Nutrients: Carbohydrates, Lipids and Proteins

• Nutrients are chemical substances in diet, needed for healthy life activities

Types of Nutrients

• Carbohydrates
• Proteins
• Lipids
• Water
• Vitamins
• Minerals
• Fibers

Carbohydrates

• Sources include starch found in potatoes, beans, peas, yams, and cereals.
• Sugars are present in honey, sugar cane, and fruits like bananas and grapes.
• Glucose provides energy through cellular respiration.
• Sugars help in creating nucleic acids like deoxyribose (DNA) and ribose (RNA)
• Glucose is stored as glycogen in animal livers and muscles, and as starch in plants

Over-eating Carbohydrates

• Can cause obesity or tooth decay

Lipids (Fats)

• Provide the most energy, over double the amount from carbohydrates and proteins, at 37 kJ/g
• Act as an energy reservoir in the body
• Store under the skin to insulate heat, maintaining body temperature
• Form part of cell membranes, acts as a solvent for vitamins A & D and hormones

Proteins

• Meat, peas, beans, fish, egg whites, peanuts, milk, lentil seeds, and cheese are sources of proteins
• Important for growth and repairing cells
• Muscles and enzymes are made of proteins, as are hemoglobin in RBCs for oxygen transport and insulin.
• Proteins also include blood clotting proteins, antibodies produced by lymphocytes, keratin in hair and nails, and collagen in skin and bones

Water

• Compromises 70% of body's mass
• A solvent for chemicals in the body
• Acts as a medium and takes part in chemical reactions such as food digestion
• Helps control body temperature (37°C) through sweating (Thermoregulation)
• Needed for digestion and for enzyme action

Vitamins

• Organic compounds for growth and nutrition that cannot be synthesized by the body
• Vitamin D sources include milk, egg yolk, sunlight on the skin, and fish liver oil.
• Vitamin D needed for strong teeth and bones, and calcium absorption.
• Vitamin D deficiency causes Rickets.
• Vitamin C sources include citrus fruits, oranges, lemons, and green vegetables.
• Vitamin C is used for healthy gums, skin repair, wound healing, and disease prevention.
• Vitamin C deficiency causes scurvy, bleeding gums, and slow wound healing.

Minerals

• Minerals are chemical elements, essential as nutrients for organisms
• Calcium sources include milk, yogurt, flour, and fish.
• Calcium is used for strong bones, teeth, muscle contraction, and blood clotting.
• Calcium deficiency causes Rickets
• Iron sources include liver, red meat, and spinach
• Iron supports hemoglobin in RBCs
• Iron deficiency causes Anemia, less oxygen, less energy, and fatigue.

Fibers/Roughage

• Made of: cellulose
• Sources include vegetables, fruit, nuts, brown rice, cereals, banana, and lettuce leaves
• Helps in peristalsis by retaining water and bulking faeces
• Prevents constipation
• Reduces colon cancer risk and absorption
• Deficiency in fiber can cause constipation and colon cancer

Balanced Diet

• A diet in correct proportions
• Necessary for healthy life

Factors That Affect Selection of Balanced Diet

• Body size
• Age
• Gender
• Physical activity
• Occupation
• Pregnancy
• Breastfeeding/Lactation
• Menstruation in adult females

Malnutrition

• Lack of balance in diet

Effects of Malnutrition

• Weak bones, teeth, slow blood clotting with calcium deficiency
• Anemia with iron deficiency
• Rickets with vitamin D deficiency
• Scurvy with vitamin C deficiency
• Constipation with fiber deficiency
• Excess carbohydrates can cause obesity and tooth decay
• Excessive animal fats can cause coronary heart disease

Famine

• Lack of food and drinkable water
• Leads to malnutrition and diseases

Causes of Famine

• Unequal food and water distribution
• Flooding
• Natural disasters like earthquakes
• Political/social instability like wars
• Poor farming techniques