1. Micronutrients Vitamins and Minerals
بسم الله الرحمن الرحيم
Micronutrients Vitamins and Minerals
Dr. Mahmoud Sirdah

2. Classes of Nutrients Macronutrients Carbohydrate Protein Lipids Water
Micronutrients
Vitamins
Minerals

3. Vitamins and minerals are called micronutrients because we only need them in very small amounts.
That doesn’t mean they aren’t important; in fact we can’t live without vitamins and minerals.
we measured protein, carbohydrate and fat needs in grams. However, Vitamins and minerals are measured in milligrams (mg), micrograms (mcg) and international units (IU).

4. Vitamins
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism.
Vitamins serve crucial functions in almost all bodily processes (immune, hormonal and nervous systems) and must be obtained from food or supplements as our bodies are unable to make vitamins.
A compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet.
Thus, the term is conditional both on the circumstances and the particular organism.
For example, ascorbic acid functions as vitamin C for some animals but not others, and vitamins D and K are required in the human diet only in certain circumstances.

5. Water-soluble Fat-soluble Vitamins are classified in two categories:
Classification is based on whether or not the vitamins can dissolve in water.
Water-soluble vitamins include the B complex of vitamins and vitamin C.
The fat-soluble vitamins include vitamins A, D, E and K

7. The fat-soluble vitamins
Because they are soluble in fat (lipids), these vitamins tend to because stored in the body's fat tissues, fat deposits, and liver.
  This storage capability makes the fat-soluble vitamins potentially toxins.
Care should be exercised when taking the fat-soluble vitamins.  The fat-soluble vitamins, especially vitamin A, should be consumed with care because of their storage capabilities.
They have the potential of building up to harmful levels. Even though very few cases of vitamin toxicity have been reported, concern has grown during recent years as the practice of taking mega doses has become popular.

8. Water-soluble vitamins
In contrast to the fat-soluble vitamins, the water-soluble vitamins are not easily stored by the body. They are often lost from foods during cooking or are eliminated from the body.
We don’t store water-soluble vitamins in your body very well so they need to be replaced constantly through your diet. That is one of the reasons we need to eat good foods every day, not just once in a while.
With exception of vitamin B6 and B12, they are readily excreted in urine without appreciable storage, so frequent consumption becomes necessary.
They are generally nontoxic when present in excess of needs, although symptoms may be reported in people taking mega doses of niacin, vitamin C, or pyridoxine (vitamin B6).
All the B vitamins function as coenzymes or cofactors, assisting in the activity of important enzymes and allowing energy-producing reactions to proceed normally. As a result, any lack of water-soluble vitamins mostly affects growing or rapidly metabolizing tissues such as skin, blood, the digestive tract, and the nervous system.

9. Water-soluble vitamins
The water-soluble vitamins include vitamins B1, B2, B3, B6, B12 and vitamin Cas well as Folic acid and Biotin.
Vitamin C has been in the spotlight for many years and is best known for its ability to combat colds and its function as an antioxidant.
The B vitamins basically act as coenzymes and are involved in the metabolism of fat, protein, and carbohydrates.
The water-soluble vitamins are not normally stored in the body in any significant amounts. Therefore, they must be consumed in constant daily amounts to avoid depletion and interference with normal metabolic functioning.

10. Coenzymes and Cofactors
Coenzymes and cofactors are any non-protein molecules (usually organic molecules or metal ions) that are required by an enzyme for its activity.
Enzymes may or may not have a nonprotein molecule attached to them. Some enzymes contain covalently bound carbohydrate groups, which do not affect the catalytic activity, but may influence enzyme stability or solubility.
Many enzymes have metal ions, while some others possess low weight organic molecules; these are called cofactors /coenzymes, and are essential for enzyme activity. An organic cofactor is commonly known as coenzyme. Cofactors and coenzymes may be covalently or noncovalently attached to the protein molecule, called apoenzyme.
Cofactors are often classified as inorganic substances that are required for, or increase the rate of, catalysis.
coenzymes are organic molecules that are required by certain enzymes to carry out catalysis.

11. Coenzymes and Cofactors
cofactors /coenzymes bind to the active site of the enzyme and participate in catalysis but are not considered substrates of the reaction.
An apoenzyme lacks catalytic activity in the absence of its specific cofactor /coenzyme.
When a cofactor is so tightly bound to the apoenzyme that it is difficult to remove it without damaging the enzyme, the cofactor is often called a prosthetic group. Both coenzymes and cofactors generally contribute to enzyme activity as well as stability. The complex of an apoenzyme and the cofactor is known as holoenzyme.
Coenzyme molecules are often Vitamins or are made from vitamins

12. cofactor Inactive enzyme Enzyme Vitamin coenzyme Substrate

13. Vitamins Overview What is a vitamin?
What are the two types of vitamins?
Where do I get my vitamins?
How much do I need?
Why are the vitamins important?
Associated diseases.

14. Vitamins Overview The term vitamin is derived from the words:
vital and amine
because vitamins are required for life and were originally thought to be amines.
Although not all vitamins are amines, they are organic compounds required by humans in small amounts from the diet.
An organic compound is considered a vitamin if a lack of that compound in the diet results in overt symptoms of deficiency.

15. Vitamins Overview
Vitamins are grouped by their biological and chemical activity, not their structure.
Thus, each "vitamin" may refer to several vitamer compounds that all show the biological activity associated with a particular vitamin.
Vitamers are often inter-converted in the body.
Such a set of chemicals are grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A," which includes the retinoid compounds (retinal, retinol , retinoic acid and many carotenoids

17. Good Sources of Vitamins Vitamin Pyramid

18. Vitamins Bioavailability
Vitamins Bioavailability = amount available + amount absorbed
Vitamins Bioavailability affected by
Efficiency of digestion
Nutrition status
Other foods consumed at the same time
Method of food preparation
Source of nutrient
synthetic, naturally occurring, fortified

19. Reference Value Definitions
Estimated Average Requirement (EAR)
a daily nutrient intake value that is estimated to meet the requirements of half the healthy individuals in a group
intake at which the risk of inadequacy is 0.5 (50 percent) to an individual
Recommended Daily Allowance (RDA)
the average daily intake level that is sufficient to meet the nutrient requirement of nearly all (97-98%) healthy individuals in a particular life stage and gender group
the intake at which the risk of inadequacy is very small—only 0.02 to 0.03 (2 to 3 percent)
Tolerable Upper Limit (UL)
highest level of a daily nutrient that is likely to pose no risk of adverse health effects to almost all individuals

21. Two Classifications of Vitamins
Fat Soluble
Vitamin A
Vitamin D
Vitamin E
Vitamin K
Water Soluble
Vitamin C
B Vitamins
Thiamin
Riboflavin
Niacin
Pantothenic Acid
Biotin
Vitamin B6
Folic Acid
Vitamin B12 21

22. Vitamin Comparisons Vits B & C Vits A, D, E, K Water Soluble
Fat Soluble
Vits A, D, E, K
Absorption
Directly into blood
Lymph then blood/protein carrier
Storage
Short term
Long term
Excretion
Kidneys detect and remove in urine
Less readily excreted – remain in fat storage sites
Toxicity
Possible
Likely
Requirements
Daily intake
Regular intake 22

23. Fat Soluble Vitamin Functions
Vitamin A
Vitamin D
Vitamin E
Vitamin K 23

24. Vitamin A Retinol
Vitamin A is a generic term for a large number of related compounds.
Retinol (an alcohol) and retinal (an aldehyde) are often referred to as preformed vitamin A.
Retinal can be converted by the body to retinoic acid, the form of vitamin A known to affect gene transcription.
Retinol, retinal, retinoic acid, and related compounds are known as retinoids (Vitamer).
Beta-carotene and other carotenoids that can be converted by the body into retinol are referred to as provitamin A carotenoids.

