Chapter 7: Eating Right

Chapter 7: Eating Right

Why do you need to know about nutrition? • Information regarding nutrition is everywhere • Nutrition • The science of certain food substances • Important terminology • nutrition - diuretics • diet - nutrient density • nutrients - requirement • deficiencies - recommendations • over-nutrition

Basic Principles of Nutrition • Diet refers to food selection • Nutrients serve three major roles • Growth, repair and maintenance of all body cells • Regulation of body processes • Supply of energy for cells • Some nutrients can be made by the body • Essential nutrients • Must be supplied by an individual’s diet

Macronutrients • 6 major nutrients • Carbohydrates • Fats • Protein • Water • Minerals • Vitamins • If all necessary nutrients are not brought into the body nutritional deficiencies may develop • With a consistently low quality diet individual runs the risk of developing a nutritional deficiency Micronutrients

Over-nutrition • Eating too much food or specific nutrients • Common problem in the United States • Can lead to obesity • Some nutrients are toxic in large doses as well • Typically linked to vitamin/mineral usage • Energy for the Body • Energy value of food is measured in calories • Carbohydrates = 4 calories per gram • Fat = 9 calories per gram • Protein = 4 calories per gram • Alcohol = 7 calories per gram

MACRONUTRIENTS

Carbohydrates (CHO) • Provide body with energy • While body will also run on fat and protein, CHO is preferred source of energy • 55% of total caloric intake should be accounted for by CHO • Classified into simple (sugars) or complex (starch, glycogen, fiber)

Sugars • Simple carbohydrates that occur as single or double-sugar chemical units • Glucose (blood sugar) is needed to fuel cells • Sources – fruit, syrups, honey • Fructose (fruit sugar) occurs naturally in honey • Lactose (milk sugar) • Sucrose (table sugar) • Must be careful not to consume too much sugar in diet (empty calories) • Replaces other nutritious foods from diet

Added sugars • Incorporated into foods and beverages during production • Found in candy, soft drinks, fruit drinks, pastries • Increased consumption results in lower consumption of essential nutrients • Sugars are usually referred to as quick energy • Must be broken down and absorbed by the digestive tract

Starches • Complex carbohydrates (long glucose chains) • Found in cereal grains, potatoes, and beans • Broken down during digestion into glucose units and stored as glycogen in the body • Glycogen is stored in the liver and muscles • Glycogen is broken down and released as glucose in the body when necessary

Fiber • Helps individual avoid constipation • Most forms are complex carbohydrates • Not digested in small intestine • Moves through digestive tract relatively unchanged • Sources • Fruits, vegetables, whole grain breads and cereals, nuts, beans, and peas • Low fiber diets are blamed for intestinal problems • Hemorrhoids • Colon cancer • Diverticulosis

Certain fibers attract water and aid in the formation of bulky stools, which are more easily passed during bowel movements • Can utilize fiber in diet to reduce constipation and laxative use • Also may be helpful in lowering blood cholesterol levels, which are a major risk factor for cardiovascular disease • Oats, fruits, and vegetables are recommended • Help to interfere with absorption of cholesterol in the intestinal tract • Reduces cholesterol entering the blood stream • 38 grams and 25 grams are recommended for men and women, respectively

Total fiber • Combination of dietary fiber and functional fiber • Dietary fiber • Edible, non-digestible components of CHO and lignin (found in plants) • Cereal bran, flaked corn cereal, sweet potatoes, legumes, and onions • Functional fiber • Have health benefits • Found in natural sources or are synthetic

Fats • Extremely important in one’s diet • Extra calories consumed as carbohydrates, proteins and fats can all be converted into triglycerides and stored as adipose tissue • Stored for future use • Stored fat serves multiple functions • Serve to cushion organs • Provide energy to muscles

Fats provide flavoring and texture to food substances • Most Americans consume too much fat, contributing to obesity and cardiovascular disease • Saturated vs. Unsaturated Fats • Saturated fats are derived primarily from animal products • Found in meat (pork, chicken, beef), eggs, and dairy products • Also can be found in coconut and palm oils

Unsaturated fats are liquid at room temperature • Canola, peanut, olive oil and vegetable oils • Mono- and polyunsaturated fatty acids reduce blood cholesterol • Some polyunsaturated fats are essential as they are not produced by the body • Omega-3 fatty acids • Found in corn oil and fish oil • 1 tablespoon – recommended amount • Omega-6 fatty acids • Located in milk and some vegetable oils • Less than ½ teaspoon – recommended amount

