Vitamin Bioavailability

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					Historical Perspective
•Funk coined the term
“vitamin” in 1912
•Vitamin A was identified in
•Vitamin B12 was identified
in 1947
Vitamin Bioavailability
  Quantity in food
     Water soluble vs. fat soluble
     Efficiency of digestion
     Previous nutrient intake/status
     Other foods eaten at the same time
     Method of food preparation
     Source of nutrient (natural vs. synthetic)
The B-Vitamins
  Coenzymes in the breakdown of glucose
     Folate & B12
  Deficiencies often occur together
     Anemias, pellagra, beriberi
  Food Sources:
     Meat: thiamin, niacin, B6, B12
     Milk: riboflavin, B12
     Fruits and vegetables: folate
     Grains: thiamin, niacin, riboflavin
Folate/Folic Acid **
  Daily Value = 400 mcg
  Deficiency: macrocytic (megaloblastic)
  anemia; elevated homocysteine; neural
  tube defects
  Sources: fortified grains, leafy green
  vegetables, legumes, seeds, orange
  juice, liver
Folic Acid Sources
  1/2 cup chicken liver: 539 mcg
  1/2 cup beef liver: 184.5 mcg
  1/2 cup lentils: 179 mcg
  1/2 cup cereal (fortified): 146-179 mcg
  8 ounces orange juice: 109 mcg
  Medium-sized papaya: 115 mcg
  1 oz. wheat germ: 100 mcg
  4 spears steamed or boiled asparagus: 88 mcg
  ½ cup cooked turnip greens: 85 mcg
  ½ cup cooked spinach: 54 mcg
  1/2 cup steamed broccoli: 52 mcg
  1 cup cantaloupe: 27.2 mcg
  Large hard-boiled egg: 22 mcg
Neural Tube Defects
Neural Tube Defects
Vitamin B        12   **
 Daily Value: 6 mcg
 Deficiency: pernicious anemia; smooth,
 sore tongue, fatigue, paralysis, skin
 Sources: animal foods, fortified cereals,
 fortified soy products
 Deficiency usually due to poor
     Atrophic gastritis
     Achlorhydria
     Lack of intrinsic factor
Vitamin C **
Daily Value: 60 mg New RDA: 75 mg
   Smokers: 100 mg
Collagen formation, antioxidant, amino acid
metabolism, possible antihistimine, iron
absorption, infection resistance, thyroxin synthesis
Excess vitamin C does not prevent colds
   May help to shorten duration
Deficiency (Scurvy): poor wound healing;
microcytic anemia; bone fragility; joint pain;
bleeding gums; muscle degeneration; frequent
infections; pinpoint hemorrhages
Vitamin C