25. Vitamin A Vital – promote growth and reproduction and maintain health
organic
do not supply calories
required in the diet in small amounts (micrograms or milligrams per day) for the maintenance of normal health and metabolic integrity

26. Vitamin A
Vitamin A was the first fat-soluble vitamin identified (in 1913).
Vitamin A comprises the preformed retinoids (Retinol, retinal, retinoic acid), plus the precursor forms, the provitamin A carotenoids.
Preformed retinoids is a collective term for retinol, retinal, and retinoic acid, all of which are biologically active.
The provitamin A carotenoids include mainly beta-carotene, which is converted to retinoids with varying degrees of efficiency.
Retinoids are sensitive to heat, light, and oxidation by air. while Beta-carotene is relatively more stable.
There is some loss of vitamin A with cooking, but only after boiling for a comparatively long period.

27. Vitamin A
Retinoids are converted to retinol in the intestines and transported with dietary fat to the liver, where it is stored.
A special transport protein, retinolbinding protein (RBP), transports vitamin A from the liver to other tissues.
Carotenoids are absorbed intact at a much lower absorption rate than retinol. Of all the carotenoids, beta-carotene has the highest potential vitamin-A activity.

28. Vitamin A functions
The active forms of vitamin A have three basic functions:
vision,
growth and development of tissues,
immunity.
Vision. Vitamin A combines with a protein called opsin to form rhodopsin in the rod cells of the retina. When vitamin A is inadequate, the lack of rhodopsin makes it difficult to see in dim light.

29. Vision
Retinal is the key molecule involved in vision and responsible for converting the energy in light photons into electrical impulses in the retina
The precursor of 11-cis-retinal is the alcohol all-trans-retinol (Vitamin A). These molecules (11-cis-retinal or vitamin A) cannot be synthesized by mammals and has to be acquired through the diet.
Precursors to Vitamin A are carotenes, which are found in many vegetables including carrots. Perhaps this leads credence to the old superstition that carrots help you see better in the dark - indeed, it is known that a deficiency of Vitamin A leads to night blindness and eventually damage to the retinal cells involved in vision.

30. Vision All-trans-retinol is converted to 11-cis-retinal.
The photosensitive molecule involved in vision is called rhodopsin, (also known as visual purple) which consists of a large protein (having a molecular weight of around 38,000) called opsin, joined to 11-cis-retinal.
Opsin does not absorb visible light, but when it is bonded with 11-cis-retinal to form rhodopsin, the new molecule has a very broad absorption band in the visible region of the spectrum.
rhodopsin

31. The rhodopsin cycle

32. Vitamin A functions, continue
Growth and development of tissues. Vitamin A is involved in normal cell differentiation specially for epithelial tissue cells of Cornea, skin, respiratory lining, GI tract lining
Vitamin A supports male and female reproductive processes and bone growth.
Immunity. Vitamin A is essential for immune function and vitamin-A deficiency is associated with decreased resistance to infections.
Respiratory infections and diarrhea 2-3X more likely in kids with low Vitamin A.
Bacteria and viruses more likely to invade unhealthy epithelial tissue
The severity of some infections, such as measles and diarrhea, is reduced by vitamin-A supplementation among those who suffer from vitamin-A deficiency.

33. Vitamin A functions, continue
It has been suggested that beta-carotene and other carotenoids (also called phytochemicals) may function as antioxidants by neutralizing free radicals.
Free radicals are unstable, highly reactive molecules that damage DNA, cause cell injury, and increase the risk of chronic disease.
Beta-carotene has also been associated with reducing the risk of lung cancer.
Lutein and zeaxanthin, yellow carotenoid pigments in corn and dark green leafy vegetables, may reduce the risk of macular degeneration of cornea or retina (تبقع القرنية او الشبكية ) and age-related cataracts (الماء الازرق).
Lycopene, a red carotenoid pigment in tomatoes, may help reduce the risk of prostrate cancer, cardiovascular disease, and skin damage from sunlight.
Repairs skin and promotes the growth of elastin e.g Retain A

34. Retin A is retinol that Repairs skin and promotes the growth of elastin

35. which foods are rich in vitamin A sources (preformed and provitamin A precursors)?
Provitamin A Carotenoids
Dark greens
Yellow-orange
Carrots,
kale (اللفت),
spinach,
squash,
sweet potatoes,
cantaloupe,
peaches,
broccoli,
apricots
Preformed Retinoids
Liver
Fish
Fish oils
Fortified milk
Egg

36. which foods are rich in vitamin A?
Essential Nutrient 36

37. Toxicity
Sources
People at risk
Deficiency symptoms
Functions
Vitamin A
Headache, vomiting, double vision, hair loss, dry mucous membranes, bone and joint pain, fractures, liver damage, hemorrhage, coma, teratogenic effects (مسخ او تشوه خلقي): spontaneous abortions, birth defects.
Preformed vitamin A: liver, fortified milk, fish liver oils Provitamin A: red, orange, dark green, and yellow vegetables, orange fruits
Rare in United States but common in preschool children living in poverty in developing countries, alcoholics
Poor growth, night blindness, blindness, dry skin, Xerophthalmia (جفاف الملتحمة)
Vision in dim light and color vision, cell differentiation and growth, immunity
Preformed retinoids and provitamin A carotinoids

38. it is the leading cause of blindness in children worldwide.
Vit A deficiency
Dietary deficiency of vitamin A is rare in North America and western Europe.
it is the leading cause of blindness in children worldwide.
Newborn and premature infants, the urban poor, older adults, people with alcoholism or liver disease, and those with fat malabsorption syndrome are all at increased risk.
One of the earliest symptoms of vitamin-A deficiency is night blindness. It is a temporary condition, but if left untreated it can cause permanent blindness. This degeneration is called xerophthalmia جفاف الملتحمة)), and it usually occurs in children after they are weaned.
Symptoms of xerophthalmia include dryness of the cornea and eye membranes due to lack of mucus production, which leaves the eye vulnerable to surface dirt and bacterial infections.

