Water soluble vitamins
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Water -Soluble Vitamins. Thiamin. Thiamin consists of a central carbon to which is attached a six-member nitrogen containing ring and a five-member sulfur-containing ring. The name comes from thio , meaning "sulfur,"

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Water -Soluble Vitamins

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Water-Soluble Vitamins

Dr. May Hamdan


  • Thiamin consists of a central carbon to which is attached a six-member nitrogen containing ring and a five-member sulfur-containing ring.

  • The name comes from thio, meaning "sulfur,"

    and amine, referring to the nitrogen groups in the molecule.

  • participates in carbohydratemetabolism.

Dr. May Hamdan

  • The chemicalbond between each ring and the central carbon in thiamin is easily broken by prolonged exposure to heat, thus destroying the functions of the vitamin.

  • This destruction also occurs if food is cooked in alkaline solutions (pH> 8.0 ).

    Sometimes bakingsoda is added to the water in which fresh green beans are cooked to retain their bright green color; this practice is not recommended.

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Thiamin

  • Thiamin is absorbed mainly in the small intestine by active absorption process.

  • It is transported in the blood by red blood cells.

  • Storage is poor; only a small reserve is found in muscles and the liver.

  • Any excess intake is promptly excreted in the urine.

Dr. May Hamdan

Functions of Thiamin

  • in the metabolism of carbohydrates and of branched-chainamino acids(leucine, isoleucine, ,and valine ) .

  • Itspecificallyparticipates in the action of the enzynmetransketolase,

    Transketolaseistheenzymeresponsible for the formation of the five-carbon sugar components of RNA and DNA from the six-carbon glucose using a series of reactions called the pentose phosphate pathway.

    3.also plays a role in nerve function. It may aid in the synthesis of neurotransmitters and participate in the conduction of nerve impulses.

Dr. May Hamdan

Thiamin in Foods

  • Thiamin is found in a wide variety of foods, although generally in a small amount.

    Foods rich in thiamin are

  • pork products,

  • sunflower seeds,

  • legumes,

  • wheat germ,

  • And watermelon.

  • whole grains and enriched grains,

  • green beans,

  • asparagus,

  • Organ meats (such as liver ),

  • peanuts and other seeds,

  • and mushrooms.

Dr. May Hamdan

  • ThiaminNeeds

  • The RDA for thiamin for adult men and women is approximately 1.2 mg/day and 1.1mg/day, respectively.

Dr. May Hamdan

  • Thiamin-DeficiencyDiseases

  • The classic thiamin-deficiency disease beriberi has afflicted polished rice-eating populations forcenturies.

  • thediseasedevelops because thiamin is so important to energy metabolism and because all cells needenergy.

Dr. May Hamdan

  • three parts of the body are especially at risk to a deficiency of thiamin:

  • Onepartisthenervous system because nerve cells use a lot of energy compared to most cells.

  • In addition, the skin and GI tract are very sensitive to deficiencies of thiamin.

    The reason is that skin and GI tract cells are replaced frequently, which requires much energy input .

Dr. May Hamdan

The clinical signs of thiamin deficiency include:

  • anorexia,

  • weight loss,

  • apathy,

  • loss of short-termmemory,

  • confusion ,

  • GI tractdistress,

  • irritability,

  • and muscleweakness.

Dr. May Hamdan


  • The B vitaminniacinactuallyexists in twoforms-

  • nicotinicacid (niacin)

  • and nicotinamide(niacinamide).

  • The two coenzyme forms of niacin are :

  • nicotinamide adenine dinucleotide (NAD+) and

  • nicotinamideadeninedinucleotidephosphate (NADP+) .

    Both forms participate in numerous chemical reactions in the body.

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Niacin

  • Nicotinic acid and nicotinamide are readily absorbed from the stomach and the intestine by: active transport and passive diffusion, so that almost all niacin consumed is absorbed.

