Genetic Health Aging Immune System

There is no getting around it. Our bodies change as we grow older, including our immune systems. Your immune system is an integrated defense mechanism against infection. When invaded by foreign organisms — such as viruses or bacteria or molecules like pollen — the immune system rallies the troops for battle. But like an aging foot soldier, the immune system loses some of its effectiveness as we age. Will this once-powerful defense system let us down? Is there anything we can do? While you cannot stop aging, you can take steps to boost your immune system to prolong its tour of duty.

Concerns About Aging

You do not come into this world with your immune system fully developed, and it will more than likely not be as effective later in life. You may be concerned that changes to your immune system will make you more susceptible to infection and diseases, such as cancer. To take steps to boost our immune system, it is helpful to understand what happens to the immune system as we age.

The Aging Immune System

The thymus is one of the organs in the immune system’s arsenal. The thymus houses T-cells, one of the major components of the immune system. T-cells destroy pathogens that cause disease, as well as the cells infected by those pathogens. As you age, your T-cells become less effective, and parts of your immune system weaken.

The thymus shrinks as you age, and can become non-functional by age 60. It is not clear what effect this has on immunity in our old age, since most of the T-cells have already passed through the thymus by then.

The immune system can have only a set number of T-cells in operation at any given time. The more threats we encounter, the more cells become assigned to memory. A reserve of T-cells is needed to respond to new threats. If too many cells are assigned to memory, sooner or later we will not have enough T-cells left in our defense.

Some of the effects of aging on our immunity system may include:

  • autoimmune disease, as our body becomes less tolerant of its own cells
  • decreased ability to fight disease
  • increased risk for cancers
  • increased risk for infection.

Tips for Staying Healthy

There are things you can do as you age to stay healthy and to combat or manage disease. Health care providers may recommend certain immunizations, such as those to prevent pneumonia, flu vaccines, or hepatitis immunizations, as you age. These are generally optional immunizations and may not be necessary for all older people.

There are positive behaviors that can help you maintain a healthy immune system as you age, including:

  • eating a well-balanced diet
  • exercising
  • moderate use of alcohol
  • not smoking.

The above behaviors can either boost your immune system no matter what your genetic makeup might be. The reward just might be a healthier, longer life.


Newman, J. (2004).Why does aging reduce immune system function? Retrieved from June 29, 2009, from the Medical News Today Web site:

Fight Aging. (2006). When and how does the decay of the immune system start?. Retrieved June 26, 2009, from the Fight Aging Web site:

Medline Plus. (n.d.). Medical Encyclopedia: Aging changes in immunity. Retrieved June 26, 2009, from the Medline Plus Web site: