Nutrients and a Balanced Diet

Introduction

Nutrition is the study of food and how the body uses it. In the Kenyan Senior School CBC (KICD) Home Science curriculum, good nutrition is the foundation of family health. A nutrient is a substance in food that the body needs for growth, energy, repair and protection.

Classes of nutrients

1. Carbohydrates - energy

• Sources: ugali, rice, chapati, sweet potatoes, bananas, sugar
• Lack causes weakness; excess may cause obesity.

2. Proteins - growth and repair

• Sources: meat, fish (omena), eggs, milk, beans, lentils (ndengu)
• Deficiency causes kwashiorkor (swollen belly and feet) and marasmus (severe wasting).

3. Fats and oils - concentrated energy, insulation, carry vitamins A, D, E, K

• Sources: cooking oil, butter, groundnuts, avocado

4. Vitamins - protection and regulation

• Vitamin A: carrots, liver; lack causes night blindness.
• Vitamin B group: whole grains; lack causes beriberi.
• Vitamin C: oranges, guavas; lack causes scurvy.
• Vitamin D: sunlight, eggs; lack causes rickets.
• Vitamin K: green vegetables; helps blood clotting.

5. Mineral salts

• Calcium: milk, small fish; strong bones and teeth.
• Iron: liver, sukuma wiki; makes haemoglobin, prevents anaemia.
• Iodine: iodised salt, seafood; prevents goitre.
• Sodium and potassium: regulate body fluids.

6. Water - transports nutrients, regulates temperature and removes wastes. Take about 8 glasses daily.

7. Dietary fibre (roughage) - from whole grains, fruits and vegetables; prevents constipation.

Balanced diet

A diet containing all nutrients, fibre and water in the right proportions for age, sex, activity and health. Factors that affect needs: age (children need more protein), pregnancy, illness, occupation, and climate.

Planning meals

Consider the family's budget, season and availability of foods, preferences and cultural practices. Use a variety of foods from each group, and prepare them hygienically while avoiding nutrient loss (don't overcook vegetables or throw away cooking water).

Malnutrition

Malnutrition is poor nutrition caused by too little or too much of a nutrient. It includes undernutrition, overnutrition (obesity) and specific deficiencies.

Worked example 1

A child has a swollen stomach, thin limbs and pale hair. Identify the likely condition and suggest a remedy. Answer: Kwashiorkor. Give protein-rich foods such as milk, eggs, beans and fish, under medical guidance.

Worked example 2

Why is it advised to eat sukuma wiki with ugali? Answer: Ugali provides energy while sukuma wiki supplies vitamins, iron and fibre, completing the meal.

Try it

• Record everything you ate yesterday and classify the nutrients.
• Make a table of five vitamins, their sources and deficiency diseases.
• Plan a balanced supper for a family of five with a low budget.
• Explain why a pregnant woman needs more iron.