I find it very commendable when the general public gets
interested in their diet and actively seeks our information about which foods
are good for their body and which are not. The problem is, not all information
they find is correct and substantiated with science. Food science and
nutritional science are legitimate disciplines – scientists carefully design
experiments to find out what effect various foods and substances have on human
health, and they are also quick to follow trends in consumer preferences with
new research. With the rapid growth in gluten-free diet popularity among normal
population (that is, people who do not objectively suffer from coeliac disease
or wheat allergy), there has been research effort to find out whether it is
just a fashion or if not consuming gluten can really have beneficial effect on
our health. In this article, I would like to give you an overview of their
findings. If you think there are some
gluten-related hypothesis I failed to include, mention them in comments and I
will look into them when I have time. I’m also very much open to opposing views,
provided it is substantiated with real science. And lastly, feel free to re-post and translate.
What is Gluten?
Gluten is a summarizing name for a group of proteins present
in wheat, barley and rye. Because of the abundance of certain nitrogen-rich
amino acids in these proteins, they serve as a source of nitrogen and carbon
for the germinating seed. In terms of production of bakery goods, gluten
proteins are responsible for the dough-forming properties of wheat-based flour,
as they form an elastic cross-linked matrix when water is added and simply
said, they help to keep the dough together and elastic1. This also explains why
gluten-free products tend to have a more crumbly structure, as they lack
proteins that would give it cohesiveness and elasticity.
3 Types of Gluten-Related Disorders
Celiac Disease (CL)
Celiac disease is an immune system-mediated disease affecting
approximately 1% of population worldwide, though it is speculated that the occurrence
is slightly increasing, with discussion about whether this increase means
simply more reported cases or a real increase of the disease. It is triggered
by specific gluten proteins which cause an immune response resulting in inflammation
in the small intestine. The disease is pretty well understood and individuals
suspecting they may have this disease can be tested to confirm or rule out such
diagnosis2.
Wheat Allergy (WA)
A not very well understood disorder, wheat allergy is for
the time being classified as food allergy, with similar symptoms to other food
allergies. The molecular mechanism is not yet well explained, but might be
related to specific structural characteristics of gluten proteins2.
Non-Celiac Gluten Sensitivity (NCGS)
NCGS is a disorder manifested through various physiological
and psychological symptoms in people who do not have CL or WA, and whose
symptoms are alleviated when gluten is excluded from their diet2, 3.
Despite the name, new research shows that NCGS sufferers also negatively
respond to other components of wheat, such as other proteins, fermentable
saccharides and polyols. NCGS manifests with symptoms related to both the gastrointestinal
tract and other parts of the body (muscle/joint pain, fatigue, rash,
anxiety/depression, headache…). NCGS is believed to be more common than CD, but
the prevalence is not well defined yet and the mechanisms by which it is caused
are not well known either. One study found prevalence of 0.55%4. Other sources estimate the
prevalence in the US to range between 1 and 6% of the population5, though some estimates went
as high as up to 15%. To add more confusion, some authors argue whether NCGS
existence is even substantiated2.
There has been research trying to understand more about this
disorder and gluten. One study suggested there might be a link between “depression”,
or rather pessimistic mood and gluten ingestion, but the researchers admitted
themselves that the study had many limitations3. Another study showed that self-reported
NCGS people did not respond to gluten in diet in a particular way once all
other potential sources of response were eliminated2, which may however also mean
that it is other components of wheat that are responsible for the disorder,
such as the above mentioned saccharides, polyols or other proteins.
Self-diagnosis
Basically, both CD and AW are quite easily detectable by
doctors. However, NCGS, as it is yet to be well-defined and understood, is
often a subject of self-diagnosis.
One qualitative study compiled several points which seem to
be common for many people who have never been formally diagnosed with CD or WA.
(The study was conducted in America, and is therefore linked with the “typical
American diet” and USA healthcare system.) These are:
- Distrust in doctors because the diagnosis and medication failed to alleviate their symptoms, and belief that doctors are only interested in treatment related to using commercially interesting drugs;
- Belief that going gluten-free rid them of issues such as being overweight, tired, slow, depressed and generally unwell, having stomach pain and generally feeling better than when they ate gluten;
- Preference for alternative, non-science-based therapies;
- Tendency (in about 1/3 of participants) to diagnose others with gluten disorders not based on any scientific evidence (mostly with the self-perception of wanting to help others)6. However, are they right? Above, I showed that NCGS prevalence is estimated to be at most 15%2, yet some of gluten-free advocates claim that while approximately 1 in 130 people has celiac disease, 120 in 130 should avoid gluten6 – apparently just because.
