THE LAST time Jeff Gyllenspetz ate the wrong kind of food he was so ill he had to be carried off a plane. Jeff, 57, a consultant in energy and environment management from Harrogate is one of the thousands of Britons who suffer severe food intolerance.

He has Coeliac Disease, an extreme reaction to all products containing gluten - which means everything from bread and cakes to potato crisps and ice cream.

Since he was diagnosed in his early 30s he is vigilant about what he eats. The last lapse involved an in-flight spoonful of rice which was flavoured with soy sauce.

"I swallowed the rice and that was it - bang! I was so ill they had to carry me off the plane," he remembers.

"I am very intolerant. If I eat anything, even a small amount I will be sick within a few hours, be in for two or three days and then it will take me six to nine months to get my insides back to normal."

Eating out is a minefield but home-cooking by Jeff's wife, Kath, ensures that any craving for cakes and pastry can be met.

"Kath has coped absolutely brilliantly. She gets special flour which is gluten-free. We also get a list of foods from the Coeliac Society," he says.

Experts say Jeff is a member of an increasingly large club whose members are suffering from food intolerances, most typically aversions to wheat and dairy food.

One of the main reasons for this is dietary. In particular, the growth of convenience foods which are often bulked out by wheat and cereal substances, which can trigger allergic reactions in certain people.

While no two food intolerances are the same, symptoms can include asthma, chronic fatigue, breathing difficulties and muscle stiffness, as well as bloating and digestion problems.

But whether it is wheat, gluten or dairy products that are the cause, the solution is the same - an avoidance of the foods which trigger the allergic reaction.

Those with coeliac disease, for instance, should avoid gluten permanently, while people with dairy intolerances should switch to soya products.

But cutting out those ingredients means that getting a meal on the table can be a problem, as many of these ingredients can be found in everyday food.

People suffering from a gluten intolerance need to cut out durum wheat (used in pasta), barley, sausages, malt, starch, rusk, beer, bran, wheat flour or oats while wheat intolerance means no bread, noodles, cakes, pancakes, scones and prepared sandwiches, soups and meals. An intolerance to dairy products keeps butter, cheese, cream, yoghurt and other dairy derivatives off the menu.

It sounds like a desperate situation for a cook, but Antoinette Savill, author of The Gluten, Wheat and Dairy Free Cookbook, says that it is possible to eat imaginatively without putting your health in danger.

''It is impossible to buy ready-made foods. You may find a high-quality organic pesto sauce has no starch in it but you have to be wary. But the gluten, wheat and dairy free diet is a very healthy diet. What my book is saying is you can eat healthily and normally like everyone else. There are recipes for cakes and puddings. All I've done is taken normal food and changed it to use an alternative flour and non-dairy products,'' she says.

But anyone trying to eliminate wheat, dairy and gluten from their diet knows the problems of finding safe ingredients. However, Savill points out that as the number of people with food intolerances increase, the number of specialist stores and supermarkets offering alternative ingredients will rise. And the bonus for sufferers is that once they cut out the problem ingredients from their diet, they will lose a few pounds.

Wheat and dairy products often form the basis of snack food so cutting them from your diet will encourage healthy eating.

Some sufferers who suspect they have an unidentified food intolerance get in touch with the York Nutritional Laboratory. The North Yorkshire centre is Europe's leading specialist in food intolerance testing. It has been bringing relief to suffers worldwide for 18 years. Using a small pinprick sample of blood the lab workers provide a rapid and precise method of detecting the foods which are causing the problem.

A spokeswoman for the lab said: "Dairy produce and wheat are amongst the most common foods people have a reaction to, and are also two of the most difficult foods to cut out of a diet." She welcomed the new cookbook as good step forward for people needing to cook without these ingredients.

For details on food intolerance call York Nutritional Laboratory on 0800 074 6185 or visit www.allergy-testing.com

l The Gluten, Wheat and Dairy Free Cookbook is published by Thorsons priced £12.99. (Call 0141 306 3349 for details.