Diet and Nutrition Basics

Diet and Nutrition

• A healthy diet includes carbohydrates, lipids, protein, vitamins, minerals, dietary fiber, and water.
• A balanced diet provides all the necessary nutrients in the right quantities.
• Carbohydrates provide energy and are found in foods like bread, potatoes, rice, and pasta.
• Lipids provide energy and insulation and are found in foods like nuts, dairy products, meat, oils, and sweets.
• Proteins are essential for growth and repair of cells and tissues and are found in foods like eggs, pulses, fish, meat, nuts, and dairy products.
• Vitamins and minerals are crucial for various bodily processes and are found in high quantities in fruit and vegetables.
• Calcium is a mineral that helps build bones and teeth.
• Fiber adds bulk to food and aids digestion, found in foods like fruit, vegetables, and wholegrain cereals.
• Water is essential for transporting substances and facilitating chemical reactions in cells.

Malnutrition and Health Consequences

• Malnutrition occurs when a person lacks a balanced diet.
• Diet imbalances can lead to health consequences like obesity, starvation, and deficiency diseases.

Food Tests

• Iodine solution changes color from brown to black in the presence of starch.
• Benedict's reagent changes color from blue to orange/red when heated in the presence of simple sugars like glucose.
• Biuret reagent changes color from blue to purple in the presence of protein.

The Digestive System

• The digestive system breaks down food molecules into soluble substances for cell absorption.
• Food passes through the mouth, oesophagus, stomach, small intestine, large intestine, and rectum.
• Mechanical digestion involves physical breaking down of food, while chemical digestion involves enzymes and chemicals.
• In the mouth, both mechanical and chemical digestion occur.
• Salivary glands secrete enzymes for chemical digestion.
• The stomach contains acid and performs mechanical and chemical digestion.

The Small Intestine

• Chemical digestion takes place in the small intestine, and small molecules diffuse into the bloodstream.
• The small intestine has villi to increase surface area for nutrient absorption and a good blood supply for absorption into the blood.

Enzymes

• Enzymes speed up chemical reactions in the body.
• Digestive enzymes break down large nutrient molecules into smaller molecules for blood absorption.
• Carbohydrases like amylase break down carbohydrates into simple sugars.
• Lipases break down lipids into glycerol and fatty acids.
• Proteases break down proteins into amino acids.
• The lock and key theory explains enzyme function through specific active sites.

Plant Nutrition

• Plants require minerals for healthy growth, including nitrates for protein production and magnesium for chlorophyll production.
• Plants obtain necessary minerals from the soil through their roots.
• Deficiencies can harm plants, with magnesium deficiency affecting photosynthesis.