Docstoc

The Vitamins

Document Sample
The Vitamins Powered By Docstoc
					The Vitamins
            Classifying Vitamins
 Fat     Soluble Vitamins
     A
     D
     E
     K
        Water Soluble Vitamins
 VitaminC
 B Vitamins:
     Thiamin             -- Biotin
     Riboflavin          -- Pantothenic acid
     Niacin
     B6
     Folate (folic acid)
     B12
        Water Soluble Vitamins
 Digestion,     Absorption, and Transport
     No chemical digestion needed
     Absorbed in the SI into the capillaries
       • Vitamin B12 must bind with a protein called the
         intrinsic factor (IF) in the stomach for absorption to
         occur in the SI
     No carriers required for transport in the blood
        Water Soluble Vitamins
 Storage     and excretion
     Travel freely in the blood
     Cells take up water soluble vitamins as
      needed
       • Limited storage beyond tissue saturation
     Excess excreted in the urine
        Water Soluble Vitamins
 Deficiencyis more common than toxicity
 for the water soluble vitamins
     Why??
     Any toxicity is likely to be due to overuse of
      vitamin supplements, not food intake
        Water Soluble Vitamins
 Other   interesting information:
     Many are destroyed by light, heat, or
      exposure to oxygen
     Best to cook whole in a minimum amount of
      water
       • Why??
     Frozen vegetables are often higher in vitamin
      content than grocery store “fresh” veggies
       • Why??
          Fat Soluble Vitamins
 Digestion,   Absorption, and Transport
     Bile needed to emulsify fat soluble vitamins
     Form chylomicrons (along with long chain
      fatty acids and monoglycerides)
     Chylomicrons are absorbed into the lacteals
     Travel through lymph system  blood  liver
     Many require protein carriers to be
      transported in the blood
          Fat Soluble Vitamins
 Storage
     Stored in liver and fatty tissue
     Unlimited stores possible
 Greater risk of toxicity than deficiency for
 fat soluble vitamins
     Why??
          Fat Soluble Vitamins
 Other       interesting facts:
     Found in the fatty parts of food
     Removed with the fat when low-fat products
      are made
       • Many low-fat foods are supplemented with these
         vitamins to make up for this
             E.g. milk is vitamin A and D enriched
               The Vitamins
 For   each vitamin we will consider:
     Functions
     Dietary needs and food sources
     Deficiency
     Toxicity
                       Thiamin
History
Functions:
  1.   Needed for energy metabolism
       •   E.g. -- required for conversion of pyruvate to
           acetyl CoA
  2.   Needed for nerve and muscle function
                      Thiamin
Recommended Intake
     1.1-1.2 mg/day
Food Sources
     Found in small amounts in many foods
     Easily destroyed by heat (cooking)
     Lost in cooking water
     Good sources include
       • Pork products, soy, legumes, vegetables, whole
         grains, watermelon….(pg 327)
             Thiamin Deficiency
       Prolonged deficiency leads to beriberi
         Results in damage to nervous system and
          muscles (to include the heart)
            Thiamin Deficiency
   Symptoms Beriberi:
     1. Dry form- muscle wasting, poor coordination
        Muscle weakness
     2. Legs heavy, hard to walk, calf pain
     3. Apathy, confusion, memory loss
     4. Anorexia and weight loss
     5. Wet form has additional symptoms of:
        –   edema, irregular heart beat, enlarged heart
   alcoholics thiamin deficiency results in
 In
  Wernicke-Korsakoff syndrome.
      Symtpoms
       • Mental confusion
       • Staggering
       • Rapid eye movements or paralysis of the eye
         muscles
            Thiamin Deficiency
 Populations      at risk:
     Alcoholics
       • See in alcoholics who obtain the majority of their
         calories from alcohol
       • Alcohol inhibits thiamin absorption and hastens its
         excretion
     Cultures that eat primarily refined grains (and
      little else)
     Thiamin deficient moms  infant deaths
 The City of New York
 DEPARTMENT OF HEALTH AND MENTAL HYGIENE
      Michael R. Bloomberg Thomas R. Frieden, m.d., m.p.h.
      Mayor Commissioner

