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There is no other physiological system more important to staying healthy than the immune system. It protects us against infectious organisms and invaders that cause bodily harm. The vast majority of ailments and health problems we experience can be attributed to lapses in immune function and to oxidative stress and related inflammation.
The immune system is a complex network of organs, tissues, cells, and cell products which collectively launch the immune response by utilizing a varied arsenal made up of macrophages, lymphocytes including the B cells (B meaning derived from bone marrow) and T cells (T meaning derived from the thymus), and antibodies.
An antibody is a blood protein produced in response to a foreign substance in the body. The body views these foreign substances (called antigens) as alien. Antigens include invaders like bacteria, viruses, and toxins. Antibodies protect us by combining chemically with antigens, which renders them inactive and removes them from the body.
The four major sites involved in immunity are the bone marrow, thymus, spleen, and lymph nodes. Additionally, the liver is now recognized as an important contributor of factors involved in immune function.
The immune system is generally divided into two categories, cellular immunity and humoral immunity. Cellular immunity involves mostly T cells and responds to cells that are altered in a specific way, including tumor cells, transplanted cells, and cells invaded by pathogens. The humoral response (or antibody‐mediated response) involves B cells that recognize antigens or pathogens that circulate in the lymph or blood.
Nutrition is a critical determinant of immune function capability, and malnutrition is the most common cause of immunodeficiency. Low protein intake as well as deficiency or suboptimal intakes of single nutrients results in altered immune responses. Zinc, selenium, iron, copper, vitamins A, C, E, and B-6, and folic acid are among the most influential immune boosters.
Excessive alcohol and drug use harms the body’s immune system in two ways. First, it depletes the body of many of the key nutrients required for immuno-competence (zinc, B vitamins, folic acid plus others) and second, it directly impairs cells and molecules that shape the immune response. The liver plays an important role in producing specialized proteins as part of the immune response, and direct damage to liver cells by ethanol or other drugs can also compromise immune function.
While the immune system does not include an antioxidant component per se, the two are tightly intertwined in that antioxidant protection is crucial to maintaining a strong, vital immune system.
Antioxidants and anti-inflammatories are important tools in the repertoire of the immune system. Antioxidants are agents that inhibit the oxidation of other molecules. Oxidation is a chemical reaction that can produce free radicals, leading to chain reactions that may damage cells. Free radicals or reactive oxygen species (ROS) are highly reactive compounds that adversely alter the structure and integrity of lipids and proteins, including many of the protein components of the immune system. They can attack at several sites, starting with DNA damage. If the DNA of a compound is altered, it will ultimately lead to mutations and genomic instability. These changes could result in the development of a variety of cancers or inflammation. It has been proposed that the process of aging is in part due to accumulation of DNA damage.
Oxidative damage that changes the chemical structure of a compound will almost always affect its function, given the precision with which biological compounds are designed. Lipid membranes are very susceptible to peroxidation, the oxidative degradation of lipids in which free radicals “steal” electrons from the lipids in cell membranes. This damage leads to leaky membranes and loss of cellular integrity and function.
Damage of this nature to cells involved with immune function will compromise the ability of the immune system to ward off bacteria, viruses, and other harmful compounds. The body relies on internal and external sources of antioxidants to assist in coping with this oxidative stress. Many immune boosters serve a dual purpose as antioxidants, such as vitamin E, vitamin C, β-carotene, selenium, copper, iron, and zinc. Dietary antioxidants are important in establishing resistance to infectious pathogens.
Inflammation is another way in which the immune system acts to heal injured body parts.
Acute inflammation occurs in response to a specific injury, such as an infected cut or an ingrown toenail. It is characterized by redness, swelling, and soreness around the injured tissue as white blood cells infiltrate the area to destroy germs, dead and damaged cells, and other foreign material.
Many of us today are concerned with “chronic systemic inflammation.” Habitual or environmental factors, such as excess body weight, poor diet, lack of exercise, stress, smoking, pollution, poor oral health, illicit drug use, and alcohol consumption lead to chronic inflammation.
There is a specific physiological basis to this type of inflammation and it is related to the release of pro-inflammatory cytokines from immune-related cells. Cytokine refers to a number of substances, such as small proteins like interferon, interleukin, and growth factors. These immune cells have an effect on other cells which, when released throughout the body, can result in the chronic activation of the immune system.
Control of both types of inflammation may be disrupted by an inadequate supply of either macronutrients (protein in particular) or micronutrients. A strong immune system then, is dependent upon proper nutritional strategies that fortify and optimize function. An immune system replete with solid antioxidant and anti-inflammatory defences is absolutely necessary for good health and can be assured by proper nutrition, rest, and an active lifestyle.
AGING = MUSCLE LOSS = DISEASE LEARN MORE