  • Niacin is transported from the liver to all tissues, where it is converted to its coenzyme forms, NAD+ and NADP+,

  • Niacin coenzymes are stored in the liver

  • and excess niacin intake is excreted as a variety of metabolic products in the urine

Dr. May Hamdan

Niacin in Foods

  • Niacin can be found in foods as the vitamin itself or as the amino acid tryptophan, which can be synthesized into niacin by the body.

    Rich sources of niacin are

  • mushrooms,

  • wheat bran ,

  • tuna (as well as other fish),

  • chicken,

  • turkey,

  • asparagus,

  • and peanuts.

  • Animal proteins which are especially rich in tryptophan.

    Unlike some other water-soluble vitamins, niacin is very heat stable, and little is lost in cooking.

Dr. May Hamdan

  • NiacinNeeds

    For adult men the RDA for niacin is 16 mg/day, and for adult women it is 14 mg/day

  • Function:

    participate in numerous cellular metabolic pathway.

Dr. May Hamdan


  • In the early 1900s, the niacin deficiency disease pellagra was epidemic in the southeastern United States.

  • Pellagra was prevalent because the diet among the poor people consisted of cornmeal which is a poor sources of niacin.

  • Pellagracauses symptoms that are remembered as the three Ds:

  • dermatitis,

  • diarrhea,

  • and dementia.

    If untreated, a fourth “D” results—death.

Dr. May Hamdan

Excess of niacin

  • megadoses of niacinmayhave adverse effects, including:

  • flushing of the skin (the initial adverse effect ).

  • itching,

  • GI tract upsets (such as nausea and vomiting),

  • and liver damage.

Dr. May Hamdan


  • Pantothenic acid is part of coenzyme A (CoA), which plays a vital role in energy metabolism.

    Absorption, Transport, Storage, and Excretion of PantothenicAcid

  • It is released during digestion in the small intestine, then absorbed there.

  • Storage is minimal and is as the coenzyme form in the liver.

  • Excretion of pantothenic acid is via the urine.

Dr. May Hamdan

  • Functions of PantothenicAcid

    Coenzyme A is essential for the formation of ATP from the breakdown of carbohydrate, protein, alcohol, and fat.

  • PantothenicAcid in Foods

  • The Greek word pantothen, meaning " from every side," reflects the ample supply of pantothenic acid in foods,

    Rich sources of pantothenic acid are

  • mushrooms,

  • liver,

  • peanuts,

Dr. May Hamdan

  • eggs,

  • broccoli,

  • milk.

  • meat,

  • And many vegetables .

Dr. May Hamdan


  • For adults, the Adequate Intake set for pantothenic acid is 5mg/day.


  • A deficiency of pantothenic acid might occur in cases of alcoholism in which a vary nutrient deficientdietisconsumed.

    symptoms of Deficiency:

  • headache,

  • fatigue,

  • impaired muscle coordination ,

  • and GI tract disturbances.

Dr. May Hamdan


  • Riboflavin contains three linked six-memberedrings, with a sugar alcohol attached to the middle ring.

  • The name comes from its yellow color (flavin means "yellow" in Latin ).

  • Riboflavin is a component of two coenzmes that play key roles in energy metabolism:

  • flavinmononucleotide (FMN)

  • and flavinadeninedinucleotide (FAD)

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Riboflavin

  • In the stomach, HCIreleases riboflavin from its bound forms.

  • Absorption is primarily via:

  • active transport

  • or facilitated diffusion

    in the small intestine.

  • In the blood, riboflavin is transported by protein carriers.

Dr. May Hamdan

  • Riboflavin is converted to its coenzyme forms, FMN and FAD, in most tissues, but mainly in:

  • the small intestine,

  • liver,

  • heart ,

  • and kidney.

  • A small amount of riboflavin is stored in:

  • the liver,

  • kidneys,

  • and heart .

Dr. May Hamdan

  • Any excess intake is excreted in the urine.

