2. VITAMINS

3. Definition
Vitamins are naturally occurring organic compounds, present in very small quantity in diet and which are essential for normal health.

4. Later on it was concluded that
Normal metabolic functions cannot be executed without these compounds
If deficient, certain specific metabolic disorders are seen.
Participate as coenzyme in various enzyme catalyzed reaction.
Vitamins do not provide energy.

5. DIETARY SOURCES
Mainly derived from food meat, fish, milk, vegetables, fruits
As Can not be synthesized in appropriate quantities, must be present in human diet.

6. Other Sources Few are synthesized by normal intestinal flora
Few others are synthesized by some body tissues like skin Vit-D

7. Functions (Contd.) Maintenance of optimal Health
Prevention of chronic diseases may require certain vitamins in amounts greater than RDA.
Normally 15 iu/day of vit E is required for health
100 iu of vit E is required for significant reduction in risk of CAD
It is also believed that vitamins play a role in prevention of Cancer.

8. Classification
14 different vitamins so far have been isolated and purified into crystalline form. These are classified in to two groups
Classification is based on solubility characteristics.

9. Requirements
Varies with metabolic activity Age, Size, Sex of an individual
Requirement increase during
Exercise
Fever
Disease
Pregnancy
Lactation

10. Requirements (Contd.)
Requirement of B, are particularly increased in CHO rich diet.
For every 1000 Calories obtained form carbohydrate rich diet 1mg of B1 is needed

11. Storage Water Soluble:
Not stored in our bodies. Must therefore be present in diet to an appreciable extent for normal health and growth.
Fat Soluble:
Are stored, if taken in excess. Stores are sufficient to meet the demand of our body for almost months, if no vitamins are taken through diet.

12. Wastage
During therapy and intestinal infection, drugs like sulfonamides and antibiotics kill the normal intestinal flora which synthesizes vit.of B complex group.
Demand increases, and
Supplementation is advised

13. Wastage
Water soluble vitamins are lost when cooked in water and Specially when water is thrown away.
Vegetable should not be washed after cutting.
Milling and polishing of rice destroys B2.
Hydrogenation of oils, inactivates Vit A & D,and before marketing fortification with A & D be done.

14. Wastage
Water soluble vitamins are lost when cooked in water and Specially when water is thrown away.
Vegetable should not be washed after cutting.
Milling and polishing of rice destroys B2.
Hydrogenation of oils, inactivates Vit A & D, and before marketing fortification with A & D be done.

15. Vitamin A
Vitamin A is an important fat soluble vitamin required for growth and normal eye function

16. Sources
Major sources of vit A are the carotenes , synthesized by plants
Animals including humans can convert carotenes in plants to Vit A.
Alpha, beta and gamma carotene are of nutritional importance.

17. Chemical Structure

18. Sources Alpha and gamma carotenes yield 1 molecule of Vit A
Beta carotene yields 2 molecules of vit A upon hydrolysis
Vitamin A is present in 2 forms in diet
Preformed Vit A (retinol)
Provitamin A carotenoid (Vitamin A precursors).

19. Dietary sources Animal sources Fish Olive oil Milk Butter Cheese Liver
Eggs
Vegetable sources
Deep green & yellow plants
Carrots
Turnip

20. Absorption and Metabolism
Absorption occurs in the intestine
Activation: To be active,
Pro vitamins A, carotenoids must be converted into retinol during absorption.
Hydrolysis of carotenes occurs in the mucosa of small intestine.

21. Absorption
Absorption of Vit A is facilitated by dietary fat, bile, thyroid hormone and Vit E.
Mineral oil prevents the absorption of Vit A
Vit A is also absorbed directly into portal circulation and transported in chylomicrons
Enters the blood circulation and reach the liver.

22. Functions
In the retina of the eye there are two types of light receptors
Cones for vision in bright light & color vision
Rods for vision in dim light
The photo sensitive receptors (Rhodopsin visual purple in rods and Iodopsin or visual violet in cones) contains Vit A plus different proteins.
When struck by light the pigments are split apart into Vit A and the constituent protein.

23. Mucous Membranes
Vit A is involved in the synthesis of mucoproteins and mucopolysaccharides.
The integrity of the epithelium, particularly the membranes of the genitourinary , respiratory and GI tract, eyes and mouth are maintained by mucous secretions.

24. Recommended Dietary Allowances
Infants 0 – g
0.5 – g
Children 1 – g
4 – g
7 – g

25. Recommended dietary allowances
Adults Male Female
11 –
15 –
19 –
23 –
Pregnancy
Lactation

26. Recommended dietary allowances
The allowances for children and adolescents are based on average body weight and growth needs.
Adults Males RDA is retinol equivalents(5000iu)
Adults Female RDA is 800 retinal equivalents (4000 iu)
In pregnancy and Lactation it is increased to 1000 and 1200 retinal equivalents respectively.
Vit A is stored in liver and normal individuals have a three month supply

27. Deficiency Disease The deficiency may be due to Poor intake
Incomplete absorption and metabolism (chronic diarrhea and use of mineral oils)
Abnormal fat metabolism (pancreatic disease)
Hepatic diseases

28. Effects Night blindness (nyctalopia)
Inability to see well in dim light when entering a dark space form bright light
Night blindness occurs when there is insufficient Vit A in the blood to quickly regenerate visual purple .
4. Alcoholic liver disease (cirrhosis) causes night blindness which is due to hepatic damage affecting Vit A release.

