Food intolerances and allergies

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When Judi Muller was diagnosed with painful psoriatic arthritis, she heard plenty of conventional wisdom from friends, family and colleagues on what foods could be contributing to her condition.

“I heard foods with a high acid content could be implicated. So I cut out tomatoes, which was hard because I really love them. But I didn’t notice that it made any difference to my condition,” she says.

It’s a long-held piece of popular thinking that certain foods can be a culprit in arthritis and other autoimmune conditions like eczema, psoriasis and lupus. Everything from corn and wheat to dairy foods and the ‘nightshade’ vegetables – tomatoes, capsicum and potatoes – have been implicated.

Understanding autoimmune problems
Autoimmune conditions arise when your own immune system turns destructive. Dr Glenn Reeves, an immunologist at John Hunter Hospital, explains: “An autoimmune problem is when there’s a civil war in the body, where the immune system attacks parts of oneself.” Arthritis, eczema, psoriasis and lupus are just some of the diseases that can arise from an autoimmune disorder. Not surprisingly, when the body attacks itself, many people point the finger at what foods they’re putting into their body. But the evidence for the role of diet in these conditions is not fully understood, and is a much-debated topic among researchers.

So what is the evidence?
Dr Reeves says the best known example of food causing an autoimmune problem is the condition known as coeliac disease, which can mimic conditions such as arthritis, eczema, psoriasis and many others. This disorder is the result of an allergy to gluten, a substance found in wheat products including bread, pizza, cakes and pasta.

“Coeliac disease can lead to a range of neurological, liver, skin and mood problems, and changes in virtually any organ you can name,” says Dr Reeves. The best way to check if you have coeliac disease is to have a blood test. With conditions such as arthritis, eczema, psoriasis and lupus, there are no clear answers. A small proportion of people definitely benefit from excluding certain foods, but everyone is different.

Problems with diet studies
Many doctors are reluctant to recommend dietary changes because the scientific evidence isn’t conclusive. It’s difficult to study the role of diet in these conditions because it’s not as simple as studying someone taking a pill. People who partic-ipate in diet studies often find it hard to maintain a dramatic change in their eating habits throughout the course of the study. It’s also hard to design a study that accounts for the placebo effect – where a person’s beliefs influence the way they feel. So, if someone believes dairy foods cause their arthritis, they may feel better not eating dairy because of their own personal beliefs, rather than an actual intolerance. To account for the placebo effect in dietary studies, scientists would have to design a study where the subjects don’t know what they’re eating, which is difficult to do.

This means few large studies on the topic have been published in peer-reviewed journals (generally the benchmark for accepted scientific knowledge). “There’s not enough good evidence to recommend excluding any particular food in most cases,” says Dr Reeves. However, there are some exceptions. “Alfalfa can trigger lupus flares in certain individuals,” he says. “And echinacea is often used as an immune tonic but can actually flare autoimmune conditions.”

The Cretan diet cure?
Studies that have been widely published suggest a Mediterranean diet, in particular the diet from the Greek island of Crete, may have a preventative effect for some types of arthritis and other conditions. In fact, one study found some people with rheumatoid arthritis showed an improvement in their condition after switching to the traditional Cretan diet. “The Western diet may be pro-inflammatory, in that there’s not enough omega-3 (found in fish) in the diet. That may also pre-dispose us to a range of autoimmune problems,” says Dr Reeves.

The Cretan diet is rich in olive oil, fish, grains, fruits and vegetables. Most meals are prepared from scratch using olive oil and unprocessed, seasonally fresh ingredients. Low amounts of yoghurt and cheese are part of the diet, as well as a small amount of red wine with lunch or dinner. Fish and chicken are eaten regularly, but red meat and eggs are limited to once or twice a week. Fresh fruits are eaten as a sweet kick for dessert.

Elimination diets
Many people are turning to alternative therapists, who have long advocated for a dietary link to autoimmune conditions. Sydney naturopath Lynne Goldstein frequently recommends elimination diets for her patients. “Most people should notice some improvement by changing their diet,” she says.

An elimination diet is useful if you are trying to discover whether a particular food might be contributing to your condition. The diet involves severely restricting your diet to a few basic foods, such as vegetables and rice, for a period of time. After the initial elimination period of one or two weeks, foods are reintroduced one by one to see if any cause flare-ups. “Common culprit foods are milk, chocolate, wheat, eggs, shellfish, nuts, citrus and food colourings,” she says.

If a particular food is found to be flaring your condition, you can either exclude that food completely or go on a rotation diet. “On a rotation diet, every four days you introduce the foods. Reintroducing the foods every four days is important so the food doesn’t start causing an allergic reaction,” explains Lynne.

Dietary wisdom
One thing the experts do agree on is the importance of a healthy, balanced diet for anyone with a chronic health problem. Dr Reeves advises applying “general dietary wisdom, in terms of having a balanced diet with adequate carbohydrates and protein and not
too much saturated fat, and plenty of exercise to go along with it.”

Find out more

• The Food of the Greek Islands by Aglaia Kremezi (Houghton Mifflin, 2000) features many traditional recipes from Crete, from one of New York’s most renowned Greek chefs. 
• A naturopath can give you advice on elimination diets. Your naturopath should be accredited by the Australian Natural Therapists Association (www.anta.com.au), or the Australian Traditional Medicine Society (www.atms.com.au). Naturopath Lynne Goldstein runs a practice in Sydney: www.viewtohealth.com.au.
• The Allergy Exclusion Diet by Jill Carter and Alison Edwards (Hay House, 2003) is a guide to food allergies and intolerances, including elimination diets.

Words: Claire Buckis. Photography: Sam McAdam