Introduction

Every minute of every day our body is exposed to bacteria, viruses, and fungi that can gain entry to our body either through open areas on the skin or by being ingested via our respiratory or digestive passages. Some of these minute microbes are benign and mean us no harm. Others have a more sinister agenda and look to take up residence and multiply. Thanks to the vigilance and precision of our immune system, the majority of these invasive interlopers are shown the door or destroyed. But sometimes, a germ can take hold and make us sick. This is why it’s important to provide support for our immune system in every way we can.

Our immune system is just that, a system that functions within a series of checks and balances and includes a working “memory” of all the antigens it has encountered, and how to handle them, for future reference. Many different types of cells (each designed for a specific purpose), tissues, and organs make up our “inner guard” as a whole. Through a series of steps, called the immune response, the immune system works to protect us from getting sick.

Effects of our lifestyle on our immune system shouldn’t be overlooked or dismissed. Quite a number of researchers are exploring the effects of diet, exercise, age, psychological stress, herbal supplements, and other factors on the immune response, both in animals and in humans. 1 What you eat, how much you sleep, your blood pressure, your age, and the amount of stress in your life can all have an effect on the efficiency of your immune system. Let’s take a closer look at some specifics.

An Overview of the Immune System

The crucial cells of the immune system are lymphocytes and macrophages. Two important types of lymphocytes are 1) B lymphocytes (or B cells) and 2) T lymphocytes (or T cells). Another more ominous type of lymphocyte are cells known as natural killer (NK) cells. The role of the macrophage cell is to assist lymphocytes with what they do. Upon maturation, B cells are like the body’s “military intelligence” system, seeking out targets and sending defenses to the site. T cells are like the soldiers, destroying the invaders identified by the B cells. Macrophages come in afterward and clean up the battle ground.

NK cells operate, more or less, on their own by “policing” the body in blood and lymph. They can kill virus-infected body cells well before B cells are even enlisted in the fight. Unlike certain lymphocytes which can only recognize and react against specific virus-infected cells, NK cells can act spontaneously against any such target by recognizing certain sugars on the “intruder’s” surface. NK cells attack the target cell’s membrane and release several chemicals. Shortly thereafter, the target cell’s membrane and nucleus disintegrate.

The cells of the immune system circulate through the body between lymphoidorgans, including the thymus, spleen, and bone marrow. Lymph nodes, clumps of lymphoid tissue located in the neck, under the arm, and at the groin, also house immune system cells.

Lymphocytes all begin life the same. Where they mature, or become immunocompetent, depends on where they migrate to. Some lymphocytes migrate and mature in the thymus. Others migrate and mature in bone marrow. An important part of a lymphocyte’s maturation process is the cell’s ability to recognize “self” (self-antigens), or the body’s own cells.

An inability to recognize one’s own cells can lead to the body turning on itself, otherwise known as autoimmune disease. Lymphocytes that cannot distinguish self from foreign antigens are not allowed to mature and are destroyed.

Lymphocytes grow and mature and specialize, much the same way we do as we grow older and choose a profession. During the maturation process, all the receptors on the cell’s surface start to gear themselves toward recognizing one specific type of antigen or another. For example, the receptors of one lymphocyte might recognize part of the hepatitis A virus, while another lymphocyte’s receptors might recognize only the pneumococcus bacteria.

Macrophages are formed in bone marrow. The word “macrophage” literally means “big eater” which fits in perfectly with their main role in the immune response. T cells release chemicals that cause a serious case of the munchies in macrophages, which turns them into killer macrophages, actively engulfing foreign particles like a starving man with a bag of Cheezies. These interactions between lymphocytes and macrophages are the basis of virtually every phase of the immune response.

Signs of a Weakened Immune System 
Now that we have a basic understanding of some of the more central elements of the immune system, it’s time to look at how to recognize an immune system in a weakened state. If a person falls sick at the drop of a hat, and with alarming regularity, it is very likely that his/her immune system is lacking. Some common signs of impaired immune function include:

• Fatigue and listlessness
• Repeated infections, slow recovery time
• Chronic cough, runny nose, watery eyes, body aches
• Allergic reactions
• Wounds that are slow to heal
• Frequents cold and flu

Age and Immunity

What We Do Know For Sure Is That We Don’t Know For Sure
Immunogerontology is the study of the immune system in the elderly and arose as a direct result of the human race living longer now than ever before. As a relatively new field, definitions have yet to be agreed upon, and not a lot of studies have been conducted nor data collected.

