Vitamins & Minerals New

7/30/2019 Vitamins & Minerals New

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Vitamins & MineralsNiacin (B3) & Selenium


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Vitamin- Niacin (B3)


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Sources

- Tuna, Beef, Chicken, Turkey,

Pork and Other Meats.

Cereal Grains, SeedsAnd Legumes

Tea and coffee also contain some amount


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Approximately 200 enzymes require NAD,NADP as H donor or electron acceptor.

NADP(major role): transfer of electrons frommetabolic intermediates to electron transport

chain to produce ATP.


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Glycolysis Oxidative decarboxylation of pyruvate TCA Beta oxidation of fatty acids Oxidation of ethanol Degradation of ketone bodies

Degradation of amino acids Catabolism of pyridoxal to excretory productpyridoxic acid

Oxidation of glutamate


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in biosynthetic pathway

( fatty acids, cholesterol, steroid hormones etc)

dehydro ascorbate

(oxidized form of vit C)

for glutathione reductase

of folate to dihydrofolate andtetrahydrofolate (active form of folate)


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In protein synthesis NAD acts as a(ADP-ribose)

for post translational modification of proteins ,notably proteins of the chromosomes. Here NAD

does not serve its usual role as an oxidant orreductant. When ADP- ribosyl moiety of NAD isdonated to the acceptor protein , a molecule ofnicotinamide is discharged.

In case of some proteins ,are transferred to proteins forming a

poly(ADP-ribose) grp. This is seen duringand


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a molecule used in cell

signalling NAD serves as a donor of an ADP-ribose grp for the synthesis of cyclic ADP ribose.this works within the cell as cell-signallingmolecule , provokes release of calcium ions from

an internal storage site.

NADP(and not NAD) is converted in the cell tonicotinic acid adenine dinucleotide phosphate

(NAADP), which also seems to be as a cellsignalling molecule and to provoke a burst ofintracellular ions.


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Characterized by 4 Ds-and .

These symptoms can occur in any order :-: similar to sunburn at first and appears on

areas exposed to sun. Skin changes include cracking of theskin, hyperkeratosis and hyper pigmentation. Dermatitis

due to B deficiency is characterized by- Skin changes occur symmetrically on the neck,

face, hands, arms, and legs, in areas exposed to sun. Rashis initially red and latter on becomes dry.


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and other signsinclude angular stomatitis, cheilosis and glossitis.

The buccal musosa , colon, esophagus and stomachare grossly affected. Dysfunction signs in the G.Itract are manifested by nausea, vomiting, achlor

hydra ( HCl defeciency ) and diarrhoea.-neurological manifestations include

peripheral neuritis, paralysis of extermities, dementiaor delerium

depression, headache, dizziness,irritability and tremors.

is always a manifestation of pellagra

responds to iron therapy.


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Brewer's yeast and wheat germ, liver, butter, fish(mackerel, tuna, halibut, flounder, herring, smelts)and shellfish (oysters, scallops, and lobster), garlic,whole grains, sunflower seeds, and Brazil nuts areall good sources of selenium.

Selenium levels in food depend on how muchselenium was in the soil where the food was grown.

Selenium is destroyed when foods are refined orprocessed. Eating a variety of whole, unprocessedfoods is the best way to get selenium in your diet


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Functions:-( )

Selenium into selenoproteinsand it occurs during protein synthesis.

As selenite selenium becomes incorporated into.

All cells and animal plasma contain glutathioneperoxidase . GPX activity

in plasma and cells in, and selenium supplementation

restores activity to normal.


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(leukocytes andmacrophages) in these cells , peroxides are by products of

oxidative destruction of foreign matter thereforethese cells from being destructive. Another site , acts in an

enzyme reduces F.A. peroxideformation and ratio of prostacyclin (antiaggregating

factor) to thromboxane (proaggregant) becomesincreased. Therefore andatherosclerosis and .

GPX cell membranes, composed ofunsaturated fatty acids that may be susceptible to

oxidation. Therefore GPX for .;- implicated in aging process

and as an initiating event in tumor development .adequate SI levels assure that sufficient GPX will beavaliable and protect against tumor development and

aging process.


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Selenium deficiency is in people.

However, selenium deficiency may occur when aperson is fed through a vein (IV line) for longperiods of time.


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- Keshan disease is caused bya lack of selenium. This leads to an abnormality

of the heart muscle. Keshan disease causedmany childhood deaths.

, which results in joint

and bone disease. whichresults in mental retardation


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Srilaxmi

Human nutrition- Bamji

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