Roshina Rabail M.Phil Human Nutrition and Dietetics

3. Group Members:
Roshina Rabail
Iqra Khan
Umrah zafar
Nimrah

4. What are Vitamins
 A vitamin is an organic compound and a vital
nutrient that an organism requires in limited
amounts.

5. Vitamin Classification

6. Introduction
Vitamin B3 also known as Niacin
Water soluble vitamin of B complex
Essential for growth and metabolism

7. Introduction
Niacin (vitamin B3) ~ a generic term for
nicotinic acid and nicotinamide.
Nicotinamide is important Component of
NAD and NADP
Essential for metabolism of protein, fat and
carbohydrates

8. Introduction
Niacin is also named as:
Vitamin PP (Pellagra Preventing Factor)
Vitamin G (Goldberger’s Name)
Goldberger (1915) observed for the first time
its existence as a pellagra-preventing factor

9. Chemistry
White crystalline substance
Soluble in water
Stable to air, heat, light, oxidation, acids,
alkalies and ordinary cooking methods.

10. Chemistry
Pyridine derivative
Simplest in structure among Vitamins
Can be synthesised in our body

11. Chemical Structure

12. Dietary Sources
Protein rich foods are rich in Niacin
Abundantly present in animal sources
Presence is poor in plant sources
Rich Sources are: Yeast, Liver, Salmon,
meat, peanuts, eggs

13. Dietary Sources
Plant Sources
Animal Sources

14. Endogenous Synthesis
Can be synthesised from Amino Acid
Tryptophan
This process requires presence of Vitamin B6
60mg Tryptophan provide 1mg Niacin

15. Endogenous Synthesis

16. Recommended Daily Allowance
Half of dietary requirement can be met from
its endogenous synthesis from tryptophan.

17. Metabolism
• Hydrolyzed in small intestine by
simple diffusion
• Absorbed in duodenum
Absorption
Conversion
• Enters circulatory system
• Enters cellsTransport
• Not stored in sufficient amounts
• Access amounts are converted
into coenzymes
• Remaining amounts are excreted
in urine
Storage
To nicotinamide occurs in kidney.
Brain and liver

18. Metabolism

19. Biochemical Functions
 A sufficient intake of vitamin B3 (niacin) is
important as it helps the body to
 convert food into glucose,
 used to produce energy
 produce macromolecules, including fatty
acids and cholesterol
 DNA repair and stress responses.
 Maintenance of normal skin and mucous
membranes

20. Biochemical Functions

21. Biochemical Functions
 Nervous System
 Proper functioning of nervous system
 Blood Vessels
 Dilates blood vessels
 Increases blood flow to peripheral capillary
circulation
 Hormones
 Production of estrogen, progesterone and
testosterone
 Nicotinic acid Lowers eleveated LDL and
increases lower levels of HDL

22. Biochemical Functions
 Energy derived from Redox reactions
 About 200 enzymes require Niacin
Coenzymes
 Mainly to accept or to donate electrons
 In Vitro studies provide evidence that NAD
influences the Cellular response to DNA
damage
 Helpful in this way to combat cancer
 It help delays the time needed to take
insulin in individuals with type 1 diabetes

23. Assessment of B3 status
 Urinary Excretion of Niacin Metabolites by
use of HPLC
 N-Methyl Nicotinamide
 2-Pyridone

24. Deficiency of Vitamin B3
 Early manifestations
 Anorexia, weight loss, weakness, irritability
 Later stages result in Pellagra (common in
women)
 Commonly referred to as 3 Ds
1. Dermatitis
 Inflammation of skin
2. Dementia
 Confused, disoriented
3. Diarrhoea
 Inflammation of mucous membranes
 4th D
 If not treated can lead to Death

25. Dermatitis
 Inflammation of skin
 Areas exposed to the
sunlight
 Arms, legs, V of neck
 Oral Manifestations:
 Oral mucosa is red and
painful
 Epithelium of entire
tongue is desquamated
 Tongue becomes red,
swollen
 Gingivitis

26. Dermatitis

27. Diarrhoea
 Gastrointestinal system is also disturbed
 Leading to mild to severe Diarrhoea
 Leads to weight loss
 Nausea and Vomiting
 Abdominal discomfort

28. Dementia
 Central nervous system is affected
 Confusion
 Memory loss
 Dizziness
 Hallucinations
 Insomnia

29. Treatment
 Oral administration of Vitamin B3
 50-150mg of nicotinamide
 Vitamin B Complex Supplementation

30. Niacin Supplements
2-3 Tab/D

31. Niacin Toxicity
 Large doses 150-300mg oral and 20mg
intravenous results in:
 Vasodilation
 Painful flush, Hives, Rash
 Excessive sweating
 Blurred Vision
 Liver damage
 Impaired Glucose Tolerance

32. References
 Food and Nutrition Toxicology by Stanley T. Omaye
 Handbook of Nutrition by Berdanier C., Dwyer J.,
Feldman E. B.
 Advanced Nutrition and Human Metabolism by Grooper
S. s., et al
 Munir G., Slideshare.com, University of Sindh
 www.nutri-facts.org