Nutrients Involved in Body Defenses PDF

Nutrients Involved in Body Defenses PHED/INTE 4507: Nutrients Involved in Body Defenses 1  Learning Outcomes 1. Understand oxidation and reduction, and describe how antioxidants function to neutralize free radicals. 2. Outline the functions of vitamins A, C and...

Nutrients Involved in Body Defenses PHED/INTE 4507: Nutrients Involved in Body Defenses 1  Learning Outcomes 1. Understand oxidation and reduction, and describe how antioxidants function to neutralize free radicals. 2. Outline the functions of vitamins A, C and E, selenium and zinc. 3. Describe some functions of phytochemicals that support body defenses. 4. Describe the relationships among body fatness, dietary patterns, and cancer risk. PHED/INTE 4507: Nutrients Involved in Body Defenses 2  The Immune System Collection of diverse tissues: Skin Intestinal cells White blood cells Lymphoid tissue Work together to: Prevent infection Break down aged, dying cells Remove abnormal cells PHED/INTE 4507: Nutrients Involved in Body Defenses 3  Two Categories of Immune Response Innate (nonspecific) Born with this defense Physical, chemical defenses keep foreign substance out of body Adaptive (specific): developed over time as exposed to individual pathogens. PHED/INTE 4507: Nutrients Involved in Body Defenses 4  Innate (nonspecific) Immune Response Inflammatory response-macrophages: Activated by ingesting foreign protein, pathogen. Release cytokines, cause swelling and fever, usually short lived. Chronic, low-level inflammation linked to ailments: Refined carbohydrates, added sugars, solid fats, and overall calories thought to promote inflammation. Fruits and vegetables, plant proteins, unsaturated fats from plant oils and fish, whole grains associated with lower inflammation and lower risks of chronic diseases. PHED/INTE 4507: Nutrients Involved in Body Defenses 5  Adaptive (Specific) Immunity Response Lymphocytes: Produce antibodies Bind to antigens Mark foreign proteins and microorganisms for destruction by white blood cells May take several days or weeks to eradicate pathogen Creates template to “remember” for future exposure PHED/INTE 4507: Nutrients Involved in Body Defenses 6  Nutrients That Support the Immune Response Constant cells synthesis requires steady nutrient intake. Formation of new cells: Protein supplies building blocks. Vitamin B-6 involved in amino acid metabolism to make new cell proteins. Folate, vitamin B-12, and iron needed for DNA synthesis. Destruction of pathogens: Minerals support cell structure and help destroy pathogens. Zinc and copper: structural roles and critical for the synthesis of white blood cells. Iron and zinc: for production of enzymes used by white blood cells to destroy pathogens. PHED/INTE 4507: Nutrients Involved in Body Defenses 7  Vitamins A and D Regulate Gene Expression Active forms of vitamins A and D: Bind to receptors on DNA to switch various genes on or off. Exert control over immune system activity at the genetic level. Ability of vitamin D to limit the action of certain white blood cells. Linked to decrease risk for autoimmune diseases. PHED/INTE 4507: Nutrients Involved in Body Defenses 8  Antioxidant Nutrients Protect Immune Cells Vitamin C, Vitamin E, Selenium: Antioxidant capabilities. Protect immune cells from being damaged by oxidation reactions used to destroy pathogens. White blood cells utilize oxidation to kill pathogens. May increase proliferation of immune cells. Regulate the expression of proteins involved in the immune response. PHED/INTE 4507: Nutrients Involved in Body Defenses 9  Micronutrients That Support Immune Function Nutrient Primary Roles in Immunity Vitamin A Maintains the health of epithelial cells Contributes to function of mucus-secreting cells Supports activity of white blood cells Vitamin B-6 Maintains the health of epithelial cells Aids in synthesis of white blood cells Production of proteins involved in the immune response Vitamin B-12 Maintains the health of epithelial cells White blood cell formation and activity Vitamin C Protects immune cells from oxidative damage as an antioxidant Stimulates production and activity of white blood cells Vitamin D Modulates gene expression in white blood cells Possibly prevents autoimmune diseases Vitamin E Protects immune cells from oxidative damage May protect against age-related declines in immune function PHED/INTE 4507: Nutrients Involved in Body Defenses 10  Micronutrients That Support Immune Function (cont.) Nutrient Primary Roles in Immunity Folate Maintains the health of epithelial cells White blood cell formation and activity Zinc Development and function of white blood cells Supports ability of cells to use oxidation reactions to kill pathogens Iron Used in function of white blood cells Supports ability of cells to use oxidation reactions to kill pathogens Copper Production of white blood cells, particularly phagocytes Selenium Protects immune cells from