Human Nutrition PDF

Human Nutrition Introduction To Nutrition Objectives of this Lecture.: Define nutrition and its importance. Define the essential nutrients. Review the Human Body Composition. Review the major group of foods. Understand the Chemical Composition of food.  What is Nutrition...

Human Nutrition Introduction To Nutrition Objectives of this Lecture.: Define nutrition and its importance. Define the essential nutrients. Review the Human Body Composition. Review the major group of foods. Understand the Chemical Composition of food.  What is Nutrition Nutrition: the science of foods and the nutrients and other substances they contain, and of their actions within the body (including ingestion, digestion, absorption, transport, metabolism, and excretion). Nutrition is based on the food requirements of humans for: ❑ energy. ❑ growth. ❑ maintenance. ❑reproduction, and lactation.  DEFINITIONS Foods: products derived from plants or animals that can be taken into the body to yield energy and nutrients for the maintenance of life and the growth and repair of tissues. Diet: the foods and beverages a person eats and drinks. The science of nutrition: the study of the nutrients and other substances in foods and the body’s handling of them. Its foundation depends on several other sciences, including biology, biochemistry, and physiology. Nutrients chemical substances obtained from food and used in the body to provide energy, structural materials, and regulating agents to support the growth, maintenance, and repair of the body’s tissues. Nutrients may also reduce the risks of some diseases. Major Groups of Foods  Nutrients either Essential or Nonessential nutrients a person must obtain from food because the body cannot make them for itself in sufficient quantity to meet physiological needs; Essential Essential also called About 40 nutrients are currently known to be essential for human beings. Water is the most important nutrient for survival. one that the body can make sufficient Nonessential Nonessential quantities of it if it is lacking in the diet Nutrients either Macronutrients or Micronutrients A nutrient that is needed in relatively large amounts in the diet (many grams daily). Macronutrients protein carbohydrates lipids water a nutrient that is needed in relatively small amounts in the Micronutrients diet (milligrams or micrograms daily). vitamins minerals Nutrients either Macronutrients or Micronutrients A. Macronutrients A nutrient that is needed in relatively large amounts in the diet (many grams daily). protein carbohydrates lipids water B. Micronutrients : a nutrient that is needed in relatively small amounts in the diet (milligrams or micrograms daily). vitamins minerals 1. Vitamins: organic, essential nutrients required in small amounts by the body for health. 2. Minerals: inorganic elements. Some minerals are essential nutrients required in small amounts by the body for health. The Nutrients Water Carbohydrates Hydrogen & oxygen Organic Inorganic (no carbon) Proteins Minerals Organic Simplest nutrient Contains nitrogen Inorganic Lipids (fats) Vitamins Organic Organic (contains carbon) The Six Classes of Nutrients Energy-yielding Nutrients Macronutrients: source of kcalories  Carbohydrate = 4 kcal/g  Protein = 4 kcal/g  Fat = 9 kcal/g  Higher energy density Alcohol  Not a nutrient  Yields energy – 7 kcal/g Lower energy density foods  Contribute to weight loss  Nutrients : Summary Table JUST Good Nutrition Contributes To good health prevention of chronic conditions and diseases energy needs sense of well-being Malnutrition → excess, deficiencies, or imbalance of nutrients Why is nutrition important? 2/6/2018 Why is nutrition important? Nutrition is essential for: ❑ growth. ❑ Development. ❑ health and wellbeing. Eating a healthy diet contributes to preventing future illness and improving quality and length of life. nutritional status is the state of your health as 15 determined by what you eat. ❑ Nutritional needs based on: Life stage Health-illness considerations Cultural and religious preferences Genetic influences ❑ Good nutrition = disease prevention and health promotion The Human Body Composition Reference Chemical Composition Compartment Man (70kg) Woman (60kg) Proteins 20% 18 % Minerals 6% 6% Water 60% 50 % CHO & Others 1% 1% fat 13% 25% Health care team ❖ Participate in initiatives focused on prevention of health problems. ❖ Educate clients about the benefits of nutritional diets. ❖ Advocate for the nutritional needs of clients. ❖ Develop nutritionally balanced diet plans for clients Role of Registered Dietician ❑Completes comprehensive nutritional assessments. ❑Writes nutritional diagnoses. ❑Plans interventions. ❑Monitors client’s or family’s response to nutritional plan. Nutritional Assessment: nutrition assessment: a comprehensive