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University of Guelph
NUTR 1010
Andrea Buchholz

Nutrition 1010 What is nutrition? • The science that studies how food nourishes our bodies and influences our health • The only science which combines : • biology • Chemistry • Biochemistry • physiology • anatomy • genetics • psychology • behavioral science • sociology Why is nutrition important? • one of several factors contributing to health • a nutritious diet can prevent some diseases and reduce risks for others • a poor diet can increase risk for some diseases/ health conditions Who does nutrition affect? • everyone from the womb to tomb • all stages of health and sickness • every country around the world • including u of g undergrads How can I figure out my nutrient needs? use the Dietary Reference Intakes (DRI) • Whom can you trust? • trustworthy experts are educated, credentialed (RD: Registered Dietitian) • Professional organizations provide reliable nutrition information (Canadian nutrition society ) • Government sources (Health Canada) • peer reviewed journals (american journal of clinical nutrition) • University textbooks What About... • Nutritionists • MDs NDs • • internet • be wary of .com • does the website provide a public information service or is it selling a product? • Credentials of authors • when was the website last updated • Magazines, newspapers Summary of last Class • nutrition • science that studies how food nourishes our bodies, influences health • one of several factors contributing to health • affects everyone • beware of nutrition misinformation Why do we eat the foods we eat? • availability (convenience) • culture • religion • values and beliefs • social • advertising • economy • emotional comfort • habit • personal preference • positive association (celebrity on a diet) • weight/ image • nutritional value • appetite • hunger • the foods we eat make up our diets Appetite • psychological desire to eat specific foods • pleasant sensation associated with food • influenced by: •psychological factors (friends social atmosphere) •Brain compounds (endorphins--> pleasure ... increases when we see and smell foods •inborn appetites (sweet tooth) •health conditions (cancer --> no appetite or enhanced appetite) •Medication/ drugs (depression suppresses drugs/ weed = munchies) Hunger • Physiological sensation in response to a need for food • unpleasant/ negative sensation • influenced by: •brain (hypothalamus) •blood glucose levels (insulin and glucagon) •hormones (neuropeptide Y, galanin, leptin, cholecystokinin) • amount and type of food we eat • exercise What is a Nutritious Diet? • one which provides proper combination of nutrients and energy and is adequate, moderate, varied, and balanced • Nutrients : chemicals found in foods, critical to human growth and function • Nutrients include: • Carbs, Fats, Proteins (energy-containing macronutrients) • Vitamins and Minerals (micronutrients) --> do not contain energy • H2O (most essential) What is Energy? • Amount of energy in food that can be supplied to body • measured in kilocalories (kilocal, calories) • example: medium apple has 110 kilocals • obtained from energy-containing macronutrients • Carb : 4 kilocal per gram • Fat: 9 kilocal per gram • Protein: 4 kilocal per gram • alcohol is not a nutrient but contains 7 kilocals per gram A diet is... • Adequate if: • it provides enough energy, nutrients and fibre to maintain health • may be adequate in one area (example: energy) but inadequate in another (dietary fibre) • Moderate if: • we consume right amounts • relates to portion size, frequency • example: moderate consumption of alcohol confers health benefits, regular high consumption can cause liver damage • Varied if: • we consume a variety of different foods each day • Kale equals folate • Tofu equals protein • Balanced if: • we consume combination of foods providing proper balance of nutrients • even if your diet is adequate in meats, its not balanced unless its also adequate in vegetables Dietary Reference Intakes (DRI) • a set of nutritional references values for Canada and US that apply to healthy people Estimated Average Requirement (EAR) • average daily nutrient intake level estimated to meet requirement of HALF of the healthy people in a particular life stage and gender group • based on solid evidence • example: Estimated Average Requirement for iron for female adult is 8.3 milligram per day • therefore 8.3 milligram iron per day will meet needs of half of female population • if the Estimated Average Requirement meets the needs of only HALF the people in a group then shouldnʼt the recommended intake be higher... YOU BET! Recommended Dietary Allowance (RDA) • Average daily nutrient intake level that meets nutrient requirement of 97 to 98% of healthy individuals in a particular life stage and gender group • RDA is based on Estimated Average Requirement (therefore must have sufficient evidence) • example: RDA for iron for female is 18 milligrams per day (whereas the EAR is 8.3milligrams per day) What if there isn't Sufficient Evidence Adequate Intake (AI) • based on educated guesswork • a recommended average daily nutrient intake level based on observed or experimentally determined estimates of intake by a group of healthy people • Not based on EAR (there is insufficient evidence) • roughly equivalent