Significant numbers of people are now eating gluten-free in spite of the fact that they have no medical reason to do so. This trend is being driven by media coverage, aggressive marketing, celebrity testimonials and internet reports touting the clinical benefits of avoiding gluten. As a result, many individuals believe that gluten is harmful and that avoiding it will improve their health. Some people are actually experiencing symptoms that they attribute to eating gluten-containing foods. Many of these sufferers are self-treating and have not seen a doctor to verify their condition (1,2).
In Canada about 10% of the population now claim that they prefer to buy gluten-free food when they have the choice. In a US survey, 25% of adults recently stated that they were cutting down or avoiding gluten altogether and 31% of those not eating gluten-free were interested in trying out the lifestyle. Upwards of 50% of athletes report that they try to adhere to a gluten-free diet most of the time (3). The availability of gluten-free and wheat-free foods in Canadian restaurants increased by 137% between 2010 and 2013 (4).
The prevalence of non-celiac gluten sensitivity (NCGS) is not known to any degree of accuracy (5) however the closest estimate is that “true” NCGS can be found in about 1% of the population (6). NCGS is mostly seen in adults, particularly females of 30 to 50 years of age, but has also been reported in children (7,8).
THE DRAWBACKS OF EATING GLUTEN-FREE
The problem with the gluten-free craze is that avoiding whole grains can have serious negative effects on health. Whole grains that contain gluten such as wheat, rye, barley, kamut and triticale (a hybrid of wheat and rye) are rich in many important nutrients that are necessary for health and well-being. These include fiber, vitamins, minerals, lignans, stanols, sterols and antioxidants such as phenolic compounds. In fact higher ingestion of whole grains is linked to reduced risk of coronary heart disease, cancer, diabetes and obesity and also associated with longevity (9,10). A 2017 paper published in the British Medical Journal found that those eating the lowest amount of gluten had a higher rate of coronary heart disease than those eating the highest amount (11). The risk of colorectal cancer decreases by 17% for each 90 gm daily increase in whole grain consumption with the whole grains tested being whole wheat, oats, barley, rye, oatmeal and brown rice (12). People who eat the most gluten have a 13% lower risk of type-2 diabetes compared to those eating the least gluten (13,14). Gluten ingestion can reduce blood pressure and both triglyceride and low-density lipoprotein blood levels (15). Gluten may also boost the immune system by increasing natural killer cell activity (15). Analysis of fecal microbiota and dietary intake show that a gluten-free diet results in a decrease in numbers of beneficial gut bacteria and an increase in numbers of unhealthy ones (16).
One of the popular claims made for a gluten-free diet is that is helps in weight loss. On the contrary, there is no scientific evidence that a gluten-free diet promotes loss of weight, even in celiac disease. In fact, avoiding foods containing gluten can lead to weight gain. This is hardly surprising. Gluten-free baked goods are high in fat and total energy (17). A study presented in Europe in 2017 warned that gluten-free foods have significantly more calories, protein, saturated fatty acids and sugar than their gluten-containing counterparts (18).
Reliance on gluten-free foods can result in the double whammy of a lack of many nutrients and an increase in harmful toxins. A 2016 review of the literature on gluten-free foods found them severely lacking in key nutrients such as fiber, folate, vitamin B12, vitamin D, calcium, iron, zinc and magnesium (19). In another investigation, researchers looking at the NHANES database found that those following a gluten-free diet had significantly higher body levels of total arsenic, mercury, lead and cadmium. It was postulated that this was because of the overuse of rice and seafood in gluten-free diets. Only arsenic levels were considered to be at toxic levels but this greater burden of contamination is unnecessary and destructive to overall health (20).
TIPS ON REMAINING HEALTHY WHILE EATING GLUTEN-FREE
First of all, try not to jump into avoiding gluten because a friend, colleague or newspaper article has convinced you that it is a healthy way to live. The scientific evidence discussed above tells you that it is not. Take a step back and examine your reasons for going gluten-free. Then consider the following guidelines.
A. If you have already been diagnosed with celiac disease then you have no choice. You must avoid gluten. If you do not have confirmed celiac disease but are suffering with symptoms such as abdominal pain, bloating, diarrhea or constipation, be sure to visit your doctor to check for this possibility. It is important to rule out celiac disease as, left untreated, it can cause severe intestinal damage.
