Vitamin B3 (Niacin)

Sources of Vitamin B3

Animal Sources

Chicken, beef, fish (especially tuna and salmon), and liver.

Plant Sources

Nuts, seeds, and green leafy vegetables.

Fortified Foods

Many cereals and bread are fortified with niacin.

Dairy Products

Milk and cheese.

Functions of Vitamin B3

Metabolic Role: Crucial for the metabolism of carbohydrates, fats, and proteins into energy.

Digestive System: Aids in the normal functioning of the digestive system.

Skin and Nerves: Essential for maintaining healthy skin and nerves.

Cholesterol Regulation: Helps to regulate cholesterol levels in the blood.

Effects of Niacin Deficiency

Pellagra: Characterized by dermatitis, diarrhea, and dementia. In severe cases, it can lead to death.

General Symptoms: Fatigue, canker sores, vomiting, depression, and a swollen, bright red tongue.

Digestive Problems: Such as indigestion and poor appetite.

Recommended Dietary Allowances (RDAs) for Niacin

Adult Men

16 mg/day

Adult Women

14 mg/day

Pregnancy and Lactation

Increased needs, up to 18 mg/day

Properties of Vitamin B3

Stability

Relatively stable to heat, but can be lost in cooking water.

Solubility

Water-soluble, hence not stored in the body and must be consumed regularly.

Toxicity

High doses can be toxic and lead to 'niacin flush', liver damage, and other health issues.

Example Exam Questions and Answers

1. What are the key functions of niacin in the body?

Niacin plays a vital role in energy metabolism, maintaining healthy skin and nerves, and regulating blood cholesterol levels.

2. Identify two sources of niacin.

Niacin can be obtained from animal sources like chicken and beef, and plant sources such as nuts and green leafy vegetables.

3. Describe the condition associated with niacin deficiency.

Niacin deficiency leads to pellagra, which is characterized by dermatitis, diarrhea, and dementia.