to RDA • example: AI for Vitamin K : Males: 120 unigram per day Females: 90 unigram per day Is there such thing as too much of a given nutrient? YES Summary of last class • we choose foods for many reasons • a nutritious diet is adequate, varied, balanced, moderate • Dietary Reference Intakes (DRI) Tolerable Upper Level (UL) • highest average daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in a particular life stage and gender group • example : uniLitre for fluoride for 4 to 8 year old children is 2.2 milligram per day • if exceed uniLitre for fluoride= get brown patches on teeth --> skeletal fluorosis- problem deposits fluoride in your bones Estimated Energy Requirements (EER) • Average dietary energy intake predicted to maintain energy balance in healthy adults • defined by age, gender, weight, height, physical activity • 18 year old female, 60 kilogram, 5 foot 3, active, has an Estimated Energy Requirements of 2350 kilocals per day Metabolic rate • amount of energy to keep body working • makes up 60% of calories you need • increased weight equals increased metabolic rate Acceptable Macronutrients Distribution Ranges for Adults • Carbs = 45 to 60 % • Fat = 20 to 35% • Protein = 10 to 35% Veggies and Fruit • Females 7-8 servings • Males 8-10 servings • 125 milliliter (half cup) fresh/ frozen/ canned veggies/ fruit/ fruit juice/ 1 medium sized fruit • at least 1 dark green and 1 orange veggies per day • veggies and fruit more often than juice (whole fruit = increased fiber and decreased sugar) Grain Products • Females 6-7 servings • Males 8 servings • slice of bread or half a bagel • 125 milliliter (half cup) cooked rice, pasta, or couscous • 30 milliliter (1 cup) cold cereal • each day, half of grain intake should be whole grain (oatmeal, brown rice, whole grain bagel) • choose grain products lower in fat, sugar, and salt because we already consume a lot of sugar, fat, and salt • decrease cookies pastries and pies Milk and Alternatives • Females 2 servings • Males 2 servings • 250 milliliter (1 cup) milk, skim 1% 2% or fortified soy beverage • 175 grams (three quarters cup) yogurt • 50 grams (1 and a half ounce cheese) • Low fat alternatives • cottage cheese, low fat yogurt, low fat cheese •milk products tend to be high in fat Meat and Alternatives • Females 2 servings • Males 3 servings • 75 grams (half cup) cooked fish, poultry, or lean meat • 175 milliLitre (three quarter cups) cooked beans, 2 eggs • 2 Table spoons peanut butter • eat alternatives often : beans lentils tofu • At least two servings of fish per week --> omega 3 Fatty Acids : reduced risk of heart disease • meet your nutrient needs (AI, RDA) and AMDR • decreased risk for obesity , Type 2 Diabetes , heart disease, certain types of cancer, osteoporosis •in part because Canadian food guide helps decreases intake of fat, salt, and increase intake of fibre • contribute to overall health But how do you know whether a food is low in sodium or fat or has a lot of fiber?? Read Labels WEEK 2 Summary • Donʼt consume more than the upper level for each nutrient • Estimated energy requirements • AMDR: • Carbs : 45% to 65% • Fats: 20 to 35% • Protein: 10 to 35% • Canadaʼs food guide Three main purposes of food labels • Basic product information • ingredients: product weigh/ net quantity • expiry date: grade or quality • country of origin • manufacturer • importer • Health, safety and nutritional info • amounts and types of fat, protein, and carbs, vitamins, minerals in a specific serving size • Provide a means for marketing or promoting product by label claims • low fat, cholesterol- free, high source of fibre • all regulated Food labels can have four main components 1. Ingredient list (mandatory) • descending order by weight (not volume) • source of information for people with allergies/ who avoid certain ingredients • Which ingredient is present in greatest quantity in Fibre First --> Wheat bran (good source of fibre 2. Nutrition Facts Table (mandatory) • amount of energy and 13 core nutrients in one serving •fat, saturated fat, trans fat, cholesterol, sodium, carbs, fibre, sugar, protein, vitamin A, vitamin C, calcium, iron • why these 13 nutrients? •consumer, health professional, and scientist driven choices • other nutrients optional How to read and use the Nutrition Facts Table 1. Serving size and sometimes the number of servings per container 2. Calories, calories from fat and calories from saturated and trans fats 3. % Daily Value % Daily Value • how much a serving contributed to your overall intake of various nutrients on labels • amounts of fats, sodium, carbs, and fibre in 1 serving listed in grams or milligrams and % Daily Value • Remaining nutrients as % Daily Value only •because unigram, milligram, etc. are difficult to interpret •based on recommendations for 2000 kilocal diet •easy way of determining relative amount of a nutrient in 1 serving •foods with less than 5% Daily Value of a nutrient are low in that nutrient •foods with greater than 20% Daily Value are high in that nutrient • Real Life Application •if you want to consume lower fat foods, those contain less than 5% to 10% of the Daily Value for fat will help you reach your goal •if you want to increase Calcium intake, products with greater than 20% Daily Value for calcium are excellent choices 3. Nutrient content claims (optional) • claims