Tune Your Immune System
Get your body’s defences ready for fall

Kristin Jenkins

Lindsay Morton remembers the day her doctor telephoned her at work. “Your blood tests are back, and you have both mononucleosis and hepatitis,” he said.

Morton, then 37, was stunned: she’d only gone to see her doctor because of lingering laryngitis. So what if she’d been sounding like Marlene Dietrich for two weeks; she felt fine.

“Your immune system is flat,” her doctor insisted. “Go home and get into bed—for at least six weeks. You’re a sitting duck for any kind of infection.”

Morton had assumed her immune system would do whatever it was supposed to to keep her healthy. But after a very difficult pregnancy and a traumatic emergency C-section, followed by marital breakdown, financial difficulties and returning to a hectic full-time job, Morton’s immune system was seriously stressed.

For while the body’s defence system in the war against marauding viruses and bacteria is strong, it’s not infallible. “Granny was right,” says Dr. Brian Ward, chief of infectious diseases at McGill University in Montreal. “If you’re overtired or overly stressed, there can be some  nasty consequences for your immune system.”

To keep your immune system (and others’) well armed against the challenges it faces, check out these recommendations.

1. Keep vaccinations up to date

Various infectious diseases—even a common cold or the flu—can take a sufficient toll on your immune system to put you at increased risk of other infections, including pneumonia and sepsis. “Vaccines are very  important because they provide disease-specific immunity that you just can’t achieve by doing the usual healthy things, such as getting good nutrition,” says Dr. Monika Naus, medical director of the immunization program at the BC Centre for Disease Control in Vancouver. Check with your doctor or public health authority for the recommended schedules for adults and children.

2. Wash your hands several times a day

Sure it’s low-tech, but it’s a good way to ward off germs picked up from infected surfaces. To slide off bacteria and viruses, soap up and rub your hands together for as long as it takes to sing “Happy Birthday” (about 15 seconds). Tell children, who tend to wash their palms only, that each finger has four sides. Not close to running water? Pack your alcohol hand sanitizer, which kills 99% of microbes.

A U.S. study showed that when naval recruits washed their hands at least seven times a day, respiratory infections were reduced by an impressive 45%.

3. Ruby, don’t take your bug to town

While you’re protecting your own immunity, have a thought for the immune systems of others. Instead of passing your infection along to your poor co-workers, see if you can work from home. But if a mere cold won’t wash with your boss, cover your mouth and nose when you sneeze or cough at the office, wash your hands more frequently and avoid shaking hands or sharing utensils in the lunchroom.        

4. Take antibiotics only as needed

Don’t demand an antibiotic from your doctor if she says you have a virus, against which bacteria-fighting antibiotics are useless. Furthermore, adds Naus, “while antibiotics do save lives, there’s a downside: antimicrobial resistance.” When antibiotics kill off weaker bugs, they leave an open field in which hard-to-treat superbugs can multiply. Faced with these drug-resistant strains, the immune system must fight off a more serious challenge. Antibiotics are needed only for stubborn bacterial infections such as bacterial pneumonia, which can take hold during the course of a prolonged viral infection.

5. If you smoke, stop!

Smoking puts stress on the immune system by flooding the body with a toxic cocktail of chemicals that puts you at a higher risk of illness than a non-smoker. And smokers who get a cold or the flu are more vulnerable to challenging respiratory complications such as pneumonia. That’s because smoking interferes with the airways’ natural mechanisms for clearing out infectious agents.

6. Don’t obsess about a clean house

“We now know that a little bit of dirt is probably a pretty good thing,” says Ward. The Hygiene Hypothesis asserts that if you oversanitize your environment, you overprotect your family from germs. So you rob everyone’s immune system of the opportunity to be gently stimulated, educated and programmed by not-too-threatening microbes—similar to the way in which vaccines gently teach the immune system to recognize and fight dangerous germs. Clean but don’t sterilize, Ward suggests. “Intervene if your child picks up dog feces, but you don’t need to dunk his hand in chlorine.” Water is good for most cleaning purposes and water with regular soap and elbow grease is good for 99.9%.

7. Adopt a healthy lifestyle

Get enough sleep and stay physically active. Beware of overdoing the exercise routine, however, as this can tax your immune system and may leave you temporarily vulnerable. Chronic over-exercising may cause the body to produce more immune-suppressing, stress-induced corticosteroids.

And like the microscopic army it is (see “On Guard for Thee,” p. 36), your immune system marches on its stomach. So eat a nutritious, well-balanced diet rich in fluids, proteins, vitamins, minerals and fatty acids. Learn healthy ways to cope with stress. Try not to respond to life’s pressures with poor nutrition, smoking or excess alcohol consumption.

8. Let the good times roll

Norman Cousins, author of Anatomy of an Illness as Perceived by the Patient, reported in 1979 that daily doses of belly laughter, achieved by watching funny movies, helped him recover from a crippling and potentially fatal collagen disease. Studies suggest that laughter may boost immunity by increasing production of white blood cells and antibodies, and by reducing harmful stress chemicals.

To learn more about immunity, read below.

On Guard for Thee

Your immune system is your personal home guard, ready to do battle against bacteria, viruses, cancer cells and all substances foreign. It is a highly organized system of specialized organs, tissues and cells that would put a modern army to shame.

The Generals

Innate immunity We are born with a ready-made immune system that is our first line of defence against infections. Its top brass are the toll-like receptors (TLRs)—sentinel proteins on the surface of immune cells that recognize foreign patterns and alert other cells to kill intruders.

Adaptive or acquired immunity This second line of defence protects against future infection by microbes once you’ve been exposed to them through infection or vaccination.

Maternal immunity Some protection is passed from mother to unborn child via the placenta and to the newborn via colostrum from breastfeeding.

Now meet some of the troops and their battlegrounds.

The Border Patrols 

The skin, the nose hairs and the mucous membranes lining the gut and respiratory tract act as barriers to illegal aliens. Stomach acid breaks down bugs, while benign bacteria proliferating in the intestines help crowd out infectious agents.

The Barracks

The bone marrow—soft tissue that fills cavities in the bones—is a factory that produces many of the immune system’s white blood cells, or leukocytes.

Military Intelligence

The leukocytes can recognize a returning pathogen and destroy it before it causes another infection.

Convoy Lines

The lymphatic system of vessels produces small dedicated white blood cells called lymphocytes and conducts them all over the body to fight off invaders. The lymph nodes, tiny masses of lymphatic tissue, collect bacteria and toxins.

The Engine Room

Located behind the breastbone, the thymus makes several types of white blood cells known as T- (for thymus) lymphocytes. 

The Rank and File

Natural-born killers Phagocytes (“eater cells”) capture invading microbes by sticking to them, ingesting them and then dissolving them with enzymes.

Mop-up operations A complex series of enzyme proteins in the blood, called the complement, deconstructs microbes after they’ve been ambushed by white blood cells.

Smart bombs Immununoglobulins, better known as antibodies, immobilize bacteria and viruses by targeting proteins on their surfaces.

Special forces Killer T-cells induce death in virus-infected and cancer cells. Helper T-cells act as auxiliary troops that release immune cells to clear away stragglers and make booster agents called cytokines, which stimulate the production of more T-cells.

Reconnaissance Dendritic (branched) cells patrol the body looking for foreign elements. They break them apart, then present them on the ends of their branches for destruction by killer T-cells.