29. Effects
In the eye, the 1st symptom of Vit A deficiency include photophobia (sensitivity to bright light)
Inflammation of eyes and eyelids due to impaired functioning of lacrimal glands
Xerophthalmia (dry, inflamed and edematous cornea)
Keratomalcia – permanent blindness results when infection leads to ulceration and softening of cornea

30. Skin and mucous membrane changes
Keritinization of the epithelial tissues
Increase susceptibility to infections of all membranes, protected by mucous
Follicular hyperkeratosis – The sebceous glands becomes clogged and skin takes on a gooseflesh like appearance.

31. Toxic effects Drying and desquamation of skin Anorexia Loss of hair
Bone pain and fragility
Enlargement of liver and spleen

32. Vitamin D

33. Vitamin D Vitamin D occurs in two forms, as
“Vitamin D2” (ergocalciferol),
chief Vit D precursor in plants is, ergostreol.
2 “Vitamin D3” (cholecalciferol) the main form occurring in animal cells and developing in skin on exposure to ultraviolet light from dehydrocholesterol

34. Absorption
Vit D is stable through storage, processing and cooking and is absorbed effectively from GIT
Any abnormality in fat mal-absorption may cause malabsorption of Vit D

35. Animal sources of Vit D
Eggs
Liver
Butter
Fish

36. Absorption and metabolism
Vitamin D3 is obtained from two sources:
Vit D3 is obtained from diet or food supplements.
From the conversion of 7-dehydro cholesterol in the skin by ultraviolet light to pre Vit- D3 which then slowly equilibrates to Vit- D3

37. Absorption and metabolism
Before it can function, Vit D3 must be activated by hydroxylation which takes place both in liver & kidney.
The initial conversion in the liver results in 25-hydroxy cholecalciferol (calcidiol), the major circulating form of Vit D3.

39. Absorption and metabolism
2nd hydroxylation takes place in the proximal tubule of the kidney, giving rise to 1,25-dihydroxycholecalciferol or calcitriol.
This form is then transported to bones, kidneys and intestines.

42. Factors affecting Vit D synthesis
The amount of Vit D formed by the action of sunlight on the skin is dependent on
Intensity of light
Length of exposure
Skin pigmentation

43. Daily requirement
400 iu (10ug) of Vit D per day promote optimal calcium absorption and enhance growth
Higher level is recommended for infants and children

44. Daily requirement
With slowing and finally cessation of skeletal growth the daily Vit D allowance decreases to 300 i.u. (7.5 µg) for ages 19 through 22, & 200 i.u. (5 µg) for the later years.
During pregnancy and lactation the Vit D requirement is increased by 200 i.u. (5 µg) to allow for transfer across placenta and into breast milk

45. Recommended Dietary Allowances
Infants 0 – g
0.5 – g
Children 1 – g
4 – g
7 – g

46. Recommended Dietary Allowances
Adults Male Female
11 –
15 –
19 –
23 –
Pregnancy
Lactation

47. Functions
It is a steroid and functions like other steroid hormones. It is not dietary essential when there is adequate exposure to ultraviolet light
Vit D plays a major role in the regulation of calcium and phosphate metabolism by promoting their intestinal absorption, influencing the process of bone mineralization.

48. Functions
Vit D exerts its anti ricket action by making the intestinal mucosa permeable to calcium and phosphorus and facilitating the active transport of calcium across cell membranes.

49. Effects of deficiency
A deficiency of Vit D causes impaired intestinal absorption of calcium and phosphorus and faulty mineralization of teeth and bones.
Skeletal malformation result from the inability of the softened bone to withstand weight bearing . In children this bone condition is termed rickets.

50. Effects of deficiency Other symptoms of rickets include
Delayed closure of the fontanelles (suture lines in the skull) especially in premature infants
Projection of sternum (pigeon breast).
Spinal curvature.
Bowing of the legs and
Enlargement o the costochondral junction.

51. Effects of deficiency
In adults this bone condition is termed as osteomalacia and is caused purely by lack of Vit D and calcium.
Particularly prevalent among pregnant and lactating oriental women.

52. Effects of deficiency
Vit D is involved in neuromuscular activity and its deficiency cause tetany characterized by convulsions, muscle twitching and sharp flexion of the wrest and ankle joint.
This condition may also result from parathyroid disease or from insufficient dietary intake or intestinal absorption of calcium or Vit D
Dental caries are more prevalent among children with poor intakes of Vit D, calcium and phosphorus.

