The Vitamins

1
The Vitamins
2
Definitions and Classifications of Vitamins

• Vitamins
• Organic compounds
• Needed in minute amounts
• Non caloric
• Essential nutrients

3

• Definition
• Fat-soluble A,D, E, K
• In general, absorbed into the lymph
• Travel in blood in association with protein
  carriers
• Stored in the liver or with other lipids in fatty
  tissues some can build up to toxic
  concentrations
• Water-soluble B vitamins, vitamin C
• Absorbed directly into blood stream
• Most are not stored to any great extent
• Excess excreted in urine
• Lower risk of toxicity than fat-soluble vitamins

4
The Fat-Soluble Vitamins

• A, D, E, K
• Found in fats and oils of foods
• Require bile for absorption
• Stored in liver and fatty tissues until the body
  needs them
• Body can survive weeks of consuming foods that
  lack these vitamins
• Excess vitamins A and D from supplements can
  easily reach toxic levels????

5
The Fat-Soluble Vitamins

• Deficiency
• Is likely when diet is very low in fat and
  consistently low in fat-soluble vitamins
• Fat malabsorption diseases cause losses in
  dissolved undigested fat
• Mineral oil laxatives used

6
Vitamin A

• Functions
• Vision
• Maintenance of body linings and skin
• Immune defenses
• Growth of bones
• Normal cell development
• Reproduction

7
Vitamin A

• Toxicity
• From supplements or fortified foods
• Symptoms
• Abdominal pain, hair loss, joint pain, stunted
  growth, bone and muscle soreness, cessation of
  menstruation, nausea, diarrhea, rashes, liver
  damage, enlarged spleen, weakened bones
• Early symptoms loss of appetite, blurred vision,
  growth failure in children, headache, skin
  itching, irritability

8
(No Transcript)
9
Vitamin A

• Sources of A
• Found in foods of animal origin
• Liver and oil
• Milk, milk products, and fortified foods
• Sources of Beta-carotene, Vitamin A precursor
• Bright orange fruits and vegetables
• Dark green vegetables
• Deficiency
• Lack of dietary beta-carotene increases the risk
  of macular degeneration
• Loss of vision

10
Vitamin A

• Beta-carotene is an antioxidant
• (associated with reduced cancer risk)
• Dietary antioxidants are one class of substances
  in whole foods that seem to benefit health
• Other antioxidants are--vitamin E, vitamin C,
  selenium, and other phytochemicals

11
(No Transcript)
12
(No Transcript)
13

• Vitamin D
• Not essential --the body can make all it needs
  with the help of sunlight
• ???????
• Exposure to sunlight maintains adequate vitamin D
• UV exposure to a cholesterol compound in the skin
  transforms it into a vitamin D precursor which is
  absorbed into the blood
• The liver and kidneys finish converting the
  precursor to the active form of vitamin D

14
Vitamin D

• Functions as a hormone
• 1. In the brain, heart, stomach, pancreas,
  skin, reproductive organs, stimulates cell
  maturation (including immune system cells)
• 2. Regulates blood calcium and phosphorus
  levels
• Deficiency
• High blood pressure, some cancers, type 1
  diabetes, heart disease, rheumatoid arthritis,
  multiple sclerosis
• Rickets
• Disease in children-abnormal bone growth
• Bowed, or knock-knees, outward-bowed chest, knobs
  on ribs

15
(No Transcript)
16

• Vitamin D
• Groups at risk for deficiency
• Adolescents
• Consume soft drinks rather than vitamin D
  fortified milk
• Prefer indoor to outdoor activities and are
  at risk for future bone loss
• Older individuals
• May have painful joints and muscles due to low
  vitamin D levels
• Women
• May develop Osteomalacia, the adult form of
  rickets--Caused by low calcium intake, little
  exposure to the sun, repeated pregnancies and
  periods of lactation

17
Vitamin D

• Too Much Vitamin D - A Danger to Soft Tissue
• Toxic to the bones, kidneys, brain, nerves,
  heart, arteries
• Symptoms include appetite loss, nausea,
  vomiting, increased urination, increased thirst,
  form depression due to effects on the central
  nervous system