39. Vit A deficiency
Vitamin-A deficiency can cause follicular hyperkeratosis
(ضخامة و تقرن جريبات شعر الجلد), a condition in which hair follicles become plugged with keratin, giving a bumpy appearance and a rough, dry texture to skin.
In developing countries, the severity of infectious diseases such as measles is often correlated to the degree of vitamin-A deficiency.
Providing large doses of vitamin A reduces the risk of dying from these infections.
The age range of the target population for vitamin-A intervention programs is usually from birth to seven years.
Administration of high-potency doses in the range of 15,000 to 60,000 micrograms (μg) are distributed to young children in targeted areas of the world to build up liver stores for up to six months. However, consumption of adequate food sources is the most important long-term solution to vitamin-A deficiency.

40. Vit A Toxicity
None of the forms of vitamin are easily excreted, so toxicity is a risk for those with kidney disease or as people age.
Vitamin-A toxicity, called hypervitaminosis A,
It can result from long-term supplementation of two to four times the Recommended Daily Allowance (RDA) for preformed vitamin A.
Excess intake of preformed vitamin A is a teratogen, meaning it can cause birth defects.
Birth defects associated with vitamin-A toxicity include:
cleft palate (انشقاق الحنك)
heart abnormalities
brain malfunction.
Acute excess intake during pregnancy can also cause spontaneous abortions.
Pregnant women should avoid prenatal supplements containing retinal, as well as medications made from retinoids, such as Accutane and Retin-A.
Prolonged and excessive consumption of carotene-rich foods can lead to hypercarotenemia (فرط جزرنة الدم), a clinical condition characterized by deep orange discoloration of the skin and increased carotene levels in the blood. This condition is usually harmless.

41. Vitamin D (Calciferol)
Common Names: Vitamin D; Calciferol, Cholecalciferol, Ergocalciferol
Forms: Calciferol, cholecalciferol, ergocalciferol, irradiated ergosterol
Vitamin D plays a critical role in the body’s use of calcium and phosphorous. It increases the amount of calcium absorbed from the small intestine and helps form and maintain bones. Children especially need adequate amounts of vitamin D to develop strong bones and healthy teeth.
Vitamin D is Called a “conditional” vitamin.
For most people in sunny regions , sun provides % of their needs of Vitamin D
Vitamin D2 (ergocalciferol) is obtained from plants.
• Vitamin D3 is cholecalciferol derived from animal products
Vitamin D

42. Structures of Vitamin D
There are different forms of vitamin D
Vitamin D2 (ergocalciferol)
vitamin D3 (cholecalciferol)
provitamins
Vitamin D is a generic term and indicates a molecule of the general structure that contains the 4 fused rings of steroid with differing side chain structures.
Technically vitamin D is classified as a seco-steroid.
Seco-steroids are those in which one of the rings has been broken.
in vitamin D, the 9,10 carbon-carbon bond of ring B is broken, and it is indicated by the inclusion of "9,10-seco" in the official nomenclature

44. Vitamins D3 & D2 Vitamin D2 (ergocalciferol) is obtained from plants.
Vitamin D3 is cholecalciferol derived from animal products
Vitamin D3 (cholecalciferol) can be produced photochemically by the action of sunlight or ultraviolet light from the precursor sterol 7-dehydrocholesterol which is present in the epidermis or skin of most higher animals.
Thus, it is important to appreciate that vitamin D3 can be endogenously produced and that as long as the animal (or human) has access on a regular basis to sunlight there is no dietary requirement for this vitamin.
Vitamin D2 = ergocalciferol (which is equivalently potent to vitamin D3 in humans and many mammals) is produced commercially by the irradiation of the plant sterol ergosterol with ultraviolet light.

45. Absorption of Vitamin D
Vitamin D from foods is absorbed from the upper part of the small intestine, along with dietary fat, and transported to the liver.
In the skin, ultraviolet (UV) radiation from the sun converts a cholesterol derivative 7-dehydrocholesterol to cholecalciferol, which enters the blood stream and is transported to the liver.
In the liver, vitamin D is converted to calcidiol, an inactive form that circulates in blood. Kidneys take up calcidiol and convert it to an active hormone form of vitamin D called calcitriol.
People with chronic kidney failure have very low levels of calcitriol and must be routinely treated with this form of the vitamin.

46. Vitamin D – Skin Cholesterol derivative Cholecalciferol blood blood
Calcidiol (inactive)
Calcitriol (Active hormone form of vitamin D)
5-15 min Sunlight/week 46

47. Functions of Vitamin D
The group known as the D vitamins are required for growth, especially bone growth or "calcification".
The best-known function of active vitamin D is to help regulate blood levels of calcium and phosphorous. Vitamin D increases absorption of these minerals from the gastrointestinal (GI) tract. In combination with parathyroid hormone, it enhances their reabsorption from the kidneys and their mobilization from bones into the blood.
Vitamin D can be considered both a vitamin and a hormone.
Vitamin D plays an important role in maintaining adequate blood levels of insulin and may assist the metabolism of sugar.
1,25 dihydroxycholecalciferol (DHCC), the most active form of vitamin D, functions to: » Increase the absorption of calcium from the intestines by stimulating the synthesis of calcium-binding protein. This occurs in the brush border of the intestinal mucosa. » Increase the resorption (ارتشاف) of calcium from bone. » Increase serum calcium levels. Once this occurs calcium can then be stored in the bones. Thus, even though it initially causes bone resorption, the net effect is to increase calcium deposition in the bone
Vitamin D helps maintain calcium levels even if dietary intakes are not optimal. Calcitriol controls growth of normal cells and some cancer cells. Adequate vitamin-D status has been linked to a reduced risk of developing breast, colon, and prostrate cancers

48. Primary sources of vitamin D
The primary food sources of vitamin D are milk and other dairy products fortified with vitamin D.
Egg yolk
Vitamin D is also found in oily fish as well as in cod liver oil.
Vegetables are usually low in vitamin D. Leafy dark green vegetables and mushrooms are significant sources of vitamin D from non-animal sources.
In addition to the vitamin D provided by food, we obtain vitamin D through our skin which makes vitamin D in response to sunlight.

50. Although about 10 substances have fat soluble vitamin D activity, vitamins D2 (or ergocalciferol) and D3 (or cholecalciferol) are the two most significant to humans.
Vitamin D3 is found in our diet, while vitamin D2 occurs in yeasts and fungi. Both can be formed from their respective provitamins by ultraviolet irradiation; in man the provitamin (7-dehydrocholesterol), which is found in skin, can be converted by sunlight to vitamin D3 and thus is an important source of the vitamin. Human beings can utilize both vitamins D2 and D3.

51. Vitamin D deficiency
Children in particular need adequate amounts of vitamin D to develop strong bones and healthy teeth.
Symptoms of vitamin D deficiency in growing children include rickets (الكساح) (long, soft bowed legs) and flattening of the back of the skull.
Vitamin D deficiency in adults is called osteomalacia (لين او تلين العظام), which leads to muscular weakness and weak bones.

