Many people nowadays suffer from either food allergies or intolerances. These general ‘food upsets’ can lead to some significant signs and can be quite debilitating for the sufferer. There has been a general trend that food allergies and intolerances are on the increase, but medically the reason for this is yet to be understood. Many people with food upsets remarkably do not realise that they are indeed affected from either an allergy or intolerance and just tolerate the discomfort. But effective management plans exist to alleviate the signs and symptoms of food upsets so it is worth discovering these.
What Is A Food Allergy?
Food allergies happen due to an overreaction of the body’s immune system to a food protein. Around 2 in every 100 Australian adults suffer from food allergies1. Most food allergies start in infancy or as a toddler and can be outgrown – such as egg and milk allergy, which are usually outgrown by the time children are school-aged. Food allergies do not appear to be genetic, but if you have a sibling with a food allergy then you have an increased chance of developing a food allergy also.
The symptoms of food allergy can be life threatening. The key feature, though, of an allergy is that the reaction occurs every time to even just small amounts of the substance.
Common symptoms include:
- itching, burning and swelling around the mouth
- Runny nose
- Skin rash (eczema)
- Diarrhea, abdominal pains
- Breathing difficulties, including wheezing and asthma
- Vomiting, nausea
The most common foods to cause an allergic reaction in a hypersensitive individual include (in order):
- Uncooked egg
- Tree nuts
- Sesame seeds
- Prawns and other crustaceans
Food allergies are diagnosed by a skin prick test or allergy blood test. Sometimes these tests can come back ‘false positive’, which means that they have noticed an allergy but you have never experienced any symptoms. In this case a food challenge may be required where you will be given small amounts of the food, under medical supervision, to see if you react.
What Is A Food Intolerance?
A food intolerance, on the other hand, is a ‘chemical’ reaction that some people have after eating or drinking certain foods; it is not an immune response. It essentially means that individuals are unable to properly digest that food, which can lead to bloating, pain and either diarrhea or constipation. Surveys indicate that up to 25 per cent of the population believe they have some sort of food intolerance and they often run in families, suggesting a genetic predisposition.
Food intolerance has been associated with asthma, chronic fatigue syndrome and irritable bowel syndrome (IBS). It can cause significant symptoms which can come on hours or even days after you have eaten a particular type of food. This makes it difficult to determine what exactly it is that you are intolerant to. Food intolerances can also get worse depending on how much of the food you have eaten.
People who have a food intolerance react to chemicals which either occur naturally in that food or are added to it during processing. Different people will endure different amounts of chemicals. The amount of the chemical that causes symptoms is called the ‘dose threshold’. Some people have a high dose threshold to all food chemicals and may never have symptoms after eating foods. These people typically will never experience food intolerances throughout their life. Food intolerances can occur suddenly following an illness, change in diet, major life stress, pregnancy or surgical procedure.
More than one type of chemical may cause symptoms, so a person may react to many different types of foods. Some foods contain the same chemicals and a person can react after eating any of those particular foods. This is because the chemical slowly builds up in the body until the dose threshold is reached. It also explains why the same food does not cause symptoms every time it is eaten, because the amount eaten, in this instance, was not enough to cross the dose threshold.
Symptoms of a potential Food Intolerance
Common symptoms of food intolerances include:
- Headache, migraine
- Abdominal pains
- Bloating with excessive wind
- Mouth ulcers
- Flu-like aches and pains
- Mood changes
- Burning sensations on the skin
- Breathing problems – asthma-like symptoms
Food intolerances may be caused by sensitivity to the following natural food chemicals:
Salicylates – these are naturally found in many fruits, vegetables, nuts, herbs, spices, jams, honey, yeast extracts, tea, coffee, juices, beer, wine, mint and fruit flavourings, as well as scents in perfumes, toiletries, cleaning products and washing powders. It is also found in aspirin. Also, the more unripe fruit is the more salicylates they contain.
Amines – found in meats, fish and cheese especially as they age. So levels of amines will be higher in meat and fish that is not fresh as well as meat that has been slow-cooked or roasted. Amines are also found in ripe bananas, tomatoes, avocadoes, pawpaw and olives. High levels are found in tomato sauce, fruit juices, chocolate, nuts and seed pastes, and in fermented products such as yeast extracts, wine, beer.
Glutamates – it is a natural amino acid found in many foods naturally and enhances the flavour of foods in cheese, tomato, mushrooms, stock cubes, soy sauce, meat extracts, and yeast extracts.
As well as to the following:
Lactose – milk sugar malabsorption caused by a deficiency of the enzyme lactase. Levels of lactase are maintained for life in people of northern European background, but in those who are of Aboriginal, Asian, Mediterranean and Middle Eastern descent, levels fade during childhood. Drinking lactose-free milk may help to relieve symptoms.
Fructose – incomplete absorption of the sugar found in fruit, some egetables (e.g. corn), honey, and table sugar. Having excessive amounts of fruit or concentrated fruit sugar such as that found in fruit juice and dried fruit can cause symptoms such as bloating, reflux, abdominal pains, wind and diarrhea.
Short-chain Carbohydrates – malabsorption of fermentable sugars contained in many different fruits, vegetables incl. garlic and onions, beans and pulses, wheat, rye, barley, sweeteners and chocolate. This is the basis of the FODMAP diet as a management strategy for irritable bowel syndrome (IBS) as the majority of IBS suffers are thought to have short-chain carbohydrate malabsorption with or without any other food chemical intolerances.
Gluten or Wheat – different to coeliac disease, which is explained below. An intolerance to gluten or wheat likely means you will experience bloating, abdominal pains, and wind when you eat large amounts of wheat. But in smaller amounts it may be tolerated. In coeliac disease no gluten or wheat is allowable.
Cow’s Milk Protein – usually this means intolerance to the A1 type of cow’s milk protein but also sometimes the A2 cow’s milk protein. This is usually seen more so in infants and children rather than adults. Drinking A2 milk may help with digestion.
Caffeine – acts as an irritant to the bowel.
Food chemical intolerances may also be to the following food additives:
- Artificial food colours
- Flavour enhancers e.g. MSG.
If you are sensitive to natural food chemicals you are usually also sensitive to at least one preservative, artificial colour, and/or flavour enhancer. The ones that are likely to cause reactions in those intolerant are listed in Appendix C at the back of this book. The diagnosis of food intolerances is more difficult as they will not show on a blood or skin-prick test. The best way to diagnose a food intolerance is by conducting an elimination diet. For more information on how to conduct a formal elimination diet refer to the Royal Prince Alfred Hospital Elimination Diet Handbook3.
How to Manage Food Upsets
The easiest way too to manage a food allergy or intolerance is to eliminate the offending food/s from the diet. Try keeping a symptom diary for up to one week. If there are particular foods that cause digestive upset, try avoiding them for at least two weeks to see if your symptoms improve. The most common food intolerances that I see in clinical practice are to gluten and dairy.
Following the low FODMAP diet for a period of time in particular to reduce bloating signs can also be helpful. An outline of the low FODMAP diet can be found in Appendix D at the back of this book. Although, food allergies and intolerances cannot be cured the symptoms and severity of the reaction can reduce over time. Sometimes, the body can endure the food if it is avoided for a period then reintroduced in small doses, particularly for food intolerances. Before you remove or reintroduce foods, my suggestion would be to seek guidance from a specialist dietician or nutritionist. Desensitisation immunotherapy may be a choice for food allergies as a way to reduce sensitivity to that food. This is performed by an allergy specialist. It is important to note that the symptoms of food allergy and intolerance can also be caused by other conditions, so it is important to get a valid medical diagnosis.