THE IMMUNE SYSTEM AND IMMUNITY**
THE IMMUNE SYSTEM AND IMMUNITY**
Frequently asked questions on the immune system are:
“How can I boost my immune system?”
“How can I improve my immunity?”.
What is the Immune System?
There are at least 28 definitions of the immune system on the Web. The following are a sample of these:
· A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
· A biological defence system, which has evolved in vertebrates, to protect them against the introduction of foreign material (such as pollen or invading micro-organisms) and to prevent the body from developing cancer.
· The body system, made up of many organs and cells, which defends against infection, disease and foreign substances.
· The integrated body system of organs, tissues, cells and cell products that differentiates self from non-self and neutralises potentially pathogenic organisms or substances.
· An intricate complex of inter-related cellular, molecular and genetic components that defend the body against foreign organisms or substances and diseased native cells.
· The network of white blood cells, and the chemical products they produce to protect the body from foreign ‘invaders’. One major division is between the ‘cellular’ portion, which involves T-cells, and the ‘humoral’ portion, which involves B-cells that makes antibodies. The two parts work hand-in-hand.
Each of these definitions is linked to a website and details of these can be obtained from a google.com.au search on "immune+system".
An Overview of the Immune System
Thus the immune system is a set of mechanisms that protect our bodies from infection by identifying and killing pathogens. This task is extremely difficult since pathogens range from viruses, through bacteria to parasitic worms, and these diverse threats must be detected and identified with absolute specificity amongst normal cells and tissues. Pathogens are also constantly evolving new ways to avoid detection by the immune system and hence to successfully infect their host.
The immune systems of vertebrates such as humans consist of many types of proteins, cells, organs and tissues which interact in an elaborate and dynamic network.
Nowhere is the importance of effective cellular communication more relevant than in the immune system (refer to my newsletter ‘Glyconutrients’, March 2007, for more details on cellular communication).
As part of this more complex immune response, the immune system adapts over time to recognise particular pathogens more efficiently. This adaptation process creates immunological memories and allows even more effective protection during future encounters with these pathogens. This is the process of acquired immunity. It is the basis of vaccination.
Disorders in the immune system can cause disease. Immunodeficiency diseases occur when the immune system is less active than normal, resulting in recurring and life-threatening infections.
Immunodeficiency can either be the result of genetic disease, such as severe combined immunodeficiency, or be produced by pharmaceuticals, or by an infection such as the acquired immune deficiency syndrome (AIDS) which is caused by the retrovirus HIV.
In contrast, autoimmune diseases result from a hyperactive immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include rheumatoid arthritis, diabetes mellitus type 1 (juvenile), systemic lupus erythematosis (SLE) and multiple sclerosis (MS).
These critical roles of immunology in human health and disease are areas of intense scientific study.
An attempt to represent the immune system in a schematic way is set out in ‘How to Stop Feeling So Awful’, pages 46-47 (see homepage), to show the complexity and interrelationship of the immune system.
We are interested here in what we can do to create and maintain a healthy immune system.
Many different special words are used when defining and describing the immune system. The following is an overview (modified from the website britannica.com).
- Immune system consists of cells, cell products, organs and structures of the body involved in the detection and destruction of foreign invaders, such as bacteria, viruses and cancer cells.
- Immunity is based on the system’s ability to launch a defence against such invaders. For the immune system to function properly, it must be able to distinguish between the material of its own body (self) and material that originates outside of it (non-self). Failure to make that distinction can result in autoimmune diseases.
- Allergies are an exaggerated or inappropriate response by the immune system to non-harmful substances, for example, pollens, animal dander, house dust mite or foods.
- Lymphocytes are the immune system’s principal cells.
- Antigens, the invaders, are recognised by the lymphocytes, as are related accessory cells such as phagocytic macrophages which engulf and destroy foreign material.
- Bone marrow contains stem cells that give rise to lymphocytes.
- T-cells are T-lymphocytes, one type of stem cells in the bone marrow, which migrate to the thymus to mature.
- B-cells are B-lymphocytes, which mature in the bone marrow.
- Organs of the immune system include the lymphatic vessels, lymph nodes, tonsils, Peyer’s patches (in the intestinal lining) and the spleen. The mature lymphocytes, T-cells and B-cells, enter the bloodstream and many become lodged, along with accessory cells, in various body tissues including the spleen, lymph nodes, tonsils and Peyer’s patches in the intestines.
