An introduction to food intolerance

Michelle Berriedale Johnson explains what food in tolerance is, how you might diagnose it and then, how you might manage it.


I think I have a food intolerance…?

BBQ You think you may have a food intolerance. You may have been feeling under the weather—tired, bloated, headachy, no energy—or maybe you have more specific and more debilitating symptoms. Your GP can find nothing wrong. You may have been to a complementary practitioner who has suggested food intolerance—or even taken a high street test. Or maybe you just have this feeling that certain foods do not agree with you. So, what to do?

First of all, if you haven’t already done so, consult your doctor.
Go to your GP, explain your symptoms and let him or her do some basic tests—just so as you are sure that there is not anything organically wrong.

Once you are sure that you are sure that there are no other underlying problems that explain your symptoms, this guide will help you to identify if you are indeed intolerant to certain foods.

What’s the difference between allergy and intolerance?

Food intolerance is much more common than food allergy. However, many people believe they are allergic to certain foods when they are actually intolerant, so it’s you need to understand the difference.

Food allergies are caused when the immune system reacts to a particular food; these reactions are usually severe and happen very quickly; very occasionally they can sometimes be life-threatening. Someone who is allergic to a particular food must not eat it.

In contrast, food intolerance does not involve the immune system and is never life-threatening (although it can sometimes make life very unpleasant). People with an intolerance may well be able to eat the food that troubles them, but if they eat too much of it, or have it too often, then they will develop symptoms. These symptoms may take hours or even days to develop.

Typical symptoms of food intolerance:

  • Stomach cramps
  • Bloating
  • Nausea (sometimes vomiting too)
  • Fatigue
  • Joint pain
  • Night sweats

Note that someone who is food intolerant may only have some of these symptoms; it is unusual to have all of them!

The problem with wheat and dairy

If you have had a high street test, they will almost certainly have highlighted wheat and dairy as being an issue. This is not because there is intrinsically anything wrong with whole wheat or dairy products as foods. On the contrary, they are both very nutritious.

However, the average person living in the US or Europe eats a prodigious amount of both refined wheat and gluten (often added as a processing aid). Breakfast cereals, toast, biscuits with coffee, pizza for lunch, pasta for supper… This can overload your digestive system, so reducing the amount of refined wheat and gluten that you eat may be a good idea anyhow.

As regards dairy products: although milk is a highly nutritious food, we were basically designed (like every other animal) to drink milk when we were babies, but to stop doing so when we were weaned. At the point of weaning, our bodies stop producing the enzyme—lactase—that allows us to digest the sugars that are in all milks. In fact, because humans go on drinking milk even after they are weaned, most peoples’ bodies will go on making lactase, but not necessarily that efficiently. As a result many people have some difficulty metabolising the sugar in milk, suffering to a greater or lesser extent, from lactose-intolerance.

Identifying which foods you are intolerant to

So, the most common problems are with either refined wheat products or with dairy—or both! That is not to say that there are not many other foods to which you can be, or can become intolerant. Tomatoes and citrus fruits are frequent offenders but, because food intolerance is very individual, you can react to almost anything.

The first thing is to try to establish what foods are causing your problems.  If you have done a high street test then you can certainly start with the foods it highlighted. If not, the best way to start searching out the culprits is a food diary.

For two weeks ideally—at the very least, a week—note down everything that you eat —and I mean everything, down to finishing off what was left in the baby’s bowl and licking the jam spoon. And make an accurate note of the time at which you ate it.
Then in a separate ‘timed’ column, note how you felt and what symptoms you had and when they started. You will be amazed how often such simple lists will reveal that, for example, your headache always seems to start half an hour after you had orange juice for breakfast.

Excluding the problem foods: in the short-term

Once you have identified foods which you think may be causing the problems, then you need to confirm that with an ‘exclusion diet’. Now this may be quite simple—just excluding citrus fruits, for example—or it may be a lot more complicated if you are trying to exclude, say, refined wheat flour.

