Introduction to Nutrition

Transcription

1 Introduction to Nutrition

2 What is meant by Nutrition Definition:- It means that food is taken in and uses for many purposes (maintenance and production).

3 Introduction to Nutrition: what you will learn Nutrition - one of the functions of life Types of nutrition What are the Essential Nutrients What are Under nutrition and Over nutrition What are the Common Nutritional Problems Deficiencies - How They Develop and Why

4 Types of Nutrition There are two main types of nutrition: 1-Autotrophic(self-feed) 2-Heterotrophic(other-feed)

5 Types Of Nutrition AUTOTROPHS HETEROTROPHS

6 1- Auto trophic (auto:self,trophos:feed) This type of nutrition divided into: A-Photoautotrophic(Photosynthesis):it is the type of nutrition in which the organism prepare their food by their own in presence of sun light, carbon dioxide and water. Ex. all green plants and algae.

7 B-Chemoautotrophic (Chemosynthesis): in this type of nutrition the organism can produce their food by the help of chemical activities( synthesis organic compounds by oxidizing inorganic substances), they don t require for sun light, this type of nutrition can be possible in night time. The common example are iron bacteria and sulphur bacteria which oxidizing sulphur to sulphat.

8 2-Heterotrophic (heteros, other: trophos, feed): in general, animals fall into three categories: 1- Herbivores:eat mainly plants 2- Carnivores: eat only meat 3- Omnivores: eat meat as well as plants

9 Essential Nutrients: what is the Nutrient: it is the substances that are required for the nourishment of an organism There are two types of nutrients essential to life: Macronutrients Nutrients required in large amounts carbohydrates, proteins, fats. They are needed for energy production Protein is needed for growth and maintenance functions Water and fibre are also needed in significant amounts Micronutrients Nutrients required in small amounts - vitamins, minerals. They are needed for numerous functions)regulate body processes,maintain the body).

10 Essential Nutrients - Macronutrients Macronutrient Energy Provision in average adult diet Carbohydrates 50% sugars(glucose) and complex carbohydrates(starch, and fiber). they provide body with energy. Fats 35% saturated(butyric, capric,caprylic, caproic) are found primarily in animal products such as meat, cheese,butter. and unsaturated( oleic, linoleic,linolenic) fats include plant products such as vegetable oil, nut,seeds. Uses to provide energy and protection of delicate organ. Protein 15% provide essential( lysine, leucine, isoleucine) and non-essential(serine, arginine,cysteine) amino acids. There are high quality proteins, includes animal foods such as milk, eggs, meat, fishes.low quality proteins includes plants foods such as, bean,peas and cereal grains. Uses for growth, cell repair, to make enzymes and antibodies.

11 Essential Nutrients - Micronutrients Minerals: are none caloric inorganic chemical compounds found in a wide variety of foods. Divided into two classes: 1-Major elements:- required in large amounts(bulk). Such as Ca, Mg, K, P, Na, S and Cl. 2- Minor(trace) elements:- required in small amounts. Such as Fe, Zn, Cu, Mn, I, Se, Cr, Co, Mo etc. Minerals are needed for 1-formation of bones and teeth.2-for growth of body cells, especially, blood cells.3- for the essential components in various body fluids.4- work as helpers in the body. Vitamins:- are none caloric organic substances found in a wide variety of food that performed specific function in the body, needed to promote growth and other body activities. 1-Fat-soluble Vit. (can be stored in the body fat) ex.a,d,e, and K 2-Water-soluble Vit.(cannot be stored in the body) ex.b group and C

12 The Criteria for Nutrient Essentiality The nutrient. 1-Is essential for one or more of the functions of life 2- Can not be made in the body.. 3-Can be made inadequately quantities needed by the body. 4-If deficient, a recognizable loss of function. 5-. Is required by cells and must be obtained from dietary sources

13 Essential Nutrients and Life Functions Life Functions Key Essential Nutrients Movement Calcium and vitamin D bones, Protein and potassium - muscles Respiration Vitamin B metabolism, iron oxygen transport, Iodine: control metabolic rate through thyroid hormon Sensitivity B vitamins - central and peripheral nerves Iron and iodine - intellectual development Nutrition Zinc and iron - appetite Excretion Water, sodium and potassium - urine excretion Reproduction Iron and B vitamins fertility and pregnancy outcome Growth Energy, protein, iron, zinc, vitamin A infant growth Defence Protein, vitamin A and zinc - immune function