- Lymphoid tissues are those organs or tissues containing such concentrations of lymphocytes. Within these organs or tissues, the lymphocytes are confined within a delicate network of connective tissue that channels them so they come into contact with antigens. T-cells and B-cells can mature and multiply further in the lymphoid tissue when suitably stimulated.
- Lymph, the fluid draining from lymphoid tissues, is conveyed to the blood through lymphatic vessels.
- Lymph nodes are distributed along these vessels (especially in the groin, abdomen, axillae and neck) and they filter the lymph, exposing macrophages and lymphocytes, contained within, to the antigen present in the lymph.
- The spleen plays a similar role, sampling the blood for the presence of antigens. It also removes old red cells from the circulation.
- The capability of lymphocytes to pass between lymphoid tissue, the blood and lymph is an important element in the immune system’s functioning.
- Antibodies are produced by certain lymphocytes in response to specific antigens when they invade the body.
- White blood cells are lymphocytes.
The immune system is, to say the least, very complex. Briefly:
- The immune system protects the body from infection by creating and maintaining barriers that prevent bacteria and viruses from entering the body.
- If the pathogen breaches these barriers and gets into the body, the innate immune system is equipped with specialised cells that detect, and often eliminate, the invader before it reproduces and potentially causes serious injury to the host.
- A pathogen that successfully evades the innate immune cells faces a second adaptive or specific immune system. It is through the adaptive response that the immune system gains the ability to recognise a (specific) pathogen and mount stronger attacks each time the pathogen is encountered.
a) Mechanical barriers.
Skin, coughing, sneezing, saliva, tears, urine and mucus (in respiratory and gastrointestinal tracts).
b) Chemical barriers.
Skin is rich in keratin, and is slightly acid which inhibits bacterial growth. Enzymes in saliva, tears and breast milk are antibacterial. Gastric acid and enzymes in the stomach are chemical defences against ingested pathogens.
c) Biological Barriers
Normal gut floras (bacteria) compete with pathogenic bacteria for food and space, diminishing the probability that pathogens will be able to reach sufficient numbers to cause illness. Antibiotics do not discriminate between pathogenic bacteria and normal gut flora, so treatment with oral antibiotics can often lead to an ‘overgrowth’ of fungus (not affected by antibiotics) such as the yeast infection candida albicans.
Briefly, in summary:
· The response is non-specific
· Exposure leads to immediate maximal response
· Cell-mediated and humoral components
· Cells are called leukocytes
· There is NO immunological memory
Specific or Adaptive Immunity
Briefly, in summary:
· Pathogen and antigen specific response
· Lag time between exposure and maximal response
· Cell mediated and humoral components
· Cells are call lymphocytes
· Exposure leads to immunological memory
To explore the above in greater and specific detail, there are many web references that describe the immune system, for example answers.com/topic/immune-systems.
HOW TO MAINTAIN A HEALTHY IMMUNE SYSTEM & BOOST ITS FUNCTION NATURALLY
There is no doubt that living with chronic stress takes a toll on our body, our health and our well-being. Chronic stress can lead to a number of health problems including headaches, upset stomach and ulcers, rashes, insomnia, and high blood pressure. It is linked to heart disease and stroke.
In the stress response, the body, via the hypothalamus (part of the brain), the pituitary gland and the adrenal glands, releases adrenaline and cortisol. These prepare the body to cope with the perceived threat (the stress) by the flight-fight-fear response.
Chronic stress, and the chronic increased levels of these chemicals, wear down our natural defences and deplete nutrient and energy reserves, leading to blood sugar imbalance, fatigue, food cravings, weight gain, insomnia, irritability and hypertension.
Chronic stress also leads to lowered immunity, it suppresses the immune system.
Thus stress management is an essential general measure to boost the immune system, or at least to minimise the adverse effect of stress on the immune system.
Being excessively thin or severely overweight (obese) are both associated with impaired immune responses. The more overweight, the greater the adverse effect.
Well in excess of 50 percent of the population in Australia, USA , UK and western countries are either overweight (Body Mass Index (BMI) greater than 25), obese (BMI greater than 30) or pathologically obese (BMI greater than 40).
The body weight should be such that the BMI is less than 25, ideally in the region of 21.
