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The negative side effects of a gluten-free diet

The negative side effects of a gluten-free diet

The negative side effects of a gluten-free diet

Gluten avoidance is essential for someone living with celiac disease and may be beneficial for people with gastrointestinal disorders, such as irritable bowel syndrome. But even though only one percent of the population experience these disorders, living gluten-free is popular among many people who do not have proven gluten-related diseases.

In fact, a gluten-free diet may not be right for you, and even may be detrimental to your health. Read on to find out more.

What is gluten?

Gluten is a protein complex naturally found in:

  • Wheat
  • Barley
  • Rye
  • Spelt
  • Kamut

Gluten is naturally occurring, but it can be extracted, concentrated and added to food and other products to add protein, texture and flavour. It also works as a binding agent to hold processed foods together and give them shape. [1]

Wheat flours have different names based on how the wheat is milled or the flour is processed. All of the following flours have gluten:

  • Enriched flour with added vitamins and minerals
  • Farina, milled wheat usually used in hot cereals
  • Graham flour, a course whole-wheat flour
  • Self-raising flour, also called phosphate flour
  • Semolina, the part of milled wheat used in pasta and couscous [2]

Gluten is found in foods such as beer, ale, porter, stout, breads, bulgur wheat, cakes and pies, sweets, cereals, biscuits, crackers, croutons, chips, gravy, imitation meat or seafood, malt, malt flavouring and other malt products (barley), pastas, processed meats, salad dressings, sauces, including soy sauce (wheat), soups and bouillon or soup mixes.

How does gluten affect the body?

Digestive enzymes break down food in our bodies and protease is the enzyme that processes proteins. Protease can’t completely break down gluten so undigested gluten goes to the small intestine. For some people, this undigested gluten can trigger a severe autoimmune response or other symptoms. For most people, it doesn’t create any problems.

For some people gluten intolerance is a mild insensitivity. For others, consuming gluten causes a severe immune reaction known as celiac disease. Gluten intolerance causes digestive system issues but won’t cause permanent damage to your gut and other organs. Celiac disease, however, can cause permanent damage to your small intestine and a myriad of serious health issues.

Some people have small intestines that don’t work properly. In these people, the lining of the small intestine is permeable, allowing some undigested gluten, bacteria or other substances to go through the lining and into the bloodstream. This causes inflammation and increased food intolerances.

Symptoms of gluten intolerance include:

If you have gluten intolerance, you might experience many different symptoms when you eat foods containing gluten. Symptoms can be different in each person. Common symptoms are:

  • Stomach bloating and pain
  • Diarrhoea, constipation, or vomiting
  • Tiredness or fatigue
  • Bone or joint pain
  • Headaches
  • Numbness
  • Depression
  • Dermatitis

When is a gluten-free diet beneficial?

A gluten-free diet is essential for people who have celiac disease. It can also be beneficial for people experiencing gluten sensitivity. Benefits include:

  • improves energy levels
  • promotes healthy weight gain
  • eliminates bloating
  • reduces joint pain
  • reduces the frequency of headaches
  • reduces depression
  • reduces lactose tolerance
  • improves bone health

What are the possible negative effects of a gluten-free diet?

The gluten-free diet is not for everyone, however, and it can cause some unwanted side effects if you aren’t consuming the most beneficial foods.

You may not be getting all the nutrients you need

If your gluten-free diet is high in processed, gluten-free replacement foods, it is likely you aren’t getting the nutrients you need. Just because it’s gluten-free, doesn’t mean it’s good for you!

Enriched wheat flour products are a good source of iron and B vitamins. When you give up these products, you will also miss out on these nutrients as most gluten-free baked products are not fortified with extra vitamins and minerals. [3]  There are also many foods naturally free of gluten that people can eat to correct nutrient deficiencies.

Ensure you are getting the recommended amount of B vitamins and iron and eat plenty of fresh fruit and vegetables. You may also need a supplement to help you get all the nutrients you need.

It may disrupt your gut microbiome

Wheat is a good source of prebiotics, which are essential for gut health. When you take wheat out of your diet, it is important to replace these prebiotics with other prebiotic-rich foods, fermented foods with Lactobacillus and Bifidobacteria such as sauerkraut and yogurt and consider taking a prebiotic supplement.

Gluten-free sources of prebiotics include:

  • Garlic
  • Onion
  • Green plantain and banana flour
  • Tiger nut
  • Artichoke
  • Asparagus
  • Chicory
  • Berries
  • Legumes (if tolerated)

Gluten-free foods made with acellular carbs may also promote the growth of inflammatory gut bacteria while the gums and emulsifiers are commonly used in gluten-free processed foods have been found to disrupt the gut microbiota and inflame the gastrointestinal mucosa. Acellular carbohydrates are carbohydrate-containing foods that lack intact cells. The carbohydrates in these foods have a high carbohydrate density and include foods such as flour and flour-based products like gluten-free bread, bagels, biscuits and cakes. [4]

A gluten-free diet may lead to fat gain

Recent studies show an association between people who are on a gluten-free diet and weight gain, and subsequently, the risk of cardiovascular diseases and type 2 diabetes.

