Do you know how many invaders our body has to fend off every day? From someone sneezing over you on the underground to what you might find on or in your food.

Invaders come in many forms. These include viruses, bacteria, yeast, parasites, incompletely digested food particles, environmental chemicals and free radicals (ie highly reactive particles that may damage cells). If poorly nourished, your immune system will not function to its maximum potential and you'll be more susceptible to infections and their worst effects.

Your body's ability to react quickly to a new invader might make the difference between a slight sniffle and a week in bed with a full blown complaint.

The immune system is one of the most remarkable systems in the human body, with the responsibility of both identifying and then disarming each of the million foreign bodies we might encounter.

There are two lines of defence which the body must rely on. The first prevents bugs entering the body e.g. skin, tears, tiny hairs in nose and respiratory tract, mucous, stomach acid and friendly gut bacteria which keeps unwanted visitors under control. The second swings into action if the first line of defence is breached e.g. the lymph system which carries defence cells, white blood cells which are the main defenders, red blood cells which deliver oxygen and defence cells, plus antibodies which identify and destroy the invaders.

Your body needs essential nutrients that include B vitamins, vitamin A, C & E, zinc, magnesium and selenium which each have direct actions on the immune system.

A well-balanced diet to include good sources of protein (e.g lean chicken, lamb or beef, fish, nuts and seeds, eggs, soya products, pulses and legumes), whole grains (e.g. brown rice, rye, oats, barley, quinoa), plenty of colourful fresh fruit and vegetables rich in phytonutrients and low in saturated fat (with fats obtained from essential sources such as nuts, seeds and fish) is the way to boost your immune system. It is important to ensure that both the body's respiratory and digestive tracts are looked after and why you need to ensure that your diet contains all the nutrients to help support your immune system.