Transcript lecture 10x
HLTH 120N Lecture 10 Objectives Understand the process of oxidation & production of free radicals Recognize the major antioxidant vitamins & minerals and their role in preventing cancer, heart disease, and age related eye disorders Explain the glutathione peroxidase antioxidant system Understand the 3 stages in the development of cancer Identify the difference between modifiable and unmodifiable risk factors for disease Know the newest known risk factor for heart disease Why do we need antioxidants? Compounds that protect cells from damage caused by oxidation Oxidation Atoms electrons Usually an even exchange or 2 unstable electrons pair Highly unstable Free Radicals form if they do not pair Free radicals form with ATP production, immune reactions, radiation, environmental toxins, Free radical oxygen is considered (ROS). Cell damage Free radicals can damage cells May take an electron from stable molecules one of most significant sights Nutrient & fluid transport no longer regulated LDL, DNA, cell proteins also damaged Negative effects , heart disease, diabetes, Alzheimer’s, Parkinson’s, etc. Antioxidants stabilize free radicals Vitamins Stabilize by donating electrons & hydrogen Minerals Co in antioxidant systems, convert free radicals to compounds we can excrete Systems Superoxide Dismutase: convert to other substances Catalase: removes H2O2 from body Glutathione Peroxidase: removes H2O2 & stops free radical damage Phytochemicals Vitamin E Functions as . Antioxidant, stops ROS production when fat is oxidized. Protects PUFA’s & LDL Enhances immune function, cell signaling, gene expression Improves absorption of Vitamin A Prevents hemolytic anemia Food Sources Fortified cereals, seeds, nuts (almonds) , vegetable oils Green leafy vegetables, sweet potatoes, broccoli Deficiency When? Fat metabolism disorders Very low birth weight infants Develop disorder of fat metabolism What? Neurological Disorders Genetic spinal disease Myopathy muscle fibers do not function, resulting in weakness Retinopathy Toxicity May increase risk of bleeding/hemorrhage muscle fibers do not function, resulting in weakness UL - 1,000 mg per day Food sources and amount of Vitamin E Wheat Germ Oil 1 tbs 20 mg Fruit of 1 Avocado 12 mg Tomatoes 11 mg Sunflower Seeds, ¼ cup 8.3 mg Hazelnuts, 1oz 4.3 mg Peanut Butter, 2tbs 2.9 mg Canned Blue Crab, 1 cup 2.5 mg Mango, 1 fruit 2.3 mg Peanuts, Dry Roasted, 1oz 2.2 mg Olive Oil, 1tbsp 1.9 mg Almonds, 1 oz= 7.4 mg Spinach, 1 cup cooked 6.7 mg Vitamin C Metabolic Functions Antioxidant Protects LDL, lungs, white blood cells, stomach cells Regenerates vitamin E; gains electrons from GSH Synthesizes . RDA Found in many food sources naturally Possible for most people that eat a balanced diet to meet to RDA Smokers have 35 mg higher recommendation Who else needs more? • Food Sources Fruits and vegetables are the best source Fruits and vegetables that are high in vitamin C , potatoes, strawberries, tomatoes, kiwi, broccoli, spinach, and other leafy greens, cabbage, green and red peppers, and cauliflower • destroy vitamin C Steam & Stir-fry to compromise the least Deficiency – _____________ Collagen is too unstable to function Brown spots on the skin, spongy gums & bleeding from all mucous membranes Symptoms could be completely reversed by additional supplementation of only 10 mg/day Toxicity Excess excreted in the urine; UL is 2000 mg/day risk of toxicity. Increased formation of kidney stones Indigestion, especially on an empty stomach Diarrhea, nausea, vomiting, flushing, headache, fatigue Pro-vitamin A Inactive form, the body must convert it Carotenoids Fat-soluble plant pigments that the body stores in liver & adipose Antioxidant & Immune-Enhancing Activity •Anti-carcinogenic and anti-aging •Especially protects lipid cells/cell membranes Prevents Vitamin A Deficiency •Beta-carotene converts into retinol, active vitamin A. Promotes Proper Cell Communication •Ability to stimulate cell to cell communication Essential for normal growth and development, immune system function, and vision; decreases risks of certain cancers •No specific deficiency symptoms •Can cause symptoms associated Vitamin A deficiency. •Excessive Intake: •Reversible and harmless •No RDA for pro-vitamins •Found in