nutrients. objectives 1. define nutrients 2. classify nutrients 3. comprehend structure and...
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- OBJECTIVES 1. Define nutrients 2. Classify nutrients 3. Comprehend structure and functions of nutrients
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- NUTRIENTS Nutrients have been defined as chemical substances found in food that cannot be synthesized at all or in sufficient amounts in the body, and are necessary for life, growth and tissue repair. or are organic and inorganic complexes contained in food, which are responsible for the functions of foods and protect the body from disorders. Nutrient or food factor are organic and inorganic complexes contained in food, which are responsible for the functions of foods and protect the body from disorders.
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- NUTRIENTS Nutrients Nutrients include; 1. Proteins Proteins 2. Carbohydrates Carbohydrates 3. Lipids Lipids 4. Vitamins Vitamins 5. Minerals Minerals 6. Water Water
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- CLASSIFICATION OF NUTRIENTS Classification on Basis of Requirement: 1. Macronutrients: Carbohydrates (65 80%) Fats and oils (10-30%) Proteins (7-15%) These ore often called proximate principles because they form the main bulk of food.
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- NTS CLASSIFICATION OF NUTRIE NTS 2. Micronutrients: Minerals Vitamins Require in small amounts i.e milligram to micrgram
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- CARBOHYDRATES (CARBS) Carbohydrates (from 'hydrates of carbon') or saccharides (Greek , skcharon, meaning "sugar") are the most abundant of the four major classes of biomolecules.hydratescarbonGreeksugarbiomolecules providing 4 kcal per gram Carbohydrates provide the largest single source of energy in the diet; providing 4 kcal per gram and satisfy our instinctual desire for sweetness. Carbohydrates are substances having the empirical formula Cx(H2O)y, e.g C6(H2O)6 = glucose (Fig. 2.1).
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- Fig. 2.1 :The structure of glucose, fructose & sucrose
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- CLASSIFICATION OF CARBOHYDRATES The basic building block of carbohydrates is a monosaccharide, often glucose itself. Carbohydrates are classified depending on the number of monomer (sugar) units they contain.
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- CARBOHYDERATES CLASSIFICATION OF CARBOHYDERATES SIMPLE CARBOHYDERATES COMPLEX CARBOHYDERATES MONOSACCHARIDE (Glucose, Fructose, Galactose) DISACCHARIDE (Sucrose, Lactose, Maltose) OLIGOSACCHARIDE (Human milk oligosaccharide) POLYSACCHARIDE (Starch, glycogen, dietary fibers)
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- SIMPLE CARBOHYDRATES: MONOSACCHARIDES The simplest carbohydrates are the monosaccharides, or simple sugars. The three most common monosaccharides are; i. Glucose ii. Fructose iii. Galactose
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- SIMPLE CARBOHYDRATES: DISACCHARIDES Disaccharides are double sugars which contain two monosaccharide units linked together. Examples of disaccharides are: 1. Sucrose (Glucose + Fructose) 2. Lactose (Glucose + Galactose) 3. Maltose (Glucose+ Glucose)
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- SOURCES OF CARBOHYDRATES
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- COMPLEX CARBOHYDERATES: POLYSACCHARIDES Oligosaccharides contain between 3 and 11 monosaccharide residues. Polysaccharides are those with longer chains of monosaccharides. The polysaccharides tend to be insoluble in water, and only some can be used by human beings to produce energy.
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- COMPLEX CARBOHYDERATES: POLYSACCHARIDES Polysaccharides are classified as: 1. Starch Polysaccharide 2. Non-starch Polysaccharide
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- STARCH POLYSACCHARIDES Glycogen is made in the human body and is sometimes known as animal starch. Surplus monosaccharides that are not used to produce energy are converted to glycogen which is stored in liver and skeletal muscles for later use as an energy source. The bodys glycogen stores are relatively small (250 500 g in a 5070 kg adult human); Most of the stored glycogen is released and oxidized within 12 hrs.
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- STARCH POLYSACCHARIDES Starch is an important source of energy for humans. Starch molecules in plants occur as granules in the form of amylose and amylopectin. Starch is liberated during cooking when the starch granules rupture because of heating. As much as 1020% of dietary starch in individual foods and mixed meals is not digested to glucose; It is referred to as Resistant Starch.
