The immune system is the body’s silent but powerful defense mechanism against “foreign invaders”. These invaders might be those capable of causing infections such as viruses, bacteria or fungus. On the other hand these invaders may be the body’s own cells, growing in an abnormal malignant fashion.
The immune theory of ageing suggests that as we get older our immune system becomes less efficient and we become more prone to infections and cancer. Even in the recent severe acute respiratory distress syndrome (SARS) epidemic the disease was more severe in the older age group. Hence having a powerful and efficient immune system could be one of the keys to age successfully.
Like the brain, the immune system is one of the body’s most complex organizations. The precise coordination of the billions of cells and numerous chemicals is truly phenomenal.
Our immune system
The immune system is composed of billions of white blood cells that move in and out of the immune system organs such as the thymus, lymph nodes, liver and spleen. These disease fighters also travel in the in the blood system and lymphatic channels to wherever they are needed, for instance to the skin, intestine, lungs or brain. Each cell is very specialized and they all interact with each other in intricate, very rapid patterns to protect us from foreign invaders.
The five main cells in the immune system are:
- The T-cells : helper, suppressor and killer
- The B-cells
- The macrophages
The system is never totally at rest. It is on guard 24 hours a day. The most important task of the immune system is the recognition of its own cells against an intruder or foreign invader.
Macrophage- The macrophage is a large cell that wanders around the body looking for intruders and is usually the first cell to come in contact with an invader. Macrophages can flow along with the blood and can move very fast when stimulated. When really stimulated , they actually eat live virus, bacteria and cancer cells. If they have any problem in identifying an invader, they can call a T-helper cell for verification.
T-helper cell- This cell is the main cell of the immune system because it is the cell that activates the whole system to go to war. AIDS is a disease of the T-helper cell. The T-helper cell works with the macrophage in identifying an intruder. Besides just turning the system on, the T-helper cell excites the whole immune system. He starts the war and keeps it going at a high level of activity. To keep the balance someone has to calm things down when the war is over. That’s where the T-suppressor cells come in.
T-suppressor cell- The T- suppressors calm down the immune system when the war is over. When the battle is won, the suppressors slow down the activity and restore the system to normal.
B-cells- These cells produce antibodies. These are specific chemicals to destroy or neutralize invaders. Each antibody is designed for one invading organism.
T-killer cells- They are our first line of defense against cancer cells. They are able to recognize own cells gone badly and destroy them before they can multiply and cause harm.
Immunity and ageing
The following features of the immune system are associated with ageing:
- Cell-mediated immunity wanes, leading to a resurgence of tuberculosis and varicella (in the form of herpes zoster).
- Mucosal immunity declines.
- There is a decline in humoral immunity (antibody production), but only to antigens requiring T- helper cells which are depleted following thymic involution. This impairment of immune surveillance may impede the elimination of abnormal and neoplastic cells. Hence the use of thymic extracts to boost immune response has shown results.
- Immunization to influenza remains effective but that to hepatitis seems to less so.
- The T- suppressor cells function less well, so auto-antibody production increases leading to some increase in autoimmune diseases.
- The macrophage response seems less vigorous.
- Malnutrition and diabetes are likely to compound these problems.
Gerontologists believe that this failure in immune system that ultimately leads to premature death in an older person.
The question is what weakens the immune system and what can we do to maintain and strengthen the immune system.
Immune System Destroyers
- Inadequate rest- This includes adequate sleep. Poor sleep quality and insufficient rest weakens the immune system.
- Fat and high cholesterol- Lab. Studies have shown that the speed of the macrophages had slowed down considerably in people with high cholesterol levels.
- Heavy metals- Such as lead, mercury and cadmium all depress the immune system even at very low levels.
- Over consumption of sweets and junk food.
- Alcohol and Tobacco abuse
- Toxic environmental chemicals- Pesticides, herbicides and the thousands of chemicals from our huge industrial complex.
- Obesity- Depresses T-cell response and movement of the macrophages
- Hormone deficiency- Especially growth hormone as this is needed for the various cells to communicate with each other.
- Free radical damage- This reduces the response of the whole immune system.
How to maintain a healthy immune system
This includes correcting all the above factors.
A well balanced healthy diet with a lot of fruits and vegetables and high quality protein is important.
There are also certain nutrients that are known to boost the immune system.
Immune system boosters
- High quality low fat protein
- Echinacea- To be used as needed rather than on a continual basis.
- Gamma linolenic acid
- B vitamins
Due to advances in biotechnology various new products will soon become available to further boost our immune system. This includes products like thymic extracts, stem cell technology to deal with cancer cells and nanotechnology where “smart bombs” will be injected into our system to look out for and destroy any cancer cells.
However it is important to remember that a healthy lifestyle is still the key for a healthy immune system and a healthy immune system is one of the important keys to longevity.