed in order to have OFSP juice to be considered as a healthy juice drink. ...
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Sweet potato (Ipomoea batatas (L.) Lam) is one of the main crops worldwide. However, systematic properties characterization of this crop is still required, particularly on the Malaysian local sweet potatoes. Hence, this study aims to determine the proximate composition and the energy value of five common varieties of local sweet potato (Anggun 1, Anggun 2, Anggun 3, White, and VitAto) in Malaysia. For each variety, three different parts of the tuberous root which were the skin, the cortex, and the mixture of cambium and parenchyma were characterized. The findings indicated that VitAto exhibited the highest starch (16.95% – 17.17%) and crude protein (0.86% – 1.15%) contents in all parts as compared to other varieties, hence reflecting its potentials to be further processed for a mass starch production. Among all the parts, the skin contained the highest crude protein, crude fat, ash and crude fibre, which can be further utilized to produce by-products such as animal feed. The findings in this study serve as a baseline for the future starch and byproducts production from local sweet potatoes.
... Gluten effects and the benefits of a gluten-free diet (GFD) have been the focus of much discussion during recent decades [1,2]. The popularity of GFD has grown recently, with claims that it promotes weight loss and health. ...
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Background and aims There is no clear evidence about the effects of gluten intake on obesity. It is known that gluten's effects on gut permeability are mediated by zonulin, a protein identified as pre-haptoglobin 2, a physiological regulator of the intestinal barrier. We investigated the obesogenic and inflammatory effects of gluten and its association with the haptoglobin genotype. Methods This was a single blinded, crossover study, including 40 overweight or obesity women free of celiac disease. Participants adopted a gluten-free diet (GFD) for 8 weeks and consumed a gluten-free muffin (GF-M) or a gluten-containing muffin (GLU-M, 24 g gluten) for 4 weeks, switching muffin type during the subsequent 4 weeks. During a follow-up period of 4 weeks we evaluated the usual diet (UD). Food diaries were collected to estimate the macronutrient intake and dietary inflammatory index (DII®). Bodyweight and composition, resting energy expenditure (REE), and cytokines were assessed. Haptoglobin alleles (Hp1 and Hp2) were genotyped to characterize zonulin expression. Results Energy and macronutrient intakes were similar during both periods, except for protein intake, which was higher during GLU-M. DII scores indicated a more inflammatory profile during the GF-M and GLU-M periods compared to UD. No differences were observed in body composition or REE between interventions when the Hp genotype was not considered. Nonetheless, those carrying the Hp2-2 genotype (overexpressing zonulin) presented lower REE and higher levels of IL6 and IL1beta only during gluten intake (GLU-M and UD) compared to age- and body mass index-matched Hp1-1 carrier. These results suggest an obesogenic and inflammatory action of gluten only in those overexpressing zonulin (Hp2-2). Conclusion These results highlight the importance of zonulin as the mediator of gluten obesogenic and inflammatory effects. Our data suggest that in the presence of gluten, zonulin release is associated with a reduction of REE and an increase of inflammatory markers that are not seen in zonulin low producers.
... To counteract the increasing uncertainty among consumers, numerous counterstatements of the scientific community [e.g., (120,(162)(163)(164)(165)] have emphasized that wheat consumption is safe for the vast majority of the population and that wheat avoidance is only necessary after medical diagnosis of a true WRD. These reviews have compiled convincing evidence to refute the abovementioned statements and assert that the regular consumption of whole-grain products is associated with reduced risks of type 2 diabetes and of colorectal cancer, likely reduced risks of colon cancer and cardiovascular diseases, and more favorable weight management (166). ...
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Wheat-based foods have been staple foods since about 10,000 years and constitute a major source of energy, dietary fiber, and micronutrients for the world population. The role of wheat in our diet, however, has recently been scrutinized by pseudoscientific books and media reports promoting the overall impression that wheat consumption makes people sick, stupid, fat, and addicted. Consequently, numerous consumers in Western countries have started to question their dietary habits related to wheat consumption and voluntarily decided to adopt a wheat-free diet without a medical diagnosis of any wheat-related disorder (WRD), such as celiac disease, wheat allergy, or non-celiac gluten sensitivity. The aim of this review is to achieve an objective judgment of the positive aspects of wheat consumption as well as adverse effects for individuals suffering from WRDs. The first part presents wheat constituents and their positive nutritional value, in particular, the consumption of products from whole-grain flours. The second part is focused on WRDs that affect predisposed individuals and can be treated with a gluten-free or -reduced diet. Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet.
