Nutrition and Health (ANT1005) PDF

Nutrition and Health (ANT1005) © 123RF  TOPIC 2 MACRONUTRIENTS © 123RF  MAIN INTENDED LEARNING OUTCOME Describe the roles of macronutrients and its importance for health 3 CARBOHDRATES (CHO) WHAT ARE C...

Nutrition and Health (ANT1005) © 123RF  TOPIC 2 MACRONUTRIENTS © 123RF  MAIN INTENDED LEARNING OUTCOME Describe the roles of macronutrients and its importance for health 3 CARBOHDRATES (CHO) WHAT ARE CARBOHYDRATES (CHO)? (Latin Word) = carbon and water molecule (CH2O)n Carbohydrates are organic compounds that contain carbon (C), hydrogen (H) & oxygen (O) in the ratio of 1 : 2 : 1, respectively. C : H : O 6 : 12 : 6  CHO = SUNSHINE’S SUGAR CH2OH C O H H H C C OH H OH OH C C H OH Glucose Through the process of photosynthesis, plants use carbon dioxide from the air, water from the soil & energy from the sun to produce carbohydrates & oxygen. Photo synthesis = “light” + “combining to form a product” © 123RF  CHO – CLOSE-UP Carbohydrates are made up of building blocks called monosaccharides (“single sugars”) mono = 1 saccharide = sugar Building blocks = Carbohydrates monosaccharides  CLASSIFICATION Carbohydrates are divided into 4 main categories, depending on the number of saccharide/ sugar units they contain. 1. Monosaccharides (one) 2. Disaccharides (two) 3. Oligosaccharides (a few) 4. Polysaccharides (many)  CLASSIFICATION Carbohydrates are divided into 4 main categories, depending on the number of saccharide units they contain. Simple 1. Monosaccharides (one) CHO 2. Disaccharides (two) Complex 3. Oligosaccharides (a few) CHO 4. Polysaccharides (many)  MONOSACCHARIDES “SINGLE SUGARS” Major building blocks of dietary sugars, starches & fibre. The most common monosaccharides in our diet are: Glucose – also known as dextrose or blood sugar Fructose – also known as levulose or fruit sugar Galactose - is part of lactose (milk sugar)  fructose glucose galactose Monosaccharides Disaccharides sucrose maltose lactose  DISACCHARIDES – SUCROSE Sucrose = Glucose + Fructose Sucrose is also known as table sugar. Primary food source: – Sugar cane & sugar beets Also found naturally in: – honey, maple syrup, fruits & vegetables  DISACCHARIDES – SUCROSE Refined sugars are the most common form of sucrose; examples are: – Castor sugar, syrups, jam, soft drinks Foods high in refined sugars provide our bodies with energy, but little or no other nutrients. These foods are said to contain “empty calories”  When bees make honey, they breakdown sucrose into glucose & fructose, which yields a sweeter taste. Nutritionally, honey and sugar are very similar after digestion, since honey only contains trace amounts of other nutrients. © 123RF  DISACCHARIDES – LACTOSE Lactose = Glucose + Galactose Lactose is also known as milk sugar. Primary food source: – Milk and milk products Breast milk has a higher concentration (~7g/100ml) of lactose than cow’s milk (~4.5g/100ml); therefore, breast milk tastes sweeter than cow’s milk.  DISACCHARIDES – LACTOSE Lactose stays in the intestinal tract longer than other disaccharides before being digested. Lactose encourages the growth of certain beneficial bacteria, which helps to eliminate waste, & synthesize certain vitamins in the large intestine. Some people are lactose intolerant, due to the lack of the enzyme lactase, which is used to digest lactose.  DISACCHARIDES – MALTOSE Maltose = Glucose + Glucose Maltose is produced whenever starch breaks down. – In plants, when seeds germinate – In humans, when the body digests starch Maltose is found in beer & malted beverages as a result of the fermentation process.  GRAINS (Brown Rice & Whole meal Bread) Bran → High in fiber → ~14% of the grain Endosperm → small amount of vit. & minerals → protein, CHO, iron, soluble fiber → forms ~83% of the grain Germ → nutrient-rich (antioxidants, vit. Bs & E, healthy fats) → ~2.5% of the grain CHO is stored in grains in the form of starch. Our digestive enzymes act on starch & break them into glucose molecules  absorbed & converted to energy  COMPLEX CHO Complex CHO contain many monosaccharide units 1. Oligosaccharides (a few) 2. Polysaccharides (many)  OLIGOSACCHARIDES Oligosaccharides are short-chain complex CHO with 3 to 10 units of monosaccharides (oligo means “few”) Component of fibre from plant tissue Primary food sources of oligosaccharides are: – Dry beans, peas & lentils Two common oligosaccharides are: – Raffinose sources: beans, cabbage, broccoli – Stachyose source: chinese artichoke, various beans and legumes  OLIGOSACCHARIDES Oligosaccharides are not easily broken down by our digestive system. They are metabolized by intestinal bacteria, which causes the gaseous effects (flatulence) of eating foods such as beans.  