Making a juice using your favorite fruit and vegetables is the perfect way to ensure your daily diet receives all the essential nutrients and vitamins

Both common cold and flu are caused by viruses, because new strains of viruses are constantly emerging, people seldom develop any immunity. Children are more vulnerable than adults, and so are people who live or work in conditions where the virus can spread rapidly.

For people in a high-risk group, such as diabetics, flu vaccination is advisable. It is now offered to anyone working in an institution for the elderly or sick. The vaccine carries little risk, but because it is made from egg protein, it should be avoided by anyone who is allergic to eggs.

We all get a cold from time to time, but you may be able to boost your resistance to cold viruses by eating plenty of the foods that enhance your immune system. In particular, ensure that your diet is rich in foods that contain high levels of vitamin A and vitamin C.

Beta-carotene, which is used in the body to make vitamin A, is found in all red, yellow and orange fruit and vegetables, especially apricots oranges, pumpkins, sweet potatoes, carrots and red peppers, vegetables such as broccoli and salad greens like watercress.

In order to boost your vitamin C intake, opt for citrus fruit and juices, blackcurrants, strawberries, blueberries and kiwi fruit --- you can combine it with other fruit in a juice if you do not enjoy it on its own.

Leafy green vegetables and broccoli are also good sources, but eat them as soon as possible after purchase, as the vitamin content diminishes with time. Steam or boil them for a short time to conserve vitamin Cc.

Garlic is said to help your immune system resist infections, so add it to stews, salad dressings, sauces or meat such as lamb whenever you can.

If you are unlucky to get a cold or even worse---flu, you may not feel like eating much for a few days. However, fruit juices or hot drinks made with lemon ice, honey and water may help both to soothe your throat and keep up your fluid intake.

Dietary tips

Some experts believe that very high intakes of vitamin C may not only help to ward off colds and flu but also shorten their duration if you do succumb to an infection. However, the suggested amounts are so high that you may not be able to reach them without taking plenty of vitamin supplements.

Vitamins may be more effective when consumed in their natural form - that is, in fruit, vegetables and so on --- because their action is enhanced by other substances that are not found in supplements, such as flavonoids.

Complementary therapists sometimes advise avoiding milk and other dairy produce when you have a cold, on the grounds that they encourage the production of mucus; so you may like to try cutting them out while you have symptoms.

Editor: Donald