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Discover relevant biomedical interactions in the literature is crucial for enhancing biology research. This curation process has an essential role in studying the different processes and interactions reported that affect the biological process (e.g., genome, metabolome, and transcriptome). In this sense, the objective of this work is twofold: reduce the manual effort required to curate and review the existing biochemical interactions reported in the gluten-related bibliome, while proposing a novel vector-space integrated into a deep learning model to assists manual curators in a real curation task by learning from their previous decisions. With this objective, the present work proposes a novel vector-space that combine (i) high-level lexical and syntactic inference features as Wordnets and Health-related domain ontologies, (ii) unsupervised semantic resources as word embedding, (iii) semantic and syntactic sentence knowledge, (iv) abbreviation resolution support, (v) several state-of-the-art Named-entity recognition methods, and, finally, (vi) different feature construction and optimization techniques to support a semi-automatic curation workflow. Therefore, the application of the proposed workflow over a classified set of 2,451 relevant gluten-related documents produces a total of 8,349 relevant and 471,813 irrelevant relations distributed in thirteen domain health-related categories. Experimental results showed that the proposed workflow is a valuable approach for a semi-automatic relation extraction task. It was able to obtain satisfactory results in the early stages of a real-world curation task and saved manual annotation efforts by learning from the decisions made by manual curators in iterative annotation rounds. The average F-score for the proposed relation categories was 0.731, being the lowest F.score at 0.47 and the highest F.score at 0.929. The different resources used in this work as well as the manually curated corpus are public available on our GitHub repository.
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The increasing number of scientific research documents published keeps growing at an unprecedented rate, making it increasingly difficult to access practical information within a target domain. This situation is motivating a growing interest in applying text mining techniques for the automatic processing of text resources to structure the information that helps researchers to find information of interest and infer knowledge of practical use. However, the automatic processing of research documents requires the previous existence of large, manually annotated text corpora to develop robust and accurate text mining processing methods and machine learning models. In this context, semi-automatic extraction techniques based on structured data and state-of-the-art biomedical tools appear to have significant potential to enhance curator productivity and reduce the costs of document curation. In this line, this work proposes a semi-automatic machine learning workflow and a NER+Ontology boosting technique for the automatic classification of biomedical literature. The practical relevance of the proposed approach has been proven in the curation of 4,115 gluten-related documents extracted from PubMed and contrasted against the word embedding alternative. Comparing the results of the experiments, the proposed NER+Ontology technique is an effective alternative to other state-of-the-art document representation techniques to process the existing biomedical literature.
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Nowadays, gluten and FODMAP food components (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are increasingly studied due to their possible relation with extraintestinal-associated conditions. In recent years, gluten-free diets (GFD) and low-FODMAP diets (LFD) are becoming more popular not only in order to avoid the food components that cause intolerances or allergies in some people, but also due to the direct influence of marketing movements or diet trends on feeding habits. Likewise, neurological and psychiatric diseases are currently of increasing importance in developed countries. For this reason, a bibliographic systematic review has been carried out to analyse whether there is a pathophysiological relationship between the dietary intake of gluten or FODMAPs with mental disorders. This review collects 13 clinical and randomized controlled trials, based on the PRISMA statement, which have been published in the last ten years. Based on these results, limiting or ruling out gluten or FODMAPs in the diet might be beneficial for symptoms such as depression, anxiety (7 out of 7 articles found any positive effect), or cognition deficiency (improvements in several cognition test measurements in one trial), and to a lesser extent for schizophrenia and the autism spectrum. Nevertheless, further studies are needed to obtain completely reliable conclusions.
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The gluten-free (GF) products market represents one of the most prosperous markets in the field of food and beverages in the immediate future. Historically, counselling for celiac disease has focused on the absence of gluten in foods, however the nutritional quality of GF foodstuffs is an important aspect to consider. The aim of the present work was to compare the nutritional composition of the 206 GF rendered products most consumed in Spain, against the composition of 289 equivalent foods with gluten, and to make a comparison between the diet including GF products and the same diet with equivalent products with gluten in a 58 adult celiac population. The results of the present collaborative study pointed out differences in calorie, macronutrient, fiber, sodium, salt and cholesterol content between GF rendered and gluten-containing foodstuffs. Thus, calorie and nutrient intake in a GF diet is different when compared to its equivalent diet with gluten. Following a diet based on GF products could suppose a nutritional imbalance for celiac patients as well as for non-celiacs who follow a diet that includes many GF rendered foodstuffs.