B. The time to check for celiac disease is before you go gluten-free. Celiac disease is diagnosed by a simple blood test that tests for an immune response in your body to the gluten you are eating. If you cut out wheat or gluten before you have the test done you can get a false negative on the test. Intriguingly the importance of this may lessen soon. Just recently a new test has been developed that claims it can diagnose celiac disease even in a person who has been eating gluten-free (21,22).
C. Are your symptoms actually relieved by avoiding gluten? Maybe it’s time to check. It is important to try eating a little gluten every six months or so to see how your body reacts. Some people appear to be able to tolerate gluten again after following a gluten-free diet for a few months. Try this simple challenge. For a couple of weeks eat strictly gluten free. Then check your symptoms. Do you have any? How bad are they? Next, eat a small amount of any gluten-containing food that you like. An example might be one-quarter of a slice of whole wheat bread. Do you notice any increase in your symptoms? If not, try eating a slowly increasing amount of gluten-containing food every day for a few days. Listen to your body. Perhaps there is no need for you to avoid gluten anymore. Note that if you decide to add gluten back into your diet be sure to increase it very gradually (23,24).
D. Other foods can cause gluten-sensitivity-like symptoms. To distinguish if you are reacting to foods other than gluten you might want to try a low FODMAP diet. As explained in the last blog, FODMAPs are foods that are poorly absorbed in the small intestine and so they end up in the large intestine where they are fermented by bacteria. In some people this can cause gas, bloating, abdominal discomfort and pain. If you are considering a low FODMAP trial diet, consult your physician for a referral to a dietician knowledgeable about food intolerances and the FODMAP diet. The procedure usually involves reducing FODMAPs for a period of two to six weeks to give your gastrointestinal tract a respite from undigested food components and time for any discomfort to subside. This is followed by re-introducing foods one at a time to determine which specific ones are problematic for you. (25,26).
E. If you decide that a gluten-free diet is right for you it is very important to pay attention to nutrition (27). Many gluten-free products lack fiber so be sure to include fiber-rich whole grains such as brown rice, quinoa, buckwheat, sorghum, millet and teff in your daily diet. Remember that products made with white rice flour lack considerably in healthy nutrients. Legumes such as beans, lentils and chickpeas are also high in fiber and are gluten-free. All these fiber-rich foods are also great sources of vitamins, minerals, antioxidants and protein.
Avoid processed foods since gluten can easily hide within them. For example, soups are often thickened with a wheat product.
Check labels on any processed gluten-free products for high fat and sugar content and choose those high in fiber but low in energy.
Canada and the USA have regulations for the fortification of white flour with nutrients such as thiamin, riboflavin, niacin, folic acid and iron. There are no such corresponding regulations for enriching gluten-free products. Be sure to check labels on your gluten-free foods for these nutrients. If they are not included make sure you are eating an alternate source.
Women of childbearing age who are eating gluten-free should take a folic acid supplement (28).
Your best bet is to consult with a dietician to be sure that you are getting all the nutrition you need for a happy, healthy life.
1 – Aziz, I., Lewis, N. R., Hadjivassiliou, M., Winfield, S. N., Rugg, N., Kelsall, A., et al. A UK study assessing the population prevalence of self-reported gluten sensitivity and referral characteristics to secondary care. Eur. J. Gastroenterol. Hepatol. 2014; 26: 33–39.
2 – Niland, B., Cash, B.D. Health Benefits and Adverse Effects of a Gluten-Free Diet in Non–Celiac Disease Patients. – Volume 14, Issue 2 Gastroenterology & Hepatology Feb 2018; 14(2):
3 – Lis, D.M., Stellingwerff, T., Shing, C.M., Ahuja, K.D., Fell, J.W. Exploring the popularity, experiences, and beliefs surrounding gluten-free diets in nonceliac athletes. Int J Sport Nutr Exerc Metab. 2015; 25(1):37-45.
4 – Agriculture and Agri-Food Canada 2013; http://www.agr.gc.ca/eng/industry-markets-and-trade/canadian-agri-food-sector-intelligence/processed-food-and-beverages/trends-and-market-opportunities-for-the-food-processing-sector/gluten-free-claims-in-the-marketplace/?id=1397673574797
5 – Catassi, C. Gluten Sensitivity. Ann Nutr Metab. 2015; 67 Suppl 2():16-26.