oxidative damage Involved in the expression of cytokines that regulate the immune response PHED/INTE 4507: Nutrients Involved in Body Defenses 11  Oxidation and Reduction Anatomy of an atom Nucleus: Protons and neutrons Positively (+) charged Electrons circle nucleus in pairs: Negatively (-) charged Positive and negative charges balance: Atoms has no overall charge Atoms bond together in molecules PHED/INTE 4507: Nutrients Involved in Body Defenses 12  Oxidative Stress Oxidative stress: Imbalance between production of reactive compounds and body’s ability to protect against their adverse effects. Reduction: gain of a negatively charged electron. Oxidation: loss of a negatively charged electron. Sharing electrons in outer shell makes strong bonds between atoms or molecules. Oxidation of these bonds produces stable compounds. PHED/INTE 4507: Nutrients Involved in Body Defenses 13  Free Radicals Unstable atoms with unpaired electron in the outermost shell. A week bond between atom or molecule produces possible molecule or atom left with an unpaired electron in its outer shell. Overproduction of free radicals can be harmful to healthy cells. PHED/INTE 4507: Nutrients Involved in Body Defenses 14 Electrons Transferred Between Molecules in Oxidation-Reduction Reactions PHED/INTE 4507: Nutrients Involved in Body Defenses 15  Antioxidant Defenses Body has two defense mechanisms: Enzyme systems and antioxidant chemicals. Work together to limit free radical formation. Enzyme activity Requires the presence of minerals such as selenium, manganese, zinc, iron, copper. Antioxidant enzymes include superoxide dismutase, glutathione peroxidase, and catalase. Dietary antioxidant “substance in foods that significantly decreases adverse effects of reactive species such as reactive oxygen and nitrogen species on normal physiological function in humans”. Has ability to prevent or repair damage caused by oxidation. PHED/INTE 4507: Nutrients Involved in Body Defenses 16  Free Radicals Damage DNA Free radicals damage specific structures, such as DNA, within cells. Antioxidants defend against the adverse effects of free radical. PHED/INTE 4507: Nutrients Involved in Body Defenses 17  Oxidative Stress Linked to Many Chronic Disease Oxidative stress: Imbalance between production of reactive compounds and body’s ability to protect against their adverse effects. PHED/INTE 4507: Nutrients Involved in Body Defenses 18  Forms of Vitamin A Preformed vitamin A: Retinoids Three active forms Retinol, retinal, and retinoic acid Exist only in animal products Stored retinol: Esterified to a fatty acid and becomes retinyl ester In supplements: Retinyl acetate or retinyl palmitate PHED/INTE 4507: Nutrients Involved in Body Defenses 19  Carotenoids Plants contain pigments called carotenoids: Phytochemicals with health-promoting chemicals Precursors of vitamin A have antioxidant properties Carotenoids that are provitamins can be turned into vitamin A: Beta-carotene Alpha-carotene Beta-cryptoxanthin Other carotenoids may have health benefits: Lycopene, zeaxanthin, lutein PHED/INTE 4507: Nutrients Involved in Body Defenses 20  Functions: Health of Epithelial Cells and Immune Function Epithelial cells Line internal and external surfaces of eyes, skin, lungs, intestines. Important barriers to infection. Retinoic acid required for immature epithelial cells to develop into mature, functional cells. Vitamin A also supports the activity of T-lymphocytes (T-cells). PHED/INTE 4507: Nutrients Involved in Body Defenses 21  Functions: Eye Health and Vision Night Blindness Vitamin A functions in light–dark and colour vision. Vitamin A deficiency: lose ability to see under low-light conditions. Retina: Lining of cells (rods, cones, and nerve cells). Light entering eye reaches retina. Rods and cones require vitamin A (retinal) for normal function. Rods detect black and white, responsible for night vision. Cones are responsible for colour vision. PHED/INTE 4507: Nutrients Involved in Body Defenses 22  Carotenoids and Age-related Macular Degeneration Macula: central area of retina Responsible for detailed central vision. Contains carotenoids lutein and zeaxanthin in high concentrations—impart a yellow color. Age-related macular degeneration: Cause of blindness in older adults. Higher intakes of carotenoids may help to prevent or slow its progression. Green leafy vegetables are rich sources of lutein and zeaxanthin. PHED/INTE 4507: Nutrients Involved in Body Defenses 23  Functions: Growth, Developmental and Reproduction Vitamin A: 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. Aids in male sperm production, and normal reproductive cycle in women. PHED/INTE 4507: Nutrients Involved in Body Defenses 24 Functions: Cardiovascular Disease Prevention Carotenoids may inhibit oxidation of low-density lipoproteins (LDLs). Consume a total of at least five servings of a combination of fruits and vegetables per day. As part of an overall effort to reduce