Testing for food intolerances

If you suffer from fatigue, IBS, headaches and bloating after eating certain meals it could be a reaction to foods in the diet. Food intolerances are on the rise and differ slightly from food allergies which tend to have more obvious symptoms such as anaphylaxis and hives. There are a variety of ways in which culprit foods can be identified so that they can be avoided if needed.

What is a food intolerance?

Food intolerance is a chemical reaction that some people have after eating or drinking certain foods. It could involve enzyme deficiencies i.e. the inability to digest lactose, a milk sugar present in dairy products—resulting in bloating and diarrhoea.

Food intolerances can be hard to identify as symptoms are not always obvious and may have been experienced for many years. Sometimes the offending food can be tolerated in small amounts but then when large amounts are eaten, only then does it cause problems. When the intolerance deals with a reaction to natural chemicals in foods, such as salicylates—these are found in a wide variety of foods and makes it even harder to identify. 

The difference between an allergy and an intolerance

Allergies and intolerances are commonly confused, usually because intolerances can cause allergy-like symptoms. Allergies are usually more severe than intolerances and can be life-threatening. When the body has an allergic reaction –the immune system is involved. It responds to proteins from the offending food as if it were toxic, even though they are completely harmless substances.

Symptoms of food intolerances

After eating certain foods, symptoms may develop immediately or take up to 2 days. Some of the most common signs and symptoms include:

• anxiety
• asthma
• bloating
• fatigue
• constipation
• diarrhoea
• headaches/migraines
• itchy skin
• malabsorption
• insomnia

Causes of food intolerances

Foods that tend to cause intolerance reactions in sensitive people include: 

• cow’s milk and other dairy products
• chocolate
• wheat
• eggs, particularly egg white
• flavour enhancers such as MSG (monosodium glutamate)
• food additives such as preservatives and colours
• strawberries, citrus fruits and tomatoes
• foods high in fructose such as honey
• wine, particularly red wine
• histamine, amines and salicylates in foods

Identifying food intolerances

It is always best to seek the advice of a health professional such as a naturopath, nutritionist or dietician when determining food intolerances. They may suggest some of the following tests or diets to help determine what foods you are sensitive to.

Elimination diet

The elimination diet involves removing the most common offending foods from the diet and then each suspect food is challenged individually to see if there are any ill effects.

On this diet foods that are challenged include: 

• dairy
• eggs
• gluten
• fish
• shellfish
• peanuts
• nuts
• soy
• corn
• tomatoes
• oranges
• chocolate
• caffeine
• alcohol

When the food is challenged, 3 serves are consumed in one day and then taken back out of the diet. All foods consumed during the elimination diet are recorded in a dairy as well as any adverse symptoms.

There is a sensitive level which can completed for those who don’t respond to these basic guidelines. It may indicate that there is a wider range of food sensitivities which may include:

• salicylates
• amines
• preservatives
• colours
• yeast
• legumes
• certain meats

Low FODMAPs

Foods high in FODMAPs have been identified as problematic food groups in people with IBS. They can lead to diarrhoea, gas, bloating and wind.

FODMAP is the acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols.

These are groups of short-chain carbohydrates and polyols which are found in grains, vegetables, legumes, cow’s milk, fruit and sweetened products.

To determine individual food sensitivities, follow the low FODMAP diet for 2 weeks and then rechallenge each FODMAP one at a time to determine where the intolerance lies. Symptoms are recorded in a diary in a similar way to the elimination diet.

Alcat test

This kind of food sensitivity/intolerance test is usually ordered through a health practitioner and conducted through a medical laboratory that conducts functional health and wellbeing tests. The ALCAT diagnostic system detects a change in the size and number of white blood cells (a type of immune cell) in response to different foods. It then categorises the tested foods as having a mild, moderate or severe reaction or no reaction at all. The person is then provided with a precise list of foods to avoid and those which are safe to consume.

Recently, researchers from the Yale School of Medicine published their evaluation of the efficacy of the ALCAT test for food sensitivity in the management of patients with IBS. They found that when individuals avoided foods which tested positive for them they experienced a significant reduction in their symptoms.

IgG test

An antibody is a specialised protein produced by the body’s immune system when foreign bodies (such as viruses, bacteria and toxins) enter the body. They are produced by special white blood cells called B-Lymphocytes as a defence against these foreign substances.

IgE antibodies are a type of antibody mostly found in the skin, nose, lining of airways and lungs, and are usually produced in classical allergies.

In comparison to this, IgG antibodies are the type of antibodies that tests for food intolerances. The test usually involves a small blood sample and some health practitioners can conduct this test in their clinic. Research has found that if foods are eliminated from the diet that are producing high IgG levels, the symptoms of food intolerance can be reduced.

References

1. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/food-allergy-and-intolerance
2. http://emerge.org.au/wp-content/uploads/2014/11/RPAH-Elimination-Diet-Handbook-with-food-shopping-guide.pdf
3. Lomer MC. Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance. Aliment Pharmacol Ther. 2015 Feb;41(3):262-75 https://www.ncbi.nlm.nih.gov/pubmed/25471897
4. Ali A, et al. Efficacy of individualised diets in patients with irritable bowel syndrome: a randomised controlled trial. BMJ Open Gastroenterol. 2017 Sep 20;4(1):e000164 https://www.ncbi.nlm.nih.gov/pubmed/29018540
5. Atkinson W, et al. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut. 2004 Oct;53(10):1459-64 https://www.ncbi.nlm.nih.gov/pubmed/15361495
6. Shakoor Z, et al. Prevalence of IgG-mediated food intolerance among patients with allergic symptoms. Ann Saudi Med. 2016 Nov-Dec;36(6):386-390 https://www.ncbi.nlm.nih.gov/pubmed/27920409