Human Nutrition 3(3+0)

Lesson 45 : Water Functions and Water Balance

Introduction

Water is considered as the most important nutrient for the body. It forms the greatest component of the human body, making up 50% to 60% of body weight. Lean muscle tissue contains about 73% water. Fat tissue is about 20% water. Thus as fat content increases in the body, total body water content declines towards 50%. Water – the most versatile medium for all kinds of chemical reactions constitutes the major portion of our bodies. Without water, the life processes would cease in a matter of days.

The water content of soft tissues ranges from 70 to 80 per cent while that of bone about 20 per cent.

Body water is distributed as follows:

1. inside the cells of tissue – intracellular water (50 per cent) and
2. outside the tissue cells – extracellular water (20 per cent).

The extra cellular water is further sub divided into

1. water in blood plasma (about 4 per cent);
2. interstitial water – water in tissue spaces (9 per cent) and
3. Lymph in the lymphatic vessels (7 per cent).