Nutrition Chapter 8

Lecture Objectives List the six essential nutrients and describe their functions in the body. List the acceptable macronutrient distribution ranges. Explain the difference between the following: Complete and incomplete proteins Saturated, unsaturated, and trans fat Simple and complex carbohydrates Soluble and insoluble fiber Explain the role of fiber and antioxidants in the body.

Nutritional Requirements: Components of a Healthy Diet Essential nutrients Proteins Fats Carbohydrates Vitamins Minerals Water Essential nutrients = substances the body must get from food because it cannot manufacture them at all or fast enough to meet its needs

Acceptable Macronutrient Distribution Ranges CHO CHO (45-65%) FAT FAT (20-35%) - 10% saturated PRO PRO (10-35% or less) Three classes of essential nutrients supply energy Kilocalorie = a measure of energy content in food; the amount of heat it takes to raise the temperature of 1 liter of water 1°C; commonly referred to as “calorie”

Proteins: The Basis of Body Structure Protein is a compound 9 / 20 common amino acids in foods are essential Protein = a compound made of amino acids that contains carbon, hydrogen, oxygen, and nitrogen Proteins form key parts of the body’s main structural components—muscles and bones—and of blood, enzymes, cell membranes, and some hormones

Complete and Incomplete Proteins Complete protein sources Meat, fish, poultry, eggs, milk, cheese, and soy Incomplete protein source Plants, including legumes, grains, and nuts Complete protein sources = foods that supply all the essential amino acids in adequate amounts Incomplete protein sources = foods that supply most but not all essential amino acids

Recommended Protein Intake 0.8 gram per kilogram (0.36 gram per pound) of body weight daily Acceptable Macronutrient Distribution Range = 10–35% of total daily calories as protein

Protein Sources 3 ounces lean meat, poultry, or fish 1/2 cup tofu 20–25 grams of protein 1 cup legumes 15–20 grams of protein 1 cup milk or yogurt or 1-1/2 ounces cheese 8–12 grams of protein Cereals, grains, nuts, vegetables 2–4 grams of protein per serving

Fats: Essential in Small Amounts What role do fats play in my diet? Essential fats are key regulators Fats supply energy, insulate the body, support and cushion organs, absorb fat-soluble vitamins, add flavor and texture to foods Essential fats (linoleic acid and alpha-linolenic acid) are key regulators of body process such as the maintenance of blood pressure and the progress of a healthy pregnancy

Types and Sources of Fats Saturated fat Monounsaturated fat Polyunsaturated fat Trans Fat Saturated fat = a fat with no carbon-carbon double bonds; usually solid at room temperature Monounsaturated fat = a fat with one carbon-carbon double bond; usually liquid at room temperature Polyunsaturated fat = a fat with two or more carbon-carbon double bonds; usually liquid at room temperature Two key forms of polyunsaturated fats: Omega-3 fatty acids are produced when the endmost double bond of a polyunsaturated fat occurs three carbons from the end of the fatty acid chain Found primarily in fish Omega-6 fatty acids are produced when the endmost double bond of a polyunsaturated fat occurs six carbons from the end of the fatty acid chain Found primarily in certain vegetable oils, especially corn, soybean, and cottonseed oil Trans Fatty Acids: The process of hydrogenation, in which hydrogens are added to unsaturated fats, produces a mixture of saturated fatty acids and standard and trans forms of unsaturated fatty acids Trans fatty acids have an atypical shape that affects their chemical activity ______________________________ Fats affect blood cholesterol levels Low-density lipoprotein (LDL) = “bad” cholesterol High-density lipoprotein (HDL) = “good” cholesterol Saturated and trans fats raise levels of LDL; trans fats also lower levels of HDL Unsaturated fats lower levels of LDL _________________________ Fats also affect triglyceride levels, inflammation, heart rhythm, blood pressure, and cancer risk Best choices = monounsaturated fats and polyunsaturated omega-3 fats Limit intake of saturated and trans fats

Fats and Health Fats affect blood cholesterol levels “Bad” cholesterol vs. “good” cholesterol Saturated and trans fats vs. unsaturated fats Fats also affect triglyceride levels, inflammation, heart rhythm, blood pressure, and cancer risk Best choices = monounsaturated fats and polyunsaturated omega-3 fats Limit intake of saturated and trans fats Low-density lipoprotein (LDL) = “bad” cholesterol High-density lipoprotein (HDL) = “good” cholesterol Saturated and trans fats raise levels of LDL; trans fats also lower levels of HDL Unsaturated fats lower levels of LDL

Total Fat Content of Foods Talk about importance of food choices. Some are everyday foods, some are sometimes foods. There is no “bad” food, all foods in moderation is key.