  Food Sources: citrus fruits, cruciferous
  vegetables, dark green vegetables
  (green pepper, spinach), tomatoes,
  strawberries, kiwis, papayas, mangoes,
  Easily destroyed by heat and oxygen
Vitamin C sources
  1 large yellow pepper: 341 mg.
  1 large green pepper: 120 mg.
  8 ounces orange juice: 97 mg.
  1 medium kiwifruit: 74 mg.
  1 cup whole strawberries: 84 mg.
  ½ cup steamed broccoli: 58 mg.
  ½ cup cooked Brussels sprouts: 48 mg.
  1 baked potato: 31 mg.
  1 baked sweet potato: 28 mg.
  ½ cup cooked cauliflower: 28 mg.
  ½ cup canned tomatoes: 19 mg.
  ½ cup cooked spinach:12 mg.
  Saving Vitamin C
Vitamin C can be lost from foods during preparation, cooking, or storage.
   To retain vitamin C:
   Serve fruits and vegetables raw whenever possible.
   Steam, boil, or simmer foods in a minimal amount
   of water, or microwave them for the shortest time
   Cook potatoes in their skins.
   Refrigerate prepared juices and store them for no
   more than 2 to 3 days.
   Store cut raw fruits and vegetables in an airtight
   container and refrigerate--do not soak or store in
   water. Vitamin C will leach into the water.
Thiamin (Vitamin B1)
 Daily Value: 1.5 mg
 Deficiency disease: Beriberi (wet or dry)
 Symptoms: Enlarged heart, cardiac
 failure, weakness, apathy, confusion,
 irritability, poor short-term memory
 Sources: whole grains, pork
 Easily destroyed by heat
Riboflavin (B2)
  Daily Value: 1.7 mg
  Ariboflavinosis: inflammation of mouth, skin,
  eyes, GI tract
   Symptoms: inflamed eyelids; reddening of
  the cornea; sore throat; cracks at the corners
  of the mouth; smooth, painful, purplish red
  Sources: dairy products, whole grains, liver
  Easily destroyed by light
Niacin (B3)
  Daily Value: 20 mg NE
  60 mg tryptophan = 1 mg
  Pellagra: diarrhea, dermatitis, dementia,
  Symptoms: depression; apathy; smooth, red
  tongue; rash; nausea; vomiting; diarrhea;
  blurred vision
  Sources: milk, eggs, meat, nuts, whole grains
Vitamin B6
  Daily Value: 2 mg
  Toxicity: identified in 1983 – results in
  neurological damage
  Deficiency: dermatitis, depression,
  microcytic anemia, fatigue,
  headache,muscle weakness, numbness,
  Sources: meats, fish, poultry, potatoes,
  legumes, liver, soy, fortified grains
Fat soluble vitamins (A,D,E,K)
  Absorbed into the lymph first, then the
  May require protein carriers
  Stored in cells associated with fat
  Less easily excreted
  Supplements can cause toxicity
  Needed in periodic doses due to storage
Vitamin D **
  The “Sunshine Vitamin”
  Food sources are limited: fortified milk
  and some cereals, egg yolks, cod liver
  oil, fatty fishes
  Both sources produce/provide inactive
  vitamin D – must be hydroxylated in the
     Kidney
     Liver
Role of Vitamin D
  Increase serum calcium levels:
     Increases calcium absorption
     Decreases calcium excretion through the
     Increases mobilization of calcium from the
Vitamin D recommendations
 Adequate Intake for Adults
    19 to 50: 5 micrograms/day (200 IU’s)
    51 to 70: 10 micrograms/day (400 IU’s)
       This is also the daily value!!!!!
    Over 70: 15 micrograms/day (600 IU’s)
    Proposed new Adequate Intake (or RDA?): 800 to
     1000 IU’s per day to maintain vitamin D levels
 Upper level for Adults
    50 micrograms/day (2,000 IU’s)
    Does new research back this up?
Vitamin D Deficiency
     Children
     Failure of bones to calcify properly
     Adult form of rickets
     Increased risk of fracture
Vitamin D toxicity
  Nausea, vomiting
  Loss of appetite
  Calcification of soft tissues
Vitamin E **
 Major Anti-Oxidant
 Stabilizes cell membranes
 Protects polyunsaturated fatty acids
 Sources: margarine, salad dressings,
 shortenings, leafy green vegetables,
 wheat germ, whole grains, liver, egg
 yolks, nuts, seeds
Vitamin E Recommendations
  Deficiency: hemolytic anemia, leg
  cramps, weakness
  Toxicity: Hemorrhaging, increased
  effect of anti-clotting meds, nausea,
  cramps, fatigue
     Adults: 15 mg/day
  Upper Level
     1000 mg/day
Pharmacological Uses of
Vitamin E
  Supplement sources
  Generally recommended: 400 IU’s
  Has been recommended for:
     Heart disease prevention
     Cancer prevention
     Improved immune function
  What does the research show?
Vitamin A & Beta Carotene **
Major Roles of Vitamin A
   Vision
   Protein synthesis & cell differentiation (maintains
    health of epithelial tissues & skin
   Reproduction and growth
   Bone Remodeling
Beta Carotene
   Can be converted into vitamin A
   Found in fruits and vegetables
   Also acts as an anti-oxidant
Vitamin A Requirements
 Measured in IU’s and RAE’s (Retonol
 Activity Equivalent)
 2001 RDA
    Women: 700 micrograms RAE/day
    Men: 900 micrograms RAE/day
 Upper Level
    3000 micrograms/day
Vitamin A Deficiency
  Hypovitaminosis A
  Infectious Disease
  Kidney stones
  Cessation of bone growth
  Painful joints
  Night Blindness
     Early sign of deficiency
Vitamin A Toxicity
 Not caused by Beta-Carotene
 Hypervitaminosis A
 Bone decalcification – increased fractures
 Stunted Growth
 Cessation of Menstruation
  Slowing of Clotting time
 Enlargement of the liver
 Dry, itching skin
Vitamin K
Roles: blood clotting, synthesis of
   Men: 120 mcg/day
   Women: 90 mcg/day
Toxicity: interference with anti-clotting meds
Deficiency: hemorrhagic dx.
Sources:large intestine synthesis, liver, leafy
greens, cruciferous veggies, fort. milk
     Retain identity
  Variable Bioavailability
     Usually due to binders
     Must consider % bioavailability and total
      amount in food
  Nutrient Interactions
             SODIUM **
Principal cation in the extracellular fluids of
the body
Filtered by the kidneys
  fluid balance