52. Osteomalacia and osteoporosis in adults
rickets in children
Osteomalacia and osteoporosis in adults

53. Vitamin D Deficiency: Children = Ricket’s Disease
Adults = Osteomalacia
Calcium absorption; Blood Calcium = bone deficiency
Toxicity: 10x RDA
Calcium absorption; Blood Calcium = Calcium deposits on soft tissue
eg kidney stones
RDA: 5 μg/dl 5 μg/dl (19-30 yrs) 53

54. Vitamin D deficiency
Long-term deficiency of vitamin D affects the skeletal system. In children, vitamin-D deficiency leads to rickets, a condition in which bones weaken and bow under pressure.
In adults, vitamin-D deficiency causes osteomalacia, or "soft bones," increasing the risk for fractures in hip, spine, and other bones.
Vitamin-D deficiency also contributes to osteoporosis(هشاشة العظام). In elderly persons, vitamin-D supplementation reduces the risk of osteoporotic fractures.
Infants are born with stores of vitamin D that last about six months. Breast milk contains very little vitamin D, however, and infants beyond six months of age who are exclusively breastfed must obtain vitamin D via exposure to sunlight or a supplement given under the guidance of a physician.

55. Vitamin D deficiency
Older adults are especially at risk for vitamin-D deficiency for several reasons. The skin, liver, and kidneys lose their capacity to synthesize and activate vitamin D with advancing age, and older adults typically drink little or no milk, a major dietary source of vitamin D.
Older adults also rarely venture outdoors, and when they do, they apply sunscreen to exposed areas of the body, further contributing to the decline in vitamin-D synthesis in the skin.
Sunscreens with a sun protection factor (SPF) of 8 and above prevent vitamin-D synthesis. Sunscreen should be applied only after enough time has gone to provide sufficient vitamin-D synthesis.
Exposure to the sun does not cause vitamin-D toxicity, and for most people, exposing the hands, face, and arms on a clear summer day for fifteen minutes a few times a week should provide sufficient Vitamin D.
Dark-skinned people require longer sunlight exposure because melanin, a skin pigment, is a natural sunscreen.

56. Vitamin D deficiency
Dietary recommendations assume that no vitamin D is available from exposure to sunlight. Thus, people who do not venture outdoors or who live in northern or predominantly cloudy climates need to pay attention to dietary sources.
Plants are poor sources of vitamin D, so strict vegetarians must meet their vitamin-D needs through exposure to sunlight, fortification, or supplementation.

57. Vitamin D toxicity
Vitamin D is most likely to have toxic effects when consumed in excessive amounts through supplementation.
vitamin D is the most potentially toxic vitamin in human nutrition, with an upper limit (UL) of 50 micrograms per day. We can obtain the vitamin in an inactive form from food and sunlight exposure
Excess vitamin D raises blood calcium levels, resulting in calcium precipitation in soft tissues and stone formation in the kidneys, where calcium becomes concentrated in an effort to excrete it.
The adult DRI for vitamin D is 5 micrograms per day of cholecalciferol or 200 international units (IU) of vitamin D (1 microgram of calciferol equals 40 IU of vitamin D).
However, because of vitamin D's potential toxicity, caution must be taken not to consume too much. Excess Vitamin D intake may lead to vomiting, diarrhea , kidney damage, high blood calcium levels, increased frequency in urination, nausea, loss of appetite and weight loss, muscle weakness, dizziness, calcification of heart, blood vessels and lungs; and possibly death.
symptoms reverse after overdosing is discontinued.

58. Vitamin E
vitamin-E was firstly associated with reproductive failure in rats in 1922
Vitamin E comprises a family of eight naturally occurring compounds:
tocopherols (alpha-, beta-, gamma-, and delta-)
tocotrienols (alpha-, beta-, gamma-, and delta-).
The chemical name of vitamin E, is derived from toco, meaning "related to childbirth.“
The tocopherols, are a closely related group of biologically active compounds. The active tocopherols are named in order of their potency. Thus, alpha-tocopherol is the most active.
alpha- tocopherol is the only one to have vitamin-E activity in the human body. It is also the most common form of vitamin E in food.
Vitamin E is highly susceptible to destruction by oxygen, metals, light, and deep-fat frying. As a result, prolonged food storage lowers the vitamin-E content of food.

59. Chemical structure of Vitamin E

60. Overview of Vitamin E
Unlike vitamins A and D, Vitamin E, is not stored primarily in liver but instead stored primarily within body fat.
Virtually every tissue has some vitamin E within cell membrane
Absorption is dependent on the absorption of dietary fat
Absorption is dependent on bile and pancreatic enzyme for absorption
Much excreted via bile and urine

61. Overview of Vitamin E
The vitamin E α-Tocopherol is necessary for normal growth.
The main function of alpha-tocopherol in humans appears to be that of an antioxidant(protects cells from toxic compounds, heavy metals, radiation, and free radicals).
free radicals are formed primarily in the body during normal metabolism and also upon exposure to environmental factors, such as cigarette smoke or pollutants.
Fats, which are an integral part of all cell membranes, are vulnerable to destruction through oxidation by free radicals. 
The fat-soluble vitamin E, alpha-tocopherol, is distinctively suitable to catch free radicals and thus prevent a chain reaction of lipid destruction of cell membranes and other fats of the tissues.
The vitamin E α-Tocopherol enhances retinal development; protects vitamin A in eyes protecting vitamins C, red blood cells and essential fatty acids from destruction.
Taking antioxidant supplements, vitamin E in particular, might help prevent heart disease and cancer.
Everybody needs E. This hard-working vitamin maintains a lot of our body's tissues, like the ones in our eyes, skin and liver. It protects our lungs from becoming damaged by polluted air.

62. Overview of Vitamin E
absorption of vitamin E requires adequate absorption of dietary fat.
the percentage of absorption declines as the amount consumed is increased.
Vitamin E is stored mainly in adipose tissue, while some is stored in the muscle. The remaining vitamin E is found in cell membranes in tissue.
Vitamin E interrupts free-radical chain reactions by getting oxidized, thus protecting cell membranes from free-radical attack.
oxidative stress is highly involved in the development of cancer, arthritis, cataracts, heart disease, and in the process of aging itself.

66. Overview of Vitamin E
Many of the anti-oxidant properties of Vitamin E have been hypothesized to protect from chronic diseases (i.e. heart, lung cancer, parkinsons, alzheimer’s,etc).
However, it is not yet documented whether supplementation with large doses of vitamin E offers protection against heart disease and cancer beyond that provided by positive dietary and lifestyle changes.
Several other functions of alpha-tocopherol have been identified that are not likely related to its antioxidant capacity.
alpha-tocopherol is known to inhibit the activity of protein kinase C, an important cell-signaling molecule.
Alpha-tocopherol appears to also affect the expression and activities of molecules and enzymes in immune and inflammatory cells.
Additionally, alpha-tocopherol has been shown to inhibit platelet aggregation and to enhance vasodilatation !!!!!!!

67. Sources of Vitamin E
About 20% of vit E in the diet comes from veg. oils
Fruits and veggies
Fortified cereals and grain products
Wheat germ oil
Corn and soybean oil
Nuts
Seeds
animal fat NOT good source - almost none there
Destroyed easily by heat.

