Human Nutrition Chapter 1

Human Nutrition - 10.01.2020    Nutrition Research o nutrition: the study of  nutrients and other biologically active compounds in foods  in the body  sometimes human behaviours related to food o diet: the foods and beverages a person usually eats and drinks o foods: any substance that the body can take in and assimilate that will enable it to stay alive and healthy  carrier of nutrients o health: the state of a human when it functions optimally without evidence of disease or abnormality  optimal health for Canadians can only be achieved when greater efforts are made in health promotion and prevention of illness and then nutrition is an integral part of these efforts nutrition and disease prevention o diet influences long term health outlook o genetics play an important role o genetics and nutrition affect health in various ways (fig. 1.1) o nutritional genomics: the science of how nutrients affect the activities of genes and how genes affect the activity of nutrients o nutrients: components in food that are indispensable or essential to the functioning of the body  provide energy, building material, help maintain or repair the body and support growth  energy providing: carbs, fat, protein  other: water, vitamins, minerals o essential nutrients: the nutrients that the body cannot make for itself from other raw materials; must be obtained through foods  8 essential acids: (TV TILL PM)  threonine; valine  tryptophan; isoleucine; leucine; lysine  phenyl aline; methionine  2 essential fatty acids  linoleic acid, linolenic acid  vitamins  3 fat soluble (A, D, E), 1 conditional (K)  all water soluble  minerals (all) o conditionally essential: the body can not make enough to meet the requirements for health  ex: animo acids histamine to support protein synthesis during growth Energy: o calorie value of energy yielding nutrients      o food quantity measured in grams Nutritious diets: o adequate in essential nutrients, fibre, and energy o Balance in nutrients and food types o Calorie control: foods provide amount of energy o Moderation in fat, salt ,sugar, or other unwanted constituents, set limits, not to excess o Variety: choose different foods each day food choices o advertising o availability o economy o comfort o habit o personal preference o genetic inheritance o positive associations o region o social pressure o values o weight o nutritional value Nutrition Research o designs: case study, epidemiological, intervention, laboratory o can we trust the media as consumers? o how do we separate imposters from real nutrition experts? o p.22 and Tables C1-3 in text o nutrient density: a way to assess which foods are most nutritious Identify Valid Nutrition Information o information derived from scientific research  test ideas through proper scientific experiments  recognize inadequacies of anecdotal evidence and testimonials  do not apply research findings from animals to humans  do not generalize to all groups  reported in respected journals that are peer reviewed Nutritionist: o term is not regulated o may not have a university degree in nutrition may not have formal training, self-taught, variable degree of nutrition information accuracy Registered Dietitian (R.D.) o term regulated by law o member of provincial regulatory body (CDM) o optional membership to dieticians of Canada o 4 year undergrad + 8-12month internship o  Self-check questions for Ch.1 Methods for food intake analysis:    diet recall usually 24hrs o advantages: easy to do, not much commitment o disadvantages: depends on memory, social desirability diet record, usually 3-5 days o advantage: not relying on recall as much o disadvantage: may cause them to eat differently food frequency questionnaire o targeted at different nutrients o fast and easy o disadvantage: may not include all foods equally Dietary guidelines and nutrition objectives    set to help guide people in what to eat to stay healthy American guidelines differ from Canadian (focus on Canadian) Dietary reference intakes Interpretation of food intake:   compare the average daily intake to at least 2-3 guidelines note influence of season, cost, convenience, ethnic and regional foods Dietary reference intakes (DRI)     developed jointly by Canada and the USA as nutrient standards goal: set intake goals for individuals values for o vitamins, minerals, carbs, fibre, lipids, protein, water, energy designed for healthy maintenance and disease prevention in health people o based on available scientific research are recommendations for optimal intakes, not minimum intakes reflect daily intakes to be achieved on average, over time factors considered: o BMI (reference weight and height) o age: to account for physiological changes of life cycle o time: not based on 1 day of food intake, rather an average consumption factors NOT considered: o activity: elite athletes vs inactive o diets: vegans vs omnivores o geographic area: southern vs northern Canada (Vit. D) o lifestyle: smoking increases fit C requirement o illness, malnutrition Proper use of DRI: o most nutrients (except energy):  mean +2 SD  energy is the mean (50%) o the DRI RDA meets the nutritional needs of 97.5% of the population o thus the RDA exceeds the requirement of most individuals in the population )except 2.5%) o energy recommendations set at the mean (50%)  average requirement based on referent height and weight o if a person has less than the DRI for one nutrient this does not mean that they have a deficiency of that particular nutrient, only an increased risk of developing one  consuming less than 2/3 of recommendations indicates risk (based on the 3 day average) o o   