POLYSACCHARIDES Polysaccharides are long chains of monosaccharides. (poly = many) – Straight chains – Branched chains The way the monosaccharides are linked make them digestible (starch) or indigestible (dietary fibre). Three types of polysaccharides important in nutrition are: starches, glycogen & fibre. POLYSACCHARIDES – STARCHES Sources of starch in our diet are: – Grains (rich source): rice, wheat, corn, & oats; made into noodles, bread, buns, biscuits & breakfast cereals. – Legumes(moderate): beans, peas, lentils & soybeans. – Tubers (rich source): potatoes, sweet potatoes, yam & cassava. POLYSACCHARIDES – STARCHES Our digestive enzymes act on starch & split them into glucose molecules  absorbed & converted to usable energy. A small portion of the starch in plants may remain enclosed in cell structures and escape digestion in the small intestine. This is known as resistant starch. CHO IN FOODS Content of CHO based on per 100g of food Ref: Food Composition Guide Singapore Food Item CHO Starch Sugar (g) (g) (g) Rice, white, cooked 31.1 31.0 0.1 Biscuit, chocolate 76.1 48.2 27.9 Bread, white 52.0 49.8 2.2 Potato, without skin, 20.0 18.9 1.2 boiled Banana (pisang mas) 22.9 4.4 18.5 Milk, fluid, whole 4.7 0.0 4.7 Cola, soft drink 10.9 0.0 10.9 POLYSACCHARIDES – GLYCOGEN The storage form of carbohydrate in animals and human. Made up of many glucose molecules linked together in a highly branched structure. The highly branched structure allows glycogen to be broken down quickly when glucose is needed. POLYSACCHARIDES – GLYCOGEN 2 major sites of glycogen storage in our body is: the liver & the muscles. Liver Is broken down to provide glucose to glycogen the body when blood glucose level drops Muscle Provides glucose for the muscle during glycogen activity Liver glycogen provides 100-150mg of glucose per minute for up to 24 hours without eating. Fibre POLYSACCHARIDE – DIETARY FIBRE Dietary fibre are the structural parts of plants. Most dietary fibre are polysaccharides. Humans do not have the digestive enzymes to break the bonds between the monosaccharide units, so most fibre pass through the body undigested Negligible energy Intestinal bacteria can break down some fibre by fermentation, yielding water, gas & short-chain fatty acids, which are beneficial to the colon.  What is the daily recommended servings of Fruit and Vegetables?  DIETARY FIBRE – CLASSIFICATION & BENEFITS Soluble Fibre Insoluble Fibre Dissolve in water → viscous gel Tough, fibrous cell wall of fruit, Easily digested by bacteria in vegetables & grains, that do not the colon (fermentable) dissolve in water Food sources: fruits, legumes, Food sources: whole grains oats, barley (bran, brown rice), vegetables, Benefits: fruits (peels & seeds) Reduce the absorption of Benefits: dietary cholesterol in small Regulate bowel movement intestine by adding bulk to fecal Regulate blood sugar levels matter Helps in weight help hydrate and move management fecal matter through the Preferential growth of intestines health promoting Reduce risk of microorganism in gut diverticulosis, colon and rectal cancers 35% soluble 65% insoluble DIETARY FIBRE – CLASSIFICATION & BENEFITS Soluble Fibre Reduce the absorption of cholesterol in small intestine Have you heard of these fibre supplements? DIETARY FIBRE - RECOMMENDATION Health Promotion Board recommended daily fibre intake: 20g for women 26g for men  MY HEALTHY PLATE Source: Health Promotion Board  ACTIVITY 1 Estimate the total energy contributed by this enriched fibre white bread (100g). Amount Energy (kcal) (gram) Soluble dietary fibre 3 Insoluble dietary fibre 1 Starch 40 Fat 2.5 Protein 9.5 Total kcal ?  