Although allergies have been identified as an asthma trigger, they
won’t cause asthma on their own. In fact, not all allergic people have
asthma, and many asthmatics are not allergic.
Food allergy is not a particularly common cause of asthma. It only
affects about one per cent of children and 0.05 per cent of adults.
Inhaled food allergens, such as housedust mites, cat fur and pollen,
are more likely to trigger an asthma attack than are foodstuffs.
Some people may be sensitive to some additives and preservatives. It
has been estimated that about five per cent of asthmatics are sensitive
to sulphur-containing compounds (especially sulphites), which are added
to foods to prevent them from becoming oxidised and contaminated with
microbes.
When sulphites are present in a final food in amounts more than 10
ppm (parts per million), the food label must carry the chemical name
and purpose of the additive (for example, potassium bisulphate as a
preservative). Food-labelling protection regulations exclude
sulphite-treated foods that are served as ‘fresh’, such as salad-bar
ingredients, and menu items that are delivered to restaurants
pre-prepared. Here, sulphites are used to preserve, for example, the
crispness of green salads, or the whiteness of peeled, uncooked
potatoes.
Asthma can also be triggered by the preservative sodium benzoate
(found in fruit juices, soft drinks and foods with fruit), colourants
like tartrazine, flavour enhancers like MSG (monosodium glutamate) and
salicylates (found in aspirin).
The prevalence of food anaphylaxis due to masked allergens
contaminating certain manufactured products has increased over the last
10 years. One study, which aimed to test levels of sensitivity to egg,
peanut, milk and sesame seed, showed that respiratory symptoms were
observed in 12 per cent (egg), 20 per cent (peanut), 10 per cent (milk)
and 42 per cent (sesame), with subjects being highly sensitive to
relatively low levels of the allergens.
Back to How You Beat Asthma