  • For people who take excessive amounts in supplement form, riboflavin imparts a bright yellow color to the urine.

Dr. May Hamdan

Functions of Riboflavin

  • Riboflavin coenzymes are involved in many enzyme reactions, a number of which are critical to energy metabolism.

  • participates in the breakdown of fatty acids

  • synthesize the amino acid tryptophan into the B vitamin niacin,

  • and participate in folatemetabolism

Dr. May Hamdan

Riboflavin in Foods

  • The richest source of riboflavin is milk and milk products.

  • Rioboflavin intake typically comes from:

  • white bread,

  • rolls , enriched

  • and crackers

  • eggs

  • and meat.

Dr. May Hamdan

Foods rich in riboflavin are:

  • liver,

  • mushrooms,

  • spinach

  • and other green leafy vegetables,

  • broccoli,

  • asparagus,

Dr. May Hamdan

  • Exposure to lightcauses riboflavin to break down rapidly.

    To prevent this light-induced breakdown, paper cartons-not glass- should be used in packaging riboflavin-rich foods such as milk, milk products, and cereals.

  • RiboflavinNeeds

  • The RDA for riboflavin is 1.1 to 1.3 mg/day for adults.

Dr. May Hamdan


The signs and symptoms associated with riboflavin deficieny (technically called ariboflavinosis) include:

  • inflammation of the tongue,

  • cracking of tissue around the corners of the mouth (cheilosis),

  • inflammation of the mouth and throat ,

  • Various eye and nervous system disorders,

  • confusion

  • and headaches

Dr. May Hamdan


  • Biotin is commonly found in two forms in foods:

  • the free vitamin

  • and the protein-bound coenzyme form, called biocytin.

    In the formation of biocytin, biotin forms a bond with the amino acidlysine in a protein.

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Biotin

  • Biotin is absorbed from the small intestine , whereas the biocytinform is not absorbed until the enzyme biotinidase, which is present in the small intestine, cleaves the bond linking biotin to a protein, releasing the free vitamin.

  • Biotin is stored in small amounts in:

  • the muscles,

  • liver,

  • And brain.

  • Biotin excretion is mostly via the urine

Dr. May Hamdan

Functions of Biotin

  • biotin is involved in important metabolic pathways,

  • fatty acid synthesis,

  • and amino acid catabolism

Dr. May Hamdan

Sources of Biotin

Sources of biotinincluded:

  • Wholegrains,

  • Eggs,

  • nuts,

  • and legumes

    A protein called avidin in raw egg whites binds biotin and inhibits its absorption.

    cooking denatures avidin in such a way that it can no longer bind biotin and becomeavailable for absorption.

Dr. May Hamdan

  • BiotinNeeds

  • The Adequate Intake for biotin for adults of 30 μg/day.


  • Overall a biotin deficiency is rare.

    Signs and symptoms of deficiency:

  • a skin rash

  • hair loss.

  • neurological disorders,

  • and impaired growth.

Dr. May Hamdan

Vitamin B-6

  • The generic name for the vitamin is B-6 or pyridoxine.

  • Vitamin B-6 is actually a family of three compounds:

  • pyridoxal,

  • pyridoxine,

  • and pyridoxamine

    All three forms can be phosphorylated to the active vitamin B-6 coenzymes,

  • the primary one being pyridoxal phosphate (PLP).

    The coenzymes participate in numerous metabolic reactions.

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Vitamin B-6

  • The free forms of vitamin B-6 can be absorbed bypassive means.

  • Vitamin B-6 as such is transported to the liver via the blood. where ultimately the three forms of the vitamin are phosphorylated.

  • The coenzyme forms is absorbed by passive diffusion.

Dr. May Hamdan

  • The main storage of vitamin B-6 in the body takes place in muscle tissue.

