9. Nutrients Involved in Body Defenses Flashcards
What are the functions of the immune system?
Collection of diverse tissues:
- skin
- intestinal cells
- white blood cells
- lymphoid tissues
Work together to:
- prevent infection
- break down aged, dying cells
- remove abnormal cells
What are the roles of the skin?
Essential fatty acids, protein, vitamin A, niacin, and zinc help maintain skin health.
Skin lesions provide opening for bacterial to penetrate.
Nutrient deficiencies weaken integrity of skin.
What are the roles of intestinal cells?
Cells of small and large intestine:
- packed close together
- form barrier to microorganisms
Gut-associated lymphoid tissues (GALT):
- assists cells of GI tract in keeping pathogens from entering bloodstream
Nutrients: adequate protein, vitamin A, vitamin B-6, vitamin B-12, vitmin C, folate and zinc
What are the roles of white blood cells?
Cell-mediated immunity:
- phagocytes: monocytes (precursors to macrophages), neutrophils, and eosinophils
- phagocytosis: cells engulf, ingest, digest substances, including microorganisms, destroy pathogens via lysosomes
Antibody-mediated immunity:
- lymphocytes produce antibodies in response to foreign proteins (antigens)
- antibodies mark invaders for destruction by other immune cells
What are the roles of lymphoid tissues?
Thymus, bone marrow, spleen, lymph nodes, other clusters of immune cells throughout the body.
Thymus: with bone marrow, helps mature white blood cells; active in infancy through adolescence, tapers off during adulthood
Spleen: contains many macrophages, removes foreign proteins, dead, damaged cells from blood
Clusters of lymphoid tissue: mostly around lungs and GI tract (GALT) activity
Explain oxidation and reduction.
Nucleus:
- protons and neutrons
- positively (+) charged
Electrons circle the nucleus in pairs:
- negatively (-) charged
Reduction: gain of a negatively charged electron
Oxidation: loss of a negatively charged electron
How do antioxidants function to neutralize free radicals?
Free radicals:
- unstable atoms with unpaired electron in the outermost shell; overproduction can be harmful to health cells
- damage specific structures, such as DNA, within cell
Antioxidants:
- defend against the adverse effects of free radicals
What are the functions of Vitamin A?
- supports the activity of T-lymphocytes (T-Cells)
- functions in light-dark and colour visions (rods and cones require vitamin A for normal function)
- binds to receptors on DNA to increase synthesis of a variety of proteins, some required for growth
- functions in differentiation and maturation of cells, ultimately forming tissues and organs
- assists with breakdown and formation of healthy bone tissue
- role in cellular differentiation and embryonic development
What are the functions of Vitamin C?
- formation of body proteins: collagen synthesis; found in connective tissue, bone, teeth, tendons, blood vessels
- formation of other compounds: carnitine synthesis; transports fatty acids
- supporting body defenses
- absorption of iron
What are the functions of Vitamin E?
- essential for rat fertility (1920s)
- antioxidant
- formation of muscle
- formation of central nervous system
- maintains nervous tissue and immune function
donates electrons or hydrogens to free radicals to make cell more stable
What are the functions of selenium?
- trace mineral
- aids glutathione peroxidase
- antioxidant enzyme: chemically converts dangerous peroxides to water
- spared vitamin E and helps maintain cell membrane integrity
- part of thyroid hormone activation
What are the functions of zinc?
- DNA synthesis and function
- protein metabolism, wound healing, and growth
- development of bones and reproductive organs
- storage, release, and function of insulin
- cell membrane structure and function
- white blood cell formation
Describe some functions of phytochemical’s that support body defenses.
- antibacterial or antiviral properties
- influence blood pressure or blood clotting
Variety of mechanisms to reduce risk for:
- cardiovascular disease
- cancers
- type 2 diabetes
- neurogenerative diseases
What are some benefits of probiotics?
Live microorganisms with positive effects on human health.
Bacteria: lactobacillus, lactococcus, and streptococcus
- provide barrier against pathogen invasion
- enhance immune function by transiently altering composition of microbiota
- bind to pathogens or secrete substances that kill them
- reduction of diarrhea
- may improve seasonal allergies
- reduce symptoms of inflammatory bowel disease like Crohn’s
Describe the relationships among body fatness, dietary patterns, and cancer risk.
Excess body fat stimulates secretion of:
- hormones, insulin, and estrogen
- proteins that promote inflammation and oxidative stress
Cancer fighting foods:
- antioxidants and phytochemicals
- vitamins C and E prevent formation of nitrosamines in GI tract
