Going Gluten Free: What the Science Says

Going Gluten Free: What the Science Says
Going Gluten Free: What the Science Says

Gluten: throw this word into conversation and everyone from your colleague to your favourite great aunt will tell you that they have at some point tried the trendy gluten free diet.

Whilst the majority of people do so as a personal preference, the truth is that only a small percentage of people really need to be gluten free.

What is Gluten?

Gluten is one of many wheat proteins1 (others include albumin, globulin, and gliadin) found in grains like wheat, barley, and rye.

Being gluten free means excluding these foods from your diet, which can be a challenge as wheat is in many foods.

These include bread (including chapattis, rotis, and naan), breakfast cereals, pasta, couscous, pizza, wraps, and baked goods like biscuits, crackers, crumpets, scones, pancakes, wafers, cakes, and pastries.

If you read food labels, you will see that wheat is also hidden in many other foods like ready-made soups, sauces, and condiments (e.g. soy sauce, salad dressings, tomato sauce), spices blends, some processed meats (e.g. viennas and boerewors), and frozen meals.

Oats are naturally gluten free, but may be contaminated with gluten during processing, and there is even gluten in beer.

What is Gluten Intolerance?

Gluten intolerance is an umbrella term for three major types of gluten-related disorders1: wheat allergy, celiac disease, and non-celiac gluten sensitivity (NCGS).

These disorders have similar symptoms (like bloating, vomiting and diarrhoea) but are quite different.

Wheat Allergy: Wheat allergy2 occurs when wheat is eaten, touched, or even inhaled, and the immune system detects the wheat protein as a danger to the body.

To diagnosis a wheat allergy, a blood test and/or skin prick tests can be done to show the presence of the IgE antibodies, coupled with a detailed dietary analysis.

A wheat allergy will occur within a few hours and causes no permanent gut or other organ damage.

Most allergic reactions to wheat are mild, causing hives (urticaria), swelling, or vomiting.

Interestingly for some, reactions to wheat can be worse with exercise or occur only with exercise.

Interestingly, a wheat allergy is much less common than allergies to milk, egg, and peanuts.

While wheat allergies are self-reported in about 4.5% of people, true wheat allergies have been confirmed in less than 1%.3

A local study published in the Journal of Allergy and Clinical Immunology4 reported that 0.1% of participants self-reported a previous reaction to wheat.

People with wheat allergy can have reactions to other cereals like rye, oats, and barley as there is often a cross-reactivity between the allergens.

This is why both a wheat free and a gluten free diet is needed.

Celiac Disease: Celiac disease is very different as it is not an allergy but an autoimmune disease, estimated to affect a mere 1 % of the world’s population.1

If you have this disease, eating even tiny amounts of gluten can trigger the immune response into overdrive, and over time, this reaction damages the lining of the gut.

This intestinal damage affects the absorption of nutrients and can lead to serious complications like diarrhoea, fatigue, excess weight loss, bloating, and nutritional deficiencies like iron (leading to anaemia) and calcium (leading to osteoporosis).

Though the exact cause is not known, there is a lot of research to show that genetics play a big role.

HLA5 is the key gene identified which may predispose a person to celiac disease.

There are two variants of this gene, DQ2 and DQ8, and a person may have either variant or both.

About 30 – 40% of people have these variants, though most do not develop celiac disease.

If these genes variants are not present, then coeliac disease can virtually be excluded.

Non-Celiac Gluten Sensitivity: One more gluten-related disorder has recently been proposed – non-celiac gluten sensitivity (NCGS).1,5 People are diagnosed with NCGS when they neither have celiac disease nor a wheat allergy but still show symptoms when eating wheat.

Symptoms improve or disappear when gluten is removed and reappear after a gluten challenge, usually within hours or days.

The HLA gene variants is found in 50 % of those with NCGS.6

So, Should I go Gluten Free?

Unless you’ve been formally diagnosed with one of these disorders, there is actually no need to be gluten free.

In fact, if you do, you could be doing more harm than good.

A gluten free diet tends to be too low in fibre, important for good gut health.

A gluten free diet may lead to deficiencies in vitamin C, vitamin B12, vitamin D, and folic acid.7

Studies have also shown that gluten free diets tend to contain high amounts of sugar and hydrogenated fats,8 which could lead to high insulin levels and an increased risk for weight gain.

Gluten free products are also notoriously more expensive. Gluten free pasta in Italy is double the cost of normal (wheat-based) pasta9 and gluten free bread in the UK is 360 % more expensive.10

If you choose to be gluten free, aim for naturally gluten-free foods that are much more cost effective and also contain some fibre.

These include starches like potato, baby potato, sweet potato, brown rice, quinoa, and corn/ maize.

All fruit and vegetables as well as legumes like beans, chickpeas and lentils are also naturally gluten free but fortunately contain great nutrients and fibre.

Remember to read food labels to be sure you’re not replacing gluten with sugar and fat, and if you are eating a gluten-free food like bread, choose an option with at least 3 – 6 g of fibre per 100g.


  1. Balakireva AV, Zamyatnin AA. Properties of Gluten Intolerance: Gluten Structure, Evolution, Pathogenicity and Detoxification Capabilities. Nutrients. 2016;8(10:644. Doi: 10.3390/nu8100644.
  2. Cianferoni A. Wheat allergy: diagnosis and management. Journal of Asthma and Allergies. 2016;9:13-25.
  3. Gray CL, Goddard E, Karabus S, Kriel M, Lang AC, Manjara AI, et al. for the South African Food Allergy Working Group (SAFAWG). Epidemiology of IgE-mediated food allergy. South African Medical Journal. 2015;105. http://dx.doi.org/10.7196/SAMJ.9103.
  4. Botha M, Basera W, Facey-Thomas HE, Gaunt B, Gray CL et al. Rural and urban food allergy prevalence from the South African Food Allergy (SAFA) study. Food Allergy and Gastrointestinal Disease. 2019;143(2):662-68.
  5. Leonard ML, Sapone A, Catassi C, Fasano A. Celiac Disease and Nonceliac Gluten Sensitivity A Review. JAMA. 2017;318(7):647-56.
  6. Tanveer M, Ahmed A. Non-Celiac Gluten Sensitivity: A Systematic Review. Journal of the College of Physicians and Surgeons Pakistan.2019;29(1):51-7.
  7. Hallert C, Grant C, Grehn S, Grappo C, Hulten S, Midhagen G, Strom M, et al. Evidence of poor vitamin status in coeliac patients on a gluten-free diet for 10 years. Aliment Pharmacol Ther. 2002 Jul; 16(7):1333-9.
  8. Lamacchia C, Camarca A, Picascia S, Di Luccia A, Gianfrani C. Cereal-based gluten-free food: how to reconcile nutritional and technological properties of wheat proteins with safety for celiac disease patients. Nutrients. 2014;6(2):575-90.
  9. Gorgitano MT, Sodano V. Gluten-Free Products: From Dietary Necessity to Premium Price Extraction Tool. Nutrients. 2019;11. Doi:10.3390/nu11091997.
  10. Singh J, Whelan K. Limited availability and higher cost of gluten-free foods. Journal of Human Nutrition and Dietetics. 2011;24(5):479-86.
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