macronutrient and micronutrient.pdf midwifery
- 1. Human Nutrition Fikirte Gedamu(BSc, MpH in Nutrition) October, 2024 1
- 2. Macronutrients • Are nutrients that are required by our body in larger quantities on a daily basis and need to be transformed in to smaller units by the body in order to give essential function in the body processes. -These include 1. Carbohydrates 2. Proteins 3. lipid 2
- 3. 1. CARBOHYDRATES: • Carbohydrates are substances having the empirical formula • Cx(H2O)y , e.g C6(H2O)6 = Glucose: ✓ the basic building block of carbohydrates is a monosaccharide, often glucose itself. • Carbohydrates that can be digested and absorbed in the human small intestine are referred to as ‘glycaemic’ carbohydrates. • Some plant polysaccharides in foods are resistant to hydrolysis by human digestive enzymes and are referred to as ‘dietary fibre’ 3
- 4. Types of carbohydrate 1. Simple carbohydrate: sometimes called “sugars” or “simple sugars.” There are 2 types of simple carbohydrates: monosaccharides and disaccharides. • Monosaccharides: contain just one sugar unit, so they’re the smallest of the carbohydrates. (The prefix “mono-” means “one.”) The small size of monosaccharides gives them a special role in digestion and metabolism. ✓There are 3 monosaccharides: 1. Glucose 2. Fructose 3. Galactose 4
- 5. Cont… 1. Glucose • In humans, glucose is one of the most important nutrients for fueling the body. It’s especially important for the brain and nervous system, which aren’t very good at using other fuel sources. • Muscles, on the other hand, can use fat as an energy source. (In practice, your muscles are usually using some combination of fat and glucose for energy. • Food sources of glucose: Glucose is found in fruits and vegetables, as well as honey, corn syrup, and high fructose corn syrup. ✓All plants make glucose, but much of the glucose is used to make starch, fiber, and other nutrients.
- 6. Cont… 2. Fructose • Fructose is special because it is the sweetest carbohydrate. • Plants make a lot of fructose as a way of attracting insects and animals, which help plants to reproduce. For example, plants make nectar, which is high in fructose and very sweet, to attract insects that will pollinate it. • Food sources of fructose: Fruits, vegetables, honey, high fructose corn syrup. 3. Galactose • Food sources of galactose: Galactose is found in milk (and dairy products made from milk), but it’s almost always linked to glucose to form a disaccharide (more on that in a minute).
- 7. Cont… • The second type of simple carbohydrates is disaccharides. They contain two sugar units bonded together. There are 3 disaccharides(Compound sugar): 1. Maltose (glucose + glucose): germinating seeds 2. Sucrose (glucose + fructose): Most fruits and vegetables contain a mixture of glucose, fructose, and sucrose. e.g usually sugar cane or sugar beets) to make refined table sugar. 3. Lactose (glucose + galactose): it is found in dairy products like milk, yogurt, and cheese.
- 8. Cont… 2. Complex carbohydrate: are also called polysaccharides, because they contain many sugars. There are 3 main polysaccharides: 1. Starch: Starch is the storage form of carbohydrate in plants. Plants make starch in order to store glucose. ✓Source of foods: grains, legumes (soybeans, lentils, pinto and kidney beans, for example), nuts, and seeds. 2. Glycogen: The branched structure of glycogen makes it easier to break down quickly to release glucose to serve as fuel when needed on short notice. ✓Thus, glycogen is not found in our food. Instead, we have to make it in our liver and muscle from glucose.
- 9. Cont… 3. Fiber: indigestible to human enzymes. ✓ made by plants to provide protection and structural support. ✓Think about thick stems that help a plant stand upright, tough seed husks, and fruit skin that protect what’s growing inside. ✓In our food, we find fiber in whole plant foods like whole grains, seeds, nuts, fruits, vegetables, and legumes.
- 10. Cont… • Digestion, absorption, and metabolism of carbohydrates involve the following steps: ➢Digestion: begins in the mouth with the action of salivary amylases. ✓The remaining starch is further broken down by pancreatic amylase and brush border enzymes in the intestines. ➢Absorption: in the small intestine. ➢Metabolism: carbohydrates are converted in to energy for functioning to cell growth and repair.
- 11. Cont… • The two hormones, which control the metabolisms of carbohydrates, are insulin and glucagons ❖Insulin is secreted by the beta cells of the islets of Langerhans and the secretion is stimulated by: – Hyperglycemias – Parasympathetic nervous activity • Function of insulin ✓To facilitate glucose transport to the liver and muscle cells ✓To facilitate formation of glycogen in the liver and muscle cells ✓To incorporate formation of protein from the amino acids.
- 12. Cont… ❖Glucagons is secreted by the alpha cells of the islet of Langerhans and the secretion is stimulated by - Hypoglycaemia - Sympathetic nervous activity • Function of glucagon ✓To facilitate the breakdown of glycogen in the liver and muscle cells into glucose
- 13. Discussion 1. What are carbohydrates and their importance? 2. What are the sources of carbohydrates? 3. Discuss the digestion and absorption of carbohydrates.