Current understanding of our immune system’s functionality appears to show that as the body ages a reduction in immune response capability occurs. This can lead to an increase in the number of respiratory infections, colds, flus, and inflammatory diseases (such as arthritis) you may contract. It is thought that the decreasing number of T cells (soldier cells) might be the problem and can be attributed to an aging thymus; the older we get, the less it produces. However, the sad fact is that, as an extremely energy-expensive organ, the thymus begins to deteriorate by the time we reach 12 months of age. It’s thought that if we lived to age 120, we would have no thymus at all.

The rate of B cell maturation also decreases with age. Although B cells are produced in the bone marrow throughout life, the number of B cells generated declines with age. Having fewer mature B cells contributes to the observed decrease in the amount of antibody produced in response to infection. 2

Another reason thought to affect the speed and efficiency of the immune system is drop in a T cell’s ability to communicate what’s on the outside to the inside. When a T cell binds to an antigen on the outside, a call to action must be communicated to the inside of the cell. This communication involves a cascade of chemical reactions, each dependent on the previous step to be completed properly. T cells in older individuals seem to be missing crucial proteins on the cell’s surface which results in no response from the inside to the presence foreign pathogens on the outside. What we do know for sure is that we don’t yet fully understand why our ability to fight disease drops off with age.

Immune-Building Tips

Nutrition
Like “location, location, location”, “nutrition, nutrition, nutrition” is something you’ll hear a lot of and is of key importance when proactively trying to maintain a healthy immune system. After all, most of the vitamins, minerals, and nutrients needed by the body are obtained through a healthy, well-balanced diet of antioxidant-rich fruits and vegetables, lean proteins, whole grains, and low in saturated fat.

Weight A healthy diet will also help keep you at a healthy weight. This doesn’t mean you can’t indulge once and a while, but save the sweet treats for a special occasion.

Exercise
Maintaining a healthy weight also relies on daily exercise. Try to get out into the fresh air as much as possible. Even better, get out with friends and enjoy an activity together. If mobility is an issue for you, try some of the techniques geared to individuals who feel more comfortable exercising in a chair.

Don’t Smoke
If you’re putting all that effort into maintaining a healthy weight and getting your daily exercise, it seems counterproductive to continue to smoke. Smoking weakens the immune system by depressing the production of antibodies that protect against antigens. There also appears to be a significant decrease in the overall number of immune cells that normally help the body fight off these pathogens. The good news is that all this can be reversed when you quit smoking.

Stress Levels and Blood Pressure
A little stress is okay, a lot is not, and here’s why. While under the influence of stress, your body produces chemicals (catecholamines) that raise your blood pressure and heart rate. Increases in the presence of these chemicals have been shown to suppress aspects of immune function. In fact, it is thought that high levels of epinephrine (raises heart rate) and norepinephrine (raises blood pressure) in the body inspire lymphocyte migration from bone marrow and the thymus to other areas of the body. When the immune system is suppressed, as it is under stress, latent viruses can stage a comeback and new antigens can gain a foothold.

Many researchers report that stressful situations can reduce various aspects of the cellular immune response. A research team from Ohio State University that has long worked in this field suggests that psychological stress affects the immune system by disrupting communication between the nervous system, the endocrine (hormonal) system, and the immune system. These three systems “talk” to one another using natural chemical messages, and must work in close coordination to be effective. The Ohio State research team speculates that long-term stress releases a long-term trickle of stress hormones — mainly glucocorticoids. These hormones affect the thymus, where lymphocytes are produced, and inhibit the production of cytokines and interleukins, which stimulate and coordinate white blood cell activity.3

Another study was carried out to determine to what extent stressors affected NK cells. A significant correlation was found between the capacity of individuals to cope with daily life stress and their NK activity. Individuals who were diagnosed as having anxiety neurosis had a significantly weaker NK activity.4 It sort of gives a whole new meaning, with regard to your immune system, to the saying “Keep Calm and Carry On”.