  _______________________________________________________________
           nyc.gov/health
   2003 Health Alert # 39:
   A cluster of infantile thiamine (vitamin B1) deficiency (beri-beri) has
    been reported in Israel among infants fed a vitamin B1-deficient
    kosher soy-based formula distributed by Remedia. It is possible
    that this product may be imported into New York City and there
    may be children in the Orthodox Jewish community who have
    consumed it.
   The New York City Department of Health and Mental Hygiene
    (NYCDOHMH) asks that providers report immediately any suspect
    case of thiamine deficiency among infants who have been fed this
    product to:
   The New York City Poison Control Center at:
    1-212-764-7667 (212-POISONS) or 1-800-222-1222.
   Please distribute to Pediatric staff in the Departments of
    Cardiology, Critical Care, Emergency Medicine, Family Medicine,
    General Pediatrics, Outpatient Pediatrics, Neonatology, Neurology,
    and Infectious Disease
                    Thiamin
 Toxicity
     None known
     Excess thiamin is excreted and not stored
                     Riboflavin
Functions:
  1.   Needed for the metabolism of
       carbohydrates, fats, and proteins
       •   Places a role in Kreb’s cycle
       •   Part of FAD
                      Riboflavin
Recommended Intake:
     1.1 – 1.3 mg/day
Food Sources:
     Destroyed by ultraviolet light (sun light)
     Good sources include:
       •   Milk and milk products
       •   Liver
       •   Whole grain breads and cereals, oatmeal
       •   Clams and squid!
       •   Mushrooms (page 329)
                    Riboflavin
Deficiency Symptoms
  1.   Eyes are inflamed and sensitive to light
  2.   Cheliosis (cracks at the corners of the mouth)
  3.   Sore throat
  4.   Inflammation of the tongue and mouth –
       painful
  5.   Inflamed skin, with lesions covered with
       greasy scales
  6.   Anemia
                    Riboflavin
Populations at Risk for Deficiency
     alcoholics
     any one with a marginal diet
      • Poor, elderly, eating disorders, drug addicts…
Toxicity
     None reported
     Excess excreted
                        Niacin
Functions
  1.   Plays an essential role in energy metabolism
       •   Part of NAD
       •   Needed by every cell of the body
                       Niacin
Recommended Intake:
     14 – 16 mg/day of niacin or of NE
     NE = Niacin Equivalents
       • Niacin can be made from the essential amino acid
         tryptophan
       • It takes 60 mg of tryptophan to make 1 mg of
         niacin
       • Therefore, 1 NE is 60 mg of tryptophan
                        Niacin
Food Sources:
     Sources of complete protein
       • Dairy, meats, poultry, fish,…
     Peanut butter
     Tomato paste
     Mushrooms
     (page 332)
             Niacin Deficiency
Niacin deficiency disease is called pellagra
  Symptoms, 4 D’s:
     1.   Dermatitis with sun exposure (pg 330)
     2.   Diarrhea, vomiting
     3.   Dementia
     4.   Death
  Other symptoms:
     1. Inflamed, swollen, red, smooth tongue
     2. Loss of appetite
                           Niacin
 Pellegra      - Other interesting information
     Originally believed to be caused by infection
     Common up to early 1900’s in US and Europe
       • Many in mental hospitals in south had niacin
         deficiency, not mental illness
             Incidence declined in US after WW II when mandatory
              enrichment of grains began
     Still common in Africa and Asia
       • Poor bioavailability form corn unless it’s soaked in
         lime juice
                       Niacin
Toxicity
     Tolerable Upper Intake Level (UL) = 35
      mg/day
     High doses of niacin are commonly used to
      treat high cholesterol
       • 1500 -3000 mg/day recommended for treating high
         cholesterol
                       Niacin
Toxicity Symptoms
  1.   Niacin flush
  2.   Excessive sweating
  3.   Tingling
  4.   GI distress
  5.   Frequent need to urinate
       •   May mask prostrate cancer symptoms in men
  6.   Blurred vision, headaches
  7.   Liver damage
             Folic Acid = Folate
Functions:
  1.   Needed for DNA synthesis
       •   Need to make all new cells
       •   E.g. Need to make new RBC
  2.   Reduces incidence of neural tube defects
       •   Defects occur in first weeks of pregnancy
                     Folate
3.   Plays a role in protein synthesis
4.   Breaks down the amino acid homocysteine
     – High levels of homocysteine increases risk of
       blood clot formation
5.   May reduce risk some cancers
     – Pancreatic cancer in men who smoke
     – Breast cancer in women who drink
                        Folate
 Absorption     and Activation
     Folate in foods must be acted upon by an
      intestinal enzyme for it to be absorbed and
      transported to cells
     Folate in cells needs to be activated by
      vitamin B12
       • Process also activates the B12
                  Folate
 Recommended     intake:
    400 micrograms/day
                      Folate
 Factors   impacting needs
     Pregnancy -600 mcg/day
     Aspirin, antacids, smoking, oral
      contraceptives reduce absorption
     Some cancer drugs reduce absorption
     GI tract damage reduces absorption
      • Occurs with alcoholism, anorexia
      • Poor absorption, leads to even more damage to GI
        tract
                          Folate
 Food      Sources
     Cooking destroys up to 50% of folate
     Oxygen destroys folate
     Good sources include:
       •   Green leafy vegetables
       •   Legumes
       •   Fortified cereals and Seeds
       •   Liver
       •   Orange juice (ok, but not great source) pg 341
                    Folate
Folate Deficiency
 Impairs cell division and protein
   synthesis
 Symptoms:
     1. Megaloblastic anemia
         Fewer red blood cells (RBC) made
         RBC larger than normal
         RBC do not carry oxygen as well
            Folate Deficiency
2.   Confusion, irritability, weakness, fatigue
     •   Related to the anemia
3.   GI tract deterioration
4.   Elevated homocysteine levels
5.   Smooth red tongue
6.   Increased risk neural tube defects
                       Folate
 Toxicity
     No known symptoms
     May mask a vitamin B12 deficiency
       • B12 deficiency is VERY serious
                  Vitamin B12
 Dorothy     Crowfoot Hodgkin
     Awarded the Nobel prize in chemistry for
      deducing the structure of vitamin B12
       • Took her eight years
     Headline in the London paper announcing this
      read
             “Nobel Prize for British Wife”
                  Vitamin B12
Functions:
     Needed to activate folate
       • Therefore, needed for DNA and new cell (RBC)
         synthesis
     Helps maintain myelin sheath around nerve
      cells
                    Vitamin B12
Recommended intake:
     2.4 microgams per day
Food Sources*:
     ONLY found naturally in animal products
       • Meat, poultry, fish, eggs, dairy, liver….
     Fortified grains

