Chapter 8: The Vitamins

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Chapter 8 The Vitamins
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Vitamins

• Essential organic substances
• Yield no energy, but facilitate energy-yielding
  chemical reactions
• If absent from a diet, it will produce deficiency
  signs and symptoms

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Function of Vitamins

• Coenzyme
• Antioxidant
• Structure and formation of tissue

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RDAS

• Recommended Dietary Allowances
• Established for Average, HEALTHY Populations
• Set higher than actual needs so most could meet
  needs by only consuming only 75 of RDA
• What about taking more than RDA?

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Fun Facts

• Named in order of discovery
• Plant and animal foods provide vitamins
• Scientists believe they have discovered all the
  vitamins

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Classification

• Fat Soluble
• A, D, E, K

• Water Soluble
• C
• Bs - B1, B2, B3, B6, B12

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Fat-Soluble Vitamins Overview

• Dissolve in organic solvents
• Not readily excreted can cause toxicity
• Absorbed along with fat
• Concern for people with fat malabsorption

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Vitamin A

• Deficiency is most common cause of non-accidental
  blindness
• Preformed
• Retinoids
• Found in animal products
• Proformed
• Carotenoids
• Found in plant products

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Functions of Vitamin A

• Night blindness
• Cell health
• Growth, development, reproduction
• Cardiovascular disease prevention
• Cancer prevention

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Vitamin A and Your Skin

• Topical treatment and oral drug
• Accutane (oral) and Retin-A (topical)
• Can induce toxicity symptoms
• Not recommended for pregnant women
• Use only under supervision of a physician

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Vitamin A from the Food Guide Pyramid
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Deficiency of Vitamin A

• Night blindness
• Irreversible blindness
• Follicular hyperkeratosis
• Bumpy, rough, and dry, flaky skin

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Who is at Risk For Deficiency

• Breast fed infants
• Those with poor vegetable intake
• Urban poor and the Elderly
• Alcoholics and people with liver disease
• HIV, AIDS

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Toxicity of Vitamin A

• Large intake of vitamin A over a long period
• Bone/muscle pain, loss of appetite, skin
  disorders, headache, dry skin, hair loss,
  increased liver size, vomiting
• Spontaneous abortion, birth defects
• May occur with as little as 3 x RDA of preformed
  vitamin A

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Toxicity of Carotenoids

• High amounts of carotenoids in the bloodstream
• Excessive consumption of carrots/squash/beta-carot
  ene supplements
• Skin turns a yellow-orange color

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Vitamin D

• Prohormone
• Derived from cholesterol
• Synthesized in skin with adequate sun exposure
  for Caucasians and other light skinned races

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Functions of Vitamin D

• Regulates blood calcium
• Influences cell differentiation

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Role in Bone Formation

• Vitamin D causes Ca Phos to deposit in the
  bones
• Strengthen bones
• Rickets- children
• Osteomalacia (soft bone) is rickets in the adult

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Food Sources of Vitamin D

• Fatty fish (salmon, herring)
• Fortified milk
• Some fortified cereal

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The Adequate Intake (AI) for Vitamin D

• 5 ug/d (200 IU/day) for adults under age 51
• 10-15 ug/day (400 - 600 IU/day) for older
  Americans
• Infant are born with enough vitamin D to last 9
  months of age.

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Toxicity Warning

• Vitamin D can be very toxic
• Regular intake of 5-10x the AI can be toxic
• Result from excess supplementation (not from sun
  exposure or milk consumption)

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Vitamin E

• Fat-soluble antioxidant
• Resides mostly on cell membranes
• Protects the cell from attack by free radicals
• Protects PUFAs within the cell membrane and
  plasma lipoproteins
• Prevents the alteration of cells DNA and risk
  for cancer development
• Prevention of ischemic heart disease

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Vitamin E, An Antioxidant
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The More The Better?

• Vitamin E is only one of many antioxidants
• It is likely that the combination of antioxidants
  is more effective
• Diversify your antioxidant intake with a balanced
  and varied diet
• Megadose of one antioxidant may interfere with
  the action of another

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Food Sources of Vitamin E

• Plant oils
• Wheat germ
• Asparagus
• Peanuts
• Margarine
• Nuts and seeds

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RDA for Vitamin E

• 15 mg/day for women and men
• (22 IU of natural source or 33 IU of synthetic
  form)
• Average intake meets RDA
• 1 mg d-?-tocopherol 0.45 IU (synthetic source)
• 1 mg d-?-tocopherol 0.67 IU (natural sources)

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Deficiency of Vitamin E

• Hemolytic anemia
• Rare

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Toxicity of Vitamin E

• Inhibit vitamin K metabolism and anticoagulants
• Possible hemorrhage

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Vitamin K (Koagulation)

• Synthesized by the bacteria in the colon and are
  absorbed
• Role in the coagulation process
• Calcium-binding potential

