Gluten Free Diet and Celiac Disease
Less than 1% of Americans suffer from celiac disease, and they must consume a Gluten Free Diet (GFD) to avoid the health effects and risks associated with their condition.
There is another group, those with "wheat allergy": people suffering from Nonceliac Gluten Sensitivity or NCGS. This is a relatively new and controversial disorder with prevalence rates that range from 0.5 to 13% of the population and which may or may not respond to a GFD.
These are the only groups that should follow a compulsory gluten free diet.
What is Gluten anyway?
Gluten is a family of proteins known as prolamins which are found in several cereal grains such as wheat, barley and rye.
These proteins are elastic and viscous which helps the dough made with them retain the gas generated by yeast, which makes it very suitable for the preparation of leavened bakery products. Gluten also makes these products palatable.
The digestion of gluten
Prolamins (such as glutenin and gliadin) are not broken down by the acid produced by the human stomach. So they move on, untouched into the small intestine.
Gluten proteins have long molecular chains which make them difficult to digest, but in the small intestine enzymes break them down into shorter peptide chains, which are more easily digestible chunks.
But these "chunks" can provoke immune responses in susceptible individuals, provoking a celiac disease.
Gluten and Coeliac Disease
There can be as many as 45 different types of gliadins in a single wheat variety, which in turn exhibit different biological properties.
As the cells that line the small intestine (the "villi") absorb the broken-down segments of prolamins, they come into contact with "strings" of molecules such as a gliadin residue known as α2-gliadin 57-89, which is a strong stimulator of antibodies called T lymphocites.
These antibodies detect "foreign" invaders known as "antigens" (that is, cells that are not our own) and destroy them: toxins, bacteria, viruses, cancer cells, etc. They identify these antigens by the moleculer shape of their outer surfaces, and latch on to them.
But in the case of gluten, the T lymphocites mistakenly recognize the gluten residues as antigens and unleash an immune response against it.
And this action causes inflamation and the death of the cells containing the gliadin residues, resulting in damage to the intestinal lining that absorbed the digested gluten proteins.
Now, every time the T cells find gluten residues they will provoke an autoimmune reaction.
Health Risks in Celiac Disease
The damaged intestinal cells can't absorb nutrients and this "malabsorption" leads to deficiency in vitamins and minerals provoking anemia (lack of iron) and osteoporosis (brittle bones due to lack of calcium).
Chronic inflammation is somehow linked to an increase of certain types of cancer in people suffering from celiac disease (such as lymphoma). ( 1 )
So those who suffer from CD must eat a GFD for the rest of their lives.
What is the cause of Celiac Disease?
Three factors have to come together to cause CD: gluten, an innate immune system mutation and a trigger:
Cereal consumption is relatively new among humans (it emerged during the last 12,000 years) so it is possible that human intestinal tracts have not yet fully evolved to cope with these grain proteins.
To make matters worse, genetic modification of cereal varieties over the past few decades (van den Broeck et al., 2010) ( 2 ) may have increased the content of immune-activating gluten in our food.
Scientists believe that the different sequences of amino acid chains present in the gluten protein residues are very similar to those of harmful antigens and it is this that provokes an autoimmune responses in susceptible individuals.
Some people are more predisposed to an immune overreaction due to the type of HLA they have inherited from their parents.
The Human leukocyte antigen (HLA) is a key molecule in the immune response and protects us against disease. There are many different types and variants of HLAs in the human population and certain mutations in HLA can provoke autoimmune responses, such as the HLA DQ2 (which have also been found in some sequences of gliadin) and HLA DQ8. ( 1 )( 4 )
3. Environmental Factors
However, having HLA DQ2 ⁄ DQ8 does not necessarily mean that the person will suffer from CD. There are other factors which trigger the disease. It is believed that virus (adenovirus, rotavirus) or even alterations in the gut microbiome may be the trigger that causes the disease.( 5 )
The point is that once T cells learn to identify gluten as an antigen, they never forget. So gluten has to be avoided at all costs, because even small quantities or trace amounts can trigger the immune response.
The Food and Drug Adminstration (FDA) sets a limit of less than 20 ppm (parts per million) as a criteria for labeling a product as "Gluten Free". This is the lowest level that can be detected in foods using scientific tests. ( 6 )
Nonceliac Gluten Sensitivity
This condition, known as NCGS covers a broad range of symptoms such as bloating, flatulence, fatigue, depression, irritability, abdominal pain, altered bowel habits, etc. Which responds to a GFD. (3)
The causes are unknown.
Potential Harmful effects of a Gluten-Free Diet
The key to avoiding harmful effects when adopting a GFD is to eat a Balanced Diet with the adequate intake of nutrients.
Some studies (3) have found that processed gluten-free foods when compared to food containing gluten are not fortified or enriched with certain vitamins and minerals.
Furthermore to make up for their lack of palatabilty some processd gluten-free foods are formulated with extra fat, salt or sugar, which doesn't make them a healthy option and may increase the risk of heart disease.
People avoiding gluten tend to eat less whole grains which reduces their intake of fiber and also impacts on cholesterol levels (fiber helps control blood lipids).
A Healthy Gluten Free Diet
But, processed foods shouldn't be so important in a balanced diet, there are plenty of healthy nutrient rich alternatives for those following a GFD:
- Fruits, vegetables, pulses: full of vitamins, minerals and fiber, and gluten free.
- Potatoes, squash, rice, chickpeas, beans, quinoa, amaranth, lentils are great alternatives to a dish of processed pasta.
