WHAT IS FOOD INTOLERANCE?

Food intolerance is a broad term that is used to describe a wide range of adverse reactions to foods, that cause symptoms after eating some foods. These include stomach pain, bloating, gas/flatulence, diarrhoea, irritable bowel syndrome (IBS), rashes, hives (urticaria), recurrent mouth ulcers or headaches. If food intolerances are not properly managed, these symptoms can adversely affect general health and wellbeing.

Food intolerances are sometimes confused with, or mislabelled as food allergies. Food intolerances involve the digestive system, whilst food allergies involve the immune system. Unlike Immunoglobulin E (IgE) antibody mediated food allergy, food intolerances (except for sulphite and benzoate reactions) do not cause anaphylaxis (severe allergic reactions), that can be life threatening.

What are the symptoms of a food intolerance?

Symptoms of a food intolerance include:

• Abdominal (belly) pain.
• Diarrhoea.
• Gas and bloating.
• Headaches or migraines.
• Heartburn.
• Nausea.
• Upset stomach.

Natural substances in foods can cause food intolerances

Foods are composed of proteins, carbohydrates, fats, nutrients and several natural chemicals. The following naturally occurring substances often add flavour and smell to food, but they can trigger symptoms in some people:

• Lactose intolerance is an example of an enzyme deficiency, which occurs when people are born with, or develop, insufficient lactase enzymes to digest lactose in cow’s milk and other dairy products. This can result in bloating, gas/flatulence, stomach upset and diarrhoea after having dairy products. This condition is uncomfortable but not dangerous and does not cause rashes or anaphylaxis. Diagnosis is by temporary elimination of lactose and reintroduction.

• Monosodium glutamate -Glutamates also occur naturally in foods such as camembert cheese, Parmesan cheese, tomatoes, soy sauce, and mushrooms. MSG stimulates nerve endings, which may be why it is used as a flavour enhancer when it is added to food.

• Vasoactive amines such as tyramine, serotonin and histamine are well known triggers of migraines in some people. They are naturally present in pineapples, bananas, baked meat, vegetables, red wine, wood-matured white wine, avocados, chocolate, citrus fruits, and mature cheese. Amines can act directly on small blood vessels to expand their capacity. This may be why they can trigger flushing, migraines, and nasal congestion in some people.

• Salicylates are natural aspirin like compounds that are present in a wide variety of herbs, spices, fruit and vegetables. Reactions to salicylates may be even more common than reactions to artificial colours and preservatives. Aspirin can trigger hives, by acting directly on skin mast cells, and therefore salicylates can also worsen hives in some people.

• Toxins can cause severe symptoms. Contamination of food with micro-organisms (such as bacteria) or their products (due to spoilage) can cause food poisoning due to toxins. For example, if some types of fish are stored poorly, their gut bacteria can convert histidine to histamine, resulting in allergy like symptoms.

• Irritants such as caffeine and curry are gut irritants that can trigger indigestion in some people. It is important to realise that reactions to these substances are not due to allergy.

How is a food intolerance managed or treated?

You may need to change your diet to limit or eliminate problem foods. Many people with food intolerances find that consuming small amounts of food causes few symptoms if any. When symptoms occur, over-the-counter medicines like antacids or antidiarrheal can help.

People who are lactose intolerant can consume lactose-free milk and dairy products. You can also buy lactase enzymes at drugstores. You can take lactase pills before consuming dairy products or add lactase drops directly to milk to break down the lactose.