Food For Thought!

Along with Lord of the Rings, David Blaine in a box and the Atkins diet, food intolerance is fast becoming the next big thing. A recent study published in the medical journal The Lancet suggests that 19.4% of the British population believe they have a food intolerance, when in fact the actual prevalence is 1.4%.

Figure 1. Peanuts and peanut-containing foods are commonly known sources of food allergies. Source: Scott Bauer/United States Department of Agriculture.

Figure 1. Peanuts and peanut-containing foods are commonly known sources of food allergies. Source: Scott Bauer/United States Department of Agriculture.

Food Intolerance and Food Allergy – What's the difference?

Finding a concrete definition of food intolerance/allergy is difficult. Many people perceive them as the same thing. "It's difficult to get actual definitions of food intolerance and allergy," says Tanya Wright, a dietician who has worked and published material on this subject. "Even experts can't give clean-cut definitions; therefore if professionals cannot offer definitions it's very hard for anyone else to know the difference."

Generally, food intolerance refers to an adverse reaction to a food that causes feelings of discomfort, such as nausea, bloating or migraine. Food allergy involves the antibody immunoglobulin E (IgE) recognizing a food as "foreign." The ensuing immune responses vary from local swelling to life-threatening anaphylactic shock.

How do you know if you have a food intolerance?

Debbie, a schoolteacher from Oxford, England, had been feeling unwell for some time. As she explains, "It was January 2002, I had bad sickness and diarrhea and was referred to a hospital consultant in March but due to the waiting list the appointment was not until August." Exasperated with this long wait and not wanting to feel ill on her summer vacation, Debbie decided to buy a food intolerance home test kit she had seen in her local pharmacy, for the cost of about £200 (US$340). The test procedure was simple: send a blood sample and the results would come back in two weeks. Also included in the price of the test was a one-hour consultation with a dietician to discuss the test results.

"The results of my test showed that I was intolerant to gluten, wheat, cow's milk, and soya," Debbie says. "They recommended that I cut these, as well as oats and rye, from my diet." Even though she was not intolerant to the latter two foods, the dietician informed her that if she had intolerance it was usually easier to detect if "the whole lot were cut out of the diet."

"By August," Debbie says, "I had been completely off all the suggested foods for one month and was feeling better."

In August, Debbie also saw the hospital consultant, who suggested a series of tests. These took about a year in total to complete, due to waiting periods of two to three months between each one. It also meant re-including the foods into her diet that she had previously been avoiding. The test results showed some intestinal inflammation, which the consultant attributed to fat in her diet. He did not believe that her discomfort was linked to any of the foods suggested by the home test dietician.

Given conflicting opinions and advice, Debbie tried to do some reading around the subject herself but with little success. "It was difficult to get any solid facts as there were many different bodies of thinking, which made it very hard to get a clear diagnosis," she said. "It was pretty much a trial and error method that I had to adopt to find out what was wrong."

How is food intolerance diagnosed?

Food intolerance is notoriously hard to diagnose, as Debbie found out; it involves a process of skin tests, blood tests, and exclusion diets. Although these procedures are necessary to achieve a proper diagnosis, they can be all-consuming. Patients may have to take time off work and the social implications of being on a strict diet can also be quite tough.

Poor provisions of allergy services

Due to a number of reasons, in Debbie's case not being able to see a professional for some time, people are taking matters into their own hands. This can have detrimental effects. Although people may eventually identify the causes for their food complaints, exclusion diets , when not properly managed by a healthcare professional , can lead to a decline in an individual's nutritional health.

Wright believes this may be due to a lack of services providing diagnosis and treatment of food intolerance and food allergy. "The provisions for allergy services are very poor," she says. "There are long waiting lists for many allergy clinics, for example the waiting list for allergy clinics in Scotland is up to two years."

Is food intolerance fashionable?

Talk of food, or to be more specific, diets, constantly surrounds us. Whether it is via the television, glossy magazines or the Internet, there is constant discussion of what foods to eat or avoid.

"Recently food intolerance had almost become trendy,'" says Wright. "The marketing of intolerance-substitution foods may also have an effect. The manufacturers of these foods claim that if you feel tired or run down then you could have a food intolerance, when in many cases this may not be true."

Whether it is due to trends, an ill sufficiency of allergy services offering diagnosis or simply an increase in awareness of this disorder, the cause of the apparent discrepancy between actual and perceived cases of food intolerance is uncertain. What is certain is the effect that it has on sufferers. Food intolerance causes them distress, from diagnosis, the intolerance itself, and detrimental effects on their health if it remains untreated.


Related Websites

www.allergyfoundation.com

References

Buttriss, J., ed. Adverse Reactions to Food. Oxford: Blackwell Science (2001)

Jansen, J.J., et al. Prevalence of food allergy and intolerance in the adult Dutch population. Journal of Allergy and Clinical Immunology, 93:446-456 (1994)

Wright, T. Food Allergies – Enjoying Life with a Severe Food Allergy. London: Class Publishing (2001)

Young E., et al. A population study of food intolerance. The Lancet. 343:1127-30 (1994)

JYI has a science journalism program, which trains undergraduates how to write news and feature articles about science and about how to communicate effectively to the public.
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