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Public Health · 300 Level
This is the complete lecture note for PHS 308 Public health nutrition, prepared for Public Health students at 300 Level. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS COURSE CODE: PHS 308 COURSE TITLE: Public Health Nutrition COURSE CREDIT LOAD: (2 Unit C: LH 30) LISTS OF SERIES: 1. Classification and Nutritional Value of Food 2. Nutrition in Disease Prevention and Management 3. Community Nutrition Problems and Resources 4. Nutrition Programmes for Children and Adolescents 5. National Nutrition Goals, Policies, and Challenges Series 1 Outline: Classification and Nutritional Value of Food • Part 1: Concept and classification of food • 1.1 Definition of food • 1.2 Major classes of food • 1.3 Basis of classification • Part 2: Nutritional value of food groups • 2.1 Carbohydrates and their functions • 2.2 Proteins and their functions • 2.3 Fats and oils and their functions • 2.4 Vitamins and minerals • 2.5 Water and fibre • Part 3: Health effects of food consumption • 3.1 Positive health effects of balanced diets • 3.2 Negative health effects of poor diets • 3.3 Role of nutrition in maintaining wellbeing • Part 4: Special diets in health and illness • 4.1 Diets for children and adolescents • 4.2 Diets during illness (e.g. diabetes, obesity, heart disease) • 4.3 Therapeutic and preventive diets Introduction Food is central to human survival and wellbeing, yet its role goes far beyond simply satisfying hunger. The types of food we consume, their composition, and the way they are classified all have direct implications for health. In public health nutrition, understanding the classification and nutritional value of food is essential, as it provides the foundation for addressing community nutrition problems and designing effective interventions. This Series sets the stage for your learning by introducing you to the basic concepts that underpin the rest of the course. The aim of this Series is to help you define and classify food, explain the nutritional value of different food groups, and analyse their health effects, including the role of special diets in maintaining health and managing illness. We shall commence this Series by exploring the concept and classification of food, including the major classes and the basis of classification. Next, we will examine the nutritional value of food
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS groups such as carbohydrates, proteins, fats, vitamins, minerals, water, and fibre. Following that, we will consider the health effects of food consumption, looking at both the benefits of balanced diets and the risks of poor diets. Finally, we will conclude by discussing special diets in health and illness, focusing on dietary needs for children, adolescents, and individuals with conditions such as diabetes, obesity, and heart disease. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define the concept of food and explain the basis of its classification, • SLO 1.2 classify the major food groups and describe their distinguishing features, • SLO 1.3 analyse the nutritional value of carbohydrates, proteins, fats, vitamins, minerals, water, and fibre, • SLO 1.4 evaluate the health effects of food consumption, distinguishing between balanced and poor diets, and • SLO 1.5 apply knowledge of special diets to health and illness contexts, including children, adolescents, and individuals with nutrition-related diseases. 1.1 Concept and Classification of Food 1.1.1 Definition of food Food refers to any substance consumed by humans to provide essential nutrients for growth, energy, and maintenance of life. Nutrients are the chemical components of food that the body requires, such as carbohydrates, proteins, fats, vitamins, minerals, water, and fibre. Food is not only a source of nourishment but also plays cultural, social, and psychological roles in communities. Fill in the blank: __________ are the chemical components of food that the body requires for growth and energy.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Diagram showing food as a source of nutrients, energy, and cultural value. Figure 1.1: Concept of food and its functions 1.1.2 Major classes of food Food can be classified into major groups based on their nutrient composition. These include: • Carbohydrates: The body’s main source of energy. • Proteins: Essential for growth, repair, and maintenance of tissues. • Fats and oils: Provide concentrated energy and aid absorption of fat-soluble vitamins. • Vitamins and minerals: Regulate body processes and support immunity. • Water: Vital for hydration, digestion, and transport of nutrients. • Fibre: Supports digestion and prevents constipation. Fill in the blank: __________ are essential for growth, repair, and maintenance of tissues. 