Vitamin D

Introduction

Vitamin D, specifically cholecalciferol (Vitamin D3), is a crucial nutrient for maintaining overall health and well-being.

Sources of Vitamin D (Cholecalciferol)

Animal Foods

Primarily found in oily fish, fish liver oils, egg yolks, and liver.

Sun Exposure

Cholecalciferol is synthesized in the skin upon exposure to sunlight.

Fortified Foods

Some foods like milk, cereal, and orange juice may be fortified with Vitamin D.

Functions of Vitamin D

Calcium Absorption: Enhances the absorption of calcium and phosphorus from the gut.

Bone Health: Vital for maintaining healthy bones and teeth by regulating calcium and phosphorus levels in the body.

Immune System: Supports the immune system and modulates cell growth.

Muscle Function: Plays a role in muscle function and reduces the risk of falls and fractures in the elderly.

Effects of Vitamin D Deficiency

Rickets in Children: Causes soft and weak bones, leading to skeletal deformities.

Osteomalacia in Adults: Results in weak bones and muscle weakness.

Osteoporosis: Increases the risk of fractures, especially in older adults.

Immune Dysfunction: May lead to increased susceptibility to infections.

Recommended Dietary Allowances (RDAs) for Vitamin D

Children and Adults: 600 IU (15 micrograms) per day.

Older Adults (over 70 years): 800 IU (20 micrograms) per day.

Pregnant and Lactating Women: 600 IU (15 micrograms) per day.

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Properties of Vitamin D (Cholecalciferol)

Fat-Soluble Vitamin

Requires dietary fats for absorption and is stored in the body's fat tissues.

Stability

Stable to heat and unaffected by cooking methods.

Formation

Formed in the skin under the influence of ultraviolet (UV) light from the sun.

Exam Focus: Questions and Answers

1. What are the main functions of Vitamin D in the body?

Vitamin D enhances the absorption of calcium and phosphorus, essential for healthy bones and teeth. It supports the immune system, aids in muscle function, and reduces the risk of falls and fractures in older adults.

2. Describe the effects of Vitamin D deficiency.

Vitamin D deficiency can lead to rickets in children and osteomalacia in adults, characterised by weak and soft bones. It can also increase the risk of osteoporosis, leading to fractures, and may cause muscle weakness and immune dysfunction.

3. What are the sources and properties of Vitamin D?

Vitamin D sources include oily fish, fish liver oils, fortified foods, and synthesis in the skin through sun exposure. It is a fat-soluble vitamin, stable to heat, and formed under the influence of UV light.