Sources and structures of fat soluble vitamins

1. VITAMINS
SOURCES AND STRUCTURES

2. INTRODUCTION
 The vitamins comprise a diverse group of organic compounds that are
nutritionally essential micronutrients.
 Perform diverse functions : enzyme cofactors, biological antioxidants,
hormones etc.
 Most vitamins are not single molecules, but groups of related
molecules called vitamers. For example, vitamin E consists of
four tocopherols and four tocotrienols.
 Thirteen substances are generally recognized as vitamins: vitamin
A ,vitamin B1 ,vitamin B2 , vitamin B3 , vitamin B5, vitamin B6 ,
B7 , vitamin B9 , vitamin B12 , vitamin C , vitamin D , vitamin E , and
vitamin K.

3. CLASSIFICATION
 According to their solubility , vitamins are classified as either water-
soluble or fat-soluble.
 The water-soluble vitamins tend to have one or more polar or ionizable
groups(carboxyl,keto,hydroxyl,amino or phosphate),whereas the fat-
soluble vitamins have predominantly aromatic and aliphatic
characters.


4. FAT SOLUBLE
VITAMINS

5. VITAMIN A
• Includes all-trans-retinol, all-trans-retinyl-esters, as well as all-trans-beta-
carotene and other provitamin A carotenoid.
SOURCES
• There are two main sources of vitamin A: animal sources and plant sources.
• In animal sources, vitamin A is found as retinol. Such as liver, including fish
liver, is a very good source. Other animal sources are egg yolk (not the white)
white) and dairy products such as milk ,cheese and butter.
• Plant sources contain vitamin A in the form of carotenoids (provitamins)
which have to be converted during digestion into retinol before the body can
use it.
• Plant sources of vitamin A include: mangos, papaya, many of the squashes,
carrots, sweet potatoes and maize. Other good sources of vitamin A are
palm oils.
• Significance-Provides color due to carotenoids which act as pigments.

6. RDA :
Men-900 μg (RAE)/day
Women-700 μg (RAE)/day

7. STRUCTURE
Conversion of beta carotene to
retinol

8. VITAMIN D
SOURCES
 This vitamin occurs in several forms; the two most important are
vitamin D2, or ergocalciferol, and vitamin D3, or cholecalciferol.
 Vitamin D does not occur in plant products.
 Fish liver oils are particularly rich sources of vitamin D3,in free form
as well as esters of long-chain fatty acid esters.
 Smaller quantities of vitamin D3 occur in eggs, milk, butter, and
cheese.
 The provitamins like ergosterol and 7-dehydrocholesterol can be
converted to vitamin D in the human skin by exposure to sunlight.
 Because of its low amount in food, food products like
milk,grains,orange juices and baked goods are fortified.

9. RDA : 600 IU
(15mcg)

10. STRUCTURE

11. VITAMIN E
SOURCES
 Exist generally as : tocopherols and trienols.
 The richest food sources of vitamin E are plant oils.
 Wheatgerm,sunflower and safflower oils are rich sources of alpha-
tocopherol, whereas corn and soyabean oils contain mostly gamma-
tocopherol.
 Bran and germ fractions can also contain tocotrienols (in esterified
forms) unlike tocopherol.(free alcohols).
 Nuts, seeds, and vegetable oils are also good sources of alpha-
tocopherol, and significant amounts are available in green leafy
vegetables and fortified cereals .
 Significance-provides antioxidant properties to food

12. RDA:
15 milligrams a day.

13. STRUCTURE

14. VITAMIN K
SOURCES
 It occurs naturally in mainly two forms : vitamin K1,phylloquinones
and vitamin K2,menaquinone.
 Good sources of vitamin K are green leafy vegetables such as
spinach and cabbage leaves, and also cauliflower, peas, and cereals.
 Food sources of phylloquinone include vegetables, especially green
leafy vegetables, vegetable oils, and some fruits.
 Natto has high amount of menaquinones. Other fermented foods,
such as cheese, also contain menaquinones.
 Animal products contain little vitamin K1, except for pork liver,
which is a good source.
 Meat and dairy products have moderate and fruits and grains have
low vitamin K activity.

15. RDA :
Women : 90
mcg/day
Men : 120 mcg/day

16. STRUCTURE