analysis of a person’s nutrition status To prepare a nutrition assessment, a registered dietitian or other trained healthcare professional uses: Historical information Anthropometric data Physical examinations Laboratory tests Historical information One step in evaluating nutrition status is to obtain information about a person’s 1. Health status 2. Diet history, drug use 3. The health history 4. Family history 5. educational level Nutritional Assessment: nutrition assessment: a comprehensive analysis of a person’s nutrition status To prepare a nutrition assessment, a registered dietitian or other trained healthcare professional uses: Historical information Anthropometric data Physical examinations Laboratory tests Anthropometric Data reveal patterns and indicate trends in a person’s overall 1- nutrition status 2-growth failure in children, 3-wasting or swelling of body tissues in adults 4- obesity Anthropometric Data anthropometric indicators The measurements commonly used are height and weight: These can be used to calculate the body mass index(BMI) In children height and weight results can be compared with standard growth curves which indicate the physical development of child. Body Mass Index (BMI) ❑ An assessment of relative height for weight, expressed as: BMI = weight (kg) / height ()2.m Example : weight=100kg Height=150cm Calculate BMI? BMI Continue…… ❖BMI is used to classify client as underweight, healthy weight, overweight, or obese. ❖Taking into consideration: ✓ Frame size or body composition. ✓ Muscle mass. ✓ Alternative measures to determine height of clients with disabilities that make it difficult to stand straight indicators For the assessment WHO has provided charts both boys & girls( age of 5 years) Growth indicators are used to assess growth, Length/height-for-age. Weight-for-age. Weight-for-length/height. BMI (body mass index)-for-age. Methods of determining body composition and fat distribution : a) Skinfold measurements. a) Circumference measurements. Waist Circumference Waist Circumference: the most practical indicator of fat distribution and central obesity. have a high risk of central obesity-related health problems, such as diabetes and cardiovascular disease. Men> 40 in (>102 cm) Women> 35 in (>88 cm) Waist-to-hip ratio: divide waist measurement by hip measurement: a) “Apple” body type: ratio close to or exceeding 1.0 b) “Pear” body type: ratio below 0.8. Nutritional Assessment: nutrition assessment: a comprehensive analysis of a person’s nutrition status To prepare a nutrition assessment, a registered dietitian or other trained healthcare professional uses: Historical information Anthropometric data Physical examinations Laboratory tests Physical examinations A third nutritional assessment technique is Physical examinations looking for clues for poor nutrition status Nutritional Assessment: nutrition assessment: a comprehensive analysis of a person’s nutrition status To prepare a nutrition assessment, a registered dietitian or other trained healthcare professional uses: Historical information Anthropometric data Physical examinations Laboratory tests Laboratory Tests A fourth way to detect a developing deficiency, imbalance, is to take samples of blood or urine, analyse them in the laboratory, and compare the results with normal values. Laboratory tests are most useful in uncovering early signs of malnutrition before symptoms appear. biochemical indicators….CONT Analysis to blood can be used to determine: **the actual level of nutrients in relation to expected level such as vitamin B 12, folate in white blood cell. biochemical indicators….CONT Urine samples may be used to monitor the baseline excretion of water soluble nutrients. Metabolites of nutrients also appear in the Urine and their levels can be monitored. 24 hour urine collection can be assayed for creatinine to indicate muscle turnover rates or nitrogen content to check protein intake. Laboratory Value: Each laboratory value = only part of the complete assessment data What can we learn from nutritional assessment? The previous techniques can be used to obtain more detailed picture of the dietary intake and nutritional status of population. Many countries such as USA, Canada,…and others by using surveillance to monitor both what people are eating and the effects of diet on disease. Stages In The Development of A Nutrient Deficiency  malnutrition Malnutrition refers to insufficient, excessive, or imbalanced consumption of nutrients. mal = bad Malnutrition is either undernutrition or overnutrition Undernutrition: deficient energy or nutrients. Overnutrition: excess energy or nutrients. Undernutrition and Overnutrition ◦ Undernutrition: ⚫deficient energy or nutrients result from insufficient intake or low body stores. ⚫Causes: becoming extremely thin, Poor