BMI = weight (in kilograms) divided by height (in metres) squared, that is:
Weight (kg) ÷ Height (m)2
Regular physical activity is important in maintaining the best possible immune function. People who exercise at a moderate level are far less likely to succumb to illness than those who are very inactive or sedentary in their lifestyle.
There are many different types of exercise programmes and sporting activities.
A simple guide-line to acceptable physical activity is the number of steps taken throughout each day. A pedometer is a simple, cheap gadget that is worn at waist level to count the steps. The minimum number is 5000, aiming to achieve 10,000 each day.
It should be noted that very intense and prolonged exercise, such as running a marathon or over-training can, in the short-term, have a negative effect on the immune system, suppressing immunity.
Mental Health and Positive Thinking
It is well known that laughter and happiness boost the immune system. “Laughter is the best medicine”.
In contrast negative emotions, such as anger, have an adverse effect on the immune system. Bereavement and grief, especially, significantly suppress the immune system.
Reduction in Exposure to Pathogens
It is logical to avoid those coughing, spluttering and sneezing with colds and flu. The less pathogens we inhale or ingest, the less strain on the immune system to overcome the possible adverse effects they may cause.
Correct Balanced Nutrition
My book ‘How to Live to 100+ Years Free from Symptoms and Disease’ (see homepage), sets out the ‘Dietary Guidelines’ to live a long, healthy disease-free life. These guidelines for correct, balanced nutrition support the immune system to the fullest. Without this good nutrition, the goal of a healthy life, towards a 100 years, could not be achieved. This book is recommended reading.
The following discusses a few specific foods which have a strong adverse effect on the immune system.
Eating or drinking 100 grams of sugar ( 20 teaspoons), the equivalent of 1 litre of soft drink (10 percent sugar) can reduce the ability of white blood cells to kill germs (pathogens) by 40 percent.
The immune-suppressing effect of sugar starts less than 30 minutes after ingestion, and may last for 5 hours.
In contrast, the ingestion of complex carbohydrates or starches has no effect on the
· Excessive Alcohol
Excessive alcohol intake can harm the body’s immune system in two ways:
Ø Firstly, it produces an overall nutritional deficiency, depriving the body of essential, valuable immune-boosting nutrients.
Ø Secondly, alcohol, like sugar, consumed in excess, can reduce the ability of the white cells to kill germs.
High doses of alcohol:
Ø Suppress the ability of the white cells to multiply
Ø Inhibit the action of killer white cells on cancer cells
Ø Lessen the ability of macrophages to produce tumour necrosis factors.
One standard drink (10grams of alcohol in Australia, or 10 ml alcohol in UK) does not appear to bother the immune system. Damage to the immune system increases in proportion to the quantity of alcohol consumed. Amounts of alcohol enough to cause intoxication are enough to suppress immunity.
· Foods to which there is Allergy or Intolerance
In some people, probably genetically based, some elements of the complex immune system recognise an otherwise harmless substance, such as milk or wheat, as a “foreign invader” and attack it, causing an allergic reaction. Such food allergies are generally recognised: “Every time I drink milk, I develop ……. (a symptom).”
Food intolerances are much less easy to identify, but may also cause significant symptoms. The way to identify food allergies and/or intolerances is described in detail in my book ‘How to Stop Feeling So Awful’ (seem homepage).
Normally the intestinal lining is impenetrable to ‘foreign invaders’. After many or continuing exposures to food allergens and food intolerance, the lining or wall of the intestine becomes damaged, enabling invaders and other potentially toxic substances in the food to get into the blood stream, leading to various symptoms. This condition is known as the ‘Leaking Gut Syndrome’.
It is of interest that 50 percent of the immune system surrounds the gastro intestinal tract, meaning the body has been designed to mount an immune response to any unwanted food invaders.
All this has an adverse effect on the immune system.
To cite but one example, easily demonstrated: when a food to which there is an intolerance is ingested, within a short-time there is leucocytosis, ie an increase in the number of white cells in the blood.
· Too Much Fat
Obesity can lead to a depressed immune system. It can affect the ability of the white blood cells to multiply and interfere with the production of antibodies.
Adequate Fluid Intake
More, rather than less, pure water is an essential for good health, including the health of the immune system. It is important to maintain fluid levels, especially when unwell.
There are two types of immune system support via supplements:
a) Acute or short-tem supplementation, taken during an existing acute infection, such as a cold or ‘flu, to help the support immune system activity
b) Long term nutritional support and supplementation, taken to help maintain the immune system’s health.