ACTIVITY 1-answer Estimate the total energy contributed by this enriched fibre white bread (100g). Amount Energy (kcal) (gram) Soluble dietary fibre 3 Negligible Insoluble dietary fibre 1 Negligible Starch 40 40 x 4 = 160 Fat 2.5 2.5 x 9 = 23 Protein 9.5 4 x 9.5 = 38 Total = 221kcal  DIETARY FIBRE IN FOODS Per 100g Per Serving Edible portion Food Name Fibre (g) Weight (g) Fibre (g) Apple, raw, with peel 2.0 102g (1 whole) 2.0 Banana (pisang mas) 2.0 50g (1 whole) 1.0 Orange, naval, raw 2.2 160g (1 whole) 3.5 Spinach, boiled, drained 2.4 100g (¾ mug) 2.4 Kangkong, boiled, drained 1.9 100g (¾ mug) 1.9 Bread, white 2.7 50g (2 slices) 1.4 Bread, whole meal 6.5 60g (2 slices) 3.9 Rice, white, cooked 0.4 200g (1 bowl) 0.8 Rice, brown, cooked 1.5 230g (1 bowl) 3.5 Content of fibre based on per 100g of food. Ref: Food Composition Guide Singapore  DIETARY FIBRE - OVERCONSUMPTION Very high dietary fibre intakes (e.g. 60 g per day) can pose some health risks: Phytate which is associated with fibre can bind micronutrients such as zinc & iron. Less is available for absorption into the body. The more fibre in the diet, the more water is needed to prevent stools from becoming hard & difficult to eliminate. If not enough water is consumed, intestinal blockage can occur when large amounts of fibre are consumed. A sudden increase in fibre intake  intestinal gas formation & bloating.  FUNCTIONS OF CHO 1. To provide energy as the primary fuel. 2. As storage energy in the form of glycogen. 3. As storage energy in the form of fat. 4. To spare protein from being used as energy source. 5. To promote gastrointestinal health.  FUNCTIONS OF CHO 1. To provide energy as the primary fuel 1 gram of CHO = 4kcal CHO is the main supply of energy for the body. Glucose is the primary fuel source for most cells in the body, such as: – the brain and nervous system, red blood cells, intestinal mucosa, & retina Note: Fibre does not provide energy  FUNCTIONS OF CHO 2. As storage energy in the form of GLYCOGEN Food Energy for daily needs Extra/Excess CHO (beyond needs) GLYCOGEN Blood glucose low Liver Muscle Pancreas releases glycogen glycogen glucagon Liver glycogen broken down to glucose & released into blood  FUNCTIONS OF CHO 3. As storage energy in the form of FAT Food Energy for daily needs Extra/Excess CHO (beyond needs) GLYCOGEN Storage for future needs FAT Unlike glycogen, fat cells have unlimited storage capacity.  FUNCTIONS OF CHO 4. To spare protein from being used as energy source When there is insufficient energy, protein is broken down to make glucose to fuel the brain, nerve cells & red blood cells. Thus protein cannot fulfil its main function. Total muscle mass is reduced. When there is adequate energy in the diet (from CHO or fats), they have a protein-sparing effect; i.e. allows (spares) protein to perform its vital functions in the body & not be used as an energy source.  FUNCTIONS OF CHO 5. To promote gastrointestinal health Insoluble fibre contribute to fecal bulk & normal laxation. Soluble fibre & resistant starch are fermented by colonic bacteria. A byproduct, butyric acid (a short-chain fatty acid), is the preferred energy source for colon cells. Certain indigestible oligosaccharides may benefit gastrointestinal tract health via fermentation & proliferation of desirable bacterial species.  RECOMMENDED INTAKE CHO should make up 50% of total daily caloric intake. To spare protein and prevent ketosis a person needs at least 50 - 100g of CHO per day. Complex CHO should be the primary CHO source in our diet. A diet rich in high fibre complex CHO can help reduce risk for diabetes, heart disease, & some cancers. OVERCONSUMPTION OF CHO CHO are ultimately broken down to glucose for energy. Excess glucose is stored as glycogen. When glycogen storage capacity is full, the liver converts glucose to fat. Adverse health effect of too much CHO: Micronutrient deficiencies  Sugar Our body converts the excess sugar we eat into fat and stores it. By eating large amounts of sugary foods, we place ourselves at risk of obesity, diabetes, heart disease and other health problems World Health Organisation current recommendation, (2015), is that sugars should make up less than 10% of total energy intake per day. It further suggests that a reduction to below 5% of total energy intake per day (6 tsp) would have additional benefits.  