Nutrition

Nutrition

Introduction

• Nutrition is the process where organisms take in nutrients to provide energy, promote growth, and maintain bodily functions.
• Nutrients include carbohydrates, proteins, lipids, vitamins, minerals, water and fibre.

Human Nutrition

• Humans are omnivores meaning that they consume both plants and animals.
• Humans require a balanced diet which contains the right amounts and types from each food group – carbohydrates, proteins, lipids, fruits, vegetables, around 8 cups of water daily, and no more than 6g of salt.
• Digestion in humans begins in the mouth, where food is broken down mechanically by teeth and chemically by saliva.
• The main site of digestion and absorption is the small intestine where nutrients are absorbed into the bloodstream through finger-like projections called villi.
• Water and left-over nutrients are absorbed in the large intestine, forming feces which are egested through the rectum.

Plant Nutrition

• Plants are autotrophs, meaning they produce their own food through photosynthesis.
• For photosynthesis, plants require light, carbon dioxide, and water. The process produces glucose and oxygen.
• In addition to these requirements, plants also require mineral ions such as nitrates for protein synthesis.
• Some plants, known as insectivorous plants, such as the Venus flytrap, also get their nutrients from trapping and digesting small insects.

Animal Nutrition

• Animals are heterotrophs, meaning they ingest other organisms or organic matter to obtain their nutrients.
• Herbivores eat plant material, carnivores eat other animals, and omnivores eat a combination of both.
• In animals, digestion involves both mechanical and chemical breakdown of food. This process varies widely depending on the diet and feeding habits of the animal.
• Ruminant animals like cows have a unique digestive system, including a four-chambered stomach, to allow them to effectively digest grass and other plant material.