68. Sources Vitamin E 68

69. Vitamin E deficiency
Vitamin E deficiency has been observed in individuals with:
severe malnutrition
genetic defects affecting the alpha-tocopherol transfer protein
fat malabsorption syndromes
children with liver diseases who have an impaired capacity to absorb dietary fat and therefore fat-soluble vitamins, may develop symptomatic vitamin E deficiency.
Severe vitamin E deficiency results mainly in neurological symptoms, including impaired balance and coordination (ataxia), injury to the sensory nerves (peripheral neuropathy), muscle weakness (myopathy), and damage to the retina of the eye (pigmented retinopathy). For this reason, people who develop peripheral neuropathy, ataxia, or retinitis pigmentosa should be screened for vitamin E deficiency

71. Vitamin E deficiency
children who have born with severe vitamin E deficiency and are not treated with vitamin E rapidly develop neurological symptoms.
While, individuals who develop malabsorption of vitamin E in adulthood may not develop neurological symptoms for years.

72. Vitamin E and disease prevention
Cardiovascular disease
Increased vitamin E consumption has been found to be associated with decreased risk of myocardial infarction (heart attack) or death from heart disease
Cataracts
Cataracts which appear to be formed by protein oxidation in the lens of the eye; such oxidation may be prevented by antioxidants like alpha-tocopherol.  Direct association was reported between vitamin E consumption and the incidence and severity of cataracts. increased vitamin E intake protects against cataract development.
Immune Function
Alpha-tocopherol has been shown to enhance specific aspects of the immune response that appear to decline as people age .
Cancer
Many types of cancer are thought to result from oxidative damage to DNA caused by free radical formulation . The ability of alpha-tocopherol to neutralize free radicals formulated the hypothesis that Vit E could help in the cancer prevention, however results are not yet confirmed

73. Safety and toxicity aspects of vit E
RDA: 15 mg/dl (19-30 yrs)
Few side effects have been noted in adults taking supplements of less than 2,000 mg of alpha-tocopherol daily.
However, most studies of toxicity or side effects of alpha-tocopherol supplementation have lasted only a few weeks to a few months, and side effects occurring as a result of long-term alpha-tocopherol supplementation have not been adequately studied.
The most worrisome possibility is that of impaired blood clotting, which may increase the likelihood of hemorrage in some individuals.
Therfore it is recommended to discontinuing high-dose vitamin E supplementation one month before elective surgery or teeth extraction to decrease the risk of hemorrhage

74. Drug Interactions
Use of vitamin E supplements may increase the risk of bleeding in individuals taking anticoagulant drugs, such as warfarin (Coumadin); antiplatelet drugs; and non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, ibuprofen, and others.
Also, individuals on anticoagulant therapy (blood thinners) or individuals who are vitamin K deficient should not take alpha-tocopherol supplements without close medical supervision because of the increased risk of hemorrhage.
A number of medications may decrease the absorption of vitamin E, including cholestyramine (chol-less), colestipol (colestid), isoniazid (anti T.B), mineral oil, orlistat (xenical antiobesity), sucralfate (ulsanic gastric ulcer), and the fat substitute, olestra. Anticonvulsant drugs, such as phenobarbital, phenytoin, or carbamazepine, may decrease plasma levels of vitamin E.

75. Vitamin K menaquinones from animal sources.
Was first discovered in 1929, by the Danish researcher Henrik Dam.
He noted that vitamin K played a critical role in blood clotting, and he named it vitamin "K" for "Koagulation."
Vitamin K is the clotmaster!
Used by the liver for the formation of prothrombin
There are two naturally occurring forms of vitamin K.
Vitamin K comprises a family of compounds known as quinones.
These include phylloquinone from plants sources
menaquinones from animal sources.
Phylloquinone is the most biologically active form. Menaquinones are also synthesized by bacteria in the intestine and absorbed, contributing about 10 percent of total vitamin-K needs.
Vitamin-K absorption depends on normal consumption and digestion of dietary fat. It is primarily stored in the liver.

76. Chemical structure of Vitamin K

77. Overview of Vitamin K
Vitamin K is found in green leafy vegetables and also, in small amounts, in cereals, fruits, and meats.
Bacteria in the intestines also produce vitamin K, so the absolute dietary requirement is not known.
This vitamin is needed for the formation of prothrombin , which is required for the formation of blood clots.
It is possible for people who regularly take antibiotics that destroy the bacteria in the intestines (normal flora) to be at increased risk for Vitamin k.
A deficiency would cause an increase in bleeding and hemorrhages.
Vitamin K appears to be relatively nontoxic, but high intakes of synthetic forms may cause jaundice.
Supplemental doses also interfere with anticoagulant drugs.
People taking warfarin (a blood thinner) must be aware that vitamin K or foods containing vitamin K may reduce the effectiveness of their medication.

78. Overview of Vitamin K Vitamin K has also been linked to bone density.
People with low levels of vitamin K have lower bone density, which can be improved with vitamin K supplementation.
women obtaining a minimum of 110 micrograms of vitamin K are at significantly lower hip fracture risk than women who have a lower intake.
Different Studies also found a relationship between higher vitamin K intake and reduced hip fracture risk.
Vitamin K is found in so many foods, and with bacterial production in the small intestine, it would seem difficult to not get enough.
particularly children and young adults, does not obtain sufficient vitamin K.
Newborn babies lack the intestinal bacteria to produce vitamin K and need a supplement for the first week.
Also, people with chronic diarrhea may be unable to absorb enough vitamin K through the intestine. These groups of people need to take additional Vitamin K to ensure a proper level in the body.
Although a tolerable upper intake level has not been established for vitamin K, excessive amounts can cause the breakdown of red blood cells and liver damage. Large doses are not advised.

79. Sources of Vitamin K
Naturally produced by the bacteria in the intestines,
Good food sources of vitamin K are:
green vegetables such as turnip (لفت), spinach, cauliflower (قرنبيط), cabbage and broccoli, and certain vegetables oils including soybean oil, cottonseed oil, canola oil and olive oil.
Animal foods, in general, contain limited amounts of vitamin K.

80. Deficiency vitamin K
A primary deficiency of vitamin K is rare, but a secondary deficiency may result from fat malabsorption syndrome.
vitamin K deficiency results in impaired blood clotting, usually demonstrated by laboratory tests that measure clotting time. Symptoms include easy bleeding that may be manifested as nosebleeds, bleeding gums, blood in the urine, blood in the stool, or extremely heavy menstrual bleeding.
In infants, vitamin K deficiency may result in life-threatening bleeding within the skull (intracranial hemorrhage
Prolonged use of antibiotics can destroy the intestinal bacteria that produce vitamin K, precipitating deficiency in individuals at risk.
Newborn infants are born with a sterile intestinal tract and those who are breastfed, may run the risk of vitamin-K deficiency, since breast-milk production takes a few days to establish and breast milk is naturally low in this vitamin.
To prevent hemorrhaging, infants should receive injections of vitamin K within six hours of birth.

