Food Intolerance

Food intolerance is an adverse reaction to a food although the reaction is not due to a person’s immune system. The reaction to the food may be immediate or delayed by 20 hours after consumption

Gluten intolerance can be diagnosed at any age and can be called a variety of names:

  • celiac sprue,
  • gluten sensitive enteropathy,
  • non tropical sprue,
  • celiac disease,
  • idiopathic steatorrhea,
  • mal absorption syndrome.

For the purpose of this website we will refer to Gluten intolerance as Coeliac Disease.

Coeliac disease is a condition that causes damage to the bowel wall as gluten is unable to be digested normally. The adverse reaction that people with Coeliac Disease experience when they consume gluten is due to Gliadin. This protein is a component of gluten, which is naturally found in a range of wheat and cereals (including rye and barley).

Gliadin damages the lining of the intestine of people with coeliac disease, which results in damage to the villi (finger-like projections important in the small intestine for digesting and absorbing nutrients) and inflammation of the tissues. The effects of this damage occur a few hours after eating the gluten containing food. Due to damage to the small intestine, the absorption of almost all nutrients appears to be affected in some way.

When gluten is removed from the diet of a person suffering from Coeliac Disease, the small intestine recovers and the symptoms disappear. However a gluten free diet must be maintained through out a person’s life time and all gluten must be excluded, which means the exclusion of a range of grains.

Researchers are still working on determining why people get coeliac disease. There is still more research to be completed but it is recognised that the immune function and genetics of individuals play a role in the likelihood of a person being diagnosed with Coeliac Disease.

  • Once diagnosed, people have Coeliac Disease for their life time. However the removal of gluten from the diet can relieve the symptoms but gluten must be continued to be removed from the diet.
  • Coeliac Disease is more common in women than men. Some research refers to a ratio of three women to every one man being diagnosed with Coeliac Disease.
  • It can occur at any age but is more common between the ages of 40-50 years.
  • The disease is rare among Asian and African people, but is more common in people from Europe.
  • A stressful life event can cause a suppressed Coeliac condition to develop into the real full-blown disease.
  • In America it is estimated that 1 in 5000 Americans can not eat wheat because of a reaction to gluten. Although it should be remembered that gluten is found in varying amounts in wheat, rye, oats and barley.

Symptoms of Coeliac Disease can include abdominal discomfort including bloating, unexplained weight loss, tiredness and frequent headaches. Coeliac disease can be difficult to diagnose as these symptoms are generic to a range of illnesses, or could be thought of as due to the everyday stresses of life. Researchers have recently suggested that anaemia (low iron stores) may be an important indicator to check in adults, especially in those with a family history of coeliac disease. Unfortunately diagnosis may not occur until the gut wall has been damaged by malabsorption over many years of eating gluten containing foods.

An initial biopsy is required to confirm the extent of damage to the lining of the small intestine due to the disease. After a few months on a gluten-free diet a second biopsy is required to examine the repair process and improvement in the structure of the lining.

Coeliac Disease is more easily diagnosed in infants and children, as after eating gluten they become more tired and lethargic, with changes in bowel motions. In older children growth can be slowed and they can suffer from mineral deficiencies (low iron is common), abdominal pain or discomfort.

Due to damage to the small intestine and the reduction in nutrient absorption that occurs in people diagnosed with Coeliac Disease, some vitamin and mineral supplementation may be necessary to correct a deficiency or to improve intake.

The most frequent health problem experienced by people who suffer from coeliac disease is anaemia due to poor absorption. There are various types of anaemia due to a deficiency of iron, vitamin B12, folate or vitamin B6 and there may be only minor symptoms in adults.

A well-controlled gluten-free diet, the use of supplements and improved dietary intake providing plenty of these nutrients is recommended, with blood tests to monitor progress.

By far the greatest concern for people with coeliac disease as they age is bone health. Osteomalacia (weakening and softening of bone) results from the impaired absorption of vitamin D, and osteoporosis can occur due to impaired calcium absorption. People with osteoporosis appear to be 10 times more likely to have coeliac disease. Muscle cramps, due to poor absorption of calcium and magnesium are other possible health problems.

Proper diagnosis of Coeliac disease is important and if you have any concerns that you may suffer from this disease, you should make an appointment with your doctor. If you are diagnosed with Coeliac Disease then a visit with a dietitian is often recommended as they can give advice on how to change your diet to be gluten free.

For people with coeliac disease, Coeliac New Zealand Inc. have a website containing lots of useful information.

The following is a list of grains and their products which are suitable to be included a gluten free diet.


Cornflour made from corn or maize

Corn-based breakfast cereals


Unflavoured popcorn

Taco shells, unflavoured corn chips



Plain rice noodles

Rice flour

Rice breakfast cereals

Baby rice cereals

Rice bran

Plain rice crackers / cakes

Other Grains & Flours


Wild rice




Potato flour



Flours made from Legumes

Soy flour

Yellow split pea flour

Chickpea flour

A gluten free diet can be low in fibre as many of the alternative flours are lower in fibre than wholemeal wheat varieties. Higher fibre flour alternatives include:

flours from soy, buckwheat, chickpeas, rice bran
grains such as amaranath, buckwheat, millet, brown rice
fruit and vegetables.

There is an increasing range of gluten free products available made from potato flour, rice flour, buckwheat and soy flour.