18

• Vitamin D
• High blood calcium level, leaves calcium deposits
  on soft tissues
• As the heart, blood vessels, lungs, kidneys, pulp
  cavity of teeth (while enamel thins)
• At risk
• Infants whose parents think that if some is good
  more is better
• Older people who over-supplement
• Recommendations
• for vitamin D intake increases with age
• 19 to 50 years 5 micrograms/day
• 51 to 70 years 10 micrograms/day
• 70 years 15 micrograms/day
• UL 50 micrograms per day (2,000 IU on supplement
  labels)

19
(No Transcript)
20
(No Transcript)
21
Vitamin E

• Four tocopherol compounds
• Alpha-tocopherol is the standard for vitamin E
  activity
• Function
• Antioxidant-- prevents oxidative damage that
  results when free radicals disrupt the structure
  of cellular lipids, DNA, proteins
• Free radical activity may lead to cancer, heart
  disease --Vitamin E protects the cells

22
Vitamin E

• Deficiency
• Associated with fat malabsorption diseases
• Disease or injury to the liver, gallbladder,
  pancreas
• Possible when extremely-low-fat diets are
  consumed for years
• Vitamin E is widespread in food
• Body stores large amounts in fatty tissues
• Cells recycle it
• Vitamin E Requirements
• DRI 15 milligrams/day

23
(No Transcript)
24
(No Transcript)
25
Vitamin K

• Functions
• Synthesis of blood clotting proteins
• Synthesis of bone proteins that bind minerals to
  bone
• Sources
• Leafy green vegetables
• spinach, collard greens, Lettuce, broccoli,
  members of the cabbage family
• Intestinal bacteria, canola and soybean oils,
  fortified cereals, eggs and milk

26

• Vitamin K
• Deficiency
• Unlikely in adults
• Even if they seldom eat vitamin K-rich foods
• At risk
• Newborns are given vitamin K to hold them until
  vitamin K-producing bacteria establish themselves
  in their intestinal tract
• Those who have taken antibiotics that kill the
  beneficial bacteria in their intestinal tract
• Toxicity
• Rare among healthy adults
• No UL

27
(No Transcript)
28
(No Transcript)
29
The Water-Soluble Vitamins

• Vitamin C and the B Vitamins
• Cooking and washing with water leaches them from
  food
• Easily absorbed
• Excess is excreted in urine
• Toxicity
• Never from food
• Can occur from the large doses concentrated in
  some vitamin supplements
• usually results in expensive urine

30
Vitamin C

• Functions
• Maintenance of connective tissues
• Formation and maintenance of collagen
• Component of bones, teeth, skin, tendons, scar
  tissue, capillaries
• Cofactor in the production of carnitine
• Plays a role in transporting fatty acids within
  cells
• In the intestines, protects iron from oxidation
  Promotes its absorption
• In the blood protects blood constituents from
  oxidation
• Protects and recycles Vitamin E

31
Vitamin C

• Deficiency Symptoms
• Scurvy
• symptoms are due to the breakdown of collagen
• Loss of appetite, growth cessation, loose teeth,
  swollen ankles and wrists, tiny red spots in the
  skin where blood has leaked out of capillaries,
  anemia
• Risk of scurvy in the U.S. is low
• Exceptions
• Alcoholics, elderly, and infants on cows milk

32
Consumer Corner Vitamin C and the Common Cold

• One group of researchers have found the
  following
• High daily doses of vitamin C, do not prevent
  colds
• Some small benefit from vitamin C in high doses
  (1 gram) taken at the onset of a cold -reduced
  severity of symptoms
• Do you know Linus Pauling??

33
Vitamin C

• Is Too Much Vitamin C Hazardous to Health?
• One effect observed with a 2-gram dose is
  alteration of insulin response to carbohydrate in
  people with otherwise normal glucose tolerances
• Other adverse effects include digestive upsets,
  such as nausea, abdominal cramps, excessive gas,
  diarrhea

34
(No Transcript)
35
(No Transcript)
36

• The B Vitamins in Unison
• B vitamins act as part of coenzymes
• A small molecule that combines with, and
  activates, an enzyme
• B vitamins play a role in the metabolism of
  carbohydrates, lipids, and amino acids
• Thiamin, riboflavin, niacin, pantothenic acid,
  and biotin all help release the energy
• Vitamin B6 helps the body make protein
• Folate and vitamin B12 help cells to multiply

37
Thiamin

• Function
• Energy metabolism
• Nerve processes and tissue response
• Deficiency beriberi
• Loss of sensation in the hands and feet, muscular
  weakness, advancing paralysis, abnormal heart
  function
• Wet beriberi
• Characterized by edema
• Dry beriberi
• No edema

