Gluten – the “bad guy” of nutrients or better than its reputation?

Gluten-free diet was previously mainly known as the diet of people with coeliac disease but a bit over a decade ago the popularity of gluten-free diet exploded among the general public. Even though the biggest boom has calmed down due to the rising interest in for example vegan diet, many people still avoid gluten due to health reasons. Is gluten really harmful then and should other people besides the coeliacs avoid it?

What is gluten and what kind of effects does it have in the body?

Gluten is a group of proteins found in cereal grains such as wheat, rye and barley. Gluten gives dough its elasticity which guarantees a fluffy yet firm texture to baked goods. In the body gluten can however cause problems.

Food which contains gluten goes through the digestive system into the small intestine. In a normal state, the gluten proteins are absorbed from the small intestine into blood circulation. With coeliac people the gluten proteins however cause an immune response that attacks the small intestine. This attack damages the villi which line the small intestine. Villi is essential for the absorption of nutrients because it increases the surface area of the small intestine. The more surface area there is in the small intestine, the more efficiently nutrients can be absorbed into blood circulation. Damaged villi prevents the absorption of nutrients which makes the walls of the intestines to leak. This again causes digestion problems such as swelling, diarrhea and constipation.

The problems that the damaged villi causes with the absorption of nutrients can in the long term lead to iron, vitamin D and calcium deficiencies. These deficiencies can affect the growth and development of children.

The problems caused by gluten

Coeliac disease is a gastrointestinal disease which causes gut problems. A person with coeliac disease cannot consume the gluten in wheat, rye and barley. The symptoms of coeliac disease include gut and stomach problems or dermatitis herpetiformis (DH) which causes itchy rash often in elbows, knees, buttocks and hairline. Coeliac disease should always be diagnosed with blood tests before starting a gluten-free diet – which is also the only way to treat coeliac disease. Coeliac disease is important to diagnose because if untreated it can eventually lead to osteoporosis or anemia, for example. About 1-2 % of the whole general population suffer from coeliac disease, though for many people the disease can be asymptomatic and therefore remain undiagnosed.

Non-coeliac gluten sensitivity is a condition which is independent of coeliac disease, though the symptoms can be very much alike. A person with gluten sensitivity gets stomach problems from grains that contain gluten but the grains don’t damage the villa and therefore don’t prevent the absorption of nutrients either. It has been discovered in certain research that instead of gluten, gluten sensitivity can actually be caused by fructan which is a sugar found in grain. In addition to grains, fructan can also be found in onion, garlic, cabbage and chickpeas. This is why many people find aid to their stomach problems from FODMAP diet instead of a gluten-free diet. In FODMAP diet, fructans and FODMAP carbs which are absorbed poorly are left out from the diet. About 6 % of the general population suffer from gluten sensitivity.

Grain allergy is a food allergy independent of coeliac disease and gluten sensitivity. In grain allergy various grains – often wheat, barley and rye which have a similar protein structure – cause an allergic reaction. The most common grain allergy is wheat allergy. Grain allergy is the most common with children and it often disappears as the child grows up.

What is a gluten-free diet like?

Wheat, rye and barley are permanently left out in the gluten-free diet. Also the different varieties of wheat such as semolina, spelt, einkorn, couscous and durum need to be left out. In addition to grain products, gluten can be found in almost any food such as sauces and mayonnaises, cereals and mueslis, prepared foods, chocolate and beer.

Grains which are naturally gluten-free are 100 % pure oats, buckwheat, gluten-free wheat starch, rice, millet, amaranth and corn. It is good to include these in a gluten-free diet to make sure that the necessary daily intake of fibers and minerals is fulfilled. The daily intake of fiber should be at least 25-35 grams. In addition to grains, vegetables, berries, fruits, nuts and seeds also contain lots of fibers.

Gluten can also sometimes be found in medicine in the form of wheat starch. In this case wheat starch is always mentioned in the ingredients list. Gluten can also be found in cosmetics, such as hair care products and moisturizers, but gluten doesn’t cause any symptoms for a person with coeliac disease when applied on the skin.

Is it good to follow a gluten-free diet?

Gluten-free diet is the only option for coeliacs but lots of other people also avoid gluten in their diet. Gluten-free diet is justified with its health benefits. Nowadays it is also much easier to follow a gluten-free diet due to the increase of the selection of gluten-free options in grocery stores and restaurants. On the other hand, gluten-free diet on others that coeliacs is questioned by medical experts and some studies have shown it to be even even harmful.

The alleged benefits of a gluten-free diet

Many beliefs are associated with the gluten-free diet. The ones who swear on gluten-free diet also swear that cutting off gluten also takes away stomach and skin problems, helps with weight management and gives a more energetic feeling. Often the biggest reason for adopting a gluten-free diet is stomach problems which are very common. In reality, gluten-free diet doesn’t really bring aid to stomach problems unless you suffer from gluten sensitivity. The reasons for stomach problems can be found from other malabsorption syndromes such as lactose intolerance, inflammatory diseases, irritable bowel syndrome (IBS) or just irregular eating habits. If you suffer from stomach problems, the reasons for those should be examined before any diet experimentations. Experimenting with gluten-free diet can make it harder to diagnose the possible coeliac disease or gluten sensitivity.

Gluten-free diet is also believed to help with weight management. Gluten itself doesn’t however make you lose or gain weight. It is possible to lose weight when on a gluten-free diet if in addition to gluten you also leave out processed foods such as prepared foods and cookies and replace them with vegetables. In reality the situation is often the opposite: according to research, gluten-free diet can often lead to gaining weight. This is because gluten-free products often contain more fat and sugar and therefore more calories. However, it is possible to compile a gluten-free diet in a healthy way.

Many people who have switched to gluten-free diet have reported that their skin condition has improved. In this case the critical factor isn’t gluten but carbs with high GI (glycemic index), such as pastries, wheat bread and pasta. Studies have shown that foods with high GI increase acne. Skin problems can ease on a gluten-free diet because the “bad” carbs have been left out from the diet.

The possible harms of a gluten-free diet

One possible drawback of a gluten-free diet is nutrient deficiencies if the diet has been constructed poorly. Gluten-free products often contain less fibers, vitamins and minerals, though the natural gluten-free quinoa and buckwheat are nutritious options. The lack of fibers can have bigger effects: according to a Harvard study, gluten-free diet increases the risk of diabetes. The reason for this is considered to be the fact that the subjects following a gluten-free diet were eating less fibers which prevents the type 2 diabetes.

A 26-year study about the connection between gluten and coronary heart disease done by the same research group was published in the British Medical Journal in 2017. According to the study, gluten-free diet may increase the risk of cardiovascular diseases.

For whom is gluten-free diet good for?

In addition to people with coeliac disease and gluten sensitivity, people with autoimmune diseases or inflammatory bowel diseases may also benefit from gluten-free diet. These include for example Hashimoto’s disease, rheumatoid arthritis, psoriasis, type 1 diabetes and Crohn’s disease. Gluten-free diet can in these cases reduce the symptoms but isn’t enough of a treatment on its own. People with hormonal or neurological disorders can also benefit from gluten-free diet. Leaving gluten out from your diet without these reasons is not recommended.