- 14. Proteins • A protein is a large, complex molecule that is a key building block of life. • Proteins-contains C, H, N, O in the form of amino acids, are essential to cell functions • 15-20% of calories should come from protein ✓Essential AAs- AAs that cannot be synthesized from other AAs in humans, must be consumed ✓Non-essential AAs- AAs that can be synthesized from other AAs in humans. • Healthy protein sources include eggs, nuts, lean meats, fish, dairy, and certain grains.
- 15. Cont … • The digestion: of proteins begins in the stomach. ✓is accomplished by the action of several proteolytic enzymes in the gastric, pancreatic and intestinal juices. ✓Pepsin cuts proteins into smaller polypeptides and their constituent amino acids. • Absorption: protein is absorbed as tripeptides, dipeptides or amino acids and this process occurs in the duodenum or proximal jejunum of the small intestine. • Protein metabolism: occurs in liver, specifically, the deamination of amino acids, urea formation for removal of ammonia, plasma protein synthesis, and in the interconversions between amino acids. 15
- 16. Cont… • Excess protein cannot be stored in the body. The body will only use as much protein as it needs. ➢The excess is converted into glucose and burned as energy or stored as fat. ➢The body needs a daily supply of protein. ➢Small amounts of protein at each meal is better than one large serving. 16
- 17. Roles of Proteins in Body ➢Supports growth and maintenance ➢Builds enzymes, hormones, antibodies ➢Maintains fluid and electrolyte balance ➢Maintains acid-base balance ➢Provides energy 17
- 18. Lipids • A lipid is any of various organic compounds that are insoluble in water. • Nutritional importance ✓Lipids in the diet transport the four fat-soluble vitamins (vitamins A, D, E, and K) and assist in their absorption in the small intestine. ✓Main source of energy storage: more concentrated form of energy than carbohydrates and have an energy yield of 9 kilocalories per gram. 18
- 19. Cont … •Types of lipids 1. Triglycerides- contain one glycerol and three fatty acid. More than 98% form of fat found in the body and in food 2. Phospholipids- contain glycerol, two fatty acid and phosphorus (e.g., lecithin), 3. Sterols (e.g., cholesterol). 19
- 20. Cont… 1. Saturated fats – single bonds between carbon atoms in their hydrogen chain. solid or semisolid at room temperature. a. Stearic acid: founds in animal fats and cocoa butter b. Palmitic acid: Palm oil, animal fats, dairy products(ghee, butter) c. Lauric acid: coconut oil, palm kernel oil • Vegetable oils high in saturated fats (Palm oil – 50% saturated, Palm kernel oil, Coconut oil – 92% saturated) • Raise cholesterol levels in the blood as well as LDL (bad cholesterol). CVD, 20
- 21. Cont … 2. Unsaturated fats- one or two double bond in their hydrogen chain. which are liquid at room temperature, are considered beneficial fats. • Function- improve blood cholesterol levels, ease inflammation, stabilize heart rhythms, and play a number of other beneficial roles. ✓Monounsaturated fats: can be found in avocados, nuts, seeds, olives, and olive oils ✓Polyunsaturated fats can be found in sunflower, corn, • Linoleic acid(omega 6): found in vegetable oil(sunflower, safflower, corn) • Linolenic acid(omega 3): found in soybean, and flaxseed oils, fish, walnuts, and flax seeds. 21
- 22. Cont … • CHOLESTEROL: A fat-like, waxy substance found in all animal fats and some vegetable fats that may form fat deposits on the wall of the arteries a condition called atherosclerosis. 22
- 23. Cont … 2. Where does it come from? ➢The cholesterol in your blood comes from two sources: the foods you eat and your liver. a. Some cholesterol is produced in the body. ➢If a person ate no cholesterol the body would manufacture enough for its needs. ➢Your liver makes all the cholesterol your body needs. b. Some cholesterol comes from the food we eat. ➢Saturated fats ---Meat, fish, poultry, milk products, eggs ➢Fats do not mix with watery liquids. ➢ In order to carry fat in the bloodstream the body coats it with a water - soluble protein called a lipoprotein. 23
- 24. Two types of cholesterol A. Low – Density Lipoproteins – LDL – bad cholesterol • LDL is considered the “bad” cholesterol • It transports cholesterol to peripheral tissues and liver • It carries cholesterol to your arteries, where it may collect in the vessel walls and contribute to plaque formation, known as atherosclerosis. • Fat in the blood stream that is on its way to cell for storage (including the cells that line the artery walls) • Saturated fat causes the body to produce LDL 24
- 25. Cont … B. High – Density Lipoproteins – HDL – good cholesterol • HDL is considered “good” cholesterol • It removes cholesterol from tissues and transfers it to the liver or other lipoproteins • This is because HDL carries cholesterol to your liver, where it can be removed from your bloodstream before it builds up in your arteries. • Fat in the bloodstream that is in route to the liver where it is processed and excreted from the body • HDL works to minimize the harmful effects of LDL by causing it to be removed from the bloodstream and excreted. 25
- 26. Usefulness of Fats • Fuel • Storage of energy • Protection from the environment • Absorption of fat soluble vitamins • Provides flavors and texture to foods • Satiety 26