38
(No Transcript)
39
(No Transcript)
40
Riboflavin

• Function
• Energy metabolism of all cells
• Deficiency
• Likely when thiamin is deficient
• May go undetected because thiamin deficiency
  symptoms are more severe
• At risk
• Children who lack milk products and meat
• Perhaps some U.S. elderly
• Treatment A diet that remedies riboflavin
  deficiencies also remedies a thiamin deficiency

41
(No Transcript)
42
(No Transcript)
43

• Niacin
• Function
• Energy metabolism
• Deficiency
• Pellagra
• Diarrhea
• Dermatitis
• Dementia
• Death
• At risk for pellagra
• Poorly nourished people living in urban slums
• Particularly those with alcohol addiction
• Still common in parts of Africa and Asia

44
(No Transcript)
45
Niacin

• Toxicity
• Large doses of a form of niacin may be a part of
  a treatment to lower blood lipids associated with
  cardiovascular disease
• Large doses of niacin can injure the liver, cause
  ulcers, and vision loss
• Certain forms of niacin supplements in amounts
  2x-3x the DRI can cause niacin flush

46
(No Transcript)
47
Folate

• Function
• DNA synthesis
• Metabolism of several amino acids
• Activates B12
• Deficiency
• Immature red and white blood cells and cells of
  the GI tract divide rapidly and are affected by a
  deficiency
• Anemia
• Related to anemia of vitamin B12 malabsorption
• Diminished immunity
• Neural Tube defects-birth defects

48
Folate

• Toxicity
• UL for synthetic folate from supplements and
  enriched foods is 1,000 micrograms/day for adults
• Folate can mask vitamin B12 deficiency
• Excess folate may be antagonistic to the actions
  of some anticancer drugs
• Sources
• Leafy green vegetables
• Fresh, uncooked vegetables and fruits
• Eggs
• Orange juice and legumes
• Milk may enhance folate absorption

49
(No Transcript)
50
(No Transcript)
51
Vitamin B12

• Function
• Activates folate
• Maintenance of the sheaths that surround and
  protect nerve fibers
• Deficiency
• Damaged nerve sheaths
• Paralysis
• General malfunctioning of nerves and muscles
• Failure of folate to make red blood cells
  --causes an anemia (pernicious anemia)
• Large, immature red blood cells

52
Vitamin B12

• Absorption of B12
• Requires intrinsic factor
• A compound made by the stomach
• Intrinsic factor binds to vitamin B12
• It is then absorbed from the small intestine into
  the blood
• Treatment for defective absorption is B12
  injections
• All strict vegetarians must be sure to use
  vitamin B12 fortified products--fortified soy
  drink, supplements

53
(No Transcript)
54
(No Transcript)
55

• Vitamin B6
• Functions
• 100 reactions in the tissues
• Needed to convert one kind of amino acid into
  other nonessential amino acids
• Aids in the conversion of tryptophan to niacin
• Hemoglobin synthesis
• Neurotransmitter synthesis
• For example, assists in the conversion of
  tryptophan to serotonin
• Assists in release of stored glucose from
  glycogen
• Contributing to the regulation of blood glucose
• Immune actuvity
• Steroid activity
• Fetal brain and nervous system development
• Deficiency during this stage causes behavioral
  problems later

56
Vitamin B6

• Deficiency
• Weakness
• Psychological depression
• Confusion
• Irritability
• Insomnia
• Greasy dermatitis
• Advanced cases of deficiency convulsions
• May weaken the immune system
• Low intakes may be related to increased risk of
  heart disease

57
(No Transcript)
58
How Are B Vitamins Related to Heart Disease?

• Homocysteine
• High levels in the blood correlate with a severe
  early form of cardiovascular disease (CVD)
• Elevated homocysteine may be an indicator of CVD
  risk
• Deficiencies of folate, vitamin B12 or vitamin B6
  cause excess homocysteine to build up in the
  blood
• Supplements of these vitamins lead to a
  significant drop in homocysteine level
• It is unknown how this affects a persons CVD
  risk

59
Biotin

• Functions
• As a cofactor for several enzymes in the release
  of energy from carbohydrate, fat, protein
• Deficiency
• Rare
• Raw egg whites contain a protein that binds
  biotin (You need to eat many raw eggs each day to
  develop a deficiency.)
• Cooking eggs denatures this protein
• Sources
• Wide spread in foods