Cholesterol • Believed to be responsible for creating blocked arteries  cardiovascular disease • Fat-related substance found in animal foods • If enough is not consumed your body will produce it naturally • If blood cholesterol becomes too high the risk of cardiovascular disease increases • Saturated fat can increase low-density lipoprotein and bad cholesterol = increasing risk of heart disease

Trans Fatty acids • Resemble saturated fatty acids • Results in hardening oils • Often found in cookies, crackers, dairy products, meats, fast foods • Will boost levels of bad cholesterol • No safe level – no health benefit • Unsaturated vs. Saturated fats • Unsaturated fats tend to be better for an individual • Saturated fats tend to increase blood cholesterol levels

Fat Intake • Total fat consumption vs. Consuming specific fats • Makes up 40% of total calories consumed by Americans • Recommended levels (25-30%) • Cholesterol recommended levels = 300mg • Recommendations on reducing fat intake may be partially responsible for reducing cardiovascular deaths

Protein • Required for growth, repair and maintenance of cells • Major constituent of all structures and organs of the body • Not a primary source of energy • Greater need for protein during periods of growth, breast feeding, active body-building

Recommendations • Based on body weight • 0.8 grams/kg of body weight • Should be approx. 12-15% of caloric intake • Americans tend to eat much more than necessary • Most of it coming from animal sources • Composed of smaller sub-units (amino acids) • 20 amino acids in the body, 9 must be supplied by diet • All are necessary for growth • Primarily found in animal products, some in plants

MICRONUTRIENTS

Water • Most essential nutrient • 60% of the adult body is water • Required for energy production, maintaining cell function, and cooling of the body • Body requires 2.5 liters (10 glasses) daily • Dehydration • Experience fatigue, nausea, vomiting, fainting and death (worst-case scenario) • More likely when outdoors and active in the heat • Must pre-hydrate and continue during activity

Sports Drinks • Allow for hydration, electrolyte and energy replacement • Better for re-hydrating, water itself can shut off thirst response and turn on kidney function prematurely • Not all the same • Varying amounts of electrolytes and carbohydrates • 14 grams of CHO per 8 oz. is optimal • Effective in enhancing performance during endurance and short term high-intensity activities

Oxygenated Bottled Water • Water with added oxygen • Manufacturers claim that it will increase oxygen levels in the body, enhancing metabolism and improving endurance • Human physiology and science show that oxygen levels in blood and muscle will not be elevated by beverage

Vitamins • Vitamins (13) serve as regulators in many body processes • Help to regulate metabolism and energy production, not a sources of energy • Elderly, alcoholics, and those that restrict food intake severely are susceptible to vitamin deficiencies • Many people may be borderline • Consuming alcohol and smoking increase nutrient and vitamin needs

Fat soluble vitamins • Vitamins A, D, E, K • Found in fatty portion of foods and oils • Not easily eliminated from the body • Stored in liver and body fat – can make them potentially toxic

Water soluble vitamins • Vitamin C, B-complex vitamins • Help to regulate metabolism but cannot be stored • Each serves a series of roles • B-vitamins often linked to energy production • While deficits will limit energy production, overloading will not result in greater energy production

Antioxidants • May prevent premature aging, cancers, heart disease and other health problems • Helps protect cells from free radicals • Includes vitamins A, C, E • Found in a number of dark green, deep yellow and orange fruits and vegetables • Supplemental intake of antioxidants • Need to be cautious with additional intake particularly with vitamins C and E

Minerals • More than 20 minerals have essential roles in the body • Many are stored in liver and bones • Required for a number of things • Bones • Teeth • Activating enzymes • Energy production • Maintaining water balance

Calcium • Necessary for bone formation, clotting and muscle contractions • Found in dairy products • Poor food choices and weight loss are responsible for low calcium levels in young women • Over a lifetime may lead to osteoporosis (brittle bones) • Heredity, cigarette smoking, menopause, lack of physical activity and poor calcium intake could further contribute to osteoporosis

Iron • Required for oxygen carrying pigment (hemoglobin) in red blood cells (RBCs) • Without hemoglobin oxygen carrying ability of RBCs is limited • Iron deficiency can be caused by: • Menstrual blood loss • Lack of meat in the diet • Lack of iron in the diet • Vitamin C deficiency which limits iron absorption • Good sources • Meats • Iron supplements

Production of Energy • Occurs when cells break down chemical units of glucose and fats or amino acids • Must burn energy-supplying nutrients • Results in heat production and usable energy for cells to work • Proportions of nutrients burned depending on type, duration and intensity of exercise • Factors that influence amount of oxygen that cells need to generate energy • Low intensity exercise = more fat burning • Endurance activities = fat and CHO use is similar • CHO provide most energy for high intensity, short-term activity