  • Excess vitamin B-6 is generally excreted in the urine

Dr. May Hamdan

Functions of Vitamin B-6

  • Vitamin B-6 as PLP plays a coenzyme role in more than 100 enzymatic reactions, almost all of which involve nitrogen-containing compounds. Forexample:

  • Amino AcidMetabolism

  • A major role of PLP is to participate in amino acid metabolism.

    For example PLP participates in reactions to form nonessential amino acids via transamination. (If we didn't have the services of PLP, every amino acid would be essential because it would have to be supplied by the diet).

    PLP acts to loosen the bond between the nitrogen group ( NH2) and the central carbon on the amino acid, allowing it to be removed and to give a new amino acid.

Dr. May Hamdan


  • PLP is part of the enzyme that releases glucose from glycogen during glycogen breakdown.

  • Therefore, vitamin B-6 helpsmaintainbloodglucoseconcentrations.

    ((Thisactionis an exception to the rule that vitamin B-6 works with nitrogen-containing compounds))

Dr. May Hamdan


  • Not only are amino acids used to build proteins, but they are also used to make nonprotein nitrogen compounds.

  • Many of these compounds are neurotransmitters, which are important for brain function.

  • PLP plays in the synthesis of the neurotransmitters, like:

  • serotoninfromtryptophan,

  • dopamine (DOPA) fromtyrosine,

Dr. May Hamdan

4. VitaminFormation

  • PLP participates in the conversion of the amino acid tryptophan to the B-vitamin niacin.

    Vitamin B-6 in Foods

    Vitamin B-6 is stored in the muscle tissues of animals, and thus:

  • meat,

  • fish,

  • and poultry

    are some of the best sources of this vitamin B-6

Dr. May Hamdan

  • whole grains also are good sources of vitamin B-6.

  • Most fruits and vegetables are not good vitamin B-6 sources, but there are some exceptions:

  • carrots,

  • potatoes,

  • spinach,

  • bananas,

  • and avocados.

Dr. May Hamdan

  • Vitamin B-6 Needs

    The adult RDA for vitamin B-6 is 1.3 to 1.7 mg/day.

    Vitamin B-6-Deficiency Diseases

    The symptoms of vitamin B-6 deficiency include

  • dermatitis,

  • Convulsions,

  • depression,

  • and confusion.

Dr. May Hamdan


  • The word folate derives from the Latin word for leaf (folium) because dark green, leafy vegetables are ,among the best sources of this vitamin.

  • What we call folate today was known earlier as either folic acid or Folacin.

  • Today, the term folate is a generic name for the vitamin and also refers to the various forms of the vitamin found naturally in foods.

  • Folic acid refers specifically to the form of the vitamin found in supplements and fortified foods.

Dr. May Hamdan

Folate consists of three parts:

  • pteridine,

  • para-amino benzoic acid (PABA),

  • and one or more molecules of the amino acid glutamic acid (glutamate).

    If only one glutamate molecule is present, it is called folatemonoglutamate.

    In food about 90% of the folate molecules have three or more glutamates attached and are known as folatepolygltuamates .

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Folate

  • To be absorbed, folatepolyglutamates must be broken down (hydrolyzed) to the monoglutamate form in the GI tract.

  • Themonoglutamateform is then actively transported across the intestinal wall by passive diffusion.

  • is transported to the liver via the blood, where ultimately is stored.

  • and excessfolatintake is excreted as a variety of metabolic products in the urine

Dr. May Hamdan

Functions of Folate

  • Needed for the synthesis of DNA

  • and the metabolism of various amino acids

  • Another key function of folate is the formation of neurotransmitters in the brain,

  • Meeting folate needs can improve the depressed state seen in some Cases of mental illness.

Dr. May Hamdan

  • Becausefolate is needed for DNA synthesis, folate deficiency may be induced during a common form of cancer therapy.

    One example is the cancer drugmethotrexate. It inhibits folate metabolism.

    When the drug is taken in high doses, it reducesDNA synthesis throughout the body by interfering with folate metabolism.

