A Robust Immune System

The No.1 Advantage of Healthy Eating

The Body’s Staunch Defender

With every breath we take, we enable foreign bodies to enter our system. Everything we touch contains microbes that might carry diseases. Even the food we eat can wreak havoc in our bodies with all the chemicals they now contain. Every moment of our lives, we are exposed to countless agents that can do our body harm. But thanks to the body’s efficient Immune System, we can go about our lives without worrying like a hypochondriac.

From our skin, to our gut, and our ever vigilant leukocytes, our body’s multiple levels of defense ensure our health and safety. But we also have to ensure that our immune system stays strong and efficient.

It’s All About the Logistics

An effective defense is not just about “firepower;” the logistics are just as important. The body’s biggest organ – the skin – actually also serves as its first line of defense against foreign invaders. The skin does not only serve as a physical barrier between the dangers of the outside world and the body’s internal organs; it also functions as a warning system and has the ability to destroy and remove invading bodies, with its own network of specialized immune cells.

Given that one of the most common ways that foreign material enters our body is through ingestion, it only makes sense that the gut is also an integral part of the immune system. The gastrointestinal system is home to a huge amount of immune cells, as well as healthy microbes – gut flora that work hand-in-hand with the immune cells to fight harmful foreign agents that get swallowed with food.

The rest of the immune system – composed of lymphoid organs, so called because they house lymphocytes – is positioned throughout the body. Lymphocytes or white blood cells are the immune system’s key players; they are like the soldiers that do the actual fighting to protect the body against infections and diseases. The lymphoid organs include the bone marrow, where white blood cells are produced; the thymus, where T cells or T lymphocytes, a special type of white blood cell that circulates throughout the body, mature; the blood vessels and lymphatic vessels, which transport and circulate immune cells throughout the body; lymph nodes, clustered in the neck, armpits, abdomen, and groin and also found inside lymphatic vessels, which also house large amounts of immune cells; and the spleen, which provides compartments for immune cells to collect and work.

It is important to note that the major entryways to the body – the digestive tract, airways, and lungs – are lined with clumps of lymphoid tissue as part of the body’s natural defense.

Multiple Levels & Avenues of Defense

The body has three kinds of immunity: innate, acquired, and passive.

We are born with an innate immunity, which protects the body against all antigens (an antigen is any foreign body that induces an immune response). Our body’s innate immunity includes our cough reflex, certain enzymes and oils, mucus, stomach acid, certain proteins, and the skin, among others.

Acquired immunity develops when the body encounters various antigens and the immune system builds a specific defense against each and every one of them.

Passive immunity comes from antibodies that are produced outside our own body – by another person or an animal – and provides immediate but temporary protection. Examples are the tetanus antitoxin and other drugs.

How Our Complex Immune System Works

As much as possible, the immune system, mainly through the skin, does a fine job of keeping out foreign invaders. When they fail to do this, the immune system seeks out and destroys these invaders. The amazing part is how the immune system is able to recognize and remember the different enemies it needs to fight against – enemies that number in the millions – and to produce cells and secretions to counteract each and every one of them.

When the immune system detects a foreign body, an immune response is triggered and an attack is launched. The immune response includes the formation of antibodies, which attach to the specific antigen to make it easier for the immune cells to destroy it; and the attack itself, which is performed by the T lymphocytes. Physically, an immune response can manifest in the form of a rise in body temperature (fever), an allergic or inflammatory reaction (such as a rash and the sniffles), coughing, and mucus, among others.

When there is physical damage or injury due to trauma, heat, toxins, bacterial infection, and other causes, the immune response comes in the form of an inflammation. The damaged cells release chemicals which cause the blood vessels to leak fluid into nearby tissues, thereby causing swelling/edema. The swelling caused by the leaked fluid allows white blood cells to enter the affected area and fight infection, and also isolates the area so that it does not affect the surrounding tissues.

As mentioned above, the immune system has the amazing ability to remember all foreign bodies it encounters, so that when the body encounters the same ones, it can either respond faster and more efficiently or our body won’t fall ill again. As we often say, we build up an immunity against them. To experts, this is known as immunological memory. Every time we encounter a new disease-causing foreign body, the immune system performs its function of fighting the foreign invader and “remembers” the particular foreign invader.

Keeping It Strong & Healthy

Needless to say, a healthy immune system translates to a healthy body. We don’t get sick from every, single foreign body we encounter. We recover faster from injury or an infection. Age, of course, is a factor that affects the health of our immune system. Our lifestyle choices and our eating habits also determine how efficiently our immune system functions.

Here are some key points, as outlined by the British Society for Immunology, to remember about keeping the immune system in tip top shape:

• As the immune system needs a lot of the body’s resources to function, any decline in essential nutrients is likely to have an effect. When nutrients are scarce, the body tends to favour the brain and certain other organs, and this can also affect the immune system. However, this tends to be in cases of severe malnutrition. It is always best to eat a balanced, and healthy, diet.
• Most nutrients with antioxidant capacity (eg .Vitamin C, E, selenium, beta-carotene and other carotenoids) are associated with enhancing immune function, particularly in the elderly. In terms of dietary advice, however, care should be taken not to exceed upper levels of normal dietary intakes, as this may in fact have a detrimental effect. Citrus fruits are a good natural source of Vitamin C, for example.
• Although Vitamin D used to be associated solely with developing strong bones, there is mounting evidence that it could play a role in the prevention or treatment of certain diseases through its effect on the immune system – including beneficial effects for respiratory health. Vitamin D is created naturally in the skin by the body, through the action of UV light. Recent concerns about the development of skin cancer through over exposure to sunlight are important to note. However, as long as exposure isn’t excessive (and appropriate protection is applied) there are still benefits to going out in the sun!
• Stress can affect immune function – one example being marathon runners and frequency of respiratory tract infections where there seems a ‘window of opportunity’ for infections immediately after a run, where the immune system is suppressed. Depressed individuals have also experience suppressed immunity, as the nervous system can directly interact with immune cells. So-called ‘Neuroimmunology’ is a new and emerging field of study. Exercise (provided not excessive) is a simple way to beat stress and improve mood.
• Although extracts of the plant Echinacea have been claimed to improve immune function, and there are various models that may show some effect, there are, as yet, no proper clinical trials demonstrating any benefit on human immune function, in terms of health outcomes. ( Source: www.immunologyexplained.co.uk )

For an in depth study of the Human Immune System, check out the Wikipedia.org article. Θ