  nerve transmissions

  muscle contractions

  acid-base balance
RDI not established
Estimated minimum requirement for adults is
500 mg/day
Limit salt intake to 2400 mg/day
Some people more sensitive to salt
  chronic renal disease

  diabetes

  HTN

  African Americans
  Deficiency Vs. Toxicity
Symptoms:             Symptoms:
  muscle cramps        edema

  mental apathy        acute HTN

  loss of appetite     thirst
Table salt
Soy sauce
processed foods
Fresh fruits and vegetables contain the least
Moderate amounts in:
  meats

  milk

  breads

Salt is 40% sodium
1 g of salt contributes 400 mg of sodium
1 tsp of salt contributes 2000 mg of sodium
Not all foods contain salt - just sodium
   How would these foods rank in order of sodium
    content?: 1/2 c. instant chocolate pudding, 1 oz
    cornflakes, 1 oz. salted peanuts
Potassium **
 Fluid/electrolyte imbalance
 Cell integrity
 Nerve transmission & muscle contraction
 High K diets may help to prevent stroke by
 lowering blood pressure
 Sources: mainly fresh fruits and
 Daily Value: 3500 mg.
Some Sources
 Baked potato with skin: 844 mg
 1 cup orange juice: 473 mg
 1 medium banana: 451 mg
 1 cup milk: 406 mg
 ½ cup pinto beans: 300 mg
 Protein and energy metabolism, found
 in the bones
 RDA: 400 mg for men, 310 mg for
 Sources: legumes, nuts, seeds, whole
 grains, dark leafy vegetables, chocolate
 Protective role in hypertension and
 heart disease

Second most abundant mineral in the body
85% is found combined with calcium in the
hydroxyapatite crystals in bones & teeth
Other roles: energy metabolism, lipid
structure, cell membranes, some in protein
Deficiency is almost unknown
RDA: 700 mg/day (adults)
  Meats (liver: 520mg),
  milk (245 mg),
  yogurt (250 mg),
  dark sodas (~50 mg/12 ounces),
   processed foods
Calcium **

 Most abundant mineral in the body
 Found in bones & teeth
 Nerve messages
 Blood clotting
 Regulation of heartbeat
 NIH guidelines: 1000 – 1500 mg per day
Calcium Homeostasis
     Triggered by rising serum calcium
     Inhibits vitamin D activation
     Inhibits osteoclasts
  Parathyroid Hormone (PTH)
     Triggered by decreasing serum calcium
     Stimulates vitamin D activation
     Stimulates osteoclasts
   Dairy foods
      8 oz. Milk: 300 mg
      8 oz. Yogurt: 300 – 400 mg
      1 oz. Cheese: 200 mg
   Some Vegetables
      ½ cup, canned turnip greens: 135 mg
      1 cup raw broccoli: 45 mg
   Fortified foods
      1 cup calcium fortified orange juice: 300 mg
      1 oz. Fortified cereals: 100 – 1000 mg
Calcium Supplements
Calcium Carbonate
    40% elemental calcium
    Viactiv, Caltrate, OscalTums, most store brands
    300 – 600 mg of calcium per pill
    Requires hydrochloric acid for best absorption
Calcium Citrate
    23% elemental calcium
    Citracal, some store brands
    200 – 300 mg of calcium per pill
    Does not require hydrochloric acid for absorption
Osteoporosis Risk Factors