81. Toxicity vitamin K
High doses of vitamin K can reduce the effectiveness of anticoagulant drugs (Vit K antagonists) such as warfarin (Coumadin), which is used to prevent blood clotting. People taking these drugs should maintain a consistent daily intake of vitamin K.
Megadose supplements of vitamin A and E can pose a risk to vitamin-K status. Vitamin A interferes with absorption of vitamin K, and large doses of vitamin E decrease vitamin K–dependent clotting factors, thus promoting bleeding.
Toxicity from food is rare, because the body excretes vitamin K much more rapidly than other fat-soluble vitamins.

82. Water soluble vitamins
Vitamins are essential micronutrients.
vitamin elimination from the diet must result in a more-or-less clearly defined deficiency disease, and restoration must cure or prevent that deficiency disease

83. Water vs. Fat Fat Soluble Vitamin A Vitamin D Vitamin E Vitamin K
Water Soluble
Vitamin C
B Vitamins
Thiamin
Riboflavin
Niacin
Pantothenic Acid
Biotin
Vitamin B6
Folic Acid
Vitamin B12

84. Water Soluble Vitamin Functions
Water Soluble Vitamins
Vitamin C
B Vitamins
Thiamin (B1)
Riboflavin (B2)
Niacin
Vitamin B6
Folic Acid
Vitamin B12
Pantothenic Acid
Biotin
Skin, bones,
infections
Release energy from
MACROnutrients:

85. Vitamin C (ascorbic acid)
Our bodies need vitamin C to keep it in good working condition.
vitamin C helps hold body cells together, aids in wound healing, assists in bone and tooth formation, and strengthens the blood vessel walls.
Vitamin C is also crucial to the functioning of our immune system, and it helps improve the absorption and utilization of iron. (Enhances absorption of iron (protects it from oxidation) – tip: take vitamins with orange juice)
Our bodies cannot make vitamin C and our capacity to store vitamin C is limited.
We must, therefore, take in some daily.
Some conditions have been shown to increase vitamin C requirements:
environmental stress,
use of certain drugs (such as oral contraceptives),
tissue healing of wounds,
growth (children and pregnant women),
fever and infection, and
smoking.
Megadoses of vitamin C can be help prevent or possibly even cure a case of the common cold. Vitamin C also serves as a powerful antioxidant. It works synergistically with vitamin E as a free-radical scavenger.
Studies suggest that vitamin C may reduce the risk of certain cancers, heart disease and cataracts. Recent studies also suggest that the combination of vitamins C and E in high doses can help reduce the risk of developing Alzheimer’s disease.

86. Functions of Vitamin C
Vitamin C is required for the synthesis of collagen, an important structural component of blood vessels, tendons, ligaments, and bone.
Vitamin C also plays an important role in the synthesis of the Neurotransmitter, norepinephrine.
Neurotransmitters are critical to brain function and are known to affect mood.
In addition, vitamin C is required for the synthesis of carnitine (a small molecule that is essential for the transport of fat to mitochondria for conversion to energy.
 Vitamin C is also a highly effective antioxidant.
Even in small amounts vitamin C can protect proteins, lipids (fats), carbohydrates, and DNA & RNA from damage by free radicals that can be generated during normal metabolism as well as through exposure to toxins and pollutants (e.g. smoking).
Vitamin C may also be able to regenerate or potentiate other antioxidants such as vitamin E

87. Functions of Vitamin C
The argument over megadoses of vitamin C to prevent or cure the common cold and other disorders has not been resolved.
Vitamin supplements will not necessarily provide extra energy, clear up skin problems, or prevent and cure the common cold, heart disease, and cancer. Unlike scurvy, these problems are not the result of a vitamin C deficiency. What is known is that the only disease a vitamin will cure is the one caused by a deficiency of that vitamin.

88. Sources of Vitamin C
Eating vitamin C-rich foods is the best method to ensure an adequate intake of this vitamin.
While many common foods contain vitamin C, the best food sources are citrus fruits. One orange, a kiwi fruit, cup of grapefruit juice each supply enough vitamin C for one day.
Vitamin C can be found in fresh fruits and vegetables: strawberries, peppers, tomatoes, leafy green vegetables and potatoes.
It is not found in meat or animal products.
Vitamin C is present in some processed foods, too.
Since ascorbic acid is an antioxidant, it doesn’t last long in the presence of oxygen. This means that once you cut or peel fruits and vegetables and expose them to air, the vitamin C content will diminish.

89. Sources of Vitamin C

90. Vitamin C intake 3000 2000 200 125 110 100 RDA Men 90 RDA Women 75 30
UL Men
UL Women
Limited absorption and little increase in blood concentration
Rec for Men Smokers
Rec for Women Smokers
Saturates Tissues
RDA Men
RDA Women
Supports metabolism
Prevents Scurvy
3000
2000
200
125
110
100 90 75 30 10

91. Stability in foods
Overconsumption symptoms
Deficiency symptoms
Major functions
Common food sources
Most unstable under heat, drying, storage; very soluble in water, leaches out of some vegetables during cooking; alkalinity (baking soda) destroys vitamin C.
Nontoxic under normal conditions; rebound scurvy when high doses discontinued; diarrhea, bloating, cramps; increased incidence of kidney stones.
Bleeding gums; wounds don't heal; bruise easily; dry, rough skin; scurvy; sore joints and bones; increased infections.
Formation of collagen (a component of tissues), helps hold them together; wound healing; maintaining blood vessels, bones, teeth; absorption of iron, calcium,; production of brain hormones, immune factors; antioxidant.
Citrus fruits, broccoli, strawberries, melon, green pepper, tomatoes,
dark green vegetables, potatoes.

92. Vitamin C Deficiency
Severe vitamin C deficiency has been known for many centuries as the potentially fatal disease, Scurvy (داء الحفر او الاسقربوط).
By the late 1700's the British navy was aware that scurvy could be cured by eating oranges or lemons, even though vitamin C would not be isolated until the early 1930's.
Symptoms of scurvy include bleeding easily, hair and tooth loss, joint pain and swelling. Such symptoms appear to be related to the weakening of blood vessels, connective tissue, and bone, which contain collagen.
Early symptoms of scurvy such as fatigue may result from diminished levels of carnitine , needed to derive energy from fat, or decreased synthesis of the norepinephrine.
Scurvy is rare in developed countries because it can be prevented by as little as 10 mg of vitamin C daily . However, recent cases have occurred in children and the elderly on very restricted diets

94. Safety & Toxicity of Vitamin C
A number of possible problems with very large doses of vitamin C have been suggested, mainly based on in vitro experiments, including genetic mutations , birth defects, kidney stone , increased oxidative stress , excess iron absorption, vitamin B-12 deficiency, and erosion of dental enamel.
However, none of these adverse health effects have been confirmed, and there is no reliable scientific evidence that large amounts of vitamin C (up to 10 grams/day in adults) are toxic or detrimental to health.