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- STARCH Foods containing large amounts of starch include; 1. Cereals (e.g. wheat, rice, maize), 2. Root vegetables (e.g. potato) and 3. Legumes (e.g. kidney beans, baked beans) There is little starch in most fruits and vegetables, apart from bananas, roots and tubers.
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- NON-STARCH POLYSACCHRIDE Some plant polysaccharides in foods are resistant to hydrolysis by human digestive enzymes and are referred to as. Non-starch Polysaccharide. They form the main part of dietary fiber. mainly non-starch polysaccharide, present in plants. Cellulose, hemicellulose, lignin, pectin and gums are mainly non-starch polysaccharide, present in plants.
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- FUNCTIONS OF CARBOHYDERATES Carbohydrate provides 4 KCal per gram. The body can obtain all its energy from protein and fats.KCal However, the neurons generally cannot burn fat and need glucose for energy; Carbohydrates and their derivatives play major roles in the working process of the immune system, fertilization, blood clotting, and development.immune systemfertilizationblood clottingdevelopment
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- FUNCTIONS OF CARBOHYDERATES Diets high in carbohydrate are usually associated with lower prevalence of obesity, heart disease, non-insulin-dependent diabetes. Carbohydrates (dietary fiber) helps in digestion and in preventing, mainly by absorbing water, and increasing the bulk of the diet & stool. Carbohydrates (dietary fiber) helps in digestion and in preventing constipation, mainly by absorbing water, and increasing the bulk of the diet & stool.constipation Because it facilitates the rapid passage of materials through the intestine, fibre may be a factor in the control of diverticulitis, appendicitis, haemorrhoids.
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- BENEFICIAL EFFECTS OF CARBOHYDRATES The bulk in high-fibre diets may contribute a feeling of fullness or satiety which may lead to less consumption of energy, and this may help reduce the likelihood of obesity. High intakes of dietary fibers may also reduce the risk of large bowel cancer. Fibre may bind the carcinogenic substances and speed their transit through the gut. Fiber also increases the amount of water in the faeces, thereby diluting the effect of any carcinogens.
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- RECOMMENDED INTAKE OF CARBOHYDRATE The Food and Agriculture Organization and World Health Organization jointly recommend that 55-75% of total energy intake should be from carbohydrates, but only 10% directly from sugars (simple carbohydrates).Food and Agriculture OrganizationWorld Health Organization Most Pakistani diet, contains excessive amount of carbohydrate, providing as much as 90% of total energy intake.
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- DIETARY PROTEINS
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- The word protein means that which is of first importance. Proteins are complex organic nitrogenous compounds containing nitrogen and often sulphur in addition to carbon, hydrogen, oxygen. For an adult man who weighs 70 kg, about 16% of body weight is made by protein (i.e. about 11 kg); with 43% in muscles, 16% in blood and 15% in skin.
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- AMINO ACIDS Amino acids are the building blocks of protein. The amino acids are linked in chains through peptide bonds. : There are 20 amino acids required for protein synthesis and are divided in two groups: cannot be synthesized by the body) 1. Essential Amino Acids (cannot be synthesized by the body) 2. Non-essential Amino Acids (can be synthesized by the body)
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- AMINO ACIDS There are 9 EAA including; Leucine, Isoleucine, Lysine, Methonine, Threonine, Valine, Tryptophane, Phenylalanine and Histidine.
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- FUNCTIONS OF PROTEIN Functions of proteins include: i. Growth and development of the body; ii. Maintenance, repair & replacement of damaged tissues; iii. Part of metabolic & digestive enzymes and hormones; iv. Maintenance of osmotic pressure; v. Protein are essential for immunity; vi. Protein can also supply energy (4 kcal per gram)
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- contains all the amino acids needed to build new proteins. Animal sources of protein tend to be complete. 1. Biologically Complete Protein contains all the amino acids needed to build new proteins. Animal sources of protein tend to be complete. 2. Biologically Incomplete Proteins lack one or more amino acids that the body can't make at all or create by modifying another amino acid. These usually come from fruits, vegetables, grains, and nuts. These usually come from fruits, vegetables, grains, and nuts. Adults need a minimum of 0.8 to 1 gram of protein per kilogram of body weight per day. Adults need a minimum of 0.8 to 1 gram of protein per kilogram of body weight per day. CLASSIFICATION OF DIETARY PROTEINS
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- SOURCES OF PROTEIN Humans obtain protein from two main dietary sources: 1. Animal Sources, also called First Class Proteins as they are biologically of higher value. Animal Sources include milk, eggs,
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