Our immune system is made up of antibodies and other compounds which defend the body against disease, flu and bacteria.

Professor K.N. Leung from the department of biochemistry at the Chinese University of Hong Kong, says: 'Nutrient deficiency will impair immunity and reduce the body's resistance to infection.'

Adopting a well-balanced diet which contains a variety of nutrients can lessen your chance of falling ill.

Ways to fight infection include the following in your diet:

1 Antioxidants, such as vitamins A, C and E, selenium and zinc, help keep your immune system healthy.

Vitamin A: If you don't get enough vitamin A from the diet, there is an increased chance of getting infections. Vitamin A and carotenoids (plant sources of vitamin A) are essential for immune function in the body. Vitamin A-rich foods include pumpkin, carrot, squash, sweet potato, butternut, broccoli, spinach, kale and pak choi.

Vitamin C: This vitamin can't prevent flu but it does contribute to the body's immune function. White blood cells, which defend our body against harmful substances, contain the highest concentration of vitamin C. Vitamin C-rich foods include citrus fruits, such as oranges, lemons and grapefruit. They have antiviral properties as do strawberries, guavas, cabbage, broccoli, green peppers, potatoes and pineapple.

Vitamin E: This is needed to maintain a healthy defence system. Make sure you meet the daily recommended intake of 30mg a day by including avocado, sweet potato, sunflower seeds, nuts and nut butter, and wheat germ in your diet. Canola and olive oil are also rich in vitamin E.

Selenium: This is found in plant foods, such as Brazil nuts, whole grain cereals, oat bran and beans as well as in some meats, poultry, eggs, shellfish and fish. Selenium is needed to make enzymes that protect cells from damage by free radicals produced during an infection.

Zinc: This is essential for normal functioning of white blood cells. Zinc-rich foods include fish, seafood, especially fresh and canned oysters, meat, poultry, eggs, cheese, milk, peanut butter, green leafy vegetables, oranges, prunes, and unprocessed grains and cereals.

2 Probiotics: Yoghurt, yoghurt products and fermented milk products that contain probiotic bacteria may have the ability to boost immune function.

Ward off colds and flu

Wash your hands frequently and avoid touching your eyes, nose or mouth.

Get enough sleep.

Reduce stress. Too much stress can affect your immune system.

Eat a balanced diet and make sure you drink enough fluids throughout the day.

Exercise: Health agencies recommend at least half an hour of physical activity every day.

Clean your desk: A report by the US Soap and Detergent Association in 2002 found that 46 per cent of Americans don't clean their desk before lunch and warns that this may encourage the spread of colds and flu viruses.