95. B vitamins (B-complex)
These vitamins are widely distributed in foods. Their influence is felt in many parts of the body.
They function as coenzymes that help the body obtain energy from food.
They also are important for normal appetite, good vision, healthy skin, healthy nervous system and red blood cell formation.
Beriberi, pellagra and pernicious anemia are three well-known B-vitamin deficiencies.
These diseases are not a problem in the United States, but occasionally they occur when people omit certain foods or overeat certain foods at the expense of others.

96. B vitamins (B-complex)
B vitamins are needed for conversion of food to energy.
They do not provide the energy, that comes from the macronutrients, but the B vitamins are essential helpers.
When you are deficient in any of the B vitamins you will feel fatigued and some B vitamin deficiencies will lead to anemia.
B complex vitamins also help you withstand stress, keep your cardiovascular system healthy and will boost your immune system.

97. B Vitamins Thiamin (B1) Riboflavin (B2) Niacin Vitamin B6 Folic Acid
Pantothenic Acid
Biotin
Coenzymes:
Catalysts in
Biochemical Pathways

98. Thiamin (Vitamin B1)
Thiamin (Vitamin B1) functions as the coenzyme thiamin pyrophosphate (TPP) in the metabolism of carbohydrate. Thiamin is also needed for healthy muscles and normal nervous system function and conduction of nerve impulses.
A deficiency of thiamine will cause fatigue and decreased mental alertness. A severe deficiency will cause a nervous system disorder called beriberi . People with beriberi may have nerve damage in their hands and feet or heart damage.
Thiamin deficiency causes beriberi, which is frequently seen in parts of the world where polished (white) rice or unenriched white flour are predominantly eaten.
There are three basic expressions of beriberi : childhood, wet, and dry.
Childhood beriberi stunts or inhibits growth in infants and children.
Wet beriberi is the classic form, with swelling due to fluid retention (edema) in the lower limbs that spreads to the upper body, affecting the heart and leading to heart failure.
Dry beriberi affects peripheral nerves, initially causing tingling or burning sensations in the lower limbs and progressing to nerve degeneration, muscle wasting and weight loss.
Thiamine-deficiency disease in North America commonly occurs in people with heavy alcohol consumption.
It is caused by poor food intake and by decreased absorption and increased excretion caused by alcohol consumption.

99. Thiamin (Vitamin B1)
Wernicke-Korsakoff syndrome is another thiamine deficiency disorder. In this case, the brain and nervous system are affected so that a person has nerve damage and impaired mental ability. This disease is most commonly found in people who drink lots of alcohol on a regular basis. Replacing the deficient thiamine improves the symptoms.
Thiamine is found in whole grains, legumes, lean meat, fish and fortified breads and cereals.
Fruits and vegetables contain smaller amounts of thiamine. Your daily requirement for thiamine may be increased if you eat a lot of sugar or in a heavy alcohol drinker.

100. Riboflavin (Vitamin B2)
Riboflavin (vitamin B2) is a component of two coenzymes—flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)—that act as hydrogen carriers when carbohydrates and fats are used to produce energy.
Riboflavin (vitamin B2) is helpful in maintaining good vision and healthy hair, skin and nails, and it is necessary for normal cell growth.
Riboflavin (vitamin B2) is stable when heated in ordinary cooking, unless the food is exposed to ultraviolet radiation (sunlight). To prevent riboflavin breakdown, riboflavin-rich foods such as milk, milk products, and cereals are packaged in opaque containers.
Riboflavin deficiency causes a condition known as ariboflavinosis (Riboflavin deficiency ), which is marked by cheilosis (تشقق الشفتين و حرشفتهما) (cracked lips at the corners of the mouth), oily scaling of the skin, and a red, sore tongue, ulcers in the mouth, dry skin and a sore throat.
In addition, cataracts may occur more frequently with riboflavin deficiency.
A deficiency of Riboflavin (vitamin B2) is usually a part of multinutrient deficiency and does not occur in isolation.
In North America, it is mostly observed in alcoholics, elderly persons with low income or depression, and people with poor eating habits, particularly those who consume highly refined and fast foods and those who do not consume milk and milk products

101. Sources of Riboflavin B2
Riboflavin is easily obtained from a healthy diet and can be found in dairy products, legumes, green leafy vegetables and nuts.
Riboflavin can be destroyed fairly easily by light. This is the reason milk is sold in cartons or opaque bottles. Riboflavin is also reduced by alkaline conditions, so soaking legumes in baking soda and water before cooking them destroys some riboflavin.

102. Niacin (Vitamin B3)
Niacin (Vitamin B3) exists in two forms: nicotinic acid and nicotinamide.
There are two coenzyme forms of Niacin (Vitamin B3) :
nicotinamide adenine dinucleotide (NAD+)
nicotinamide adenine dinucleotide phosphate (NADP+).
They (NAD+ and NADP+) both help break down and utilize proteins, fats, and carbohydrates for energy.
Niacin (Vitamin B3) is essential for growth and is involved in hormone synthesis.
Both forms are readily absorbed from the stomach and small intestine.
Good sources for Niacin (Vitamin B3) are Protein, milk, fish, chicken; whole grains
Niacin is stored in small amounts in the Liver and transported to tissues, where it is converted to coenzyme forms. Any excess is excreted in urine.
Niacin is one of the most stable of the B vitamins. It is resistant to heat and light, and to both acid and alkali environments.

103. Niacin (Vitamin B3) deficiency
The human body is capable of converting the a.a tryptophan to niacin when needed. However, when both tryptophan and niacin are deficient, tryptophan is used only for protein synthesis.
Pellagra (بيلاجرا او الحصاف او تخشن الجلد) Diarrhea, Dermatitis, Dementia (خرف او خبل), Death results from a combined deficiency of niacin and tryptophan.
Long-term deficiency leads to CNS dysfunction manifested as confusion, apathy (lack of concern), disorientation, and eventually coma and death.

104. Pantothenic Acid (B5)
Pantothenic acid is released from coenzyme A in food in the small intestine. After absorption, it is transported to tissues, where coenzyme A is resynthesized.
Coenzyme A is essential for the formation of energy as adenosine triphosphate (ATP) from carbohydrate, protein, alcohol, and fat.
Coenzyme A is also important in the synthesis of fatty acids, cholesterol, steroids, and the neurotransmitter acetylcholine, which is essential for transmission of nerve impulses to muscles

105. Sources of Pantothenic acid B5
Sources include: Liver, kidney, meats, egg yolk, whole grains, legumes; also made by intestinal bacteria.
Deficiency syndrome are Uncommon due to availability in most foods.
Dietary deficiency occurs in conjunction with other B-vitamin deficiencies. In studies, experimentally induced deficiency in humans has resulted in headache, fatigue, impaired muscle coordination, abdominal cramps, and vomiting.
Pantothenic acid is stable in moist heat. It is destroyed by vinegar (acid), baking soda (alkali), and dry heat. Significant losses occur during the processing and refining of foods.