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OBJECTIVES:The objective of this study was to investigate whether ingestion of fructose and fructans (such as inulin) can exacerbate irritable bowel syndrome (IBS) symptoms. The aim was to better understand the origin of these symptoms by magnetic resonance imaging (MRI) of the gut. A total of 16 healthy volunteers participated in a four-way, randomized, single-blind, crossover study in which they consumed 500 ml of water containing 40 g of either glucose, fructose, inulin, or a 1:1 mixture of 40 g glucose and 40 g fructose. MRI scans were performed hourly for 5 h, assessing the volume of gastric contents, small bowel water content (SBWC), and colonic gas. Breath hydrogen (H2) was measured and symptoms recorded after each scan.RESULTS:Data are reported as mean (s.d.) (95% CI) when normally distributed and median (range) when not. Fructose increased area under the curve (AUC) from 0-5 h of SBWC to 71 (23) l/min, significantly greater than for glucose at 36 (11-132) l/min (P<0.001), whereas AUC SBWC after inulin, 33 (17-106) l/min, was no different from that after glucose. Adding glucose to fructose decreased AUC SBWC to 55 (28) l/min (P=0.08) vs. fructose. Inulin substantially increased AUC colonic gas to 33 (20) l/min, significantly greater than glucose and glucose+fructose (both P<0.05). Breath H2 rose more with inulin than with fructose. Glucose when combined with fructose significantly reduced breath H2 by 7,700 (3,121-12,300) p.p.m./min relative to fructose alone (P<0.01, n=13).CONCLUSIONS:Fructose but not inulin distends the small bowel with water. Adding glucose to fructose reduces the effect of fructose on SBWC and breath hydrogen. Inulin distends the colon with gas more than fructose, but causes few symptoms in healthy volunteers.Am J Gastroenterol advance online publication, 19 November 2013; doi:10.1038/ajg.2013.386.
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Epidemiological studies suggest an inverse relationship between the intake of dietary fiber, particularly fiber from cereal grains, and colon cancer risk. Animal model assays have demonstrated that the protective effects of dietary fiber on colon cancer development depend on the nature and source of the fiber. Wheat bran (WB) appears to inhibit colon tumorigenesis more consistently than do oat bran or corn bran. This study was designed to determine whether specific WB fractions such as WB fiber, WB lipids, or phytic acid differentially affect, colon carcinogenesis in a well-established colon cancer model. In addition, the modulating effect of specific fractions of WB on the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-1 and COX-2 enzymes were assessed in colon tumors as those have been shown to play a role in tumor progression. At 5 weeks of age, groups of male F344 rats were assigned to one of six diets: a high-fat diet containing 10% WB (control diet) and experimental high-fat diets containing 10% dephytinized WB (WB-P), 10% defatted WB (WB-F), 10% dephytinized and defatted WB (WB-PF), 10% WB-PF fortified with 2% bran oil and/or with 0.4% phytate, At 7 weeks of age, all rats except those in the vehicle-treated groups were given two weekly s.c. injections of azoxymethane (AOM) at a dose rate of 15 mg/kg body weight/week. They continued to receive their respective diets until 50 weeks after carcinogen treatment and were then killed. Colon tumors were analyzed for iNOS, COX-1, and COX-2 expression and enzymatic activities. Colon tumors were evaluated histopathologically and classified as adenomas and adenocarcinomas. We found that removal of phytic acid (WB-P) or lipids (WB-F) from WB had no significant effect on colon tumor incidence (% animals with tumors) or multiplicity (tumors/animal), whereas removal of both phytate and lipids from WB (WB-PF) significantly increased colon tumor multiplicity and volume. Interestingly, WB-PF fortified with excess bran oil or with bran oil plus phytate significantly inhibited colon tumor incidence, multiplicity, and volume; but supplementation of WB-PF with phytate alone had no significant effect on colon tumorigenesis in rats suggesting that lipid fraction of WB possesses tumor-inhibitory properties. Moreover, feeding WB-PF diet significantly increased iNOS, total COX and COX-2 enzyme activities, and iNOS protein expression in colon tumors as compared with wheat bran control diet. Feeding the WB-PF that was fortified with excess bran oil alone or with bran oil plus phytate significantly suppressed the activities of MOS and COX-2 as well as the expression of iNOS and COX-2 in colon tumors compared with that in rats fed the WB diet or WB-PF diet. The study demonstrates for the first time that the lipid fraction of wheat bran has strong colon tumor inhibitor properties. The exact mechanism(s) by which the lipid fraction of WB inhibits colon carcinogenesis in addition to alteration of iNOS and COX activities remains to be elucidated. Additional studies are warranted to identify biologically active constituents of lipid fraction of WB and their relative role in colon tumor inhibition.