the risk of cardiovascular disease. PHED/INTE 4507: Nutrients Involved in Body Defenses 25  Functions: Cancer Prevention Vitamin A: Role in cellular differentiation and embryonic development. Dietary patterns rich in provitamin A carotenoids. Associated with lower risk of skin, lung, bladder, breast cancers. Toxicity risk in megadose of vitamin A through supplement use. PHED/INTE 4507: Nutrients Involved in Body Defenses 26  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: Antioxidant Vital for immune function. May decrease formation of carcinogen nitrosamines in stomach. Aids reactivation of vitamin E. Absorption of iron: Increases iron absorption. PHED/INTE 4507: Nutrients Involved in Body Defenses 27  Functions of Vitamin E Antioxidant Formation of muscle Formation of central nervous system Maintains nervous tissue and immune function PHED/INTE 4507: Nutrients Involved in Body Defenses 28  Vitamin E as an Antioxidant Fat-soluble vitamin Found in adipose tissue and cell membrane. Membrane lipids are polyunsaturated fatty acids (PUFA). PUFAs are susceptible to oxidative attack. Vitamin E donates electrons or hydrogens to free radicals to make cell more stable. Important in areas exposed to high levels of oxygen (RBCs and lungs). PHED/INTE 4507: Nutrients Involved in Body Defenses 29 Vitamin E in Cell Membranes PHED/INTE 4507: Nutrients Involved in Body Defenses 30  Selenium Functions Trace mineral Aids glutathione peroxidase. Antioxidant enzyme: chemically converts dangerous peroxides to water. Spares vitamin E and helps maintain cell membrane integrity. Part of thyroid hormone activation. PHED/INTE 4507: Nutrients Involved in Body Defenses 31  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. Component of superoxide dismutase, an antioxidant enzyme that aids in the prevention of oxidative cell damage. White blood cell formation. PHED/INTE 4507: Nutrients Involved in Body Defenses 32  Antioxidant Phytochemicals Carotenoids: Beta-carotene: yellow-orange colors in sweet potatoes, winter squash an carrots. Lycopene: found in tomatoes, watermelon, and pink grapefruit. Lutein and zeaxanthin: found in leafy greens, squash, and yellow corn. Anthocyanins: Red, blue, and purple pigments in berries. Polyphenols: Largest group of phytochemicals. Flavonoids: blueberries, chocolate, citrus fruit, and raspberries. PHED/INTE 4507: Nutrients Involved in Body Defenses 33  Functions of Phytochemicals Variety of beneficial actions: 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 PHED/INTE 4507: Nutrients Involved in Body Defenses 34  Early Detection of Cancer Undetected, it can spread quickly- early detection. Use CAUTION acronym: Change in bowel or bladder habits. A sore that does not heal. Unusual bleeding or discharge. Thickening or lump in the breast or elsewhere. Indigestion or difficulty in swallowing. Obvious change in a wart or mole. Nagging cough or hoarseness. Unexplained weight loss an additional warning sign. Routine screenings important for early detection. PHED/INTE 4507: Nutrients Involved in Body Defenses 35  Factors That Influence Development of Cancer Genetics: Only 5% to 10% of most cancers inherited. Role in colon, breast, and prostate cancer. Environment: 90% to 95% of cancers related to environmental factors. Excessive body fatness and dietary patterns account for over half of all environmentally related cancers. Modifiable lifestyle behaviors: Smoking, alcohol intake, physical activity, UV exposure, and dietary patterns. PHED/INTE 4507: Nutrients Involved in Body Defenses 36  Body Fat Linked to Cancer Risk One of three cancer deaths linked to: Excess body fat Suboptimal nutrition Inadequate physical activity Excess body fat stimulates secretion of Hormones, insulin and estrogen Proteins that promote inflammation and oxidative stress In animals, restricting calories to 70% of usual intake, reduces tumor development by 40%. PHED/INTE 4507: Nutrients Involved in Body Defenses 37  Cancer-Fighting Foods Include antioxidants and phytochemicals. Some help prevent DNA mutations. Vitamins C and E help prevent formation of nitrosamines (carcinogen) in GI tract. Fruit and vegetable intake reduces risk of nearly all types of cancer. PHED/INTE 4507: Nutrients Involved in Body Defenses 38  Nutrition Concern During Cancer Treatment Overall goals of medical nutrition therapy Minimize weight loss Prevent nutrient deficiencies Preserve muscle mass Fatigue, mouth sores, dry mouth, taste abnormalities, nausea, diarrhea lead to poor food intake. Small, frequent, nutrient dense Liquid nutritional supplements often needed. PHED/INTE 4507: Nutrients Involved in Body Defenses 39  Cancer Prevention About 4 in 10 cancer cases can be prevented through healthy living and policies that protect the health of Canadians. Live smoke free Be sun safe Maintain a healthy body weight Eat well Move more, sit less Limit or avoid alcohol intake PHED/INTE 4507: Nutrients Involved in Body Defenses 40