    This reduction in DNAsynthesis can stop the growth of cancer cells, but it also affects other rapidly growingcells, such as intestinal cells and red blood cells.

Dr. May Hamdan

Folate in Foods

  • Thebestsources, from the standpoint of amount and availability, are:

  • legumes,

  • dark green leafy vegetables in general.

  • liver,

  • fortified ready to eat breakfast cereals and other grain products,

Dr. May Hamdan

  • Other, less rich sources of folate include:

  • eggs,

  • dried beans,

  • And oranges.

    Folate Needs

  • The RDA for folate for adults is 400μg/day.

Dr. May Hamdan


Folate deficiency can result from:

  • a low intake;

  • inadequate absorption, which often is associated with alcoholism;

  • increased need, most commonly occurring in pregnancy;

Dr. May Hamdan

  • Compromised utilization,

    typically associated with vitamin B-12 deficiency; because a vitamin B-12 coenzyme is needed to recycle a folate coenzyme for repeatedfunction.

  • use of certain chemotherapy medications;

  • and excessiveexcretion, linked to long-standing diarrhea.

Dr. May Hamdan

Megaloblastic Anemia

  • A deficiency of folate first affects cell types that are actively synthesizing DNA; Such cells have a short life span and rapid turnover rate.

  • Thus, one of the major folatedeficiencysigns is changes in the early phases of red blood cell synthesis, because these cells turn over every 120 days.

  • without folate, the precursor cells cannot divide normally to become mature red blood cells because they cannot form new DNA.

Dr. May Hamdan

  • The cells grow larger because there is continuous formation of RNAleading to increased synthesis of protein and other cell components to make new cells.

  • However, when it is time for the cells to divide, they lack sufficient DNA for normal division.

  • The cells thus remain in a large, immature form, known as megaloblasts

Dr. May Hamdan

Neural TubeDefects

  • A maternal deficiency of folate has been linked to the development of neural tube defects in the fetus.

  • These defects include:

  • spina bifida (malformed vertebra leads to bulging of spinal cord or spinal fluid through the back)

  • and anencephaly (small or missing brain),

Dr. May Hamdan

  • Victims of spinabifidamayexhibit:

  • Paralysisشَلَل,

  • Incontinenceسلس البول,

  • and learning disabilities.

  • Children born with anencephaly die shortly after birth .

Dr. May Hamdan

Vitamin B-12

What we call vitamin B-12 includes:

  • the free vitamin cyanocobalamin

  • and two active coenzmes; methylcobalamin and 5-deoxy adenosylcobalamin.

  • Thisvitamin has a complexstructurecontainingthe mineral cobalt

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Vitamin B-12

  • Absorption of vitamin B-12 is very complex.

  • In the stomach, vitamin B-12 in food is released from proteins by the action of HCI and pepsin in gastric juice.

  • The free B-12 binds to a protein, designated R-protein, that originates in the salivary gland in the mouth and is swallowed along with the food.

Dr. May Hamdan

  • The R-protein/vitamin B-12 complex travels to the small intestine, where it encounters pancreaticprotease enzymes (e.g., trypsin) which release the vitamin.

  • Awaiting the free B-12 is intrinsic factor, a proteinlike compound produced by the parietal cells.

  • Theresultingintrinsicfactor/vitamin B-12 complex travels to the terminal portion of the small intestine, the ileum, where it attaches to special receptor cells on the brush border.

Dr. May Hamdan

  • Severalhourslater, cells within the ileum absorb vitamin B-12 and transfer it to a specific blood transportprotein, transcobalamin II.

  • Thisvitamin-proteincomplexentersthe portal vein then to the liver and eventually the bone marrow and red blood cells.

Dr. May Hamdan

  • Absorption of vitamin B-12 can be disrupted by numerous defects, including the following:

  • Absence or defective synthesis of R-protein, pancreatic proteases, or intrinsic factor.