When you are eating high amounts of processed food, no matter if they are gluten-free or not, it can lead to weight gain. There is a high acellular carb content in gluten-free replacement foods that may cause this weight gain.

Get your energy from wholesome, organic, fresh foods such as organic fruits and vegetables, raw nuts and seeds, healthy oils (avocado, coconut, etc), grass-fed beef, and wild-caught salmon – all of which are free of gluten by nature. [5]

You may be consuming more refined oils

Gluten-free products often contain cheap, harmful oils to moisten and improve the texture of the food. Overall, gluten-free foods contain more saturated fat, and a higher fat content than their gluten-containing counterparts. Refined oils such as vegetable, canola, rapeseed, safflower and sunflower oils are all high in omega-6 fatty acids, which can lead to increased inflammation. [6]

You may experience gluten cross-reactivity

If you are still having symptoms but aren’t eating gluten, you may be experiencing gluten cross-reactivity. When your body makes antibodies against gluten, those antibodies can also recognise proteins in other foods that have a similar structure. When you eat those foods, even though they don’t contain gluten, your body reacts as though they do. Some common gluten cross-reactive foods are rice, corn, soy, quinoa and buckwheat. [7]

You may be increasing your intake of heavy metals

Recent studies find higher concentrations of heavy metals in blood and urine, especially arsenic and mercury, among people following a gluten-free diet compared to people not following a gluten-free diet. This could be attributed to increased rice consumption as the natural growth in flooded paddies, rice readily absorbs arsenic and mercury and can accumulate the toxins in the bran. As gluten-free products often contain a large share of rice flour, this connection should be subject to further studies. [8]

Your diet may not contain adequate fibre

When consuming a gluten-free diet, people may not be getting enough fibre in their diet as gluten-free foods are often made with low fibre refined flours and starches. Research has also suggested that a lower amount of dietary fibre consumed when a person is not eating grains may explain a higher risk of cardiovascular disease.

Insoluble fibre helps prevent constipation. Examples of foods with insoluble fibre include:

  • Quinoa
  • Buckwheat
  • Millet
  • Wild and brown rice
  • Nuts (almonds, walnuts, pecans)
  • Fruits (strawberries, papayas, mangoes)
  • Vegetables (cucumber, asparagus, okra)

You may be eating foods that contain some gluten

It can sometimes be difficult to ensure that everything you eat contains absolutely no gluten. So, check that all grains, nuts and seeds are labelled gluten-free and that there are traces of gluten in the product. This can be especially tricky when you are dining out so double check with the restaurant or café.

The key takeaway

Base your diet around healthy lean meats, omega-3 oils, fresh fruits and vegetables, seeds and nuts. Incorporate gluten-free grains into your diet. These include:

  • Amaranth
  • Arrowroot
  • Bean flours (garbanzo, fava, Romano, etc.)
  • Buckwheat, buckwheat groats (kasha)
  • Cassava flour
  • Chia seeds
  • Corn (maize), cornmeal
  • Flax, flax meal
  • Hominy
  • Manioc flour
  • Mesquite flour
  • Millet
  • Montina flour
  • Nut flours and meals (almond, coconut, hazelnut, etc.)
  • Oats (gluten-free)
  • Pea flour
  • Potato flour, potato starch
  • Quinoa
  • Rice (all), rice bran
  • Sago
  • Sorghum flour
  • Soy flour
  • Tapioca flour
  • Teff
  • Yucca [9]

You can also get carbohydrates from gluten-free foods such as sweet potatoes, squash, plantains and whole fruit.

Healthy fats include extra virgin olive oil, olives, avocados and avocado oil, nuts and seeds, seafood, coconut and full-fat dairy.

Most importantly, avoid processed foods and gluten-free replacement foods when you can.

How we can help

At Advanced Functional Medicine, we clinically find many patients do better on a gluten free diet or a low grain diet, at least while they are in the healing process.  Our team of experts can help you to find the best diet for you to alleviate symptoms and work towards optimal overall health.

Call us to find out more about how we can work with you to assess your gut health, biochemistry and to help develop a healthy sustainable diet and lifestyle.


The above information is intended to be general, educational advice only, on topics which are of interest to us. It is not intended to represent specific or individual health or medical advice and is not specific to your situation. The below information is educative and is not intended to advertise any service.

Before making any decisions in relation to your health, you should always discuss your individual situation with your own health practitioners to ensure that any advice you have read is right for you.

Jarrod Cooper – ND

Jarrod Cooper – ND

Jarrod Cooper - ND is the founder of Advanced Functional Medicine Australia. He is a Naturopathic Doctor with extensive functional medicine training from leading practitioners in the USA and worldwide.

He is leading the way with advancements of functional medicine, clinically implementing worldwide best practices in Functional Medicine throughout Australia.

Jarrod consults in person from Perth, Western Australia and also online via Telehealth throughout Australia and worldwide.

If you are looking for personalised treatment, we highly recommend contacting Jarrod Cooper’s Advanced Functional Medicine clinic in Australia.

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