  *Easily destroyed by microwave cooking
                   Vitamin B12
Deficiency:
     Pernicious anemia (VERY SERIOUS)
      •   Megaloblastic anemia
      •   Nerve damage  creeping paralysis
      •   Smooth sore tongue
      •   Fatigue
               Vitamin B12
 Pernicious  anemia frequently goes
  undiagnosed
 Pernicious anemia can be masked by high
  intakes of folate
                 Vitamin B12
 Gastric by-pass patients and vegans are
  at elevated risk
     Takes several years to develop



 Toxicity:
     None reported
                            B6
Functions:
     Need for protein and fatty acid metabolism
     Need for amino acid metabolism
       • E.g. For converting tryptophan to other niacin
       • need to make serotonin form tryptophan
     Helps make RBC
     Other functions under study
                             B6
Recommended Intake:
      1.3 mg/day
      UL: 100 mg/day

Food sources: destroyed by heat
      Meat, fish, poultry
      Legumes
      Seeds and nuts
      Liver
      Non-citrus fruits
                       B6
Deficiency: (rare)
     Anemia  Weakness and fatigue
     Depression, confusion
     Abnormal brain waves, convulsions
     Greasy dermatitis
                            B6
Increased risk of deficiency:
     Alcoholics
       • Alcohol contributes to increased B6 breakdown
         and excretion
  Oral contraceptives may increase risk of B6
   deficiency
  Drug INH inactivates B6
       INH used to treat tuberculosis
                          B6
Toxicity: Serious
     Stored in muscle cells, toxicity seen with
      supplements
     Symptoms:
       • Irreversible nerve damage  numbness in hands
         and feet  Difficult to walk
       • Convulsions
       • Insomnia, restlessness
                       B6
 B6   does not help with:
     Carpal tunnel syndrome
     PMS
     Supplementation above the UL is NOT
      recommended
                      Biotin
Functions:
     Need for energy metabolism
     Need to make glycogen
     Plays a role in fatty acid and amino acid
      synthesis
                          Biotin
Recommended Intake:
     30 micrograms/day (AI)

Food Sources*:
     Widespread in foods: liver, egg yolk,
      legumes, fish, mushrooms, whole grains…
     Some produced by GI tract bacteria

  *easily destroyed by processing
                        Biotin
Deficiency:
     RARE
      •   Skin rash
      •   Hair loss
      •   Depression
      •   Hallucinations
      •   Numbness in legs/arms
                      Biotin
          can be induced by eating
 Deficiency
  LARGE quantities of raw egg whites
     2 dozen daily for ~2 months!
     Prevents biotin absorption