  • Defective binding of the intrinsic factor/vitamin B-12 complex to receptor cells in theileum

  • Absence (or surgical removal) of much or all of the ileum and stomach.

Dr. May Hamdan

  • Bacterial overgrowth of the small intestine

  • Tapeworminfestation

  • Use of certain anti-ulcer medications that significantly reduce acid production by the parietal cells.

  • Chronicmalabsorptionsyndromes,

Dr. May Hamdan

  • vitamin B-12 is stored in the liver.

  • In the body, little vitamin B-12 is excreted via the urine.

Dr. May Hamdan

Functions of Vitamin B12

  • the maintenance of myelin, which insulates nerves and is necessary for nervetransmission.

  • to generate energy from fatty acids

  • and for a reaction that synthesizes the amino acid methionine from homocysteine.

Dr. May Hamdan

  • Sources of viramin B-12 include animal products such as:

  • meat

  • poultry,

  • seafood,

  • And eggs.

  • Especially rich sources of vitamin B-12 are organ meats (liver, kidneys, and heart)

  • Another source of vitamin B-12 is dairy products.

Dr. May Hamdan

  • Vitamin B-12 Needs

  • The RDA of vitamin B-12 for adults is 2.4μg/day.

Dr. May Hamdan

Vitamin B-12-Deficiency Diseases

  • Researchers in mid-nineteenth-century in England noted a form of anemia that causes death within 2 to 5 years of initial diagnosis.

     They called this disease pernicious anemia pernicious literally means " leading to death“ .

  • this anemia is caused by genetic problem in the production of intrinsic factor that is needed forvitamin B-12 absorption,

Dr. May Hamdan

  • this disease looks like a folate-deficiency anemia,

    becausevitamin B-12 deficiency impairs folate function.

  • For patients with either a folateorvitamin B-12 deficiency ,manymegaloblasts are seen in theblood.

  • the cause of the anemia is an interference with normal synthesis of DNA.

Dr. May Hamdan

 B-12 deficiency also produces nerve degeneration, which can be fatal.

  • Many neurological complications produce sensory disturbances in the legs, such as:

  • tingling

  • and numbness

    collectively referred to as paresthesia.

     many mental problems exist as well, such as:

  • loss of concentration

  • loss of memory,

  • and dementia

Dr. May Hamdan

  • Infants who are breastfed by vegetarian or vegan mothers can develop vitamin B-12 deficiency, accompanied by the following symptoms:

  • anemia

  • and long-term neurological problems

    The problems may have their origins during pregnancy if the mother is deficient in vitamin B-12.

Dr. May Hamdan

  • Adult vegetarians can also become vitamin B-12 deficient,

    though if an adult becomes a vegetarian, vitamin B-12 stores in the liver can delay a severe deficiency for a long time (even years).

    Vegetarians have several options for obtaining vitamin B-12:

  • Ifthey are not ((vegan)) they can obtain vitamin B-12 from dairy products. Eggs also contain some vitamin B-12.

  • In addition, vegetarians can take a supplement that contains vitamin B-12 or eat food products fortified with vitamin B-12

Dr. May Hamdan


  • For many years, choline was often included in supplements as a supposed B-vitamin.

  • However, most nutrition experts claimed that choline was not a vitamin at all because the body makes enough of it to meet its needs.

  • Recent research has contradicted some of this attitude. Apparently in some cases, the body's production of cholineis not sufficient tocoverrequiremems.

Dr. May Hamdan

  • Cholinehas thefollowingcharacteristicsratherthanothervitamins:

  • does not have a coenzyme function,

  • and the amount of choline in the body is much greater than the amount of a typical B-vitamin.

    Absorption, Transport, Storage, and Excretion of Choline

  • Choline is absorbed from the small intestine by way of transport proteins.

  • Choline is taken up rapidly by the liver from the portal vein.

  • All tissues contain some stores o f choline.

