Immune system is the system of body that makes the body fight infections. Daily, we are exposed to millions of disease causing germs and due to an active immune system; we do not fall sick often. The factors which make a person sick include the amount of germs that cause infection and the state one’s his immune system. For example, if 2 people are exposed to the same source of infection like contaminated food, the one with weakened immunity may have diarrhoea, whereas the one with a strong immunity may not be affected. It is important to have a healthy diet which contains antioxidants and fiber. This provides nutrients, as well as improves digestion and immunity. Antioxidants also prevent and help fight against cancer. Examples of such foods include fresh vegetables - spinach, broccoli, cabbage, onions, carrots, whole grains and nuts. Fruits like berries, oranges, bananas and coconut are all very useful in this regard. Avoid white sugar as it provides only calories with no nutrition. Avoid foods high in fat and cholesterol like margarine, butter, etc. Omega 3 fatty acids help in preventing wear and tear of body and boost the immune system. Walnuts and fish are a natural source of omega 3 fatty acids. It is therefore better to have more of vegetable than animal products like meat in the diet. Diet should also include adequate amount of proteins, because proteins are needed to make antibodies in the body, which contain infectious germs. One should give due attention to the amount of calories consumed to avoid obesity as well as being underweight because both these conditions impair immunity. The amounts of calories are based on gender and level of physical activity of a person. Ready-to-eat fast foods and junk foods contain chemicals as preservatives and flavouring, colouring agents which harm the immune system. Hence one should avoid them. Meals taken should be preferably freshly cooked and eaten. Sodas and bottled juices containing preservatives are also not very healthy; they should not be taken on a daily basis. Alcohol, tobacco and other abusive substances tend to weaken the immune system and it is best to avoid them. Good hygiene is important in keeping immunity strong. Repeated exposure to infections, particularly a heavy dose will tend to weaken immunity over a time due to the load, hence stress put over it. Good hygiene can prevent this. It includes personal cleanliness and cleanliness related to preparation, serving and eating food. Good hand washing goes a long way in improving immunity and preventing diseases. Safe sex and good hygiene after intercourse prevents sexually transmitted infections. Regular physical exercise is necessary to keep the body healthy, avoid obesity and also rejuvenate the cells and tissues of the entire body. Thus it also helps to boost the immune system. One should do some exercise or physical activity regularly. Current studies suggest that doing exercise just once in the morning or evening and then sitting glued to a chair all day is not healthy. After 2 hours or so of sitting continuously for any work, a person should move about physically for 15 to 20 minutes, and then resume his work again. Mental or physical stress and lack of adequate sleep are other conditions that tend to weaken the immune system. This is because of release of harmful chemicals which augment wear and tear of cells. Hence one should avoid stress and take adequate rest. If one follows all these measures, the body’s immunity will always be strong and risk of infections and cancer minimized. Dr. Rachna Pande is a specialist in internal medicine rachna212002@yahoo.co.uk