Lecture 22 (Nutrition & Metabolism) Learning Objectives.docx

1.Define the term nutrition and nutrients - Nutrition is the study of how living organisms obtain and utilize the nutrients they need to grow and sustain life. It encompasses the process of obtaining and utilizing essential nutrients, which include biological macromolecules such as carbohydrates, li...

1.Define the term nutrition and nutrients - Nutrition is the study of how living organisms obtain and utilize the nutrients they need to grow and sustain life. It encompasses the process of obtaining and utilizing essential nutrients, which include biological macromolecules such as carbohydrates, lipids, and proteins, as well as vitamins and minerals. Nutrients are the substances that the body needs for development and growth, maintenance of anatomic structures and physiologic processes, and repair of damaged tissues. These nutrients are obtained from the diet and are essential for the overall health and well-being of an individual. Macronutrients, such as carbohydrates, lipids, and proteins, must be consumed in relatively large quantities, while micronutrients, including vitamins and minerals, must be consumed in smaller quantities. Essential nutrients are those that must be obtained from the diet and absorbed by the body, while nonessential nutrients can be adequately provided by biochemical processes within the body and are not required to be part of the dietary intake. 2.Compare and contrast macronutrients and micronutrients, as well as essential and nonessential nutrients. - Macronutrients and micronutrients are two categories of nutrients essential for the body's growth and maintenance. Macronutrients, such as carbohydrates, lipids, and proteins, are required in larger quantities and provide energy for cellular respiration. They are the building blocks of the body's tissues and play a crucial role in physiological processes. On the other hand, micronutrients, including vitamins and minerals, are needed in smaller quantities and are essential for various metabolic functions, such as enzyme activity and immune system support. Essential nutrients must be obtained from the diet and absorbed by the body, while nonessential nutrients can be produced by the body's biochemical processes and are not required to be part of the dietary intake. This distinction is important in understanding the specific dietary needs and the role of different nutrients in maintaining overall health and well-being. 3.Identify the categories that are dietary sources of carbohydrates and give examples of each category. - Carbohydrates are classified into three dietary categories: sugars, starch, and fiber. Sugars include monosaccharides like glucose, fructose, and galactose, as well as disaccharides such as sucrose, lactose, and maltose. These can be found in table sugar, maple syrup, fruits, milk, and cereals. Starch, on the other hand, is a polysaccharide found in foods like potatoes, carrots, grains, beans, and peas, as well as in breads and pasta. Lastly, fiber is a type of carbohydrate that includes polysaccharides from plants and animals, found in vegetables, lentils, peas, beans, whole grains, oatmeal, berries, and nuts. Each category of carbohydrates serves a different purpose in the body and can be obtained from a variety of food sources. 4.Classify the types and dietary sources of triglycerides and describe their functions. - Triglycerides are a type of lipid composed of glycerol and fatty acids. They can be classified into three categories based on their degree of saturation: saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. Saturated fats, found in meat, milk, cheese, coconut oil, and palm oil, are generally solid at room temperature. Unsaturated fats, such as nut oils and certain vegetable oils, are typically liquid at room temperature. Polyunsaturated fats, also liquid at room temperature, are found in some vegetable oils. Triglycerides serve as a primary nutrient supplying energy to cells and are necessary for the absorption of fat-soluble vitamins. They can also be synthesized by the body and are a major energy source, providing approximately 9 kilocalories of energy per gram of fat. 5.Describe the sources and functions of cholesterol. - Cholesterol is obtained from animal products as dietary sources, such as meat, milk, and eggs. It is also synthesized within the liver through metabolic pathways. Cholesterol serves several important functions in the body, including being a component of the plasma membrane of cells, the precursor molecule for the formation of steroid hormones, bile salts, and vitamin D. Additionally, cholesterol plays a role in the transport of lipids in the blood, being released into the blood as a component of very-low-density lipoproteins (VLDLs) and delivered to cells as part of low-density lipoproteins (LDLs). It is also transported from peripheral tissues back to the liver as part of high-density lipoproteins (HDLs). 