 Toxicity:   none reported
                Pantothenic Acid
Functions:
     Need for energy metabolism
       • Part of acetyl CoA
     Plays a role in the synthesis of many
      substances:
       •   Lipids
       •   Hormones
       •   Neurotransmitters
       •   Hemoglobin
             Pantothenic Acid
Recommended intake:
     5 mg/day (AI)


Food Sources:
     Widespread in foods
              Pantothenic Acid
Deficiency: Rare
     Fatigue
     GI distress
     Insomnia, depression
     Apathy, irritable
     Increased sensitivity to insulin
              Pantothenic Acid
 Toxicity:   none known
                    Vitamin C
Functions:
     Collagen synthesis
       • Part of scar tissue
       • Strengthens blood vessels
       • Provides matrix for bone growth
     Antioxidant
     Need for healthy immune system
     Need for thyroxine production
                    Vitamin C
Functions:
     Need for thyroxine production
       • Regulates body temperature and metabolic rate
     Enhances iron absorption
     Need to make hemoglobin
                    Vitamin C
Recommended intake:
     Men: 90 mg/day
     Women: 75 mg/day
     Smokers: an extra 35 mg/day
      • More free radicals that need to be “neutralized”


     UL: 2000 mg/day
                    Vitamin C
Food sources*:
     Citrus fruits
     Strawberries, melon
     Vegetables
       • Tomatoes, dark green leafy vegetables, potatoes,
         broccoli…

       *Heat and oxygen sensitive
                   Vitamin C
Deficiency:  Scurvy
     Poor wound healing       - Increased infection
     Weakness
     Bleeding gums
     Loose teeth
     Broken blood vessels
     Loss of appetite
     Joint pain and fragile bones
     Anemia
                    Vitamin C
Populations at increased risk:
     Alcoholics
     Elderly
     Babies and toddlers fed only milk/cereals
     Smokers
     After illness or stress
       • Fever and stress deplete vitamin C stores
                  Vitamin C
Toxicity Symptoms:
     Diarrhea
     Cramps, nausea
     Headaches, insomnia
     May interfere with lab tests and meds
     Increased risk kidney stones
     Over-absorption of iron
     Fat Soluble Vitamins
A
D
E
K
                     Vitamin A
Chemical nature:
     Active forms of vitamin A
       • Retinol
       • Retinoic acid
       • Retinal
     Precursor form
       • Beta-carotene
       • Converted to active vitamin A as needed
                     Vitamin A
Functions:
     Need for night vision
       • See handout
     Need for protein synthesis
     Plays a role in cell differentiation
       • Need to build healthy epithelial and mucous tissue
       • Need to maintain healthy cornea
                    Vitamin A
Functions:
     Plays a role in reproductive health
       • Sperm production
       • Fetal development
       • Sexual maturation
     Need for bone growth
               Beta-Carotene
Functions beta-carotene;
     Can be converted to active vitamin A as
      needed
     Antioxidant
                     Vitamin A
Recommended intake:
     700-900 RAE micrograms/day
     RAE = retinol activity equivalents
       • Older unit is IU = International Units
       • See page 360 for conversions between these units
     UL 3000 RAE
       • UL refers to active vitamin A only, not beta-
         carotene
                       Vitamin A
Food Sources Vitamin A:
     All animal sources
       •   In fatty portion of the food
       •   Dairy products
       •   Eggs
       •   Meat, liver
       •   Fortified skim milk and margarine
                Beta-Carotene
Food Sources:
     All plant sources
     Yellow/orange/red fruits and vegetables
       • Carrots, apricots, cantaloupe, mangos, pumpkin,
         sweet potato, winter squash, peppers……
     Dark green leafy vegetables
       • Spinach, kale, broccoli, beet greens (but not the
         beet!)
                     Vitamin A
Deficiency:
     Night blindness
     Blindness
       • Leading cause of blindness worldwide
       • ~ ½ million children go blind each year due to a
         vitamin A deficiency
                    Vitamin A
Deficiency:
     Keratinization  dry, cracked skin
     Reduced secretions
       • GI tract
       • Bladder
       • Lungs
     Above symptoms increase risk of infection
                     Vitamin A
Deficiency:
     Anemia
     Slow bone growth
     Painful joints
     Cracked, cracked teeth
     Delayed sexual maturity