106. Vitamin B6 (pyridoxal, pyridoxine, and pyridoxamine)
Vitamin B6 is present in three forms: pyridoxal, pyridoxine, and pyridoxamine.
All forms can be converted to the active vitamin-B6 coenzyme in the body.
Pyridoxal phosphate (PLP) is the predominant biologically active form.
Vitamin B6 is not stable in heat or in alkaline conditions, so cooking and food processing reduce its content in food.
Both coenzyme ( Pyridoxal phosphate (PLP) and free forms (pyridoxal, pyridoxine, and pyridoxamine) are absorbed in the small intestine and transported to the liver, where they are phosphorylated and released into circulation, bound to albumin for transport to tissues.
Vitamin B6 is stored in the muscle and only excreted in urine when intake is excessive.

107. Functions of Vit B6
Pyridoxal phosphate (PLP) participates in amino acid synthesis and the interconversion of some amino acids.
Pyridoxal phosphate (PLP) catalyzes a step in the synthesis of Hb
Pyridoxal phosphate (PLP) helps maintain blood glucose levels by facilitating the release of glucose from liver and muscle glycogen.
Pyridoxal phosphate (PLP) also plays a role in the synthesis of many neurotransmitters important for brain function. This has led some physicians to prescribe megadoses of B6 to patients with psychological problems such as depression

108. Sources and deficiency
Meats, fish, chick, spinach, potatoes, bananas, avocados, sunflower seeds, whole grains and cereals, legumes, green, leafy vegetables.
Dermatitis, anemia, convulsion , depression, confusion , decline in immune function

109. Biotin (Vitamin B8) Biotin is the most stable of B vitamins.
It is commonly found in two forms: the free vitamin and the protein-bound coenzyme form called biocytin.
Biotin is absorbed in the small intestine, and it requires digestion by enzyme biotinidase, which is present in the small intestine.
Biotin is synthesized by bacteria in the large intestine , but its absorption is questionable.
Biotin containing coenzymes participate in key reactions that produce energy from carbohydrate and synthesize fatty acids and protein.

110. Sources and deficiency
Sources include: Liver, kidney, egg yolk, milk, most fresh vegetables, Whole grains, nuts and seeds also made by intestinal bacteria.
Avidin is a protein in raw egg white, which can bind to the biotin (B8) in the stomach and decrease its absorption. Therefore, consumption of raw whites is of concern due to the risk of becoming biotin deficient. Cooking the egg white, however, destroys avidin.
Deficiency may develop in infants born with a genetic defect that results in reduced levels of biotinidase. In the past, biotin deficiency was observed in infants fed biotin-deficient formula, so it is now added to infant formulas and other baby foods.
deficiency uncommon under normal circumstances; fatigue; loss of appetite, nausea, vomiting; depression; muscle pains; anemia.
infants: Dermatitis, convulsions, hair loss (alopecia), neurological disorders, impaired growth

111. Folic Acid, Folate, Folacin (Vitamin B9)
Folacin or folate, as it is usually called, is the form of vitamin B9 naturally present in foods, whereas folic acid is the synthetic form added to fortified foods and supplements.
Both forms are absorbed in the small intestine and stored in the liver.
The folic acid form, however, is more efficiently absorbed and available to the body. When consumed in excess of needs, both forms are excreted in urine and easily destroyed by heat, oxidation, and light.
All forms of this vitamin are readily converted to the coenzyme form called tetrahydrofolate (THFA).
tetrahydrofolate (THFA) plays a key role in the synthesis of DNA and RNA, and in interconversions of amino acids.
Folate also plays an important role in the synthesis of neurotransmitters. Meeting folate needs can improve mood and mental functions.

112. Sources and deficiency Folic Acid, (Vitamin B9)
Liver, kidney, dark green leafy vegetables, meats, fish, whole grains, fortified grains and cereals, legumes, citrus fruits.
folate deficiency is one of the most common vit deficiencies.
Early symptoms are nonspecific and include tiredness, irritability, and loss of appetite.
Severe folate deficiency leads to macrocytic anemia, a condition in which cells in the bone marrow cannot divide normally and red blood cells remain in a large immature form called macrocytes. Large immature cells also appear along the length of the gastrointestinal tract, resulting in abdominal pain and diarrhea. Megaoblastic (macrocytic) anemia, abdominal pain, diarrhea, birth defects

113. Sources and deficiency Folic Acid, (Vitamin B9)
Pregnancy is a time of rapid cell multiplication and DNA synthesis, which increases the need for folate. Folate deficiency may lead to neural tube defects such as spina bifida (failure of the spine to close properly during the first month of pregnancy) and anencephaly (closure of the neural tube during fetal development, resulting in part of the cranium not being formed).
Seventy percent of these defects could be avoided by adequate folate status before conception, and it is recommended that all women of childbearing age consume at least 400 micrograms (μg) of folic acid each day from fortified foods and supplements. Other groups at risk of deficiency include elderly persons and persons suffering from alcohol abuse or taking certain prescription drugs.

114. Vitamin B12 (cyanocobalamin)
Vitamin B12 is found in its free-vitamin form, called cyanocobalamin, and in two active coenzyme forms.
Absorption of Vitamin B12 requires the presence of intrinsic factor, a protein synthesized by acid-producing cells of the stomach.
Vitamin B12 is absorbed in the terminal portion of the small intestine (the ileum).
Most of body's supply of Vitamin B12 is stored in the liver.
Vitamin B12 is efficiently conserved in the body, since most of it is secreted into bile and reabsorbed. This explains the slow development (about two years) of deficiency in people with reduced intake or absorption.
Vitamin B12 stable when heated and slowly loses its activity when exposed to light, oxygen, and acid or alkaline environments.

115. Function of Vitamin B12 (cyanocobalamin)
Vitamin B12 coenzymes help recycle folate coenzymes involved in the synthesis of DNA and RNA, and in the normal formation of red blood cells.
Vitamin B12 prevents degeneration of the myelin sheaths that cover nerves and help maintain normal electrical conductivity through the nerves.

116. Sources and deficiency
Sources include: Meat, fish, poultry, ready-to-eat fortified breakfast cereals, eggs, fermented dairy products (cheese, yogurt, etc).
Vitamin-B12 deficiency results in pernicious anemia (فقر الدم الوبيل), which is caused by a genetic problem in the production of intrinsic factor. When this occurs, folate function is impaired, leading to macrocytic anemia due to interference in normal DNA synthesis.
Unlike folate deficiency, the anemia caused by vitamin-B12 deficiency is accompanied by symptoms of nerve degeneration, which if left untreated can result in paralysis (الشلل) and death.
Since vitamin B12 is well conserved in the body, it is difficult to become deficient from dietary factors alone, unless a person is a strict vegan and consumes a diet devoid of eggs and dairy for several years.
Deficiency is usually observed when B12 absorption is hindered by disease or surgery to the stomach or ileum, damage to gastric mucosa by alcoholism, or prolonged use of anti-ulcer medications that affect secretion of intrinsic factor.
Age-related decrease in stomach-acid production also reduces absorption of B12 in elderly persons. These groups are advised to consume fortified foods or take a supplemental form of vitamin B12