The immune system is an amazing defense mechanism that works on two fronts – defense and offense – to keep you healthy.

On the front line of defense, your body works to resist or attack bacteria or viruses that try to invade your body. Protection can be as simple as the cilia (tiny hairs) inside nostrils and ears that screen out germs. Or it can be as complex as skin secreting acidic oils that prevent the build-up of illness-causing bacteria. Internally, stomach acids, tears and saliva all contain enzymes that destroy bacteria.

If a germ or virus does manage to break through the first barrier, the body launches into attack mode with the release of antibodies that target the invader. Your body determines which antibodies it will use depending on the type of germ it’s trying to kill. In fact, humans are capable of releasing more than 100 billion types of antibodies. And your system also has a great memory – once you’ve had a germ, the immune system remembers which antibody it sent out to combat it – and sends it out again.

How well you eat and sleep determines how good your body will be at fighting off disease. Frequent hand washing is an easy one precaution to adopt. Infectious diseases such as the common cold, influenza and some forms of diarrhea can all be spread through hand-to-hand contact. The World Health Organization says you should wash your hands (using friction) with soap under warm water for a minimum of 10 seconds. Alcohol-based hand sanitizers (those that don’t require water) also work.

Proper nutrition is key, too. For example, a deficiency in zinc may mean your immunity system is not operating at full capacity. A shortage slows the rate at which antibodies attack viruses. Since meat and shellfish are the best sources for zinc, strict vegetarians and vegans are most at risk. The recommended amount of zinc is 15 mgs per day.

Immunity Boosting Tactics

Don’t worry – you don’t have to live in a plastic bubble to avoid catching a bug. Follow these tips and your risk of catching a cold from that the guy in the next cubicle will decrease dramatically.

• Make sure you get enough rest. When you’re in a deep sleep, the pituitary gland increases production of a growth hormone that stimulates the thymus gland. The thymus gland actually “programs” T-cells which go on the warpath to kill bad cells.
• Get moving. Moderate exercise increases your blood flow and gets your immune cells pumping through your body.
• Drink lots of liquids. Mucous membranes in your nose and throat need to be kept moist to stave off viruses. Dr. Keith Berndtson, co-author of The Immune Advantage (available at Amazon.com) says: “In dry, indoor air and especially airplane air, drinking plenty of non-caffeinated, non-alcoholic liquids can make all the difference between catching something and not.”
• Stock up on C. Vitamin C stimulates white blood cells to help combat germs. Nutrition experts recommend at least 500 milligrams a day.
• Take defensive action early. Reach for some Echinacea as soon as you feel a cold coming on. Studies suggest that it can reduce the duration and severity of your illness.
• Beta-carotene packs a mighty immunity punch. Best food sources are carrots, sweet potatoes and green leafy vegetables such as spinach, broccoli and kale.

A healthy lifestyle, starting with proper diet, is your best weapon against illness. Says Simin Nikbin Meydani, director of the Cell and Molecular Nutrition program at Tufts University in Boston: “Eating a variety of foods is the surest way to achieve peak immune function, since each component of the diet contributes to immune response in a different way.”