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Niacin: Benefits, Deficiency, and Sources

Niacin, also known as vitamin B3, plays important roles as a coenzyme in the body. It exists in the active forms NAD and NADP. A deficiency in niacin causes the disease pellagra, whose symptoms include dermatitis, diarrhea, and dementia. Niacin is obtained through the diet by eating foods like yeast, rice, liver, peanuts and meat, and it can also be synthesized in the body from the amino acid tryptophan. Maintaining adequate niacin levels is important for overall health.

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209 views14 pages

Niacin: Benefits, Deficiency, and Sources

Niacin, also known as vitamin B3, plays important roles as a coenzyme in the body. It exists in the active forms NAD and NADP. A deficiency in niacin causes the disease pellagra, whose symptoms include dermatitis, diarrhea, and dementia. Niacin is obtained through the diet by eating foods like yeast, rice, liver, peanuts and meat, and it can also be synthesized in the body from the amino acid tryptophan. Maintaining adequate niacin levels is important for overall health.

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Chemistry Ustad
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Niacin

Vit B3
Introduction
• Niacin is nicotinic acid
• Its co-enzymes are NAD and NADP+ active
form of vit b3
• It is associated with disease PELLAGRA
• Nicotin from tobacco source when oxidized is
converted in to nicotinic acid
• Deficiency of niacin causes pellagra was first
discovered by Goldbeger
Chemistry
• Niacin is a pyridine derivative. Structurally, it is
pyridine3-carboxylicacid
• The amide form of niacin is known as nicotine
amide
• Tryptophan is essential amino acid important
for synthesis of nicotine amide from nicotine
• Sixty milligrams of tryptophan is equivalent to
I mg of niacin for the synthesis of niacin
coenzyme
• Glutamine donates amide group. ln the
structure of the coenzyme
Absorption and transport
• Nicotin amide, liberated on the degradation of
NAD+ and NADP+ is mostly excreted in urine
as N-methyI nicotin amide
• Niacinamide is the active form of the vitamin
• It is synthesized from enzyme tryptophane
Metabolic role
Niacin Deficiency
• Pellagra
Deficiency of niacin leads to the clinical condition
called pellagra. Pellagra is an Italian word, meaning
"rough skin". Pellagra is caused by the deficiency of
Tryptophan as well as Niacin. Pellagra is seen more
in women; this may be because tryptophan
metabolism is inhibited by estrogen metabolites.
The symptoms of pellagra are
1. Dermatitis 2. Diarrhea 3. Dementia
RDA
• The daily requirement of niacin for an adult is
15-20mg and for children is around 10-15 mg
• Pregnancy and lactation in women icreases
niacin requirements
Dietary Sources of Niacin
• The richest natural sources of niacin are dried
yeast, rice, liver, peanut, whole cereals, meat
and fish. About half of the requirement is met
by the conversion of tryptophan to niacin.
About 60 mg of tryptophan will yield 1 mg of
niacin.
Therapeutic Use of Niacin
• Nicotinic acid inhibits the flux of free fatty
acids from adipose tissue; so acetyl CoA pool
is reduced; and hence serum cholesterol is
lowered.

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