Vitamins by fjzhangxiaoquan


									Vitamins and Nutrition

            HL Chemistry Human
Vitamins and Nutrition

   Our bodies need food for:
    –   1. energy storage (carbohydrates, etc.)
    –   2. energy source (proteins, fats)
    –   3. vitamins (nutrients)
    –   4. minerals (nutrients)
    –   5. trace elements (nutrients)
   Nutrients are chemicals that are necessary to
    support, nourish, and promote good health.
What are vitamins?

   Organic molecules needed
    –   for some enzymes to function properly
    –   To act as antioxidants, getting rid of free radicals
        that can cause DNA mutations
   Inorganic molecules, by the way, are

   1795, British Navy ships carried a mandatory
    supply of limes or lime juice to prevent scurvy
    among the sailors – they were given the
    name “limeys”
   Japanese Navy gave sailors whole grain
    barley to ward off beriberi
   It wasn’t til 1912 that people knew why these
    “prescriptions” worked to prevent diseases

   Casimir Funk named vitamins – vital amines
    because they were compounds that
    contained nitrogen (amines contain nitrogen)
    and were vital for health
   Along with Frederick Hopkins, they came up
    with the idea that scurvy and beriberi were
    diseases that resulted from the deficiency of
    certain compounds that could be found in
       RDA (Recommended Daily

   Lists levels of essential nutrients needed to
    meet the nutritional needs of most healthy
MDA (Minimum Daily Allowance)

   Minimum levels of nutrients needed to avoid
    deficiency diseases.
Calories (vs. calories)

   1 Calorie = 1000 calories (1 kcal)
   Example. A 10.0 g sample of a chocolate bar
    with a total mass of 30.0 g was combusted in
    a calorimeter. It raised the temperature of
    500.0 g of water from 20.0 degrees C to 75.5
    degrees C. What is the calorific value (in kJ)
    of the chocolate bar?
∆H = 500.0g(75.5-20.0C)(4.18J) = 115.995J(3) = 348 kJ   (30g)

   Must know structures (see IB Data Booklet)
   Definition: something that cannot b
    synthesized by the human body and must be
    supplied by our diet.
Important Vitamins

There are 18 vitamins and minerals essential in
  a healthy diet…but IB only wants you to
  know detailed info about:
 Vitamin A (retinol)
 Vitamin C (Ascorbic Acid)
 Vitamin D (Calciferol)
Vitamin Classification

   Fat-soluble vs Water soluble
    –   Too much of a water soluble vitamin = ok, comes
        out in urine
    –   Too much of a fat soluble vitamin = sickness
        because it doesn’t dissolve in your urine readily
        and gets stored in your body.
   Fat soluble vitamins:
    –   All Dogs Eat Kibbles
                           CH3          CH3   CH3

Vitamin A                        CH3

   Fat Soluble: will stay dissolved within body
   Vitamin A (Retinol)
    –   Source: green veggies
    –   Needed for: synthesis of visual pigments in the
        eye. Important anti-oxidant (reacts with free
                                          CH3             CH3             CH3

Vitamin A                                       CH3

   Required for the production of rhodopsin (light-sentistive
    material in the rods of the retina).

   Too Little:
     –   Nightblindness
     –   Xeropthalmia –have difficulty producing tears
             Effects about 500,000 children in underdeveloped nations
     –   Dry mucous membranes

   Too Much:
     –   Makes you think you have a brain tumor
             Headache, vomiting, nausea, abnormal vision, loss of hair
     –   Some precursers can make you turn orange =)
Vitamin A Poisoning

 A bizarre case of extreme vitamin A
 poisoning was reported by Artic explorers
 who killed and ate a polar bear. Those who
 ate the liver became very ill and three of
 them lost patches of skin. Later,
 scientists discovered that 0.25 lb of the
 liver contains 2.5 yrs worth of Vitamin A
 for humans.
How do we get vitamin A?

