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Antioxidants, Antioxidant role, What is Vitamin E, Non-antioxidant role -…

- - - - Claims that megadosing can cure the common cold and prevent cancer (no evidence)
    - - Release of free radicals from excess iron being released from proteins by Vit C
    - - When high levels of Vit C are reduced to normal
  - - - Alcoholics
      - Smokers
      - Burn patients
    - - Weakness
      - Pinpoint hemorrhages in the face and arms
      - Delayed healing of wounds
    - - Poor synthesis of collagen, due to decreased Vitamin C
  - - - Repairs wounds and maintains the integrity of many organs
  - - - Ascorbic Acid (reduced)
      - Dehydroascorbic acid (oxidized)
- - - - 25 different selenoproteins in the body
      - High bioavailability (60-90%)
    - - Converts T 4 to T 3 in thyroid hormone
        
        Regulates metabolism
  - - - severe joint pain
      - Keshan's disease (cardiomyopathy)
  - - - nausea/vomiting
- - - - Reducing agent (Electron donor)
  - - - Symptoms
        
        hemolytic anemia
        
        coordination impairment
        
        Muscle weakness
      - Greatest risk to preterm infants
        
        Transfer to fetus occurs in last few weeks of term
        
        Incubators put oxidative stress on infants
      - Nutrient loss from light/oxygen exposure and heat
    - - Symptoms
        
        muscle weakness
        
        nausea
        
        Diarrhea
        
        fatigue
        
        Uncontrolled bleeding
      - Caused by supplementing over RDA (15 mg/day)
    - - Plant oils
      - Animal products
      - Nuts/seed
      - Vegetables:
  - - - Reacts with oxygen-based free radicals that act on cell membranes
        
        Very active in lung tissue where there is high oxygen content
        
        Protects phospholipids from free radical damage
      - Found in mitochondrial and nuclear membranes to protect DNA and cellular components
    - - Reduces platelet aggregation
- - - - precursor to Vitamin A
      - found in plants
      - Beta-carotene
        
        12 micrograms of b-caro. equals 1microg. of retinol
        
        20-40% absorbed with fat/ fat-soluble
        
        builds in fat under skin, giving yellow colour
        
        liver converts b-caro. into retinol (vitamin A)
        
        weaker antioxidant than Vitamin E
        
        Immune system
        
        protects skin from UV damage
        
        protects eyes from aging
        
        prevents damage in macula that provides central vision
        
        inflammatory
        
        anti-inflammatory at moderate doses
        
        pro-inflammatory at higher doses
        
        Deficiency
        
        no known symptoms
        
        non-essential nutrient
        
        Risks
        
        may increase risk of DNA damage
        
        may increase risk of onset of epithelial cancers, heart disease
        
        Toxicity
        
        Hypercarotenemia
        
        high intake of b-carotene
        
        causes skin to change to orange colour
        
        reversible, harmless
        
        no known symptoms
        
        Food Sources
        
        green and orange vegetables
        
        orange and red fruit
        
        fortified margarine
        fortified breakfast cereal
  - - - Functions in the body
        
        Vision
        
        maintains cornea health
        
        Growth/Development
        
        bone health by assisting osteoclasts
        
        cell differentiation
        
        Reproduction
        
        mucus membranes
        
        protects against infections
        
        Immune system
        
        in producing immune cells ex. T-cells
    - - Vision
        
        Night blindness
        
        Xerophthalmia (dry eye)
      - Growth, Development & Reproduction
        
        Animals can not reproduce
        
        Children fail to grow properly
        
        Affect jaw development
      - Health of Mucous Membranes in Epithelial Tissues
        
        Decreased mucous productio
        
        Keratinization of cells
      - Immune Function
        
        measles
    - - Causes
        
        Food intake
        
        Supplement use at 3-4 DRI- RDA level
        
        Medical treatment for acne- teens
        
        Vitamin A stimulates cell growth, repair
      - Symptoms
        
        Loss of appetite
        
        nausea
        
        headaches
        
        Dry skin
        
        Enlarged liver, spleen
        
        Bone defects
      - Types of Toxicity
        
        Acute
        
        single large dose of a retinoid
        
        Chronic
        
        regular intakes of ~ 10X DRI
        
        Teratogenic
        
        supplement Vitamin A taken during pregnancy
- - - - fat-soluble (E, A)
      - water-soluble (C)
  - - - Inhibit oxidant formation
      - Intercept oxidants once they are formed
      - Neutralize free radicals
      - Repair oxidant-induced damage