Recommended Fat Intake Adequate daily intake of fat: Women = 13 grams Men = 18 grams Acceptable Macronutrient Distribution Range = 20–35% of total daily calories as fat

Carbohydrates: An Ideal Source of Energy Primary Function Some cells use only carbohydrates for fuel Body’s preferred fuel source Broken down and stored during digestion The primary function of dietary carbohydrate is to supply energy to body cells. Some cells, such as those in the brain, nervous system, and blood, use only carbohydrates for fuel During high-intensity exercise, muscles get most of their energy from carbohydrates During digestion, carbohydrates are broken into single sugar molecules such as glucose for absorption; the liver and muscles take up glucose and store it in the form of glycogen

Simple and Complex Carbohydrates Simple carbohydrates contain one or two sugar units in each molecule Complex carbohydrates consist of chains of many sugar molecules Simple carbohydrates contain one or two sugar units in each molecule Found naturally in fruits and milk and added to many other foods Include sucrose, fructose, maltose, and lactose Complex carbohydrates consist of chains of many sugar molecules Found in plants, especially grains, legumes, and tubers Include starches and most types of dietary fiber

Whole Grains Refined carbohydrates usually retain all the calories of a whole grain but lose many of the nutrients Before they are processed, all grains are whole grains consisting of an inner layer of germ, a middle layer called the endosperm, and an outer layer of bran During processing, the germ and bran are often removed, leaving just the starchy endosperm _____________________________ REFINED CHO VS WHOLE GRAIN Whole grains are higher than refined carbohydrates in fiber, vitamins, minerals, and other beneficial compounds Whole grains take longer to digest Choose foods that have a whole grain as the first item on the ingredient list on the food label

Recommended Carbohydrate Intake Adequate daily intake of carbohydrate = 130 grams Acceptable Macronutrient Distribution Range = 45–65% of total daily calories as carbohydrate Limit intake of added sugars Increase consumption of unrefined grains, fruits, vegetables, and legumes

Vitamins: Organic Micronutrients Four vitamins are fat-soluble (A, D, E, and K) Nine vitamins are water-soluble (C and the eight B-complex vitamins: thiamin, riboflavin, niacin, vitamin B-6, folate, vitamin B-12, biotin, and pantothenic acid) Do NOT provide kcals! Vitamins = organic (carbon-containing) substances needed in small amounts to help promote and regulate chemical reactions and processes in body cells. Vitamins are abundant in fruits, vegetables, and grains; they are also added to some processed foods If you consume too much or too little of a particular vitamin, characteristic symptoms of excess or deficiency can develop Vitamins commonly lacking in the American diet: Vitamin A Vitamin C Vitamin B-6 Vitamin E

Minerals: Inorganic Micronutrients There are about 17 essential minerals: Major minerals (those that the body needs in amounts exceeding 100 mg per day): Calcium, phosphorus, magnesium, sodium, potassium, and chloride Essential trace minerals: Copper, fluoride, iodide, iron, selenium, and zinc Minerals = inorganic (non-carbon-containing) compounds needed in small amounts for regulation, growth, and maintenance of body tissues and functions If you consume too much or too little of a particular mineral, characteristic symptoms of excess or deficiency can develop Minerals commonly lacking in the American diet: Iron = low intake can cause anemia Calcium = low intake linked to osteoporosis Potassium = low intake linked to elevated blood pressure and bone mineral loss

Water: A Vital Component Human body is composed of about 60% water; you can live only a few days without water Foods and fluids you consume provide 80–90% of your daily water intake Adequate intake? Adequate intake to maintain hydration: Women need to drink about 9 cups of fluid per day Men need to drink about 13 cups of fluid per day Drink in response to thirst; consume additional fluids for heavy exercise

Other Substances in Food: Fiber Dietary fiber=non-digestible Functional fiber=non-digestible Total fiber=dietary fiber+functional fiber Dietary fiber = nondigestible carbohydrates and lignin that are present naturally in plants Functional fiber = nondigestible carbohydrates isolated from natural sources or synthesized in a lab and added to a food or supplement Total fiber = dietary fiber + functional fiber

Types of Fiber Soluble (viscous) fiber Insoluble fiber Sources of Fiber Recommended intake? Soluble (viscous) fiber = fiber that dissolves in water or is broken down by bacteria in the large intestine Slows the body’s absorption of glucose Binds cholesterol-containing compounds Insoluble fiber = fiber that doesn’t dissolve in water Makes feces bulkier and softer Helps prevent constipation, hemorrhoids, and diverticulitis Sources of Fiber:All plant foods contain fiber, but processing can remove it Good sources of fiber: Fruits (especially whole, unpeeled fruits) Vegetables Legumes Oats (especially oat bran) Whole grains and wheat bran Psyllium (found in some cereals and laxatives) _______________________ RECOMMENDED INTAKE Women = 25 grams per day Men = 38 grams per day Americans currently consume about half this amount

Other Substances in Food: Antioxidants Antioxidant = a substance that protects Many fruits and vegetables are rich in antioxidants such as vitamin C, vitamin E, selenium, and carotenoids Antioxidant = a substance that protects against the breakdown of body constituents by free radicals; actions include binding oxygen, donating electrons to free radicals, and repairing damage to molecules Free radical = a chemically unstable, electron-seeking compound that can damage cell membranes and mutate genes in its search for electrons

Lecture Summary List the six essential nutrients and describe their functions in the body. List the acceptable macronutrient distribution ranges. Explain the difference between the following: Complete and incomplete proteins Saturated, unsaturated, and trans fat Simple and complex carbohydrates Soluble and insoluble fiber Explain the role of fiber and antioxidants in the body.