Your body contains a wonderful mechanism to fight off illness-causing organisms that try to invade your body regularly. This mechanism is called the immune system whose function is to destroy and clear away foreign substances, such as viruses and bacteria. Eating a healthy well-balanced diet helps you to receive the protective effects of vitamins and minerals. Many vitamins and minerals are being studied for their beneficial effect on the immune system:

Vitamins A, C & E: May prevent cell damage from free radicals
Vitamin B6 & B12: May boost the immune system
Zinc & Selenium: May improve white cell activity in the blood

Some helpful hints

• Eat a healthy, whole food diet (unprocessed grains).
• You should eat at least five servings of fresh fruit, vegetables or salad per day. Eat as many of the above raw when possible to preserve the nutrient content. Fruit and vegetables are rich in vitamins, minerals, anti-oxidants and immune-boosting substances know as phytochemicals, which help to protect against disease. Cherries, strawberries, grapes, yellow-orange fruit and vegetables (e.g. apricots and carrots), tomatoes and dark green leafy vegetables such as broccoli are especially beneficial.
• Even a relatively minor lack of some nutrients can lower your immunity and lead to an increased risk of disease. For example, viral infections are more likely in those lacking selenium. High selenium levels help prevent viral reproduction; the richest source is Brazil nuts - 4 Brazil nuts cover the recommended daily allowance.

Although all vitamins have specific jobs in your body, some have partners

• Vitamin B1: Works with niacin, panthothenic acid and magnesium in the digestive system
• Vitamin C : Helps folate build protein
• Vitamin D : Helps the body absorb calcium and phosphorus
• Vitamin E : Keeps vitamin A from being destroyed

Eat oily fish (e.g. salmon, mackerel, herring, sardines) at least once or twice a week. These contain omega-3 essential fatty acids important for good immune function. If you don't like fish, take an omega-3 supplement instead.

Eat organic produce. Choosing to eat organically-grown food helps to maximize intake of trace elements such as selenium found in broccoli, onions and whole grains, which are needed to make antibodies and reduces exposure to agrochemicals, such as pesticides, that may affect immune function.

Take regular exercise. Regular exercise can boost your immunity.

Get a good night's sleep. Sleep is a time for relaxation, regeneration and rejuvenation in which growth hormones and other vital substances involved in healing and fighting disease are secreted.

Take vitamin and mineral supplements. While a good diet should always come first, a multi-nutrient supplement provides a nutritional safety net. Choose one that contains 100% of the recommended daily amount (RDA) of as many vitamins and minerals as possible.

High dose vitamin C with bioflavonoids helps to protect against viral infections (a daily intake of 100 to 1000 mg is recommended).

Cigarettes. Avoid smoky atmospheres as they damage the nasal lining and don't let anyone smoke in your house. Respiratory illnesses are more common in smokers and those exposed to second-hand (passive) smoke.

Stress. When you are stressed and run down, you are twice as likely to develop symptoms when exposed to a common cold virus. This is thought to be a result of high levels of stress hormone and depleted adrenal glands that somehow interfere with the immune system.

Herbal supplements
Many natural herbs are known to boost the immune system; popular boosters include:

• Garlic tablets, which have a natural antiseptic, antibacterial and antiviral action.
• Ginseng, which increases resistance to stress and infections