Sugar The suggested limits on intake of sugars in the draft guideline apply to all – monosaccharides (such as glucose, fructose) – disaccharides (such as sucrose or table sugar) that are added to food by the manufacturer, the cook or the consumer, – sugars that are naturally present in honey, syrups, fruit juices and fruit concentrates. Dietary Guidelines - Sugars Allowance : 70 can support human growth as long as energy intake is adequate. 80  Complementary Proteins Vegetarians can improve the quality of proteins in their diets by combining different plant sources. 2 incomplete plant proteins eaten together supplies the AA lacking in each other - they complement each other’s lack of specific essential AAs. IsoLeucine Lysine Methionine Tryptophan Legumes / √ √ Beans (except soy) Grains √ √ Nuts/ Seeds √ √ √ 81  Complementary Proteins It is not necessary to balance AAs at every meal if protein intake is varied & energy intake is sufficient. Vegetarians can receive all the AAs they need over the course of a day by eating a variety of plant sources. When diet is very restricted, however, quality & quantity of protein will be impacted & protein deficiency can develop. 82 83 Recommended Intake for Protein Recommended Dietary Allowance 0.8g/kg body weight E.g. a 40 year old man who weighs 70 kg would require: 70kg x 0.8g = 56g protein Protein recommendation can also be expressed as 20% of the daily energy requirement. 84  Recommended Intake for Protein When do protein needs increase? During periods of active growth – infancy, adolescence Protein needs also increase – pregnancy (+ 9g)/ lactation (+ 19 - 25g) Severe physical stress  increase body’s need for protein – during illness (infections, fever); after injury (surgery, wound healing, burns) Sports/ Intense Exercise – RDA vary with type of exercise – Exercise – 1.2 -1.7g protein/kg body weight – Used for building muscle mass, repair muscle damage during exercise 85  Protein Content of Foods Food (per 100g edible portion) Protein (g) Energy (kcal) Chicken curry, home-cooked 11.6 180 Chicken, grilled, skinless 20.4 196 Mackerel, fried 27.8 190 Egg boiled 13.2 151 Curry, dhal 6.5 79 Long beans w tempeh, stir-fried 10.7 243 Luncheon meat, canned 9.3 313 Fish ball, boiled 8 68 Tofu, silken* 4.6 40 Tau kwa* 10.5 118 86 Source: Food Composition Guide Singapore; *from food product label  Protein Deficiency Protein-Energy Malnutrition (PEM) is a result of long-term inadequate intakes of energy & protein that leads to wasting of body tissues & increased susceptibility to infection. Protein-Energy Malnutrition (PEM) KWASHIORKOR MARASMUS (main deficiency: (main deficiency: protein protein) + energy) Occurs because of inadequate protein intake or Inadequate intake of protein, energy, vitamins & infections. minerals. Usually characterized by pot belly  enarged liver Severe weight loss & muscle wasting: negligible body fat. Edema is present. Severe growth retardation. Some weight loss & muscle wastage occurs. No detectable edema or fatty liver. 87  Excessive Protein Intake May unduly burden the High saturated fat intake  kidneys, as kidneys must associated with higher excrete the end products of incidence of heart disease protein metabolism High protein Calcium Excess protein is excretion diets, especially increases as converted to fat diets rich in animal  overweight/ protein intake protein - usually obesity increases  high in saturated fat osteoporosis & cholesterol Diets high in animal protein have been linked to pancreatic, colon, kidney, breast & prostate cancers. 88 Nutrition and Health (ANT1005) LIPID © 123RF.com  Classification of lipid LIPIDS Simple Compound Derived Lipid Related Lipids Lipids Lipids Compounds Phospholipids Fat-soluble Lipoproteins Vitamins Sterol (e.g. (A, D, E, K) Triglycerides cholesterol) Steroid hormones 1. SIMPLE LIPID - Triglycerides (TG) The predominant lipid in foods & in the body Account for nearly 95% of the lipids ingested in all forms of food & a similar % in body lipids. Also called TRIACYLGLYCEROLS or neutral FATS. Esters composed of 3 molecules of fatty acids linked to 1 molecule of glycerol. Has more carbons and hydrogens in proportion to oxygen → supply more energy per gram than carbohydrates. 