     Women are at higher risk
     Low estrogen levels play a big role
     Increased age – increased risk
 Low BMI
 GI disorders
     Poor absorption
     Use of meds that promote bone loss
Osteoporosis Risk Factors

 Low calcium intake
 Lack of weight bearing exercise
 Excessive alcohol intake
    Not a clear relationship
    Moderate alcohol may be good for bone density
 Cigarette smoking
 Certain medications: corticosteroids (ie.
 prednisone), excessive thyroid medication, some
 anti-seizure medications (ie. Dilantin)
Other nutritional
  Factors that increase calcium excretion
     Excessive sodium
     Excessive animal protein
     Excessive Caffeine
  Vitamin K
     Formation of osteocalcin
Iron **
  Hemoglobin and myoglobin
     Necessary for muscle contraction and energy
  RDA for men: 10 mg
  RDA for women: 15 mg, 10 mg after
  Sources: meats, eggs, legumes, dried fruits
  Most common deficiency worldwide
  Ferritin, transferrin
Heme Iron vs. Non-Heme Iron
  Found in meats and   Vegetables, fruits,
  poultry              and grains
  10% of iron          Some in meats
  consumed per day     2 to 20% is
  Absorbed at a rate   absorbed –
  of 23%               dependent upon
  About 40% of iron    dietary factors and
  in meat is heme      body stores
  Iron Absorption
                      Reduce Absorption:
Enhance iron
  absorption:          Phytates
 Vitamin C             Calcium and
 MFP Factor            phosphorus
 Citric/lactic acid    Tannic acid
Deficiency vs. Toxicity
                     Organ damage
Reduced resistance
                     Heart disease
to colds             Enlarged liver
Impaired wound       Infections
healing              Hair loss
Fatigue              Lethargy
Impaired cognitive
Pica                   Est. 1% of population

                       Usually men

                       Increased iron absorption
A co-factor for more than 100 enzymes
Influences behavior and learning performance
Important for taste perception
Wound healing
Sperm Development
Fetal development
Necessary to produce the active form of Vitamin A
Growth and sexual maturation
          Zinc: absorption
Phytates and fiber bind zinc
   Legumes and whole grains
   Vegetarians beware
   Sulfur containing protein
   Binds zinc in intestinal cells until needed
Enteropancreatic Circulation
   Digestive enzymes of pancreas contain zinc
   Source of zinc in addition to food
             Zinc: Deficiency

   Arrested growth
   Vitamin A deficiency symptoms
   Altered taste
   Impaired immunity
   Hair loss, poor skin integrity
Vulnerable populations
   children (rapid growth=high needs)
   pregnant women
   elderly
   poor
Zinc Deficiency
  Vulnerable populations
     children (rapid growth=high needs)
     pregnant women
     elderly
     poor
  Protein rich and fortified Foods
Important part of 2 thyroid hormones (T3 and T4)
   Thyroid hormones regulate body metabolism
   Enlargement of thyroid due to iodine deficiency,
    goitrogens, or gland malfunction
   Affects 200 million worldwide
   Irreversible mental and physical retardation 2° to
    maternal def.
Iodization of salt in US
Part of Fluorapatite
   bone and tooth crystal
   makes bones and teeth stronger
Fluoridation of water
   Dental caries prevention
      Nation’s most wide spread health problem
   1 ppm is the ideal concentration
   Too much fluoride damages teeth permanently
   Pitting and stains
   occurs during tooth development
   Important for insulin activity
   Deficiency rare
   Chromium picolinate supplements have not been
    proven to reduce body fat
   Important anti-oxidant (cancer prevention?)
   Key factor in hemoglobin synthesis
   Deficiency rare
Vitamin/Mineral Supplements
  Don’t spend a lot of money!
  Avoid overdoses
  It’s a supplement not a substitute
  Specialty supplements
  Nutrients of concern
Specialty Vitamins


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