  • Some choline is excreted in the urine,

Dr. May Hamdan

Functions of Choline

  • as a precursor for acetylcholine, a neurotransmitter associated with:

  • attention,

  • learning and memory

  • muscle control,

    2.Choline is a component of phospholipids, such as lecithin, a major component of the cell membrane and blood lipoproteins.

    3.to form methionine from homocystein.

Dr. May Hamdan

Choline in Foods

  • Choline is widely distributed in foods, mostly in the form of lecithin in membranes.

  • Milk,

  • Liver,

  • eggs,

  • and peanuts

    are rich sources.

Dr. May Hamdan

  • CholineNeeds

    The Adequate Intake of choline for adult men is 550 mg/day; for adult women425 mg/day.

  • CholineDeficiencyDiseases

    CholineDeficiencydeveloped liverdamage.

Dr. May Hamdan

Vitamin C

  • Vitamin C, also known as ascorbic acid,

  • is involved in many process in the human body, primarily as an electron donor.

  • most animals make ascorbic acid, so ascorbic acid is a vitamin only for humans, plus a few other animals.

Dr. May Hamdan

Absorption, Transport, Storage, and Excretion of Vitamin C

  • Absorption of vitamin C occurs in the small intestine by means of active transport and by facilitated diffusion.

  • The amount o f vitamin C varies widely by tissue.

    High concentrations are found in

  • the pituitary and adrenal glands,

  • white blood cells,

  • eyes,

  • and brain,

    The lowestconcentrations are in the blood and saliva.

Dr. May Hamdan

Functions of Vitamin C

  • Vitamin C performs a variety of important cell functions.

  • It does so primarily by acting as electrondonor (reducingagent).

    a reducing agent: is a substance that donates electrons and, in turn, becomes oxidized (loses electrons).

Dr. May Hamdan

  • CollogenSynthesis:

  • Collagen: is the fibrous protein that gives strength to connective tissue. Collagen fibers are critical to the structure of bone and blood vessels, and they are essential in woundhealing.

Dr. May Hamdan

  • Collagenconsists of three-polypeptidechains wound together to form a triple helix.

  • To get the three strands in the right shape to form the triple helix, vitamin C is needed.


  • vitamin C can be an antioxidantby donating electrons to free radicalsso that they become stable.

Dr. May Hamdan

3.Synthesis of Other vital Compounds

  • Carnitine is a transport compound that moves fatty acids from the cytoplasm into the mitochondria for energy production.

  • is necessary for the biosynthesis of thyroxine (the thyroid hormone)

  • and many other nervous system components.

Dr. May Hamdan


  • White blood cells, part of the immune defenses of the body, contain the highest vitamin C concentration of all body constituents.


  • facilitatesthe intestinal absorption of nonhemeiron (iron that is not in hemoglobin) because of the conversion of iron in the GI tract toferrousiron (Fe2+).

Dr. May Hamdan

Vitamin C in Foods

  • All fruits and vegetables contain some vitamin C, but certain fruits and vegetables provide much more than others. Such as

  • Citrus fruits,

  • Potatoes,

  • and green vegetables

  • Animal products and grains are generally not good sources.

Dr. May Hamdan

  • Vitamin C Needs

  • The RDA for vitamin C for adult men is 90 mg/day; for adult women it is 75 mg/day.

  • Vitamin C DeficiencyDiseases:

    A deficiency of vitamin C prevents the normal synthesis of collagen,

    thus causing widespread and significant changes in connectivetissues throughout the body,

Dr. May Hamdan

scurvy, the deficiency disease of vitamin C.

Symptoms of scurvy :

  • fatigue

  • and pinpoint hemorrhages around hair follicles on the back of the arms and legs.

    these hemorrhages are the most characteristic sign of scurvy.

  • In addition, there is bleeding in the gums and joints.

  • impaired wound healing,

  • bone pain,

  • fractures, and diarrhea.

  • Psychological problems, such as depression are common in advanced scurvy.

Dr. May Hamdan

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