Gluten-free Is Also a Good Business
While it may seem that companies producing gluten-based
products are the bad guys that should be lumped together with things like
potato crisps and instant soups; and gluten-free are the good saviors concerned
with people’s health, this is quite a naïve thinking. Gluten is nowadays a very
emotive subject, with more people feeling anti-gluten than pro-gluten (or
gluten-indifferent). Also, as gluten-free market is estimated to be around
15 – 20% of the population, celiacs constitute a minor part of it2. Even if NCGS constituted 15%
(which is not the most realistic estimate), there are still 5% that have no
medical reason to avoid gluten. From a new food product developer’s point of
view, supporting the gluten paranoia while designing one gluten-free product
after another is a great way to make more money and take market share from
gluten-containing products. A large amount of my FIPDes classmates designed
gluten-free products for the New Food Product Development Class, too. Celiacs
are a small part of the society – while the offer of gluten-free is still much
smaller than the gluten-containing one and therefore there are many
opportunities for new product introduction, the size of the market has
limitations. Therefore, persuading even gluten-tolerant people to go glu-free
is a pretty good (and currently easy) business. So yes, people and companies
have a good reason to go against gluten, and that reason is sometimes/often
money, not concern for your health.
Gluten and Type 1 Diabetes
There are links between Type 1 Diabetes and Gluten, however
the relationship is not as simple as some articles make it seem. First of all,
it has been shown that celiac patients consuming gluten have higher incidence
of T1 diabetes than those who were diagnosed early and had gluten-free diet for
longer7.
One study showed that gluten in mice feed led to the mice
developing diabetes more often than gluten-free fed mice, from the description
I assume that these mice were otherwise normal mice (not celiac). The mechanism
suggested was change in gut microflora. However, the study clearly states that
more experiments are needed to confirm the hypothesis7.
My concern with the study would be that the amount of gluten in the diet of
some mice was not mentioned and there was no information as to whether the
amount of gluten in the diet was within normal amounts. Moreover, another study
with comparable mice found that both gluten-free AND gluten-enriched diet leads
to diabetes prevention8. Yet other experiments also
showed that the amount of gluten in the diet and also the time when it is
introduced plays a role in diabetes development in mice9. Also, the effect of diet in
humans on diabetes is more complicated. It was shown that OVER-consumption
(hence my concern with amount of gluten in the mice diet) of gluten and other
foods and reduced intake of fruit and vegetables can lead to detrimental effect
on microbiota and development of diabetes9, 10.
Viruses and other pathogens, as well as genetic predispositions also most
likely play a role in diabetes development9. As you can see, the research
about gluten’s role in diabetes in non-celiac individuals is very inconclusive
and needs much more research before final verdict can be made.
Gluten and Obesity
No relationship was found between whole-wheat diet and
obesity11.
How About the Good Things You Might be Missing Out by Going
Glu-free?
No gluten means no wheat, and wheat can be pretty good. Research
suggests that not all whole-grain is the same – it seems that components of
wheat bran and wheat whole grains can prevent colon cancer better than
non-wheat grains such as oats12.
So What Should You Do If You Do Not Suffer from Gluten (or
Wheat) Related Disorder, or You’re Not Sure Yet?
Gluten-free foods do not have better nutritional properties
and are not healthier than their gluten counterparts, unless other aspects have
been changed as well. Some of the improvement in people who went for
gluten-free diet have been attributed to factors that are actually not related
to gluten. For example, gluten-free diet often requires lowering of bakery goods
in the diet in general (since gluten-free is expensive and still harder to find
than gluten-containing products) and increase in fruits and vegetables. It is
also linked to eating less processed food and fast food and to caring more
about diet and health in general. And finally, there is also the possibility of
placebo effect occurring, especially with hard to diagnose psychological
symptoms.
A good recommendation for everybody who does not have CD or AW would
be to first adhere to strictly healthy diet (varied, plenty of fruit and
vegetables, reasonable amount of lean meat, fatty sea fish and other marine
organisms, getting enough vitamins and minerals, not overeating
carbohydrate-rich food, preferring wholegrain products, cutting down on sweets,
savory snacks, fast food and overly sugary/salty processed foods…). Only if
this diet does not lead to improvement of symptoms, try gluten-free diet and
see if it makes a real difference5.
And in any case:
1) Do not blindly believe information you find on the net if
it does not provide real evidence. Real evidence are well-designed studies
conducted by scientists and doctors which critically evaluate their results and
which are published in peer-reviewed journals. Real evidence is not your
neighbor’s or favorite blogger's personal experience or random articles on
websites.
2) Do not act as a doctor and persuade people to go
gluten-free without evidence that it will help them (and no, just because it
helped you does not mean it will help everybody even if their symptoms are
similar – same symptoms can still have different causes).
Since repetition is the mother of wisdom, as we say in
Bohemia, here are the 7 take-home points of this article:
- There quite probably is a gluten, or more likely, wheat-related disorder (Non-Celiac Gluten Sensitivity) which is neither celiac disease nor wheat allergy, it has a wide range of symptoms and it was proven (well OK, there is still some doubt) that there are physiological changes in response to presence or absence of gluten.