6.Describe the general structure and functions of proteins. - Proteins are complex macromolecules composed of amino acids linked together in a specific sequence. The general structure of a protein consists of a linear chain of amino acids, folded into a three-dimensional shape. This shape is crucial for the protein's function, as it determines how the protein interacts with other molecules in the body. Proteins have a wide range of functions in the body, including serving as enzymes to catalyze biochemical reactions, acting as structural components in cells and tissues, participating in cell signaling and communication, and functioning as antibodies in the immune system. Additionally, proteins play a role in transportation, serving as channels and carriers for molecules across cell membranes, and they also contribute to the regulation of gene expression and cell growth. Overall, proteins are essential for the proper functioning and maintenance of the human body. 7.Describe why protein is a required dietary nutrient and list the recommended dietary intake of protein. - Protein is a required dietary nutrient because it plays a crucial role in the growth, repair, and maintenance of the body's tissues and organs. It is also essential for the production of enzymes, hormones, and antibodies that are necessary for various physiological processes. The recommended dietary intake of protein varies depending on factors such as age, sex, body mass, level of physical activity, and health status. For adults, the recommended daily allowance (RDA) for protein is approximately 0.8 grams per kilogram of body weight. However, this can vary for individuals with specific dietary needs or goals, such as athletes or those looking to build muscle mass. 8.Explain the difference between a complete and incomplete protein. - Complete proteins contain all of the essential amino acids, whereas incomplete proteins do not. Generally, animal proteins (meats, poultry, fish, eggs, milk, cheese, yogurt) are complete proteins, whereas most plant proteins (legumes, vegetables, grains) tend to be lacking in one or more of the essential amino acids and thus they are incomplete proteins. For example, the protein in corn has low amounts of both lysine and tryptophan. Meals containing combinations of plant proteins (such as legumes and grains) can provide all of the essential amino acids. Examples of such combination plant protein meals include beans and corn, soybeans and rice, and red beans and rice. 9.Compare and contrast water-soluble and fat-soluble vitamins and able to list examples of each. - Water-soluble vitamins and fat-soluble vitamins differ in their solubility and absorption in the body. Water-soluble vitamins, such as B-complex vitamins and vitamin C, dissolve in water and are easily absorbed into the blood from the digestive tract. Examples of water-soluble vitamins include thiamine (B1), riboflavin (B2), niacin (B3), and vitamin C. On the other hand, fat-soluble vitamins, including vitamins A, D, E, and K, dissolve in fat and are absorbed from the gastrointestinal tract within the lipid of micelles. Examples of fat-soluble vitamins are retinol (A), calciferol (D), tocopherol (E), and phylloquinone (K). Each type of vitamin has specific functions in the body and can be obtained from various dietary sources. 10.Describe the difference between essential and nonessential vitamins. - Essential vitamins are those that must be obtained from the diet because the body is unable to produce them in sufficient quantities. These vitamins are crucial for normal metabolism and bodily functions, and their deficiency can lead to various health issues. Examples of essential vitamins include vitamin C and the B-complex vitamins. On the other hand, nonessential vitamins are cofactors that the body is able to produce and recycle as needed. While they still play important roles in bodily functions, their absence from the diet does not lead to severe health issues as with essential vitamins. Examples of nonessential vitamins include NADH and FADH, which are involved in cellular respiration. 11.Define minerals and distinguish between major mineral and trace minerals. - Minerals are inorganic ions that are essential for various bodily functions. They are obtained from the foods we eat and play diverse roles in the body. Major minerals are needed at levels greater than 100 milligrams per day and include calcium, chloride, magnesium, phosphorus, potassium, sodium, and sulfur. Trace minerals, on the other hand, are required at levels less than 100 milligrams per day and include chromium, cobalt, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, and zinc. Both major and trace minerals are crucial for maintaining overall health and well-being, and a balanced intake of these minerals is necessary for optimal bodily function. 12.Describe MyPlate, which was developed by the USDA to help people to eat healthy. - MyPlate was developed by the USDA as a visual representation of the relative proportions of different types of foods that people need to consume in order to maintain a healthy diet. It replaced the previous food guide pyramid and provides a more simplified and practical approach to healthy eating. MyPlate divides a plate into sections, with one half dedicated to vegetables and fruits, and the other half divided between protein and grains, with dairy off to the side. This visual tool helps individuals to easily understand and visualize the recommended proportions of different food groups for a healthy diet. It also provides additional recommendations, such as balancing calories by eating less, switching from whole milk to low-fat or no-fat milk, decreasing consumption of saturated fats, reducing intake of high-salt foods, and cutting back on sugary drinks by drinking water instead. Overall, MyPlate is a valuable resource developed by the USDA to help people make informed and healthy food choices.