Dietitians worry about patients doing exclusion diets without proper medical oversight but, provided you are sensible, they are not dangerous. So, a few things to bear in mind:

  • Only exclude one suspect food initially. If you try to exclude several, it will be harder to do and, if you do feel better, you won’t know which food was the culprit.
    • If you have been to an alternative practitioner, or done a high street test, and you have been told to exclude more than one food, you can certainly do so. Although, if you do feel better, you will need to revisit those foods to make sure that they are all implicated, and that it is not just one. There is no point in restricting your diet more than you need to.
  • Be rigorous. If you want to pinpoint the food that is causing problems, you must exclude it completely—just cutting down a bit will not give you the answer you need.
  • Do NOT carry the diet on for more than three weeks’ absolute maximum. Two weeks should be enough to give you some idea as to whether you have got the right food.
  • If you do not feel any better after you have been on the diet for two weeks, then you will not have got the culprit food. You may then need to go through the same procedure with another suspect food. This is a pain and time consuming but it is the only really reliable way to find out whether a food is affecting your health.
  • If you do feel better, then you need to test out your conclusion by re-introducing that food again—and see whether your symptoms return. If they do, then you know that you got the right food and can continue to exclude it from your diet for a further period.

If you are excluding a food group (such as refined wheat flour or dairy products), you will need not only to read labels carefully but to be aware that flour is used in all kinds of products where you might not expect it. The new regulations which came into force in 2014 make this a lot easier as all 14 of the major allergens (which include wheat and milk/dairy products) now have to be highlighted in the ingredients list. However, you will probably find that many of your regular foods will now be off the menu!

You may well find that you need to cook more foods from scratch, so you can avoid certain ingredients. Although this may come as a bit of shock at first, cooking your own food is so much better for your health! The freefrom food market has grown hugely in recent years, so there’s a pretty wide range of alternative wheat-free and dairy-free foods available on most high streets; there’s also plenty of natural alternatives such as corn or buckwheat-based breads and coconut-based yogurts and ice-creams.

Eating Out.
You certainly can continue to eat out but you will need to be careful to choose an eaterie which is used to catering for allergic people and can offer you good alternative foods. It pays to call up in advance to discuss your need with them and, if you are not confident that they can cope with your needs, go somewhere else!!
You can check on our FreeFrom Eating Out Awards site for awards winning eateries and you can also check CanIEatThere? – an on-line guide to allergy aware eateries across the UK.

Excluding the problem foods: in the long-term

If, as a result of your exclusion diet you decide that a specific food (or foods) are causing you a problem, the you should exclude them for a further three to six months. However, you must take care to ensure that you are replacing them with other similarly nutritious foods.

After three months, ‘challenge’ yourself again with a small amount of the offending food and see how you get on. If it does not cause any symptoms, then re-introduce it but in small quantities. And try to ensure that you continue to eat it in moderate, not excessive quantities. Hopefully, you may already have found several new substitutes so will continue to eat a more varied and healthy diet.

If you still react to that food when you challenge yourself, then exclude it for a further three months and then try again. It may take quite a long time (many months or even years) for your gut to heal so be patient. The fact that you are still reacting after three or six months does not mean that you will never be able to eat the food, just that you shouldn’t yet.

Your health and food intolerance

Unlike a true allergy, a food intolerance usually reflects a more general health issue which affects the digestion’s ability to process and metabolise food properly. This could be as a result of almost anything—a bug picked up when travelling, long periods of stress or some more immediate trauma, too much ‘high living’, overuse of anti-biotics etc. But the result is that the bacteria in your gut may have become compromised, you may not be producing enough of the enzymes needed to digest your food, your gut wall may have become ‘leaky’, allowing food particles and proteins to leach out into your blood stream.

All of these things will mean that foods which your digestion, when in good shape, could deal with perfectly well, now cause it to struggle.

So a crucial part of dealing with a food intolerance is to address general health issues at the same time. The very fact of excluding the foods that are causing your digestion to struggle will already reduce the stress under which it is labouring. But if you are able, try to address other health issues at the same time—trying to get good sleep, taking more exercise, reducing stress levels with yoga or meditation or mindfulness classes, reducing the amount you smoke or drink, maybe taking some all purpose vitamin or mineral supplements and/or probiotics etc.
As your general health improves, so will your digestive health and the chances are that, in time, you may well be able to tolerate the foods that currently give you problems, at least in small amounts.

Severe food intolerance

This article covers low-key food intolerance; the kind that most people suffer from. But, food intolerance can be a great deal more serious and, in really extreme cases, can result in sufferers’ diets being reduced to only a handful of foods and, occasionally, to no foods at all.

See the dedicated section about total food intolerance on the FoodsMatter website and, in particular, the introductory article by John Scott, himself a total intolerance sufferer.

December 2016

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