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Drugs and Vitamin K

• Anticoagulant
• Lessens blood clotting process
• Antibiotics
• Destroy intestinal bacteria
• Inhibit vitamin K synthesis and absorption
• Potential for excessive bleeding

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Food Sources of Vitamin K

• Liver
• Green leafy vegetables
• Broccoli
• Peas
• Green beans
• Resistant to cooking losses
• Limited vitamin K stored in the body

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Overview of Water-Soluble Vitamins

• Dissolve in water
• Generally readily excreted
• Subject to cooking losses
• Function as a coenzyme
• Participate in energy metabolism

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Enrichment Act of 1941 and 1998

• Many nutrients lost through milling process of
  grains
• Grain/cereal products are enriched
• Thiamin, riboflavin, niacin, folate, iron
• Enriched grains still deficient in B-6, magnesium
  and zinc

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Thiamin B1

• Coenzyme
• CHO metabolism

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Deficiency of Thiamin

• Beriberi
• Weakness, nerve degeneration, irritability, poor
  arm/leg coordination, loss of nerve transmission
• Edema, enlarge heart, heart failure
• Occurs where polished rice is the only staple

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Food Sources of Thiamin

• Wide variety of food
• White bread, pork, hot dogs, luncheon meat, cold
  cereal
• Enriched grains/ whole grains

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RDA For Thiamin

• 1.1 mg/day for women
• 1.2 mg/day for men
• Most exceed RDA in diet
• Surplus is rapidly lost in urine non toxic

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Riboflavin B2

• Coenzymes
• Participate in many energy-yielding metabolic
  pathways

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Deficiency of Riboflavin

• Seborrheic Dermatitis
• Dermatitis around noses
• Cracked lips, tongue

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Food Sources of Riboflavin

• Milk/products
• Enriched grains
• Liver
• Oyster
• Brewers yeast
• Sensitive to uv radiation (sunlight)
• Stored in paper, opaque plastic containers

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RDA for Riboflavin

• 1.1 mg/day for women
• 1.3 mg/day for men
• Average intake is above RDA
• Toxicity not documented

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Niacin B3

• Coenzyme
• Metabolize CHO, Protein, Fat
• Tissue respiration
• Exchange of O2 and CO2

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Deficiency of Niacin

• Pellagra
• 3 Ds
• Occurs in 50-60 days
• Decrease appetite weight
• Prevented with an adequate protein diet
• Enrichment Act of 1941
• Only dietary deficiency disease to reach epidemic
  proportions in the U.S.

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Food Sources of Niacin

• Enriched grains
• Beef, chicken, turkey, fish
• 60mg tryptophan can be converted into 1 mg niacin

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RDA for Niacin

• 14 (mg) NE/day for women
• 16 (mg) NE/day for men
• Upper Level is 35 mg
• Toxicity S/S headache, itching, flushing, liver
  and GI damage
• Megadose can lower LDL and TG and increase HDL

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Pantothenic Acid

• Essential for metabolism of CHO, fat, protein
• Deficiency rare
• Usually in combination with other deficiencies

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Biotin

• Metabolism of CHO and fat
• Help break down certain amino acids
• DNA synthesis

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Vitamin B-6

• Coenzyme
• Activate enzymes needed for metabolism of CHO,
  fat , protein
• Synthesize nonessential amino acid
• Synthesize neurotransmitters
• Synthesize hemoglobin and WBC
• Reduces Homocysteine levels

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Food Sources of Vitamin B-6

• Meat, fish, poultry
• Whole grains (not enriched back)
• Banana
• Spinach
• Avocado
• Potato
• Heat sensitive

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RDA for Vitamin B-6

• 1.3 mg/day for adults
• 1.7 mg/day for men over 50
• 1.5 mg/day for women over 50
• Daily Value set at 2 mg
• Average intake is more than the RDA
• Athletes may need more
• Alcohol destroys vitamin B6

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B-6 As A Medicine?

• PMS
• B-6 to increase the level of serotonin
• Not a reliable treatment
• Carpal tunnel syndrome
• Toxicity potential
• Can lead to irreversible nerve damage with 200
  mg/day
• Upper Level set at 100 mg/day

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Folate

• Coenzyme
• DNA synthesis
• Homocysteine metabolism
• Neurotransmitter formation

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Deficiency of Folate

• Similar signs and symptoms of vitamin B-12
  deficiency
• Pregnant women
• Alcoholics
• Megaloblastic Anemia

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Neural Tube Defects

• Spina bifida
• Anencephaly
• Importance of folate before and during pregnancy

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Food Sources of Folate

• Liver
• Fortified breakfast cereals
• Grains, legumes
• Foliage vegetables
• Susceptible to heat, oxidation, ultraviolet light

