Asthma is an increasing common chronic disease of the respiratory system that now affects 10-15 percent of all children, as well as a high percentage of adults.

A common early symptom is a persistent cough and a little wheezing, especially at night. In an acute attack, which can be quite dramatic, there is increasing wheeziness and breathlessness, a feeling of tightness around the chest and a struggle for air.

This is caused by a tightening of the muscular walls of the small airways, which narrows the airways and consequently obstructs the flow of air into and out of the lungs.

Although some people with asthma believe that allergies to particular food can trigger their attacks, most doctors believe this applies to no more than 2-3 percent of people with the condition.

You should aim to follow a healthy eating program, making sure that you eat a good variety of fruit and vegetables every day. This will ensure a good intake of the anti-oxidant vitamins A, C and E that help to fight free radicals. These chemicals are formed in the body in response partly to cigarette smoke and other pollutants and can play a part in triggering inflammation in the airways.

Vitamin C may also promote good lung health and help the airways to resist narrowing. Researchers, who found that eating five or more apples a week was associated with improved lung function, suggested that this might result from high levels of an anti-oxidant called quercitin. As well as in apples and other hard fruits, it is found in onions, tea and red wine.

Magnesium may help relax the airways. Dark green vegetables, courgettes, peas, fish and sunflower seeds are good sources.

Caption: Dark green vegetables, such as broccoli, can provide magnesium.

A beneficial recipe for asthma:

Strawberry and cucumber salad with balsamic dressing

Ingredients:

1 cucumber, halved lengthways, deseeded and thinly sliced.

250g strawberries halved or quartered if large.

Preparation time: 10 minutes plus chilling

Balsamic dressing:

1 tablespoon balsamic vinegar

1 teaspoon coarse-grain mustard

1 teaspoon clear honey

3 tablespoons olive oil

pepper

1. Place the cucumber and strawberries in a shallow bowl.

2. To make the dressing, put all the ingredients in a screw-top jar and shake well.

3. Taste the dressing for seasoning and adjust if necessary before pouring it over the cucumber and strawberries. Toss lightly to coat and chill for 5-10 minutes before serving.

Editor: Donald