Biology (0610) Human Nutrition Revision Note

This document explains human nutrition for CAIE IGCSE Biology, covering diet, digestion, and absorption. It defines a balanced diet as one including carbohydrates, fats, proteins, vitamins, minerals, fibre, and water, tailored to age, gender, and lifestyle (e.g., calcium for children, iron for pregnant women). Nutrients and their uses are outlined: carbohydrates for energy, fats for insulation and hormones, proteins for enzymes and antibodies, vitamin C for immunity, vitamin D and calcium for bones, iron for haemoglobin, fibre for peristalsis, and water for metabolic processes. Deficiency diseases like scurvy, rickets, and osteoporosis are explained. The role of teeth in mechanical digestion is described, including incisors, canines, premolars, and molars, with tooth structure details (enamel, dentine, pulp). The digestive system is outlined step by step: ingestion, mechanical and chemical digestion, absorption in the small intestine, assimilation by cells, and egestion. Organs such as the stomach, pancreas, liver, gallbladder, and intestines are discussed, along with digestive enzymes (amylase, maltase, protease, lipase), hydrochloric acid, and bile. The section on absorption highlights villi and microvilli adaptations, thin epithelium, blood supply, and lacteals for fatty acid uptake. This resource provides complete preparation for understanding human nutrition and digestion processes.