1. SIMPLE LIPID – Triglycerides (TG) In foods lipids that are solid at room temperature are called FATS. lipids that are liquid at room temperature are OILS. In the body lipids are stored in fat cells (adipocytes) in the adipose tissues found under the skin or around organs. 1. SIMPLE LIPID – Triglycerides (TG) Degree of Saturation - Fatty acids Saturated Fat - Every C in the FA chain is connected to 2C & 2H i. No C=C bonds present: saturated fatty acid (SFA) H H H H H H H H H O H C C C C C C C C C C OH H H H H H H H H H Saturated fats: Triglycerides in which the FA are saturated 1. SIMPLE LIPID – Triglycerides (TG) ii. One C=C bond present in the fatty acid chain: monounsaturated fatty acid (MUFA) H H H H H H H H H O H C C C C C C C C C C OH H H H H H H H Monounsaturated fats: Triglycerides in which most of the fatty acids are monounsaturated 1. SIMPLE LIPID – Triglycerides (TG) iii. Two or more C=C bonds present in the fatty acid chain: polyunsaturated fatty acid (PUFA) H H H H H H H H H O H C C C C C C C C C C OH H H H H H Polyunsaturated fats: Triglycerides in which most of the fatty acids are polyunsaturated Whitney E., Rolfes S R. (2016).Understanding Nutrition. The Lipids: Triglycerides, Phospholipids, and Sterols (pp. 138) ‘14e; USA: Wadsworth, Cengage Learning 1. SIMPLE LIPID – Triglycerides (TG) More about Fatty Acid (FA) Degree of Saturation Effect on firmness Degree of saturation influences the firmness of lipids at room temperature Saturated animal fats: more firm  solid at room temperature Polyunsaturated vegetable oils  liquid at room temperature Not all vegetable oils are polyunsaturated: cocoa butter, palm oil & coconut oil are saturated. They are firmer than most vegetable oils because of saturation, but softer than most animal fats because of their shorter chains (8 to 14 carbon long). The shorter carbon chain, the softer the fat is at room temperature.  1. SIMPLE LIPID – Triglycerides (TG) More about Fatty Acid (FA) Degree of Saturation Effect on firmness Saturated FA tends to stack together → tends to be solid (or more firm) at room temperature The mixture of saturated and unsaturated FA does not stack neatly because unsaturated FA bend at the double bond (s) → tends to be liquid (or less firm) at room temperature Whitney E., Rolfes S R. (2016).Understanding Nutrition. The Lipids: Triglycerides, Phospholipids, and Sterols (pp. 138) ‘14e; USA: Wadsworth, Cengage Learning 1. SIMPLE LIPID – Triglycerides (TG) More about Fatty Acid (FA) Degree of Saturation Effect on stability All lipids become spoiled when exposed to oxygen  oxidation  rancid Oxidation of fats produces a variety of compounds that smell and taste rancid Saturated fats: more stable/resistant to oxidation  least likely to become rancid Polyunsaturated fats spoil most readily  double bonds are unstable  Hydrogenation H H H H H H H H H O H C1 C2 C3 C C C C C C C OH H H H H H H H H H A chemical process by which hydrogen atoms are added to a double bond in a monounsaturated or polyunsaturated fatty acid This reduces the number of double bonds  the fat is more resistant to oxidation Hydrogenation makes a fat more saturated It produces trans fatty acid  TRANS-Fatty Acid Natural Commercially occurring VS created Created in an industrial process that adds hydrogen to liquid Produced in the gut of vegetable oils to make them more some animals and foods made from these solid → partially hydrogenated oils animals (e.g., milk and Source: potato chips, fried foods, meat products) may baked goods including cakes, pie contain small crusts, biscuits, frozen pizza, quantities of these fats. cookies, and hard margarines Health effect: little effect on blood lipids Health effect: ↑ risk of developing heart disease, stroke and type 2 diabetes. TRANS-Fatty Acid Cheap Extended shelf life Desirable taste and texture TRANS-Fatty Acid Trans Fat Free claim