about amount of a nutrient in a food • include terms such as: free, low, more, reduced, source of , light--> means nothing Carbohydrate regulations • due to popularity of low carbohydrate/ high protein diets • Acceptable: 8 grams of carb per 30 gram serving/ 10% of the daily value for carb per 30 grams serving • NOT acceptable: net, effective, digestible carb, low glycemic index, rapid absorption, does not raise blood sugars 4. Health Claims (optionals) • statements that link a food or food component with a decrease risk of disease/ condition in context of a total diet • 5 health claims are allowed in canada “A Health Diet” • low in saturated and trans fats may reduce risk of heart disease • low in sodium and high in potassium may reduce risk of high blood pressure • adequate in calcium and Vitamin D may reduce risk of osteoporosis Also Allowed in Canada • labels of products very low in starch and fermentable sugars can state: •“does not promote tooth decay/ dental cavities We Love Eating Out • On a typical day, canadians make 17.7 million visits to commercial restaurants totaling 6.4 billion restaurant occasions per year • The most popular food and beverage ordered at Canadian restaurants are French fries and coffee What to do when eating out? • choose menu items smaller in size • order meats grilled or broiled • avoid fried foods • choose items with steamed vegetables • avoid energy-rich appetizers and desserts Your best bet • adequacy, balance, moderation, variety • choose foods high in nutrient density •high amount of nutrients for least amount of energy • Oreos : 145 kilocal, 56 kilocal from fat, 1 gram fibre • Bananas and Blackberries: 145 kilocal, less than 1gram of fat, 7 grams of fibre (nutrient dense) Summary • Labeling •nutritional facts label (mandatory) •nutrient content claims (optional) •Health claims (optional --> only limited number allowed in Canada) •tips for eating out •aim to increase nutrient density What happens to the food we eat? • Digestion, absorption, elimination •in one end and out the other •related disorders •(26 feet of digestive tract) Definitions: Digestion: • process by which foods are broken down either mechanically or chemically Absorption: • process of taking products of digestion from the GI tract into the bloodstream or lymph system Elimination: • process by which undigested and unabsorbed portions of food and waste products are removed from body Digestion begins in the mouth • chewing initiates mechanical digestion •breaks food into smaller components mixes nutrients together • saliva moistens food and initiates chemical digestion •salivary amylase starts carb digestion • products of this digestion move down esophagus with the help of Peristalsis Peristalsis • squeezing and pushing contractions that move food in one direction thru the GI tract (much like a snake eating) Stomach • lower esophageal sphincter and pyloric sphincter • muscles layers go every which way • stomach has strongest muscles of GI tract • protein digestion is main function here Stomach mixes, digests and holds food • secretes gastric juice •hydrochloric acid activates pepsin •gastric lipase (begins chemical digestion of dietary fat) •mucus (protects stomach from digesting itself) •mixes and churns food into chyme • released into small intestine by pyloric sphincter • Carbohydrates and protein leave first, then fat • Mechanical and chemical digestion pH values • Small intestine: 6 to 7, because of pancreatic secretions • stomach: 2 (acidic) Most digestion and absorption occurs in Small Intestines • bicarbonate from pancreas neutralizes acid chyme • bile from gallbladder emulsifies fat • pancreas secretes digestive enzymes into small intestines • lipase (fat) • Amylase (carbs) • protease (proteins) • Crypt glands also secrete digestive enzymes What happens next? • intestinal cells absorb products of macronutrient digestion, vitamins, minerals and water • 3 to 4 hours after eating • blood, lymph transport nutrients and fluids • blood travels to liver via portal vein • lymph travels thru lymphatic system and contents eventually dumped into blood near heart • Vitamin A, D, E, K go into lymph system • Small intestines is highly vascularized From blood, products of digestion are transported to liver • one of the most important organs in body • receives products of digestion • releases nutrients into blood for transport to rest of body • processes, stores, + regulates monosaccharides, triglycerides and amino acids • synthesized chemicals used in metabolic process (bile) Large Intestines • contains good bacteria which ferments some nutrients • bacteria fermentation: produces gas and SCFAs • absorb any remaining nutrients and water from intestinal content • produce feces from what is not digested or absorbed • store in rectum until defecation • whole process from mouth to defecation takes 1 to 3 days Summary of last class • foods and beverages are pushed along GI tract by peristalsis • nutrients are digested (broken down) • exceptions are vitamins, minerals and water - no digestion needed • digested nutrients absorbed from GI tract into blood and lymph • that which is not absorbed is eliminated • Accessory organs: pancreas, gallbladder, liver Disorders related to Digestion Absorption and Elimination Heartburn • some peo
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