Nutrient Dense vs. Junk Food • Nutrient dense • Foods containing considerable amounts of vitamins and minerals and proteins in relation to their caloric content • Junk foods • Contain too many calories (through sugar and fats) in relation to the proportion of vitamins and minerals

Nutrient Requirements and Recommendations • Requirement • Amount of a nutrient that is needed to prevent nutrient deficiency disease • Recommendations • Takes into account the amount necessary to avoid deficiency • Includes a margin for safety • US Recommended Dietary Allowances (USRDA) • Allows for comparison of the nutritional of food products

RDA serves as a benchmark of nutritional adequacy • Recently changed to Dietary Reference Index (DRI) • Factors in indicators of good health and prevention of chronic disease • Upper intake levels (UL) which helps individuals avoid consumption of too much of a nutrient • Estimated average requirement (EAR) for average daily nutrient intake level to meet requirement of half the healthy individual in a particular age group • Adequate intake (AI) = recommended intake based on experimentally developed estimates of nutrient intake when RDA cannot be determined

Dietary Guidelines • Nutrition and health recommendations for healthy children and adults • In 2005 more emphasis was placed on increasing physical activity and reducing caloric intake • Provide healthy diet information based on research • Emphasizes fruits, vegetables, whole grains, fat-free or low-fat milk, lean meats/poultry, fish, beans, eggs and nuts

MyPyramid • Replaced Food Guide Pyramid in 2005 • Emphasizes more individualized approach for diet and lifestyle • Stresses benefits of improvements in nutrition, lifestyle behavior and physical activity • Identifies amounts of food to consume depending on energy expenditure

Represents recommended proportions of every food group while focusing on the importance of making smart food choices daily • MyPyramid Symbol illustrates • Gradual improvement • Physical activity • Variety • Moderation • Proportionality • Personalization • Developed for a number of cultures and countries • Takes into account cross-cultural perspectives on eating behaviors, philosophical & religious perspective, social & cultural food technologies & political economy

Reading Labels • Lists total calories per serving • Calories from fat • Information that is based on percent daily values for a standard 2000 calorie diet • Provides information on specific nutrients relative to % daily values

What is the role of nutrition in physical activity? • Physically active people believe that certain nutrients can help in achieving fitness goals/competitive edge • Sometimes certain foods will be avoided by athletes

Nutritional Supplements • Often times supplements are consumed, providing more than the recommended amounts of particular nutrients • Little evidence that vitamin, mineral or protein supplementation enhances physical performance

Protein Supplements • Experts do not agree that more protein is necessary for body building • Most Americans ingest plenty to meet needs – even when physically active • Too many amino acids in the body could be harmful • Amino acid imbalances • Dehydration • Increased calcium loss • Be sure to consume enough CHO to compensate for increased activity levels

Vitamin and Mineral Supplements • Healthy individuals typically meet the standards • May be beneficial to elderly individuals, as they typically have difficulty obtaining all the necessary vitamins and minerals • Antioxidant, calcium and iron supplements may be recommended under certain circumstances • Deficiency, illness, hormonal changes, increased activity levels

Creatine Supplements • Naturally occurring substance in body produced by kidneys, pancreas and liver • Found in meat and fish • Role in metabolism • Two types (free creatine and phosphocreatine) • Phosphocreatine is stored in skeletal muscle and works to re-synthesize ATP during activity

Positive effects • increase intensity of workouts • lactic acid buffer • stimulates protein synthesis • decreases total cholesterol and total triglycerides and improves HDL-LDL ratio • increases fat-free mass • Negative effects • weight gain • muscle cramping • gastrointestinal disturbances and renal dysfunction

Supplements in General • Be a careful consumer • Generic vitamins and minerals are just as effective • Don’t be misled by labels • Consuming more than 150% of the recommended levels may be unhealthy • Supplements should not be a substitute for food

Sugar • Ingesting large quantities of sugar prior to activity causes increased glucose in the blood • Release of insulin stimulated, allowing cells to utilize free-circulating glucose, sparing blood glucose • Positive effect on performance • However, some athletes are sensitive to high CHO feedings and have problems with increased levels of insulin

Caffeine • Central nervous system stimulant found in carbonated beverages, coffee, tea (chocolate contains compounds related to caffeine) • Increase alertness and decrease fatigue • Too much causes nervousness, irritability, increased heart rate and headaches

Alcohol • Provides energy for the body • Little nutritional value • Central nervous system depressant • decreases coordination, slows reaction time, decreases mental alertness • increases urine production (diuretic effect) • Not wise to replace water with alcohol before, during, or following activity • Too much alcohol can damage liver and brain cells

Chapter 7: Eating Right