60
Pantothenic Acid

• Function
• Energy metabolism
• Coenzyme that plays a role in the release of
  energy from the energy nutrients
• Plays a role in 100 steps concerned with the
  synthesis of lipids, neurotransmitters, and
  hemoglobin
• Deficiency
• Rare
• Sources
• Widespread in foods

61

• Choline
• Common in foods
• Deficiencies are practically unknown outside the
  laboratory
• Carnitine vitamin BT
• Non-vitamin not an essential nutrient for humans
  
• An important component of cells
• Deficiencies can be experimentally induced
• Abundant in ordinary foods
• Inositol
• Non-vitamin not an essential nutrient for humans
• Lipoic acid
• Non-vitamin not an essential nutrient for humans
  

62
Controversy Vitamin Supplements Who Benefits?

• Nearly 40 of the U.S. population take a vitamin
  supplement
• Do healthy people benefit from a multiple vitamin
  supplement taken every day or two?
• Do the potential risks of supplementation
  outweigh the benefits?
• Should supplements only be taken when there is a
  risk of deficiency?

63
(No Transcript)
64
(No Transcript)
65
(No Transcript)
66
(No Transcript)
67
Vitamin Supplements

• Supplements Must Be Safe, or the Government Would
  Not Allow Their Sales, Right?
• The FDA does not test supplements to ensure their
  safety and effectiveness
• The FDA ensures that supplements do not pose a
  significant risk of illness
• Requires safety documentation and reports of
  adverse effects from manufacturers
• Consumers may report adverse effects directly to
  the FDA

68
Vitamin Supplements

• Dietary Supplement Health and Education Act
  (DSHEA)
• Supplements
• Must provide a Supplement Facts panel of nutrient
  information
• Must not be adulterated
• Must not make label claims for the diagnosis,
  prevention, treatment, or cure of illness
• May bear structure/function claims
• Result has been the deregulation of the
  supplement industry
• The FDA has identified hazardous supplements only
  after there has been actual harm to consumers

69
(No Transcript)
70
(No Transcript)
71
Vitamin Supplements

• Arguments Against Supplements For Chronic Disease
  Prevention
• The general results of research have shown that
  otherwise well-nourished people benefit little,
  if at all, from taking supplements
• The healthy elderly may be an exception they may
  benefit from taking supplements

72
Vitamin Supplements

• Should We Take Supplements to Ensure Adequate
  Nutrients?
• Food, not supplements, is the best source of
  nutrients
• ????

73
Vitamin Supplements

• Risks of supplementation
• High doses of vitamin A may delay blood clotting
  and may increase the risk of brain hemorrhage
• For some people, vitamin C supplements may
  increase the risk of iron overload
• Daily supplements of beta-carotene may increase
  the risk of lung cancer in smokers
• Supplements of vitamins A and D and many minerals
  can be toxic in large doses
• High doses of vitamin E interfere with the
  blood-clotting activities of vitamin K

74
(No Transcript)
75
Vitamin Supplements

• Selection of a Multinutrient Supplement
• If you cannot meet your nutrient needs from food,
  a supplement may help
• What vitamins and minerals do you need?
• Avoid supplements that provide a daily dose
  exceeding the DRI or the UL for any nutrient
• Local or store brands may be cheaper and as good
  as nationally advertised brands

76
Vitamin Supplements

• When taking a supplement look for a USP on the
  label
• This means that the product contains the
  ingredients listed and that it will dissolve in
  the digestive tract
• It does not mean that this supplement has been
  tested for safety or effectiveness

77
Vitamin Supplements
78
Vitamin Supplements

• People in developed nations are much more likely
  to suffer from overnutrition and poor lifestyle
  choices than from nutrient deficiencies
• Dont think that taking a supplement means that
  you do not have to eat properly

79
Food Processing and Nutrient Density

• Food processing involves a trade-off it makes
  foods safer and produces foods with a longer
  usable shelf life than fresh foods.
• What are the pro and cons of each method of
  processing ????
• Canning-High heat and time effects nutrients
• Freezing-Does not effect nutrients
• Drying-Reduces microbial spoilage, reduces bulk
  and weight
• Extrusion-Used for snack food and cereal, food is
  heated ground and reshaped.

80
Food Storage and Preparation

• After you have brought home nutritious foods what
  can you do to prevent nutrient losses??
• Fresh, canned, frozen??