Introduction to Nutrition and Related Definitions PDF

Lecture 1 Introduction to Nutrition and Related Definitions Prof. Faten Rabie Objectives Introduction Definitions Energy from food Functions of food nutrients Composition of human body Nutrition assessment of individual Sign of good nutrition The rel...

Lecture 1 Introduction to Nutrition and Related Definitions Prof. Faten Rabie Objectives Introduction Definitions Energy from food Functions of food nutrients Composition of human body Nutrition assessment of individual Sign of good nutrition The relationship of nutrition with other sciences Nutrient intake limits Introduction ▪ Most of the organized studies of nutrition have been confined to the 20th century. ▪ Although there was evidence of long-standing curiosity about nutrition. ▪ Hippocrates, the father of medicine(400 BC) considered food as one universal nutrient. ▪ Antonie Lauret Lavoisier(18th century, a French chemist) is known as father of nutrition. ▪ In Islam there are many verses of the Quran and Hadeeths in food and nutrition. ▪ Some of these fact has just been proved by the modern science and some not. ▪ Nutrition has played a significant role in our life, even from before our birth. ▪ Many people are concerned only with food that relives their hunger or satisfies their appetite. ▪ But in many times, these foods don't supply their bodies with all the component of good nutrition. Definitions Food Diet Nutrients Nutrition Nutrition Nitrogen balance requirement Nutrition science Adequate diet Junk food Nutritional Nutritional care Calories status Empty calories Malnutrition Metabolism Nutritive value Dietetics Nutritional genomics ❖ Food: Foods are products derived from plants or animals. that can be taken into the body to yield energy and nutrients for maintenance of life ,for growth and repair tissues. Food is that nourishes the body. Food is a prerequisite of nutrition. ❖ Diet Diet is the foods and beverages a person eats and drinks.  Food composition Food Nutrients Other 1-Macronutrients compounds 2-Micronutrients -fibers -phytochemicals -pigments -additives -alcohols -and others ❖Nutrients: Chemical substances obtained from foods used in the body to provide energy, structure materials, regulating agents to support growth, maintenance, repair of body's tissues and may also reduce the risks of some diseases.  Nutrients divided into two categories: Macronutrients Are the nutrients which the body needed in large amount such as carbohydrate, protein and fats. Carbohydrates, protein and fats are the main source of energy for human body. Are the energy yielding nutrients. Micronutrients Are nutrients needed in lesser amounts such as: Vitamins & minerals.  Chemical composition of the nutrients Nutrients Inorganic Organic (water &Mineral) (CHO, lipids , protein and vitamins) →Organic nutrients: substance that contain carbon atom. →Inorganic: substances that do not contain carbon atoms. Essential nutrients: Are nutrients a person must obtain from food because the body cannot make them for itself insufficient quantity to meet physiological needs. Also called indispensable nutrients. ❖ Nutrition: Nutrition is the science of foods, nutrients and other substances they contain their actions within the body (including ingestion, digestion, absorption, transport, metabolism and excretion). A broader definition includes the social, economic, cultural, and psychological implications of food and eating. ❖ Nutritional requirements The amounts of nutrient which are needed for covering the human needs to be healthy depend on sex, age and few other factors.  ❖ Nutritional status An individual condition of health in relation to digestion and absorption of nutrients. ❖ Nutritional care: Application of the science of nutrition in nourishing the body regardless of health problems or potential problems. ❖Adequate diet: is a diet providing all the needed nutrients in the right total amounts. ❖Junk food: Refers to foods that are harmful. ❖ Calories The energy released from carbohydrates, proteins and fats can be measured in calories. A calorie is the amount of heat necessary to raise temperature of 1 gm of water by 1 C. 1000-calorie metric units are known as kilocalories (kcal). ❖Empty-kcalorie foods a popular term used to denote foods contribute energy (from sugars, fat or both) but lack in protein, vitamins and minerals Example:(potato chips and candies). ❖ Dietetics the health profession responsible for the application of nutrition science to promote human health and treat disease ❖ Metabolism The sum of all chemical reactions that take place in the body which it maintains itself produces energy for its functioning.  ❖ Nutrition science Nutrition science: 1-The study of nutrients and other substances in foods and the body's handling of them. 2-Its foundation depends on several other sciences including biology, biochemistry, and physiology. 3- Comprises the body of knowledge governing the food requirement growth, activity, reproduction and lactation. ❖ Nutritional genomics: the science of how nutrients affect the activities of genes and how genes affect the interactions between diet and disease. ❖ Malnutrition: Malnutrition has two types: Undernutrition: deficient energy or nutrients. Symptoms of under nutrition (extremely thin, losing muscle tissues, prone to infection and disease, skin rashes, hair loss, bleeding gum and night blindness). Overnutrition: excess energy or nutrient. Symptoms of overnutrition (heart disease, diabetes, yellow skin, rapid heart rate and low blood pressure).  ❖ Nitrogen balance The proteins in the body undergo constant turnover (degraded to amino acids and resynthesized). Nitrogen balance is the difference between the amount of nitrogen taken into the body each day and the amount of nitrogen in compounds lost.  if: 1- More nitrogen is ingested than excreted, a person is said to be in positive nitrogen balance (growing individual such as children and pregnant). 2- Less nitrogen is ingested than is excreted (negative nitrogen balance, person eating either too little protein or protein is deficient in one or more of the essential amino acids, new protein cannot be synthesized and the unused amino acids will be degraded, body function will be impaired by the net loss of critical proteins. 3- In contrast, healthy adults are in nitrogen balance and the amount of nitrogen consumed in the diet equals its loss in urine. ❖ Nutritive value The amounts of nutrient which the food consist of, determined by using: ▪ Food analysis. ▪ Food analysis tables. Energy from food The amount of energy a food provide depends on how much CHO, fat, and protein contains. When completely broken down in the body, 1 gm CHO →4 kcal of energy 1 gm protein→ 4 kcal of energy 1 gm of fat → 9 kcal of energy ➔therefore fat has the greater energy density than either CHO or protein. Alcohol is not considered a nutrient because it interferes with health but it yields energy 1 gm of alcohol→ 7 kcal of energy Functions of food nutrients 1-Provide energy sources 2-Build tissues 3-Regulate metabolic process 1-Provide energy sources The major carbohydrates in the human diet are starch, sucrose, fructose and glucose. Dietary carbohydrate (starches and sugars) provided the body's primary source of fuel for energy. Oxidation of carbohydrates to CO2 and H2O in the body produces approximately 4 kcal/g. They also maintain the back-up store of quick energy as glycogen (animal starch).  Fats are lipids composed of triacylglycerols. A triacylglycerol molecule contains three fatty acids esterified to one glycerol molecule. Dietary fats, from both animal and plant sources, provided the body's secondary or storage form of energy. It is a more concentrated, yielding 9 kcal for each gram consumed. In a well-balanced diet, protein provided about 15 % of the total kcalories. Each gram of protein can yield 4 kcal. How to calculate the energy available from 1 slice of bread with 1slice of bread with 1 tablespoon of peanut butter on it contains 16 grams carbohydrate, 7 grams protein and 9 grams fat? 2-Build tissues Proteins are composed of amino acids that are joined to form linear chains. The digestive process breaks down proteins to their constituent to amino acids, which enter the blood. The primary function of protein is tissue building and repairing body tissues. Dietary protein provides amino acids, amino acids are the building unit necessary for construction and repairing body tissues. Muscle protein is essential for body movement. Other proteins serve as enzymes. Other nutrients such as minerals and vitamins used in tissue building and maintaining tissue.  Minerals are also found in the fluids of the body and influence their properties. There are 13 different vitamins, one vitamin enables the eyes to see in dim light, protect the lungs from air pollution make the sex hormones, stop the bleeding, helps repair the skin, replace old blood cells and lining of the digestive tract.  3-Regulate metabolic process Many vitamins and minerals function as coenzymes factors in cell metabolism. Other nutrients (water and fibers), water provides the environment in which nearly all the body's activities. Also, in many metabolic reactions and supplies the medium for transporting vital materials to cells and waste products away from them. Dietary fibers help regulate the passage of food material through the gastrointestinal tract and influences absorption of various nutrients. Composition of human body 6% 2% 14% water (61%) Protein (17%) Fats(13.8) Minerals(6.1%) 17% 61% Carbohydrates(1.5) Nutrition assessment of individual Evaluation of person's nutrition 1- Historical information (socioeconomic status, drug use, diet and person's family history). 2-A=Anthropometric data (height and weight). 3- B= biochemical data (Laboratory tests). 4-C=clinical assessment(Physical examinations) 5-D=Dietary assessment Sign of good nutrition 1. Well-developed body. 2. Ideal weight. 3. Good muscle development. 4. The skin is smooth and clear 5. The hair glossy and the eyes clear and bright. 6. Appetite, digestion and elimination are normal. 7. Have good resistance to infection. The relationship of nutrition with other sciences food science Medicine physiology Nutrition microbiology biochemistry biology There are three main areas of overlapping between nutrition and medicine: 1-dietary control of disease. 2-the relationship between diet as a possible causative factor in disease ex: cancer, heart diseases etc. 3-the toxicology of natural and processed foods. Thank you for listening ☺