  For others see pages 374
                    Vitamin A
Toxicity:
     Teratogenic
       • “monster producing”
     GI distress, weight loss
     Bone issues
       • Joint pain
       • Stunted bone growth and more
                  Vitamin A
Toxicity:
     Headaches, pressure inside skull
     Blurred vision
     Fatigue, muscle weakness
     Skin rashes
     Dry, cracked, bleeding lips
     Dry, brittle hair
                    Vitamin A
 Vitamin    A toxicity can be fatal
     Polar bear liver story
 Symptoms     go away quickly if diet changes
 Toxicity is never from beta-carotene
  sources
     Beta-carotene toxicity…..
                    Vitamin D
Chemical nature:
     Vitamin D is a sterol
     Body can make from cholesterol
       • Requires sunlight exposure
     Synthesis of vitamin D
       • See page 376
                        Vitamin D
Functions:
     Bone mineralization
       • Works with other nutrients
             Vitamins A, C. K
             Several minerals
                     Vitamin D
Functions:
     Regulates calcium and phosphorus levels
       • Stimulates Ca and P absorption in SI
       • Regulates movement of Ca and P in/out of bones
       • Stimulates kidneys to retain Ca and P

       • All of the above are related to bone mineralization
                   Vitamin D
Other Functions:
     Acts as a hormone
      • Not fully understood
      • Many target organs:
          Brain and CNS

          Muscle

          Reproductive cells…
                  Vitamin D
Recommended intake:
     Depends upon sun exposure and skin color
     5-10 micrograms/day (AI)

     UL: 50 mcg/day
                   Vitamin D
Food sources*:
     Fortified milk and margarine
     Butter
     Egg yolks
     Liver
     Fatty fish and fish oils

  * animal sources
                  Vitamin D
Deficiency:
     Bone abnormalities
       • Kids  rickets
       • Adults  osteomalcia
                   Vitamin D
Populations at risk for deficiency:
     Inner-city kids
     Dark skinned
     Live in a northern climate
     Limited sun exposure
     Elderly
     Kidney or liver disease
     Vegans
                     Vitamin D
Toxicity:
     Very toxic
       • Can be lethal
       • Milk story
     Toxicity is never from sun exposure
             Vitamin D Toxicity
 Symptoms:
     Calcium deposits in soft tissue
       • Muscles, lungs, heart
     Kidney stones
     Calcium deposits on walls of arteries
     Joint pain
     Frequent urination
     GI distress
                     Vitamin E
Chemical nature:
     A type of tocopherol
     4 forms
       • Alpha, beta, gamma, delta
       • Alpha-tocopherol is the most active form
       • Other forms have very limited bioactivity
                     Vitamin E
Functions:
     Antioxidant
       • Component of animal cell membranes
       • Protects unsaturated fatty acids in cell membranes
     Other roles are not clearly defined, but likely
      exist
                   Vitamin E
Recommended intake:
     15 mg/day
     Need more if eat more polyunsaturated fats

     most students did not meet their vitamin E
      requirement on the day analyzed
                     Vitamin E
Food sources*:
     Vegetable oils
     Nuts and seeds
     Whole grains
     Green leafy vegetables
     Liver
     Wheat germ
     Egg yolks         *easily destroyed by heat and oxygen
                     Vitamin E
Deficiency:
     Rare as most vitamin E is recycled
     See in premature babies
       • Transferred from mom to baby in last weeks of
         pregnancy
     Cystic fibrosis patients
       • Due to poor fat absorption
                    Vitamin E
 Symptoms       deficiency:
     Hemolytic anemia
       • RBC break open
     Neurological problems with prolonged
      deficiency
       • Loss of coordination
       • Vision and speech problems
       • Does not prevent/cure MD
                      Vitamin E
Vitamin E may help with:
     Leg cramps
       • Intermittent claudication
     Fibrocystic breasts disease
       • “lumpy” breasts
                     Vitamin E
Toxicity: Rare
     Supplements recommended by many, but not
      above the UL = 1000 mg
       • 200 mg supplement probably enough
     May interfere with blood clotting
       • Stop taking supplements prior to surgery


     Other symptoms: nausea, fatigue, blurred
      vision
                  VITAMIN K
Functions:
     Need for synthesis of blood clotting proteins
     Plays a role in regulation of calcium levels
                  Vitamin K
Recommended intake:
     90-120 mcg/day


Sources:
     Made by GI tract bacteria
     Dark green leafy vegetables, cabbage family
     Liver
     Milk
                     Vitamin K
Deficiency: rare
     Symptoms:
       • Bleeding, hemorrhaging
       • Bone weakness
     Populations at risk
       • Babies
       • After long-term antibiotic treatment
       • CF
                       Vitamin K
Toxicity: rare
     Occurs with supplement overuse
      • Take with caution, even if prescribed
     Symptoms:
      •   RBC break open
      •   Jaundice
      •   Brain damage
      •   Interferes with anti-clotting meds

				
DOCUMENT INFO