   2 Chemicals: Retinoids and carotenoids
    –   Retinoids – body can use right away
    –   Carotenoids – body can change it into a retinoid
            Beta-carotene (Why are carrots good for your eyes? Have you
             ever seen a rabbit with glasses?)
            Carotenoids don’t get stored in liver
   Foods with 25% of your RDA for Vitamin A
    –   Cearal 1oz, oatmeal 2.3 cups
    –   Fruit: apricots, canteloupe, mango (1/2 c)
    –   Veggies: carrots, kale, peas, sweet peppers (1/2 c cooked)
    –   Meat: Liver 3oz
    –   Milk: 2 cups

Vitamin D

   Fat soluble                          H3C
   Sources: eggs, vitamin D milk, produced in
   Needed for: bone growth, uptake of calcium
    from food

Vitamin D

   Required for the uptake of calcium and phosphorus
    from food.                                 H3C

   Too little:
     –   can cause weak bones (Rickets) in children
     –   In adults: osteomalacia (soft bones, fracture easily)
   Too much:
     –   Kidney stones and hard lumps of calcium in muscles and
     –   Headache, nausea, vomiting, high blood pressure, retarded
         physical growth and mental retardation in children, fetal
How do we get Vitamin D?

   3 forms
    –   Calciferol: occurs in fish oils, egg yolks
    –   Cholecaliferol: created when sunlight hits skin, reacting with
        steroids in body fat just underneath skin
    –   Ergocalciferol: found in plants      Some people claim that you
   Foods with 25% of RDA                  should not use sunscreen so
                                            that your body can use the
    –   Salmon or tuna 1.5-2 oz           sunlight to produce Vitamin D.
    –   Eggs: 3                            Most doctors, though, advise
    –   Milk: 1 cup                         getting Vitamin D through
                                          your food and wear a high SPF
                                              sunscreen at all times.
Vitamin E (tocopherols)

 Fat soluble
 Sources: meat, milk, vegetable oils
 Needed for: antioxidant, skin repair, stops
  breakdown of vitamin A
 Deficiency disease:


Vitamin C                       HO       O


  Water soluble
 Sources: citrus fruits, leafy vegetables,
 Needed for:
antioxidant, enzyme
production, connective
tissue formation


Vitamin C                                          HO           O

   Required for
     –   Production of collagen: the protein of connective tissue.
     –   Antioxidant
     –   Protects immune system, helps fight off infection, reduces allergic

   Too Little:
     –   Scurvy (bleeding gums; tooth loss; mosebleeds; bruising; painful
         or swollen joints; shortness of breath, increased susceptibility to
         infection, skin rashes; muscle pains, slow wound healing)
   Too Much:
     –   More than 1000 mcg may cause upset stomach, diarrhea, or
How do we get Vitamin C?

   On the label, look for:         Did you know that many foods are
    –   Sodium ascorbate             preserved with sodium nitrite to
    –   Isoacrobate                prevent the growth of bacteria. At
                                      high T, nitrite + protein forms
    –   Ascorbic acid
                                   carcinogen. Vitamin C prevents that
   Foods with 25% of RDA             rxn so it is added to processed
    –   Cereal: 1 oz                              meat, too.
    –   Meat: Liver 3oz
    –   Fruit: Canteloupe, grapefruit, mango, orange, strawberries,
        ½ c.
    –   Veggies: Asparagus, broccoli, brussel sprouts, kale,
        kohlrabi, sweet peppers, snow peas (cooked) ½ c. sweet
        potato: 1 med.
Fortified Foods

   Foods are fortified to provide us with the
    nutrients we need to stay healthy
   Ex: milk is fortified with vitamin D
    –   A pre-curser to vitamin D is extracted from plants,
        then irradiated to make an active form of Vitamin
        D, then it is added to food
Cooking and vitamin absorption

   Studies show that cooking foods can cause a
    decrease in the amount of vitamins in the
    –   Water soluble vitamins dissolve in cooking water
    –   Some vitamins are broken down by heating
   Some vitamins, though, are better than no
    vitamins. So eat your veggies, cooked or
Minerals vs. trace elements
Minerals                            Trace elements

   Levels needed is the only          Levels needed is the only
    difference                          difference
    –   ~100mg/day or more              –   ~10mg/day
   Examples: calcium,
   Both important for:                Examples:
    –   1. hormones (synthesis)
    –   2. nerves
    –   3. bone/teeth development
                                    iron, fluorine, chromium
    –   4. glucose metabolism
    –   5. enzyme activity

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