Although this list may not be complete, the idea of this list is to highlight foods which MAY contain gluten and are likely products that you may not have considered as having gluten present:


Baked beans/creamed corn
Baking powder
Crumb coatings for meat, fish or poultry
Sausages & processed meat
Soups & stock cubes
Sauces & gravies
Dressings including mayonnaise
Products containing malt such as breakfast cereals, malted milk drink powders
Cornflour (check the source is from corn rather than wheat)
Custard powder
Curry powder
Cocoa, drinking chocolate, cooking chocolate
Beer, lager
Some modified starches or thickeners

To ensure that you are following a strictly gluten free diet you need to become very clever at reading food labels when completing your shopping. Many supermarkets do provide lists of which gluten free foods they stock and these lists can be asked for at the service desk.

However since December 2002, Food Standards Australia & NZ have required that food ingredient list highlight the presence of gluten containing cereals, including wheat.

The Manufactured Food Database – – is a useful website which gives listings of manufactured foods available in New Zealand that are suitable for people with some common food allergies or intolerances, including wheat allergies and gluten intolerance. The database has been compiled by Nutrition Services of Auckland City Hospital from information voluntary supplied by NZ Food manufacturers.

Wheat intolerance and gluten intolerance are sometimes used as interchangeable terms but it is important to realise that this is incorrect. Avoiding wheat products gives a different and more expansive diet plan than those people required to avoid consuming gluten in the diet.

Therefore food products labelled ‘wheat-free’ are not necessarily gluten-free, but products labelled ‘gluten-free’ are often wheat-free. Although to confuse matters further there are ingredients derived from wheat (e.g. wheat glucose syrup, wheat maltodextrin) that contain no detectable gluten but still may contain other wheat proteins, making them unsuitable for a wheat-free diet.

Wheat intolerance also known as, wheat sensitivity, occurs in adults and requires the exclusion of wheat to tolerance but would not usually require the complete removal of Wheat from the diet.

Although there are some people who are highly sensitive to wheat, so much so, that they show a cross reaction to related cereals, such as, oats, rye and barley. These people would need to follow a Coeliac diet which would mean the complete exclusion of gluten.

However the key difference is that a Gluten free diet is more restrictive than a wheat free diet as gluten is present in a variety of grains apart from wheat. So usually the confusion arises when someone is advised to follow a wheat free diet wrongly assumes that they must only consume gluten free products. Doing this is not only not required but it also means that person is missing out on including a range of cereals in their diet which provide variety and important vitamins and minerals. These include fibre, B vitamins, Vitamins A and E, Selenium, Zinc, Copper and Iron.

Unlike wheat intolerance, a wheat allergy is an immune system response to wheat specifically which signals the body to cause a reaction.

True wheat allergy is most common in young children and rarely seen in adults. The good news is that children often outgrow wheat allergy by the age of two, and anaphylactic reactions are very rare.

Being diagnosed with a wheat allergy requires the complete exclusion of wheat from the diet. This means excluding even traces of wheat from the diet although other grains can still be consumed, such as, rye and barley.

Wheat-free foods are available from health food stores, some specialty stores and supermarkets; however the range available can vary.
Substitutes for wheat flour include:

Double check the ingredient list before purchasing as some varieties are made from Wheat. Cornflour is best used for:
Thickening: cornflour is better suited to thickening than wheat flour so only a half amount is required (1 tablespoon cornflour for 2 tablespoons flour)
In baking; it is best to use a combination of cornflour plus another gluten-free flour such as rice or soy flour for sponge cakes.

Rice flour
More liquid will be required to be added to a recipe.
Product may take longer to bake and the end result can be drier and more granular.
Used for muffins, biscuits and some cakes.

Soy flour
It is best combined with cornflour in biscuits, chocolate cakes and fruit cakes.

Potato flour
Acts as an effective thickener.
When combined with cornflour it can be used to make biscuits or sponges.

Many people and media overlap terms of different food reactions and self diagnose. We hope the above information has clarified what the real facts about gluten intolerance, wheat intolerance and wheat allergy are. So just to clarify here are a few answers to some commonly asked questions:

Q: Everyone I speak to seems to have an allergy to wheat…is it increasing?
A: In reality a wheat allergy is very uncommon in adults and although an allergy to wheat is more common in children the symptoms rarely occur much past infancy. Most people who avoid wheat actually suffer from Coeliac Disease, which is food intolerance to gluten, a protein found in wheat.

Q: So just to clarify what is the main difference between wheat intolerance and wheat allergy?
A: The main difference between food intolerance and a food allergy is that a food allergy is an immune system over-response to a food protein, which causes the body to trigger a reaction. A reaction can occur within minutes, or a few hours, after the food is ingested. Symptoms can include hives, itching, swelling, vomiting, diarrhoea and nausea. In some cases, it can cause potentially life-threatening symptoms, called anaphylaxis, either by breathing difficulties and/or a sudden drop in blood pressure.

Q: What is the difference between Coeliac Disease and gluten sensitivity?
A: Coeliac Disease is a medically recognised condition which is diagnosed by biopsy. On the other hand Gluten sensitivity is not a medically recognised condition. Instead it is a term that has been created by the alternative health industry, and it is possible some people are on gluten-free diets unnecessarily because of this.