- Dairy products (fortified with calcium and vitamins) such as cheeses, yougurt, kefir, milk are all gluten free (check the labels though).
- Oats are good source of fiber and only 10% of people suffering from CD are susceptible to its protein -so buy it when it is marked as Gluten free, meaning it is processd in gluten free mills and therefore free of cross-contamination.
- Oils (olive, canola, sunflower, coconut) are also GF.
- Fish, beef, pork, chicken, clams, turkey, mussles. Don't contain gluten
The key is to eat a balanced diet and eat the recommended daily allowance of minerals and vitamins, keep an eye on salt, fat and added sugars, top up on fiber and your daily portions of veggies and fruit.
Caveats of a GFD
A Gluten-Free Diet is costly
Gluten-free food costs more than regular gluten-containing food: one study (3) found that "On average, gluten-free products were 242% more expensive than regular products".
It also has a Social and Psychological toll
Adhering strictly to a gluten free diet (which is the case of patients with celiac disease) is not easy: they have to focus on what they eat, make sure it is gluten free and that it does not get cross-contaminated while it is being stored, prepared or served.
Frustration and negative emotions can lead to social reclusion, opting to stay at home instead of eating out.
Simple things such as eating out or taking a flight (in-flight GFM is an absolute necessity), become complicated and require planning.
GF meals compliance costs more money, requires more time and energy: menus have to be carefully read, and the waiter informed too. Reading food labels to find hidden gluten is a must.
And even so, accidents happen and gluten is ingested with its negative consequences. So the fun aspects of food and the social interaction around eating becomes a burden. Fast food or take out can also be a problem: regular pizza, burger buns, even the soy sauce in Chinese food contain wheat
Is a Gluten Free Diet good for you?
There are some potential Benefits in a GFD in Non-Celiac Disease subjects. A recent Danish study ( 7 ) involving Non-Celiac people, divided them into two groups eating the same amount of calories, one on a low gluten diet (2 g per day) the other on a high gluten diet (18 g daily). The study found the following changes among the Low Gluten Diet group:
- Weight loss (not much, 0.8 kg -almost 2 lbs. over an 8-week period.
- Higher blood levels of appetite reducing gut hormone peptide YY (PYY).
- A subtle immune effect, expressed as a reduced activation of inflammasome response (meaning a lower propensity to becoming inflammed).
- Less bloating.
They also found that some gut bacteria were more abundant, while others decreased, depending on the amount of gluten eaten. Among low-gluten dieters the Bifidobacterium were less common, which coincides with studies that show that people living in traditional pre-industrial lifestyles have low or absent levels of bifidobacteria compared to people living in developed countries that eat plenty of wheat and flour-based foods.
Since Bifidobacterium as probiotics have health benefits, a change in the substrate, adding more polyphenol-rich foods such as flax seeds, chestnuts, blueberries, beans, spinach, berries to the diet ( 8 ) may enhance their growth in the absence of wheat fiber.
Remember that eating a wide variety of healthy foods will promote good health and protect you against chronic disease.
A well balanced diet means eating different foods from each of the five food groups in the recommended proportions.
Avoid trans fats, saturated fats, excess sugar and salty processed foods. Eat a variety of foods from each group.
The USDA's MyPlate initiative (2) does not mention water intake, salt restriction or increased physical activity as other factors to take into account in improving health. But they too should be taken into account for a balanced and healthy lifestyle.
Cite this article:
A. Whittall. ©2018. Gluten Free Diet, risks and benefits. Patagonia Wellness, 18 Dec. 2018. http://www.patagoniawellness.com/diet-food/gluten-free-diet-pros-cons.html
Subject: Gluten Free Diet pros and cons: a GFD can entail the risk of not eating enough fiber and vitamins and eating too much sugar, salt and fats. A balanced GFD can help you lose some weight but it is costly and not so simple to follow.
References and Further Reading
(1) NHS. Complications - Coeliac disease NHS. Accessed Dec. 18, 2018.
(2) H.C. van den Broeck, et al. (2010).Presence of celiac disease epitome in modern and old hexaploid wheat varieties:wheat breeding may have contributed to increased prevalence of celiac disease. Theor. Appl. Gen., 121 (2010), pp. 1527-1539, 10.1007/s00122-010-1408-4
(3) Niland B, Cash BD, (2018). Health Benefits and Adverse Effects of a Gluten-Free Diet in Non-Celiac Disease Patients. Gastroenterol Hepatol (N Y). 2018;14(2):82-91
(4) Cecilio LA, Bonatto MW, (2015). The prevalence of HLA DQ2 and DQ8 in patients with celiac disease, in family and in general population. Arq Bras Cir Dig. 2015;28(3):183-5
(5) Sollid LM, Jabri B., (2013). Triggers and drivers of autoimmunity: lessons from coeliac disease. Nat Rev Immunol. 2013;13(4):294-302
(6) FDA, "Gluten-Free" Means What It Says. Accessed Dec. 18, 2018.
(7) Lea B. S. Hansen et al. (2018). A low-gluten diet induces changes in the intestinal microbiome of healthy Danish adults. Nature Communications, vol 9, Article number: 4630 (2018)
(8) Boto-Ordoñez M, Urpi-Sarda M, Queipo-Ortuño MI, Tulipani S, Tinahones FJ, Andres-Lacueva C. (2014). High levels of Bifidobacteria are associated with increased levels of anthocyanin microbial metabolites: a randomized clinical trial. Food Funct. 2014 Aug;5(8):1932-8. doi: 10.1039/c4fo00029c.