6 – Volta, U., Bardella, M.T., Calabrò, A., Troncone, R., Corazza, G.R. An Italian prospective multicenter survey on patients suspected of having non-celiac gluten sensitivity. BMC Med. 2014 May 23;12:85.
7 – Francavilla, R, Cristofori, F., Castellaneta, S., Polloni, C., Albano, V., Dellatte, S., Indrio, F., Cavallo, L., Catassi, C. Clinical, serologic, and histologic features of gluten sensitivity in children. J Pediatr 2014; 164:463-467.
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10 – Zong, G., Gao, A., Hu, F.B., Sun, Q. Whole Grain Intake and Mortality From All Causes, Cardiovascular Disease, and Cancer; A Meta-Analysis of Prospective Cohort Studies. Circulation Jun 14, 2016; 133(24): 2370-2380.
11 – Lebwohl, B., Cao, Y., Zong, G., et al. Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study. BMJ. 2017; 357:j1892.
12 – Vieira, A.R., Abar, L., Chan, D.S.M., Vingeliene, S., Polemiti, E., Stevens, C., Greenwood, D., Norat, T. Foods and beverages and colorectal cancer risk: a systematic review and meta-analysis of cohort studies, an update of the evidence of the WCRF-AICR Continuous Update Project . Annals of Oncology August 2017; 28(8): 1788–1802.
13 – American Heart Association. Low gluten diets linked to higher risk of type 2 diabetes. ScienceDaily. ScienceDaily, 9 March 2017. www.sciencedaily.com/releases/2017/03/170309120626.htm
14 – Zong, G., Lebwohl, B., Hu, F.B., et al. Gluten intake and risk of type 2 diabetes in three large prospective cohort studies of US men and women. Diabetologia. 2018; 61:2164-2173.
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16 – Sanz, Y. Effects of a gluten-free diet on gut microbiota and immune function in healthy adult humans. Gut Microbes 2010 May-Jun; 1(3): 135–137.
17 – Niewinski, M.M. Advances in celiac disease and gluten-free diet. J Am Diet Assoc. 2008; 108(4):661-672.
18 – https://www.eurekalert.org/pub_releases/2017-05/sh-cmb050417.php
19 – Vici, G., Belli, L., Biondi, M, Polzonetti, V. Gluten free diet and nutrient deficiencies: A review. Clin Nutr. 2016;35:1236-1241.
20 – Raehsler, S.L., Choung, R.S., Marietta, E.V., Murray, J.A. Accumulation of heavy metals in people on a gluten-free diet. Clin Gastroenterol Hepatol. 2018 Feb; 16(2): 244-251.
21 – Catassi, C., Alaedini, A., Bojarski, C., Bonaz, B., Bouma, G., Carroccio, A., Castillejo, G., De Magistris, L., Dieterich, W., Di Liberto, D., Elli, L., 0Fasano, A. et al. The Overlapping Area of Non-Celiac Gluten Sensitivity (NCGS) and Wheat-Sensitive Irritable Bowel Syndrome (IBS): An Update. Nutrients. 2017 Nov; 9(11): 1268.
22 – Sarna, V.K., Lundin, K.E.A., Mørkrid, L., Qiao, S.-W., Sollid, L.M., Christophersen, A.
HLA-DQ–Gluten Tetramer Blood Test Accurately Identifies Patients With and Without Celiac Disease in Absence of Gluten Consumption. Gastroenterology 2018; 154:886–896.
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24 – Catassi, C., Bai, J.C., Bonaz, B., et al. Non-celiac gluten sensitivity: the new frontier of
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26 – Gibson, P.R., Shepherd, S.J. Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. J Gastroenterol Hepatol. 2010 Feb;25(2):252-258.
27 – Fry, L., Madden, A.M., Fallaize, R. An investigation into the nutritional composition and cost of gluten‐free versus regular food products in the UK. Journal of Human Nutrition and Dietetics Feb 2018; 31(1): 108-120.
28 – https://celiac.org/live-gluten-free/glutenfreediet/food-options/