14 Nutrition and Health Nutrition plays a central role in all life functions Animals often spend a large amount of time and energy to obtaining food and feeding, but we humans do not Nowadays we can choose between nutritious/non-nutritious foods Food choice makes a big difference to our health and the risk of: deficiency-under nutrition excess- over nutrition Factors affecting food selection(choice): 1- habits usually established in childhood 2- Demographic factors(age,gender,income, culture background) 3- cost of food(expensive or in expensive) 4- convenience of shopping and preparing 5- education about what is nutritious( nutritional content) and healthy. 6-culture and religion

15 Characteristics of a nutritious food it has four characteristics: 1-Adequate: a food that provides enough calories, essential nutrients and fiber to keep a person healthy. 2-Balanced:a food in which are chosen to provide calories,essential nutrients and fiber in the right proportions. 3-Moderate : a food that avoid excessive amounts of calories or any particular nutrient. 4-Varied:A Food in which you eat a wide selection to get necessary nutrients.

16 What are the Common Nutritional Problems? These can be classified relating to the supply of macro and micronutrients: Under nutrition: a deficiency of one or more nutrients.iron, calcium, vitamin D, folacin, vitamin B12 and protein-energy. An under nutritional individual will:. 1 -Use up stored fat and carbohydrates 2 -Break down its own proteins 3- Lose muscle mass 4- Die or suffer irreversible damage Over nutrition: an excessive intake of one or more nutrients.referring to nutrients providing energy(calories) e. g. saturated fats, sugar causes obesity. Obesity contributes to diabetes (type 2), cancer of the colon and breasts, heart attacks, and strokes.

17 Common Problems of Under Nutrition Nutrient At-Risk Group(s) Consequences Water All ages Dehydration, collapse and death Protein/Energy Infants/Teen-agers Reduced growth/anorexia nervosa Iron Infants Anaemia, poor learning ability Zinc Children/Teen-agers Reduced height and poor immunity Fiber All ages Constipation Iron Menstruating women Anaemia Folacin (B9) Pregnant women Birth defects Vitamin D Pregnant Asian women Reduced bone development in infants Vitamin B12 Vegetarians and elderly Fatigue, poor concentration, anaemia Calcium and vitamin D Elderly Osteoporosis and increased risk of fracture Vitamin C Elderly Increased risk of stroke

18 Common Problems of Over Nutrition Nutrient At- Risk Group(s) Consequences Energy All ages Obesity Sugar - sucrose All ages Dental caries Sugar - fructose Adults Gout, liver disease Saturated Fats Adults Heart disease Animal Protein Adults Osteoporosis Sodium All ages High blood pressure Sodium Elderly Heart failure and osteoporosis Iron Genetically predisposed Haemo chromatosis Vitamin A from food/supplements Water Adults and elderly Elderly and those on anti depressants Osteoporosis Sodium depletion hypo natraemia

19 Under Nutrition VS. Over Nutrition They are usually mild in degree but if they are long-standing they can produce significant adverse health effects Many of them will be adequately addressed by: 1- eating a healthy diet 2- limiting intake of alcohol 3- adequate exercises The extremes of life very young and old, are most at risk of under nutrition Socio-economic deprivation is still a significant risk factor for both under nutrition and over nutrition Education is often a vital part in resolving both types of problems

20 Development of a Nutritional Deficiency 1-State of Negative Balance 2-Decline in Tissue Stores 3-Alteration in Function -Symptoms -Physical Signs -Organ Failure 4-Death

21 Energy input and output When energy (kilocalories) input equals energy output, body weight remains constant. When energy input exceeds energy output, body weight increases(obesity). When energy output exceeds energy input, body weight decreases(this called negative balance state).

22 State of Negative Nutrient Balance: Causes 1. Inadequate Intake Loss of appetite Poor quality diet 2. Reduced Absorption Diet: tea inhibits iron absorption Diseases causing malabsorption 3. Increased Losses Sweating sodium loss Diarrhea sodium, potassium 4. Increased Needs Growth and pregnancy 5. Altered Metabolism Disease: liver and kidney Drugs, alcohol, genetic variation

23 Time Scale for the Development of a Deficiency State Days Water; 2-7days - dehydration, renal and circulatory failure Weeks Protein/Energy 8 weeks - death from respiratory failure Vitamin B1; 2-8 weeks - fatigue, neurological deficit and cardiac failure Months Potassium; 2 months - fatigue, muscle weakness and necrosis Zinc; 4 months - loss of appetite, loss of night vision and infections Vitamin C; 4 months - fatigue, haemorrhage and sudden death Vitamin B 2-6 months - fatigue, skin changes, inanition and infection Years Vitamin A; 2 years - loss of night vision, infections Vitamin B12; 4 years - fatigue, pernicious anemia Decades Calcium; 3-4 decades - osteoporosis and fractures Chromium; decades - glucose intolerance, type II diabetes

24 The end Thank you for your attention