1.1.3 Basis of classification The classification of food is based on its nutrient composition, meaning the type and amount of nutrients present. For example, rice is classified as a carbohydrate-rich food, while beans are classified as protein-rich. Some foods, such as milk, are classified as mixed foods because they contain significant amounts of more than one nutrient group. This classification helps in planning balanced diets and understanding the role of each food in health. Fill in the blank: The classification of food is based on its __________ composition.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Box 1.1: Basis of food classification • Carbohydrate-rich foods: rice, maize, yam • Protein-rich foods: beans, fish, eggs • Fat-rich foods: oil, butter, groundnuts • Mixed foods: milk, soybeans Pilot questions 1.1 1. Define food in the context of nutrition. 2. State two major classes of food. 3. Identify the nutrient that supports digestion and prevents constipation. 4. Explain the basis of food classification. 5. Give one example of a mixed food. 1.2 Nutritional Value of Food Groups 1.2.1 Carbohydrates and their functions Carbohydrates are the body’s primary source of energy. They are broken down into glucose, which fuels physical activity and brain function. Foods such as rice, maize, yam, and bread are rich in carbohydrates. A diet lacking in carbohydrates can lead to fatigue and poor concentration. Fill in the blank: __________ are broken down into glucose, which fuels physical activity and brain function.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Diagram showing carbohydrate-rich foods and their energy pathway. Figure 1.2: Carbohydrates as energy providers 1.2.2 Proteins and their functions Proteins are essential for growth, repair, and maintenance of body tissues. They are made up of amino acids, which act as building blocks for muscles, enzymes, and hormones. Common sources include beans, fish, eggs, and meat. Protein deficiency can result in stunted growth and weakened immunity. Fill in the blank: __________ are the building blocks of proteins. 1.2.3 Fats and oils and their functions Fats and oils provide concentrated energy and help the body absorb fat-soluble vitamins (A, D, E, and K). They also protect organs and regulate body temperature. Sources include groundnuts, butter, palm oil, and avocado. Excessive intake, however, can lead to obesity and heart disease. Fill in the blank: Fats help the body absorb __________ vitamins such as A, D, E, and K.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Box 1.2: Functions of fats and oils • Provide concentrated energy • Aid absorption of fat-soluble vitamins • Protect organs • Regulate body temperature 1.2.4 Vitamins and minerals Vitamins are organic compounds needed in small amounts to regulate body processes. For example, Vitamin C supports immunity, while Vitamin D strengthens bones. Minerals such as calcium, iron, and iodine are inorganic elements that support growth, blood formation, and thyroid function. Deficiencies can lead to conditions such as anaemia or goitre. Fill in the blank: __________ is a mineral that supports blood formation. 1.2.5 Water and fibre Water is vital for hydration, digestion, and transport of nutrients. It makes up about 60 percent of the human body. Fibre, found in fruits, vegetables, and whole grains, aids digestion and prevents constipation. Both are essential for maintaining a healthy digestive system and overall wellbeing. Fill in the blank: __________ aids digestion and prevents constipation.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Image showing fruits, vegetables, and whole grains as sources of fibre and hydration. Plate 1.3: Sources of water and fibre Pilot questions 1.2 1. State the primary function of carbohydrates. 2. What are the building blocks of proteins? 3. Name one fat-soluble vitamin. 4. Identify one mineral that supports thyroid function. 5. Mention one food source of fibre. 1.3 Health Effects of Food Consumption 1.3.1 Positive health effects of balanced diets A balanced diet provides the body with all essential nutrients in the right proportions. It supports growth, strengthens immunity, and maintains energy levels. Balanced diets also reduce the risk of chronic diseases and promote overall wellbeing. For example, diets rich in fruits and vegetables supply vitamins and fibre, while proteins and carbohydrates ensure tissue repair and energy supply. Fill in the blank: A __________ diet provides the body with all essential nutrients in the right proportions.
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