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Objective: To examine the relationship between glutamine supplementation and hospital length of stay, complication rates, and mortality in patients undergoing surgery and experiencing critical illness. Data sources: Computerized search of electronic databases and search of personal files, abstract proceedings, relevant journals, and review of reference lists. Study selection: We reviewed 550 titles, abstracts, and articles. Primary studies were included if they were randomized trials of critically ill or surgical patients that evaluated the effect of glutamine vs. standard care on clinical outcomes. DATA EXTRACTION We abstracted relevant data on the methodology and outcomes of primary studies in duplicate, independently. DATA SYNTHESIS There were 14 randomized trials comparing the use of glutamine supplementation in surgical and critically ill patients. When the results of these trials were aggregated, with respect to mortality, glutamine supplementation was associated with a risk ratio (RR) of 0.78 (95% confidence interval [CI], 0.58-1.04). Glutamine supplementation was also associated with a lower rate of infectious complications (RR, 0.81; 95% CI, 0.64-1.00) and a shorter hospital stay (-2.6 days; 95% CI, -4.5 to -0.7). We examined several -specified subgroups. Although there were no statistically significant subgroup differences detected, there were some important trends. With respect to mortality, the treatment benefit was observed in studies of parenteral glutamine (RR, 0.71; 95% CI, 0.51-0.99) and high-dose glutamine (RR, 0.73; 95% CI, 0.53-1.00) compared with studies of enteral glutamine (RR, 1.08; 95% CI, 0.57-2.01) and low-dose glutamine (RR, 1.02; 95% CI, 0.52-2.00). With respect to hospital length of stay, all of the treatment benefit was observed in surgical patients (-3.5 days; 95% CI, -5.3 to -1.7) compared with critically ill patients (0.9 days; 95% CI, -4.9 to 6.8). Conclusion: In surgical patients, glutamine supplementation may be associated with a reduction in infectious complication rates and shorter hospital stay without any adverse effect on mortality. In critically ill patients, glutamine supplementation may be associated with a reduction in complication and mortality rates. The greatest benefit was observed in patients receiving high-dose, parenteral glutamine.
Article
Current evidence suggests that many patients with self-reported non-coeliac gluten sensitivity (NCGS) retain gastrointestinal symptoms on a gluten-free diet (GFD) but continue to restrict gluten as they report 'feeling better'. To investigate the notion that a major effect of gluten in those with NCGS is on mental state and not necessarily on gastrointestinal symptoms. Twenty-two subjects (24-62 years, five male) with irritable bowel syndrome who had coeliac disease excluded but were symptomatically controlled on a GFD, undertook a double-blind cross-over study. Participants randomly received one of three dietary challenges for 3 days, followed by a minimum 3-day washout before crossing over to the next diet. Challenge gluten-free food was supplemented with gluten (16 g/day), whey (16 g/day) or not supplemented (placebo). End-points included mental state as assessed by the Spielberger State Trait Personality Inventory (STPI), cortisol secretion and gastrointestinal symptoms. Gluten ingestion was associated with higher overall STPI state depression scores compared to placebo [M = 2.03, 95% CI (0.55-3.51), P = 0.010] but not whey [M = 1.48, 95% CI (-0.14 to 3.10), P = 0.07]. No differences were found for other STPI state indices or for any STPI trait measures. No difference in cortisol secretion was identified between challenges. Gastrointestinal symptoms were induced similarly across all dietary challenges. Short-term exposure to gluten specifically induced current feelings of depression with no effect on other indices or on emotional disposition. Gluten-specific induction of gastrointestinal symptoms was not identified. Such findings might explain why patients with non-coeliac gluten sensitivity feel better on a gluten-free diet despite the continuation of gastrointestinal symptoms.
