Vit B3 NIACINE.pptx

1. Dr. Anuj Singh
Asst. Professor
Community Medicine Dept.
UIMS, Prayagraj

2. Contents:-
Source
Function
Deficiency
Prevention
&

3. History
• The term niacin (vitamin B3) is considered a
generic term for nicotinic acid and nicotinamide
(also called niacinamide).
• The vitamin was once called the anti–black
tongue factor because of its effect in dogs.
• Pellagra was especially prevalent in the Southern
United States where corn (which contains a
relatively unavailable form of niacin) was a main
dietary staple in the early 1900s.In 1937
• Elvehjem isolated the vitamin, for cure of both
pellagra and black tongue.

4. Vitamin-B3 Niacin
• Vitamin B3 or Niacin is a water-soluble B
vitamin, which is also known as:
“Pellagra preventing factor"
• Niacin is pyridine -3-carboxylic acid
• It is a odourless white crystalline compound
• It is stable to heat & acid

5. • The two most common forms of niacin in food
and supplements are nicotinic acid and
nicotinamide
• The body can also convert-
Tryptophan (AA) Nicotinamide
• Nicotinamide is the amide form of nicotinic acid
• 1 mg of niacin is formed from 60 mg of
tryptophan

6. • Niacin is water-soluble so that excess amounts
the body does not need are excreted in the
urine.
• Niacin works in the body as a coenzyme, with
more than 400 enzymes dependent on it for
various reactions.
• Niacin helps to convert nutrients into energy,
create and repair DNA, and exert antioxidant
effects.

7. Functions:-
1) Niacin is important for proper blood
circulation.
2) For healthy functioning of nervous system.
3) It maintains the normal functions of GI tract.
4) It is essential for the metabolism of proteins
and carbohydrates.

8. 5) It helps to maintain a healthy skin.
6) It helps to increase the flow of blood to the
peripheral capillary system.
7) This vitamin also essential for synthesis of the
sex hormones namely oestrogen, progesterone
testosterone as well as cortisone, thyroxin and
insulin.
Functions cont..

9. • Dietary sources:
• Rich sources of niacin are liver, meat, fish,
legumes, whole grain cereals and dried yeast, tea &
coffee
• Poor sources:
• Fruits, vegetables and corn
• Zein is major protein present in corn
• Zein is very low in tryptophan –provitamin of niacin

10. RDA
Men 15-20 mg
Women 13-15 mg
Lactating women 20 mg
Children 8-15 mg
Infants 650 mcg

11. Metabolism
• Absorption:
• It is absorbed from upper small intestine
• It occurs by simple diffusion
• Transport:
• It enters portal circulation, reaches general circulation
& enters all cells
• Storage:
• It is not stored in significant amounts in tissues
• In tissues, it gets converted into its coenzymes

12. Deficiency:
Causes:
1. Inadequate intake
2. Alcoholism
3. Impaired absorption
4. Antivitamins: Chronic administration of drugs such as
isoniazid (used in T.B) & 6-mercaptopurine (Leukemia)

13. 5. Pyridoxine deficiency:
• It associated with impaired conversion of tryptophan to
niacin due to decreased activity of PLP dependent
enzyme, kynureninase
6. Hartnump disease:
• Associated with defective absorption of tryptophan

14. Deficiency symptoms
• A mild deficiency of niacin may result in -
• Coated tongue.
• Sores in the mouth.
• Irritability.
• Nervousness.
• Skin lesions.
• Diarrhoea.
• Memory loss.
• Insomnia.
• Chronic headaches.
• Digestive disorders.
• Anaemia.

15. Severe prolonged deficiency may cause
 Neurasthenia (weakness of the nerves),
 Mental disturbances.
 Depression.
 Mental dullness.
 Disorientation.

16. • Deficiency of niacin leads to the clinical condition
called pellagra
• Pellagra is caused by the deficiency of tryptophan &
niacin
• More common in women – because tryptophan
metabolism is inhibited by estrogen metabolits
• Symptoms:
• Dermatitis: In early stages, bright red erythema
occurs, in feet, ankles and face

17. • Increased pigmentation around the neck is known as
Casal’s necklace
• Dermatitis is precipitated by exposure to sunlight
• Diarrhea:
• Diarrhea may be mild or severe with blood & mucus
• Leads to weight loss
• Nausea & vomiting
• Dementia: Irritability, inability to concentrate & poor
memory

18. Pellegra. Niacin deficiency.
Dermatitis, diarrhea, dementia.

22. CASAL NECKLACE

23. Same patient after niacin treatment.

24. Healing and therapeutic
properties

25. 1. Pellagra
• Administration of small amounts of up to
10mg or 10000 mcg per day is sufficient to
cure endemic pellagra.

26. 2. High blood pressure
• Niacin has been used as vasodilator to dilate
blood vessels and to correct blood pressure
changes.

27. 3. Heart-Related Disorder
• Niacin has been found to provide relief in
angina pectoris.
• It has also been found useful in case of
cerebral thrombosis caused by blockage of
blood vessels of the brain due to clots of blood.

28. 5. High Blood Cholesterol
• Niacin has proved to have a remarkable effect
in reducing high blood Cholesterol

29. 4. Diarrhoea
• The administration of niacin in therapeutic
doses along with other B vitamins can cure
such ailments.

30. 6. Migraine
• Niacin has been found useful in treating
migraines.
• Migraine can be cure by taking large doses of
niacin.

31. Precautions
• The use of large doses of niacin for long
periods cause release of histamine.

32. Toxicity:
Toxicity when eating foods containing niacin is
rare, but can occur from long-term use of
high-dose supplements. A reddened skin flush
with itchiness or tingling on the face, arms,
and chest is a common sign. Flushing occurs
mainly when taking high-dosage supplements
in the form of nicotinic acid, rather than
nicotinamide.

33. • Toxicity: cont..
• Other signs:
• Dizziness
• Low blood pressure
• Fatigue
• Headache
• Upset stomach
• Nausea
• Blurred vision