53. Toxic Effects Precisely not known Toxicity symptoms include Polyurea
Nocturia
Weight loss
Diarrhea &
Nausea

54. Toxic Effects Severe toxicity results in
Calcification of soft tissues such as
Blood vessels
Heart
Stomach
Bronchi &
Kidney

55. Vitamin E

56. Recommended dietary allowances
A series of compounds of plant origin, tocopherols and tocotrienols, provide the Vit E activity in foods.
Alpha-tocopherol is the most powerful Vit E Beta-tocopherol, Gamma-tocopherol, Delta-tocopherol and tocotrienols estimated to be – 50% as biologically active as alpha tocopherol.

58. Functions Vit E’s main action is as an antioxidant.
It may be involved in the metabolism of glutathione and nucleic acids
In the rods of the pigment epithelium of the retina there is a high concentration of UFA.
Vitamin E in the rods of retina protects the membrane lipids from auto oxidation while retarding the accumulation of lipofuscin.

59. Functions (Contd.)
As most of the plasma Vit E is carried on the lipoproteins, condition/s that alters the plasma lipid levels also change/s the Vit E concentration

60. Functions (Contd.)
In newborn infants, the plasma level of Vit E is about 1/3rd that of adults
New born especially if premature, do not absorb Vit E well, which contributes to the low levels.
These may be due to:
Lower concentration of plasma lipids in infants,
Inefficient placental transfer of the Vit.E
Or both.

61. Stability
Vit E is stable at high temperature and under acid conditions but is readily oxidized in the presence of rancid fats, iron, or lead salts.
Ultraviolet light also adversely affect Vit E.
The requirement for Vit E is increased with the intake of PUFA and is therefore related to concentration of PUFA in cellular structures.
If diet is rich in PUFA,it will also be rich in vit. E.

62. Food sources (Contd.)
Vegetable oils (Cottonseed corn, soybean, sunflower)
Margarine
Coconut ,peanut and olive oil
Cabbage, spinach and asparagus

63. Absorption and metabolism
Both dietary fat and bile salts are required for the absorption of Vit E across the intestinal mucosa
The Vit is carried by the lymph circulation to the liver.
All tissue in the body have some Vit E, with the pituitary gland, testes and adrenal glands having the highest concentrations.

64. Recommended dietary allowances (Contd.)
The Vit E requirement increases with growing body weight during childhood and levels off during adulthood.
During pregnancy and lactation the increased caloric intake should be sufficient to provide for the additional Vit E transferred to the fetus and secreted in the breast milk.

65. Recommended Dietary Allowances
Infants 0 – mg
0.5 – mg
Children 1 – mg
4 – mg
7 – mg

66. Recommended Dietary Allowances (Contd.)
Adults Male Female
11 –
15 –
19 –
23 –
Pregnancy
Lactation

67. Effects of deficiency
Deficiency of Vit E results from long term fat mal-absorption and such mal-absorption syndromes as cystic fibrosis and billiary atresia.
Lab findings in deficiency include
1. increased fragility of the Red blood cells (anemia due to hemolysis)
2. Increased urinary excretion of creatine (caused by muscle breakdown and loss)
3. Deposition of certain pigments in smooth muscles.

68. Effects of deficiency (Contd.)
Other effects of deficiency include degeneration of reproductive tissues Muscles and liver necrosis

69. Toxic Effects Vitamin E appears to be less toxic than vit A and D
In adults prolonged therapy can interfere with coagulation and hemostatic mechanism
Other toxic effect are an increase in BP, Allergies, GI-distress, Nausea and Derangement of iron metabolism

70. Vitamin K

71. Vitamin K Vit K exists in two forms.
Vit K-1 (phyllo quinone) in green plants
Vit K-2 (menaquinone) in animals and
(Produced by intestinal bacteria)
Minadione, Vitamin K3 is the synthetic form of this vitamin and is most commonly used.

73. Food sources Spinach Cauliflower Liver Kidney
It is heat stable but can be destroyed by acids, alkalis and irradiation

74. Food sources

75. Absorption and metabolism
About half of the Vit K present in the human diet is derived from green leafy vegetables, and about half is synthesized by the gut flora.
As it is fat soluble, requires the presence of bile for its absorption, which occurs mostly in the upper part of the small intestine.

76. Functions
This Vit is necessary for the synthesis of prothrombin and other blood clotting factors by the liver.
A deficiency of Vit K causes defective blood coagulation

77. Functions (Contd.)
Advanced liver damage, as caused by cancer or Cirrhosis, causes prothrombin deficiency that cannot be alleviated by the administration of Vit K
Other physiologic functions include electron transport, growth and photosynthesis

78. Effects of deficiency A deficiency of Vit K can be produced by :
Elimination of dietary sources
suppression of growth of the intestinal microflora
Antibiotics Use for a long period and
with impaired lipid absorption such as that resulting from the use of mineral oil as a laxative.
Deficiency of Vit K also occurs in the new born infants before the establishment of intestinal flora.

79. Vitamin K Cycle