red, orange, yellow & deep green produce : Vitamin A 3 forms in the body Retinol is produced by β-carotene Attached to Fatty Acids in foods, transported in chylomicrons 90% stored in liver Measured in RAE, RE, IU Only found in animal products Liver, eggs, whole-fat and reduced-fat dairy Functions Antioxidant Scavenge free radicals to protect LDL from oxidation Decreases heart disease & cancer Vision Forms proteins in the retina of the eye Essential to reactions to brightness and color vision Cell differentiation Critical for cells to mature and perform specific function Organ development & immune cells Reproduction & bone growth Toxicity Deficiency At 3-4x the RDA usually due to . Birth defects & miscarriage, fatigue, blurred vision, hair loss, bone pain, liver & nervous system damage Acne treatment with vitamin A derivative __________________ A serious concern in pre- school aged children 250,000-500,000 suffer permanent blindness each year Night & color blindness Poor growth & cell function Hyperkeratosis Excess keratin buildup Selenium Found in varying amounts in soil Contained in 2 amino acids in our bodies (stored & active) Needed for production of thyroxine hormone Aids in immune function Best known for role in glutathione peroxidase (GSH) system, one our major antioxidant defense systems Reduces hydrogen peroxide & stops free radical production. Lowers production of inflammatory markers Selenium Intake Only needed in little amounts to maintain health Sources wheat, organ meats, seafood, foods grown in soil Too much? -brittle hair/nails -skin rashes -nausea -vomiting -weakness -cirrhosis of liver Not enough? -impaired immunity -infertility -depression -impaired cognition -muscle pain and wasting Related Deficiency Disorders Kashin-beck disease: cartilage disorder -results in deforming arthritis Keshan disease: heart disorder caused by deficiency -found in children in China -soil depleted of selenium -prevention= supplementation Higher rates of some forms of cancer Other antioxidant minerals Superoxide dismutase system Copper, Zinc, Manganese Catalase System Iron Cancer Group of diseases characterized by cell growth that is “out of control” Aggressive invasion of tissues & organs Tumors Mass of undifferentiated cells with no function Benign or malignant 3 Stages of development Initiation mutation of cells Propagation cells divide Progression spreads to other sites 5 Modifiable Risk Factors 1) 40+ carcinogenic compounds 2) Alcohol, fat, cured meat Phytochemicals, vitamins, minerals 3)Infectious Agents Bacterial infections (H.Pylori) 4) Most common form of cancer in US is . Damage DNA of immature cells, which are then uncontrollable Risk doubles after 5+ sunburns Tanning before 35 ↑ risk of most invasive by % Nonmelanoma & melanoma 5)Physical Inactivity Sedentary life increases risk of colon & other cancers Moderate-vigorous exercise = 20-30% ↓ risk Antioxidants can prevent cancer Enhance the immune system Destroy & remove precancerous cells Inhibit cancer and tumor cell growth Prevent oxidative damage to DNA Scavenge free radicals to stop chain reactions Eating whole foods (fruits, grains, vegetables) ↓ risk Antioxidant Supplements & Risk Research is controversial: association is unclear Vitamin E supplements may reduce risk for prostate, colon, and rectal cancer & may increase for stomach β-carotene may increase lung & prostate cancer in smokers Selenium found to reduce prostate, colon, lung Supplementing with β-carotene, E, and selenium reduces cancer mortality Cardiovascular Disease Encompasses all disease of the heart & blood vessels 5 Major risk factors: Also low HDL, diabetes, family history Newly identified risk factor Weakens blood vessel plaque More likely to burst causing heart attack & stroke Inflammatory Markers C-Reactive Protein levels indicate inflammation w/ high cholesterol, ↑ heart attack by 9x Vitamin E & lycopene Reduce vessel damage & inflammation Vitamin E supplements may reduce death by heart disease in smokers Age-related vision impairment Leading cause of blindness in 55+ Macula is central part of retina No known cure for reduction in site Damaged lens causes cloudiness Surgery can treat light insensitivity Antioxidant cocktail of Vitamin C & E, zinc & β-carotene can reduce progression