Clinical Nutrition

Lesson 5: Vitamin A deficiency

Introduction

In 1915, Mc Collum and Davis described “Fat soluble A” as a growth promoting factor isolated from animal fats and fish oil

Vitamin A is an essential nutrient needed only in small amounts but is necessary for the normal functioning of a large number of regulatory and other physiological processes of the human body. Vitamin A deficiency disorders occur when the body reserves are depleted to the limit at which physiological functions are impaired.

Vitamin A is stored mainly in the liver as retinyl esters and these stores are depleted due to inadequate dietary intake, sometimes associated with infection. Relatively constant levels are maintained in the blood until body stores become depleted below a critical point.