Macronutrients and Digestion 1

Macronutrients and Digestion 1

• Diet is defined as the total oral intake of substances that provide nourishment and energy. It includes the types and amounts of food consumed daily.
• A balanced diet provides all necessary nutrients in appropriate amounts and proportions.
• A balanced diet can be achieved by consuming foods from the four basic food groups in varying quantities based on age, gender, physiological state, and activity level.
• The Malaysian Food Pyramid 2020 provides a guide to daily food intake recommendations. Specific food groups and recommended servings are outlined in the pyramid.
• Recommendations are based on different caloric intakes (1500 kcal, 1800 kcal, and 2000 kcal) for adults, and less active/sedentary adults should opt for the minimum serving numbers.
• Adequate nutrition is crucial for optimal organ and tissue function.
• Insufficient nutrition can lead to increased risk of disease, infection, fatigue, and poor performance.
• Children with suboptimal diets are at increased risk of growth and developmental issues.
• Excessive intake of certain foods can lead to obesity, insulin resistance, diabetes, heart conditions, cancer, and stroke.

Basic Metabolism

• Basal metabolism is the minimum energy needed for involuntary life processes, such as breathing, blood circulation, and maintaining body temperature.
• Basal metabolic rate (BMR) is the amount of energy used per unit of time when the body is at rest.

Kilocalories/Calories

• Kilocalories (kcal) are units used to measure food energy.
• 1 gram of carbohydrate = 4 kcal
• 1 gram of fat = 9 kcal
• 1 gram of protein = 4 kcal

Recommended Dietary Allowances (RDA)

• RDA is the amount of nutrients needed to fulfill daily requirements for nearly all individuals in a population. It aims to prevent deficiencies.
• Minimum Daily Requirement (MDR) is the amount needed to avoid deficiency symptoms.
• Factors affecting RDA include age, sex, physical activity level, (sedentary, moderate, heavy), and physiological stress (pregnancy, lactation).

Energy Requirements

• Energy requirements vary based on age and gender. Specific ranges are provided for different life stages (children, adolescents, adults) and special considerations (pregnant and lactating women).
• The Nutrition Facts label provides information based on a 2,000-calorie per day diet.

Components of a Balanced Diet

• Macronutrients are essential for human survival, including carbohydrates, proteins, fats, and water.
• Micronutrients enhance the function and usability of macronutrients. Vitamins and minerals are examples of micronutrients. The difference between these is the quantities needed daily (macro-nutrients exceeding 1 gram daily).

Carbohydrates

• Carbohydrates (45-65% of total calories) are the primary source of energy.
• The brain and other parts of the central nervous system depend heavily on glucose for energy.
• Carbohydrates are necessary for oxidizing fat and synthesizing DNA, RNA, NAD+, and FAD.
• Common sources include table sugar, roots, tubers, bread, and cereals/rice.
• Excess intake can lead to weight gain, diabetes, and insulin resistance.
• Deficiency can lead to acidosis, ketosis, hypoglycemia, fatigue, and unhealthy weight loss.
• Dietary fibers (25-30 grams/day) are complex carbohydrates not digested by the human enzymes, are collectively called dietary fibers; soluble fiber (fruits, legumes) and insoluble fiber (vegetables, grains).
• Fiber functions include preventing constipation, eliminating bacterial toxins, reducing cancer risk, improving glucose tolerance, and lowering cholesterol.
• Deficient fiber intake can lead to constipation, high blood pressure, diabetes, cardiovascular diseases, obesity, and cancer.

Fats

• Fats (20-35% of total calories) are a concentrated fuel source, regulate membrane permeability, aid in vitamin A and fat-soluble vitamin absorption, function as metabolic regulators, and protect internal organs through insulation.
• Common sources include butter, cheese, red meat, cream, and eggs.

Proteins

• Proteins (10-35% of total calories) are crucial for cell structure and function, maintaining osmotic pressure, contributing to blood clotting, muscle contraction, and enzyme/hormone production and act as energy sources.
• Common sources include pulses, milk, meat, cereals, eggs, and leafy vegetables.

Deficiency Disorders

• Kwashiorkor (wet protein-energy malnutrition): This is an insufficient protein intake but with sufficient calorie intake, occurring around 12 months of age (after weaning) and leads to symptoms such as edema, skin and hair changes, and insufficient antibody production.
• Marasmus (severe protein calorie malnutrition): This condition is characterized by a deficient intake of both protein and calories, and causes stunted growth and muscle/tissue wasting. Typically develops within the first year after weaning and can be caused by other weakening conditions, like chronic diarrhea.
• Marasmic Kwashiorkor: A combination of characteristics of both Kwashiorkor and Marasmus.
• Nutritional dwarfing/stunting: Prolonged lack of food-energy and protein results in slow growth; weight and height decline proportionally, appearing superficially normal.
• Underweight: Sub-clinical PEM; weight/height significantly below normal; low plasma albumin, making them susceptible to respiratory and gastric infections.

Protein-Energy Malnutrition (PEM)

• PEM is a broad term for malnutrition that occurs due to insufficient protein and energy intake ("food gap").

Prevention

• Strategies for preventing malnutrition include promoting breastfeeding, educating about proper feeding practices, family planning, immunization, food fortification, and early diagnosis/treatment.

Summary of Learning Objectives

• Students should be able to explain balanced diets and metabolic rates.
• Summarize dietary carbohydrates, fibers, and lipids.
• Identify protein quality, requirements, and malnutrition.

This quiz explores the essentials of diet, focusing on macronutrients, balanced diets, and the Malaysian Food Pyramid 2020. Understand the importance of adequate nutrition in relation to age, gender, and activity levels while learning about recommended dietary guidelines. Test your knowledge on how proper nourishment supports overall health and well-being.