wound healing, loss of muscle mass, functional decline, altered immune status, growth faltering, night blindness, bleeding gums, and depression ◦ Overnutrition: ⚫Results from excess energy or nutrient intake ⚫Causes: Obesity, hypercholesterolemia, heart disease, diabetes and toxic levels of stored vitamins  Undernutrition: a global challenge Undernutrition is the most common health problem. Even in the milder form it can weaken the immune system. In developed countries, the diseases of malnutrition are most often associated with nutritional imbalances or excessive consumption. Different Forms of Malnutrition  Dietary Reference Intakes (DRIs) Dietary Reference Intakes (DRI): a set of nutrient intake values for healthy people in the United States and Canada. These values are used for planning and assessing diets and include: Estimated Average Requirements (EAR) Recommended Dietary Allowances (RDA) Adequate Intakes (AI) Tolerable Upper Intake Levels (UL) requirement: the lowest continuing intake of a nutrient that will maintain a specified criterion of adequacy. Used to plan and assess diets of individuals and populations  Nutrient Recommendations: Dietary Reference Intakes (cont’d.) Setting nutrient recommendations: RDA and AI – Recommended Dietary Allowances (RDA): daily amounts of nutrients adequate to meet needs of practically all healthy people in a particular life stage and gender group © Cengage Learning 2017 Copyright © 2017 Cengage Learning. All Rights Reserved.  Nutrient Recommendations: Dietary Reference Intakes (cont’d.) Facilitating nutrition research and policy: EAR – Estimated Average Requirements (EAR): average daily nutrient intake levels estimated to meet needs of half of healthy individuals in a given age and gender group – Used by public health officials to assess intakes of populations and make recommendations © Cengage Learning 2017 Copyright © 2017 Cengage Learning. All Rights Reserved. EAR and RDA Estimated Average Requirements (EAR) – Average amount sufficient for half of population Recommended Dietary Allowances (RDA) – Recommendations to meet needs of most healthy people Set near the top end of the range of EAR © Cengage Learning 2017  Adequate Intakes and Upper Intake Levels Adequate Intakes (AI) – Insufficient scientific evidence to establish EAR – AI value set instead of RDA – Expected to exceed average requirements – Used to assess the diets of individuals Tolerable Upper Intake Levels (UL) – Point where nutrient is likely to be toxic – Helps protect against overconsumption © Cengage Learning 2017 EAR and RDA Compared © Cengage Learning 2017  Nutrient Recommendations: Dietary Reference Intakes (cont’d.) Establishing safety guidelines: UL – Some nutrients are hazardous when consumed in excess – Tolerable Upper Intake Levels (UL): highest average daily nutrient intakes that are likely to pose no toxicity risk to individuals in a life stage and gender group © Cengage Learning 2017 Copyright © 2017 Cengage Learning. All Rights Reserved.  Nutrient Recommendations: Dietary Reference Intakes (cont’d.) Using nutrient recommendations – Values are safe, not minimum, intakes – Reflect average daily intakes over time – Chosen in reference to specific indicators of nutrient adequacy (not just deficiency prevention) – Designed for healthy people – Specific for gender, age, and life stage © Cengage Learning 2017 Copyright © 2017 Cengage Learning. All Rights Reserved. Inaccurate versus Accurate View of Nutrient Intakes 1. If a person’s usual intake falls above the RDA, the intake is probably adequate because the RDA meets the needs of almost all people. 2. A usual intake that falls between the RDA and the EAR is more difficult to assess; the intake may be adequate, but the chances are greater or equal that it is inadequate. 3. If the usual intake falls below the EAR, it is probably inadequate. © Cengage Learning 2017 Establishing Energy Recommendations Estimated Energy Requirement (EER) – Average dietary energy intake to maintain energy balance Healthy body weight Physical activity – No upper level © Cengage Learning 2017  Nutrient Recommendations: Dietary Reference Intakes (cont’d.) Setting energy recommendations – Estimated Energy Requirement (EER): energy intake level predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, and physical activity level – Energy balance is the key © Cengage Learning 2017 Copyright © 2017 Cengage Learning. All Rights Reserved.  Acceptable Macronutrient Distribution Ranges (AMDR) Acceptable Macronutrient Distribution Ranges (AMDR) – Ranges of intakes for the energy-yielding nutrients that are adequate and reduce chronic disease risk – 45–65% of kcal from carbohydrate, – 20–35% of kcal from fat, – 10–35% of kcal from protein © Cengage Learning 2017 Copyright © 2017 Cengage Learning. All Rights Reserved.