- 27. Special Reasons to Pay Extra Attention to Fat Intake • Heart Disease • High Cholesterol • Thrombosis • Obesity • Removal of Gallbladder 27
- 28. Cont … 1, Digestion of lipid: • Mouth: triglyceride lingual lipase begins break down • Stomach: triglyceride gastric lipase diglyceride +free fatty acid • Small intestine: Pancreatic lipase secreted by pancreas in to small intestine, breaks down triglyceride in to monoglycerides and fatty acids. This enzyme work optimally in the presence of bile sals. 2, Absorption: those products of fat digestion (fatty acids, monoglycerides, glycerol, cholesterol, and fat-soluble vitamins) need to enter into the circulation so that they can be used by cells around the body. • bile helps with this process. 28
- 29. Cont … • Lipids are an important part of an infant’s diet. Breast milk contains about 4 percent fat, similar to whole cow’s milk. Whether breastfed or formula-fed, fat provides about half of an infant’s calories, and it serves an important role in brain development. 3, Lipid metabolism: begins in the intestine where ingested triglycerides are broken down into free fatty acids and a monoglyceride molecule by pancreatic lipases. • When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. • CCK also travels to the brain, where it can act as a hunger suppressant. 29
- 30. Cont … • Lipolysis: To obtain energy from fat, triglycerides must first be broken down by hydrolysis into their two principal components, fatty acids and glycerol. • Ketogenesis: ketone bodies can serve as a fuel source if glucose levels are too low in the body. Ketones serve as fuel in times of prolonged starvation or when patients suffer from uncontrolled diabetes and cannot utilize most of the circulating glucose. ✓Ketones oxidize to produce energy for the brain. 30
- 31. Cont … • Lipogenesis: When glucose levels are rich, the excess acetyl CoA generated by glycolysis can be converted into fatty acids, triglycerides, cholesterol, steroids, and bile salts. ✓creates lipids (fat) from the acetyl CoA and takes place in the cytoplasm of adipocytes (fat cells) and hepatocytes (liver cells). ✓When you eat more glucose or carbohydrates than your body needs, your system uses acetyl CoA to turn the excess into fat. 31
- 32. Micronutrients Types and Functions • Vitamins and minerals can be divided into four categories: i. water-soluble vitamins(vit B and vit C) ii. fat-soluble vitamins(vit A, D, E and K) iii. macrominerals and iv. trace minerals 32
- 33. I. Water-Soluble Vitamins(vit B and vit C) • Most vitamins dissolve in water and are therefore known as water- soluble. • They’re not easily stored in your body and get flushed out with urine when consumed in excess. • While each water-soluble vitamin has a unique role, their functions are related. • The water soluble vitamins can result in deficiency signs more quickly than the fat soluble vitamins if they are not provided in adequate amounts in diet 33
- 34. II. Fat-Soluble Vitamins(vit A, D, E and K) • Fat-soluble vitamins do not dissolve in water. • They’re best absorbed when consumed alongside a source of fat. • After consumption, fat-soluble vitamins are stored in your liver and fatty tissues for future use. 34
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- 36. III. Macro minerals • Prevention is better than cure! • Macro minerals are needed in larger amounts than trace minerals in order to perform their specific roles in your body. The macrominerals and some of their functions are: ➢Calcium: Necessary for proper structure and function of bones and teeth. ❑ Assists in muscle function and blood vessel contraction ➢Phosphorus: Part of bone and cell membrane structure ➢Magnesium: Assists withover 300 enzyme reactions, including regulation of blood pressure ➢Sodium: Electrolyte that aids fluid balance and maintenance of blood pressure 36
- 37. Cont… ➢Chloride: Often found in combination with sodium. ▪Helps maintain fluid balance and is used to make digestive juices ➢Potassium: Electrolyte that maintains fluid status in cells and helps with nerve transmission and muscle function ➢Sulfur: Part of every living tissue and contained in the amino acids methionine and cysteine 37
- 38. IV. Trace minerals ➢Trace minerals are needed in smaller amounts than macrominerals but still enable important functions in your body. The trace minerals and some of their functions are: ➢Iron: Helps provide oxygen to muscles and assists in the creation of certain hormones ➢Copper: Required for connective tissue formation, as well as normal brain and nervous system function 38
- 39. Cont .. ➢Zinc: Necessary for normalgrowth, immune function and wound healing ➢Iodine: Assists in thyroid regulation ➢Fluoride: Necessary for the development of bones and teeth ➢Selenium: Important for thyroid health, reproduction and defense against oxidative damage 39
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- 42. WATER • human body is about two thirds water (6 to 8 cups of water a day) A. Regulator –vital to every body function (digestion, excretory, circulatory) 1. Dehydration causes malfunction of all systems – death a. Decrease urine – increase of toxins b. Decrease sweating – increase body temperature c. Decrease blood volume –increase of fatigue – decrease oxygen and nutrients 42
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