A few more steps to maintaining a healthy immune system include:

Using Nutrition to Boost Your Immune System

A diet rich in antioxidants can help boost resistance to illness. Think of “eating in color” to help maintain a healthy immune system and ward off infection. Choose dark green, red, yellow, and orange fruits and vegetables for their antioxidant value. Particularly good options include berries, citrus fruits, kiwi, apples, red grapes, kale, spinach, sweet potatoes, and carrots.

Don’t discount the old standards like chicken soup. A steaming bowl of this golden liquid can open nasal passages and help relieve inflammation. Studies on garlic reveal antiviral and antibacterial qualities and mushrooms, such as Reishi and Shiitake, contain immune-boosting and infection-fighting properties. To get more specific about it, let’s take a closer look at individual vitamins and minerals.

Selenium and Vitamin E
When combined with vitamin E, selenium protects the immune system by preventing the formation of free radicals that can damage the body. Selenium and vitamin E act synergistically to aid in the production of antibodies. Selenium can be found in Brazil nuts, broccoli, brown rice, chicken, salmon, wheat germ and whole grains while vitamin E is found in avocados, cold-pressed oils (olive, sunflower) dark green leafy vegetables, oatmeal and sweet potatoes.

Vitamin A
Vitamin A plays a role in fighting infection and maintaining mucosal surfaces by influencing certain subcategories of T and B cells and cytokines. Vitamin A deficiency is associated with impaired immunity and increased risk of infectious disease. Vitamin A can be found in apricots, asparagus, broccoli, carrots, cantaloupe, garlic, kale, peaches, spinach, and sweet potatoes.

Using Nutrition to Boost Your Immune System, cont.,

Vitamin B6 (Pyridoxine)
Several studies have suggested that a vitamin B6 deficiency can depress aspects of the immune response, such as lymphocytes’ ability to mature and spin off into various types of T and B cells.5 Sources of vitamin B6 include eggs, chicken, peas, spinach, sunflower seeds, walnuts, and carrots.

Vitamin C
Vitamin C aids in the production of anti-stress hormones and interferon, an important immune system protein. It also helps protect against the harmful effects of pollution, protects against infection, and enhances immunity. Works synergistically with vitamin E. Sources include avocados, Brussels sprouts, broccoli, citrus fruits, green peas, sweet peppers, and asparagus.

Zinc
Zinc, a trace element, is important to cells of the immune system. A deficiency in zinc affects the ability of T cells, and other immune cells, to function as they should. Zinc is also important in the healing of wounds and the prevention of the formation of free radicals. Zinc also helps maintain the proper amounts of vitamin E in the blood. Not too many foods contain zinc. A few sources include egg yolks, fish, legumes, mushrooms, pecans, poultry, soybeans and whole grains.

Protecting Your Immune System with Herbs
Certain types of herbal remedies are well-suited to support immune function; some directly, some indirectly. For example, we’ve discussed nutrition as an important element of immune function as the nutrients necessary to support your immune system come from your diet. If you’re not eating properly, maybe due to lack of appetite, you’re not supplying the necessary nutrients your immune system needs. Herbs such as burdock have antioxidant, antibacterial, and antifungal properties and help stimulate appetite, the digestive, and immune systems.

Using Nutrition to Boost Your Immune System, cont.,

Echinacea has antibacterial and antiviral properties, stimulates certain white blood cells, and is good for the immune and lymphatic systems. It is useful for colds, flu, and allergies.

Myrrh acts as an antiseptic and disinfectant. It stimulates the immune system and helps to fight harmful bacteria in the mouth, one of the prime locations for ingesting pathogens.

Garlic is thought to detoxify the body and protect against infection by enhancing immune function, lowering blood pressure, and improving circulation.

Astragalus acts as a tonic to protect the immune system, aids adrenal gland function (stress), promotes healing and provides energy to combat fatigue prolonged stress. Good for colds, flu, and immune-deficiency-related problems.

Wild oregano is an antioxidant which helps fight inflammation, bacterial, viral, fungal infections, and boosts the immune system. Useful for allergies, bronchitis, chronic infections, colds, cough, earache, fatigue, headaches, muscle pain, and parasitic infections.

 The Immune System – In More Detail
 What Foods are Good for My Immune System?
 Immune System Defender – An online game for you to try.

 Introduction to How the Immune System Works
 The Immune Response
 Overview of the Immune System