Nutrition in Humans: Carbohydrates and More

Nutrition in Humans

• Food is needed to provide energy, repair tissues, and fight disease.
• A balanced diet includes carbohydrates, lipids, proteins, minerals, vitamins, dietary fiber, and water in appropriate amounts.

Carbohydrates

• Sugars:
  • Glucose is found naturally in fruits and vegetables.
  • Fructose is found in fruits.
  • Lactose is found in milk.
  • Sucrose is transported through plant stems (e.g., sugar cane).
  • Digestion of starch produces sugar.
• Physical Properties of Sugars:
  • Sugars are soluble in water.
  • Sugars are sweet in taste.
• Functions of Sugars:
  • Sugars provide energy for cells by oxidation in cellular respiration.

Starch

• Starch is a large, insoluble carbohydrate found in plants (e.g., potatoes, rice, wheat).
• Starch is a polymer of glucose molecules.
• Starch is a storage form of glucose in plants.

Glycogen

• Glycogen is a carbohydrate similar to starch, found in animal tissues (e.g., liver, muscle).
• Glycogen is a storage form of glucose in animals.
• Large carbohydrates like starch and glycogen must be broken down into simple sugars for absorption into the bloodstream following digestion.

Cellulose

• Cellulose is the material that makes up plant cell walls.
• Humans cannot digest cellulose because they lack the necessary enzymes.
• Cellulose acts as dietary fiber, promoting gut health and preventing constipation.

Lipids

• Sources and Properties:
  • Fats are derived from animals (solid at room temperature) and have high melting points.
  • Oils are derived from plants (liquid at room temperature) and have low melting points.
  • Sources of fats: animal products, milk, butter, ghee, eggs, fish.
  • Sources of oils: vegetable oils, corn oil, olive oil, etc.
• Functions of Lipids:
  • Lipids contribute to body mass.
  • Lipids are crucial components of cell membranes.
  • Lipids are stored as energy reserves.
  • Lipids insulate the body.
  • Lipids protect organs from damage.

Proteins

• Sources:
  • Animal sources: meat, fish, cheese, eggs.
  • Plant sources: beans, peas, nuts.
• Functions:
  • Proteins promote growth.
  • Proteins repair damaged tissues.
  • Proteins are components of many enzymes in the body.
• Recommended Amount: Approximately 70 grams per day.
• Deficiency: Kwashiorkor is a protein deficiency disease.

Minerals

• Minerals:
  • Calcium is important for bone and tooth formation.
  • Phosphorus is important for making bones and teeth.
  • Sodium is a component of body fluids (e.g., blood).
  • Chlorine is a component of body fluids (e.g., blood).
  • Magnesium is found inside cells.
  • Iron is a component of haemoglobin (red blood cells).
• Deficiency:
  • Rickets is a calcium deficiency disease causing poor bone development.
  • Anemia is an iron deficiency disease causing tiredness.

Vitamins

• Vitamin A:
  • Source: carrots, liver, fish liver oil.
  • Role: Crucial for vision and maintaining the health of the eyes.
• Vitamin C:
  • Source: fresh fruits, vegetables.
  • Role: wound healing and maintaining the health of the cells lining body surfaces.
• Vitamin D:
  • Source: fish liver oil, sunlight.
  • Role: helps bones absorb calcium and phosphate.
• Deficiency:
  • Vitamin A deficiency: night blindness, damaged cornea.
  • Vitamin C deficiency: scurvy.
  • Vitamin D deficiency: rickets, poor teeth.

Water

• Water is essential for all chemical reactions in the body.
• Water is found in juices and liquids.

Energy Requirements

• Factors affecting energy requirements include age, activity level, and pregnancy.
• Energy and activity levels increase as we age and increase with increases in activity.
• Energy needed during pregnancy is higher due to the additional mass.
• Investigation of food energy content is done by measuring the mass of food, placing it in water, and recording the temperature change in the water.

This quiz explores the crucial role of food in human nutrition, emphasizing the importance of a balanced diet and the functions of carbohydrates like sugars, starch, and glycogen. Test your knowledge of dietary components and their physiological roles.