· Vitamin C.
This vitamin is useful in fighting infections from virtually all pathogens. It tops the list of immune boosters!
Vitamin C increases the production of infection–fighting white blood cells and antibodies, and increases levels of interferon, the antibody that coats cell surfaces, preventing the entry of viruses.
Ø High doses, up to 5000 mg/day, are recommended during an infection.
Ø Long term usage, a dose of 1000 mg/day, should preferably be combined with bioflavinoids, which enhance the effect of vitamin C.
Bioflavinoids are a group of phytonutrients which aid the immune system by protecting the cells of the body against environmental pollutants. Bioflavinoids include proanthocyanidins, quercetin, rutin, citrus bioflavinoids and green tea polyphenols. They have been referred to as ‘nature’s biological response modifiers’ because of their ability to modify the body’s reaction to other compounds such as allergens, viruses and carcinogens.
· Vitamin A, betacarotein and carotenoids.
These significantly affect the immune function and can be used preventatively as well as therapeutically. Betacarotein and carotenoids are best obtained from foods such as carrots. Betacarotein alone as a supplement is not recommended. Carotenoids and betacarotein increase the number of infection-fighting cells, natural killer cells and helper T-cells, as well as being a powerful antioxidant that mops up excessive free-radicals (see my January 2007 newsletter ‘Free Radicals-Antioxidants’). It is all the carotenoids working together that give the best results. Hence food sources are best. The body converts betacarotein and carotenoids to vitamin A, which in itself has anti-cancer properties and immune-boosting functions. Excessive intake of vitamin A may be toxic. 5,000-10,000 units per day is sufficient.
· Vitamin E.
This important antioxidant is also an immune booster and is important to a healthy immune system. It stimulates the production of natural killer white cells, those that seek out and destroy germs and cancer cells. Vitamin E enhances the production of B-cells, the immune cells that produce antibodies that destroy bacteria. A supplement of 500i.u. per day is recommended.
· Other Vitamins
A high dose multi-B supplement (B1, B2, B3, B5 and B6, each 50mg) gives general support for optimal health.
This mineral is essential for a wide range of physiological functions, including support of the body’s defence system, ie the immune system. When zinc levels are low, many white blood cell functions, critical to the immune response, are severely lacking. Zinc increases the production of white blood cells that fight infection, and helps them fight more aggressively. It also increases the killer T-cells that fight against cancer and helps white cells release more antibodies. Zinc supplements have been shown to slow the growth of cancer. The recommended dose is 25-50mg per day.
This trace element is a building block of one of the body’s key antioxidant enzymes, glutathione peroxidase. It is thought to also play a key role in helping the immune system cells to protect us from invading viruses and bacteria. The recommended dose is 25-50mcg per day.
These are healthy, ‘friendly’ bacteria that live in our intestines and help with our immune system. The best species of probiotics are lactobacillus acidophilus and bifidobacteria. They are available as liquid, or in powder or capsules.
This flavourful member of the onion family is a powerful immune booster that stimulates the multiplication of infection-fighting white cells, boosts natural killer cell activity and increases the efficiency of antibody production. It may protect against cancer.
This herb has potent non-specific stimulatory actions on the immune system, including anti-bacterial and anti-viral properties. It is an ‘immuno-stimulant’. Studies have not shown any toxic effects of echinacea. The suggested dosage is 300mg, three times a day.
· Olive Leaf Extract
This supports the immune system and promotes a healthy intestinal environment. It has anti-bacterial, anti-viral, anti-fungal and anti-parasitic properties.
Although almost last in this list of supplements, there are very important, since they form the basis of cellular communication. For full details of these, see my March 2007 newsletter, ‘Glyconutrients’.
· Green Barley.
Green Barley also gives support to the immune system. My November 2006 newsletter, ‘Green Barley Powder’, sets out the health benefits of this product.
· Astragalus, Golden Seal, N-Acetyl-cysteine and StJohn’s wort, have all been shown to have immune stimulating properties.
There is much that can be done to boost and support the immune system, and hence improve immunity.
A healthy lifestyle with good nutrition, regular exercise, correct weight and stress management, teamed with the taking of selected supplements, will give the immune system the best opportunity to do its work efficiently and effectively.
** Copyright 2007: The Huntly Centre.Back to the list Print friendly version