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RDA for Folate

• 400 ug/day for adults
• (600 ug/day for pregnant women)
• Average intake below RDA
• FDA limits nonprescription supplements to 400 ug
  per tablet for non-pregnant adults
• OTC Prenatal supplement contains 800 ug
• Excess can mask vitamin B-12 deficiency
• Upper Level set at 1 mg

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Vitamin B-12

• Role in folate metabolism
• Maintenance of the myelin sheaths
• RBC formation
• Pernicious anemia (associated with nerve
  degeneration and paralysis)

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Deficiency of Vitamin B-12

• Pernicious anemia
• Never degeneration, weakness
• Tingling/numbness in the extremities
  (parasthesia)
• Paralysis and death
• Looks like folate deficiency
• Usually due to decreased absorption ability
• Alzhiemers like symptoms in elderly
• Injection of B-12 needed
• Takes 20 years on a deficient diet to see nerve
  destruction

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Food Sources of Vitamin B-12

• Synthesized by bacteria, fungi and algae
• (Stored primarily in the liver)
• Animal products
• Organ meat
• Seafood
• Eggs
• Hot dogs
• Milk

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RDA for Vitamin B-12

• 2.4 ug/ day for adults and elderly adults
• Average intake exceeds RDA
• B-12 stored in the liver
• Non-toxic

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Vitamin C

• Synthesized by most animals (not by human)
• Decrease absorption with high intakes
• Excess excreted

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Functions of Vitamin C

• Reducing agent (antioxidant)
• Iron absorption
• Synthesis of collagen
• Immune functions

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Antioxidant

• Can donate and accept hydrogen atoms readily
• Needs are higher for smokers

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Deficiency of Vitamin C

• Scurvy
• Deficient for 20-40 days
• Fatigue, pinpoint hemorrhages
• Bleeding gums and joints. Hemorrhages
• Associated with poverty

• Depressed Immune
• Cuts dont heal quickly

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Food Sources of Vitamin C

• Citrus fruit
• Potato
• Green pepper
• Cauliflower
• Broccoli
• Strawberry
• Romaine lettuce
• Spinach

• Easily lost through cooking
• Sensitive to heat
• Sensitive to iron, copper, oxygen

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RDA for Vitamin C

• 90 mg/day for male adults
• 75 mg/day for female adults
• 35 mg/day for smokers
• Average intake 72 mg/day
• Fairly nontoxic (at
• Upper Level is 2 g/day

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Choline

• Newest essential nutrient
• All tissues contain choline
• Precursor for acetylcholine (neurotransmitter)
• Precursor for phospholipids
• Some role in homocysteine metabolism

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Food Sources of Choline

• Widely distributed
• Milk
• Liver
• Eggs
• Peanuts
• Lecithin added to food
• Deficiency rare

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Needs for Choline

• Adequate Intake is 550 mg/day for adult males
• Adequate Intake is 425 mg/day for adult females
• Normal consumption is 700-1000 mg/day
• High doses associated with fishy body odor,
  vomiting, salivation, sweating, hypotension, GI
  effects
• Upper Level is set at 3.5 g/day (3500 mg/day)

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Vitamin Supplement?

• Myths
• Insurance
• What to buy
• Overdose vs Megadose
• Synergistic Effect
• Phytochemicals

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Food Guide Pyramid

• Grains
• Thiamin, Riboflavin, Niacin
• Veggies
• Vit A, K, C and Folate
• Dairy
• Vit D, B12 and Riboflavin
• Meat, Fish, Eggs, Legumes
• Thiamin, Riboflavin, Biotin and Vit B6, B12
• Fats, Sweets, Oils
• Vit E

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Role of Diet on Cancer Risks

• Excessive intake of calories increases the risk
  of cancer
• Excessive body fat affect sex hormone production
• High intake of fruits and vegetables is
  associated with lower risk
• High intake of meats and protein is associated
  with higher risk
• Excessive alcohol increases the risk
• Excessive charcoal broiling increases risk
• Nitrosamines (from nitrite) increases risk
• Mycotoxins (from fungi) increases risk

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Fat and Cancer

• The National Academy of Sciences recommend 30
  of total calories from fat
• Excessive intake is a likely cause of growth of
  cancerous cells

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Recommendations to Reduce the Risk for Cancer

• Remain physically active
• Avoid obesity
• Engage in physical training that promotes lean
  muscle mass
• Consume abundance of fruits and vegetables
• Consume plenty of low-fat/nonfat dairy products
• Avoid high intakes of red meat and animal fat
• Avoid excessive alcohol

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Warning Signs

• Early detection is critical
• Unexplained weight loss
• A change in bowel or bladder habits
• A sore that does not heal
• Unusual bleeding or discharge
• A thickening or lump in the breast or elsewhere
• Indigestion or difficulty in swallowing
• An obvious change in a wart or a mole
• A nagging cough or hoarseness