- This newly described disorder is more prevalent than celiac disease, but most likely with prevalence somewhere between 0.55% and 6%, at the very most 15%. This means that at most 3 in 20 people have it.
- People who do not have any of the 3 described diseases will not have any benefit at all from omitting gluten from their diet, unless they make other dietary and lifestyle changes as well and unless they are subject to a placebo effect.
- Gluten is NOT related to obesity and type 1 diabetes, based on currently available evidence.
- Wheat whole grain constituents may protect against colon cancer better than other grains.
- Gluten free is a pretty good business for food companies too.
- If you’re not a gluten related disorder sufferer, then as with everything, moderation may be a good way to think about gluten. Eat wholegrain bakery goods, consumer different grains (yes, including wheat) and eat a healthy and balanced diet.
Yours truly
Vita
References
1. Coultate TP, Tom PC. Food: the chemistry of its components:
Royal Society of Chemistry Cambridge,, UK; 2002.
2. Biesiekierski
JR, Muir JG, Gibson PR. Is Gluten a Cause of Gastrointestinal Symptoms in
People Without Celiac Disease? Current
Allergy and Asthma Reports. Dec 2013;13(6):631-638.
3. Peters
SL, Biesiekierski JR, Yelland GW, Muir JG, Gibson PR. Randomised clinical
trial: gluten may cause depression in subjects with non-coeliac gluten
sensitivity - an exploratory clinical study. Alimentary Pharmacology & Therapeutics. May
2014;39(10):1104-1112.
4. Caio
G, Volta U, Tovoli F, De Giorgio R. Effect of gluten free diet on immune
response to gliadin in patients with non-celiac gluten sensitivity. Bmc Gastroenterology. Feb 2014;14:7.
5. McCarter
DF. Non-Celiac Gluten Sensitivity: Important Diagnosis or Dietary Fad? American Family Physician. Jan
2014;89(2):82-+.
6. Moore
LR. "But we're not hypochondriacs": The changing shape of gluten-free
dieting and the contested illness experience. Social Science & Medicine. Mar 2014;105:76-83.
7. Marietta
EV, Gomez AM, Yeoman C, et al. Low Incidence of Spontaneous Type 1 Diabetes in
NonObese Diabetic Mice Raised on Gluten-Free Diets Is Associated with Changes
in the Intestinal Microbiome. Plos One. Nov
2013;8(11):9.
8. Funda
DP, Kaas A, Tlaskalová‐Hogenová H, Buschard K. Gluten‐free but also
gluten‐enriched (gluten+) diet prevent diabetes in NOD mice; the gluten enigma
in type 1 diabetes. Diabetes/metabolism
research and reviews. 2008;24(1):59-63.
9. Barbeau
WE. What is the key environmental trigger in type 1 diabetes - Is it viruses,
or wheat gluten, or both? Autoimmunity
Reviews. Dec 2012;12(2):295-299.
10. Bengmark
S. Gut microbiota, immune development and function. Pharmacological Research. Mar 2013;69(1):87-113.
11. Brouns
F, van Buul VJ, Shewry PR. Does wheat make us fat and sick? Journal of Cereal Science. Sep
2013;58(2):209-215.
12. Zoran
DL, Turner ND, Taddeo SS, Chapkin RS, Lupton JR. Wheat bran diet reduces tumor
incidence in a rat model of colon cancer independent of effects on distal
luminal butyrate concentrations. The
Journal of nutrition. 1997;127(11):2217-2225.
I feel like these 'something-free' trends pop up every now and then, with it being a different thing each time. Lately it is gluten free, a while back it seemed fat-free was all the rage. I really don't understand it haha...there is too much false information going around about what is good and bad, and then you hear about food that was previously good being bad! My boyfriend's dad has had minor health troubles for the past few years and he would rather decide he is wheat intolerant, or lactose intolerant (it changes weekly) rather than go to the doctor and find out what it really is! Similarly my friend has decided to stop eating bread for reasons unknown, yet will happily eat potatoes and pasta. It could be for the wheat in bread but I hope it's not because he is trying to cut down on carbs XD
ReplyDeleteHaha I coud sign what you just wrote. It's totally true that the diet fads change all the time!
Deletevery interesting article. i personally don't go all out and eat gluten-free food since i am not gluten intolerant. i consume naturally gluten-free food like quinoa & chia seeds. however, i do avoid chinese vegetarian gluten-loaded mock meats as i find them meaningless and unhealthy.
ReplyDeletexoxo
mochaccinoland.blogspot.com
Oh, is quinoa popular in HK? I should eat it more, but it doesn't seem to be that widely available in many places.
DeleteOh very interesting post, a lot of information and I love it because many people believes that Free Gluten is more healthy.
ReplyDeletexx
www.sakuranko.com
Thank you!
Delete