Article
A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) is often used to manage functional gastrointestinal symptoms in patients with irritable bowel syndrome (IBS), yet there is limited evidence of its efficacy, compared with a normal Western diet. We investigated the effects of a diet low in FODMAPs compared with an Australian diet, in a randomized, controlled, single-blind, cross-over trial of patients with IBS. In a study of 30 patients with IBS and 8 healthy individuals (controls, matched for demographics and diet), we collected dietary data from subjects for 1 habitual week. Participants were then randomly assigned to groups that received 21 days of either a diet low in FODMAPs or a typical Australian diet, followed by a washout period of at least 21 days, before crossing over to the alternate diet. Daily symptoms were rated using 0-100 mm visual analogue scale. Almost all food was provided during the interventional diet periods, with a goal of <0.5 g intake of FODMAPs per meal for the low-FODMAP diet. All stools were collected from days 17-21 and assessed for frequency, weight, water content, and King's Stool Chart (KSC) rating. Subjects with IBS had lower overall gastrointestinal symptoms scores (22.8; 95% confidence interval, 16.7-28.8 mm) while on a diet low in FODMAPs, compared with the Australian diet (44.9; 95% confidence interval, 36.6-53.1 mm; P<.001) and the subjects' habitual diet. Bloating, pain, and passage of wind were also reduced while IBS patients were on the low-FODMAP diet. Symptoms were minimal and unaltered by either diet among controls. Patients of all IBS subtypes had greater satisfaction with stool consistency while on the low-FODMAP diet, but diarrhea-predominant IBS was the only subtype with altered fecal frequency and KSC scores. In a controlled, cross-over study of patients with IBS, a diet low in FODMAPs effectively reduced functional gastrointestinal symptoms. This high-quality evidence supports its use as a first-line therapy. Clinical Trial number: ACTRN12612001185853.
Article
The avoidance of wheat- and gluten-containing products is a worldwide phenomenon. While celiac disease is a well-established entity, the evidence base for gluten as a trigger of symptoms in patients without celiac disease (so-called 'non-celiac gluten sensitivity' or NCGS) is limited. The problems lie in the complexity of wheat and the ability of its carbohydrate as well as protein components to trigger gastrointestinal symptoms, the potentially false assumption that response to a gluten-free diet equates to an effect of gluten withdrawal, and diagnostic criteria for coeliac disease. Recent randomized controlled re-challenge trials have suggested that gluten may worsen gastrointestinal symptoms, but failed to confirm patients with self-perceived NCGS have specific gluten sensitivity. Furthermore, mechanisms by which gluten triggers symptoms have yet to be identified. This review discusses the most recent scientific evidence and our current understanding of NCGS.
Article
A tryptic gliadin hydrolysate was fractionated into peptide fractions, which were assigned to either the central domain (CD) or terminal domains (TD) of gliadins. The domains were expected to contain amino acid (AA) sequences which, when released from the parent protein, inhibit the angiotensin I-converting enzyme (ACE), which plays a key role in regulating blood pressure. A proline (Pro) poor TD related fraction, containing the smallest peptides, showed the highest ACE inhibitory activity (IC50=0.33mg/ml). Additional peptidases were selected based on their in silico predicted ability to release ACE inhibitory peptides. Further hydrolysis of the tryptic hydrolysate fractions with thermolysin, Clarex, Alcalase and Esperase increased ACE inhibitory activities. Immobilised Ni2+-ion affinity chromatography (IMAC) purification of a TD related peptide fraction obtained by sequential hydrolysis with trypsin and thermolysin yielded a fraction with an IC50 value of 0.02mg/ml. This IMAC fraction was enriched in histidine and hydrophobic AA (Pro, Val, Ile, Leu and Phe).
Article
Background and aim: Current treatment for irritable bowel syndrome (IBS) is suboptimal. Fermentable oligo-, di-, mono-saccharides and polyols (FODMAPs) may trigger gastrointestinal symptoms in IBS patients. Our aim was to determine whether a low FODMAP diet improves symptoms in IBS patients. Methods: Irritable bowel syndrome patients, who had performed hydrogen/methane breath testing for fructose and lactose malabsorption and had received dietary advice regarding the low FODMAP diet, were included. The effect of low FODMAP diet was prospectively evaluated using a symptom questionnaire. Furthermore, questions about adherence and satisfaction with symptom improvement, dietary advice and diet were assessed. Results: Ninety patients with a mean follow up of 15.7 months were studied. Most symptoms including abdominal pain, bloating, flatulence and diarrhoea significantly improved (p < 0.001 for all). 75.6%, 37.8% and 13.3% of patients had fructose, lactose malabsorption or small intestinal bacterial overgrowth respectively. Fructose malabsorption was significantly associated with symptom improvement (abdominal pain odds ratio (OR) 7.09 [95% confidence interval (CI) 2.01-25.0], bloating OR 8.71 (95% CI 2.76-27.5), flatulence OR 7.64 (95% CI 2.53-23.0) and diarrhoea OR 3.39 (95% CI 1.17-9.78), p < 0.029 for all). Most patients (75.6%) were adherent to the diet, which was associated with symptom improvement (abdominal pain, bloating, flatulence and diarrhoea all significantly associated with adherence, r > 0.27, p < 0.011). Most patients (72.1%) were satisfied with their symptoms. Conclusions: The low FODMAP diet shows efficacy for IBS patients. The current strategy of breath testing and dietary advice provides a good basis to understand and adhere to the diet.