Learn How to boost your immune system and what you can do to stay healthy.

• Green tea: Polyphenols, potent plant antioxidants, are what’s believed to give green tea its immune-boosting effects. One laboratory study suggested that a particular type of polyphenols called catechins may kill influenza viruses.

If you’re turned off by the bitterness of green tea—one downside of
the polyphenols—proper brewing techniques can help. To maximize benefits
and minimize bitterness, the Tea Council recommends using
just-below-boiling water and steeping green tea no more than a minute or
two. A little lemon and honey can also help blunt the bitterness. But
don’t add milk, because the proteins will bind to the polyphenols,
making them ineffective.

• Probiotics: These so-called “good bacteria,” found in yogurt,
sauerkraut and other foods, are touted as helping prevent the GI upsets
many of us succumb to during the holidays. According to a recent review
in the Journal of the American Dietetic Association, regular
consumption of probiotics may help your immune system work better,
reduce the incidence of intestinal infections and improve digestion.

Fermented dairy products such as yogurt or kefir (a yogurt-like
beverage), are good bets. Look for those labeled with a “Live &
Active Cultures” seal from the National Yogurt Association, which
signifies that the yogurt contains a set minimum amount of two
particular types of beneficial bacteria. (While it’s not a guarantee of
probiotic power—the bacterial counts don’t differentiate between added
probiotic organisms and the bacteria that’s used to ferment the
yogurt—the seal is a helpful start.)

With the new “probiotic” cereals and granola bars, it’s not always
clear how much good bacteria the manufacturers actually add to the
products or whether the strains included are effective. If you really
want to know about the science backing a product’s “probiotic power,”
contact the manufacturer.

• A multivitamin: If you’re not eating as well as
you should, consider taking a multivitamin/mineral supplement—one with
no more than 100 percent of the DRV—as extra insurance.

What is the Immune System?

The immune system is a network of cells, tissues, and organs that work together to defend the body against attacks by “foreign” invaders. These are primarily microbes—tiny organisms such as bacteria, parasites, and fungi that can cause infections. Viruses also cause infections, but are too primitive to be classified as living organisms. The human body provides an ideal environment for many microbes. It is the immune system’s job to keep them out or, failing that, to seek out and destroy them.
When the immune system hits the wrong target, however, it can unleash a torrent of disorders, including allergic diseases, arthritis, and a form of diabetes. If the immune system is crippled, other kinds of diseases result.
The immune system is amazingly complex. It can recognize and remember millions of different enemies, and it can produce secretions (release of fluids) and cells to match up with and wipe out nearly all of them.
The secret to its success is an elaborate and dynamic communications network. Millions and millions of cells, organized into sets and subsets, gather like clouds of bees swarming around a hive and pass information back and forth in response to an infection. Once immune cells receive the alarm, they become activated and begin to produce powerful chemicals. These substances allow the cells to regulate their own growth and behavior, enlist other immune cells, and direct the new recruits to trouble spots.
Although scientists have learned much about the immune system, they continue to study how the body launches attacks that destroy invading microbes, infected cells, and tumors while ignoring healthy tissues. New technologies for identifying individual immune cells are now allowing scientists to determine quickly which targets are triggering an immune response. Improvements in microscopy are permitting the first-ever observations of living B cells, T cells, and other cells as they interact within lymph nodes and other body tissues.
In addition, scientists are rapidly unraveling the genetic blueprints that direct the human immune response, as well as those that dictate the biology of bacteria, viruses, and parasites. The combination of new technology and expanded genetic information will no doubt reveal even more about how the body protects itself from disease.

Bacteria: streptococci.

Virus: herpes virus.

Parasite: schistosome.