Nicotinic Acid (Niacin) - Vitamin B5

The Fat Soluble Vitamins
· Vitamin A
· Vitamin D
· Vitamin E
· Vitamin K

The Water Soluble Vitamins
· The B-Group Vitamins
· Thiamine - Vitamin B1
· Riboflavin-Vitamin B2
· Pantothenic Acid - Vitamin B3
· Biotin - Vitamin B4
· Nicotinic Acid (Niacin) - Vitamin B5
· Pyridoxine - Vitamin B6
· Cyanocobalamin - Vitamin B12
· Ascorbic Acid - Vitamin C

Niacin is a white crystalline substance readily soluble in water and resistant to heat oxidation and alkalis.

Physiological Action
The essential activity of nicotinic acid is as a component of the NAD molecule that is one of the enzymes concerned with tissue oxidation. The human body is not entirely dependent on dietary sources of nicotinic acid as some can be synthesised from the amino acid tryptophan. Niacin in foods is generally calculated as nicotinic acid equivalent ie. the nicotinic acid content and the tryptophan content of foods are added to estimate the value of niacin in that food. There are toxic symptoms of dermatitis in skin exposed to the sun, diarrhoea and dementia, when niacin is given in mega doses.

Dietary Sources
Nicotinic acid has no relationship to nicotine!

Nicotinic acid is widely distributed in plant and animal foods, but in only relatively small amounts, except in meats, fish, wholegrain cereals and pulses. Cooking causes little actual destruction of nicotinic acid but considerable amounts may be lost in cooking water or drippings from cooked meats if these are discarded.

Recommended Minimum Dietary Intakes (measured as niacin equivalents)

Infants 4-7 milligrams
Children 9-22 milligrams
Adult men 14-20 milligrams
Adult women 10-14 milligrams
Pregnancy 14-16 milligrams
Lactation 17-19 milligrams