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An Overview of Nutrition Chapter 1 © 2016 Cengage Learning. All Rights Reserved. Introduction • Daily food choices • Benefit health • Harm health • Chronic disease • Diet • Foods and beverages © 2016 Cengage Learning. All Rights Reserved. Food Choices Are Highly Personal • Personal preference • Taste: sweet and salty, genetics • • • • Habit Ethnic heritage or tradition Social interactions Availability, convenience, and economy • Benefits of home-cooked meals • Positive and negative associations © 2016 Cengage Learning. All Rights Reserved. Food Choices – Other Factors • Emotions • Boredom, depression, anxiety • Stress • Values • Religious beliefs, political views, environmental concerns • Body weight and image • Nutrition and health benefits • Functional and fortified foods © 2016 Cengage Learning. All Rights Reserved. The Nutrients • Water • Hydrogen & oxygen • Inorganic (no carbon) • Minerals • Simplest nutrient • Inorganic • Vitamins • Organic (contains carbon) © 2016 Cengage Learning. All Rights Reserved. • Carbohydrates • Organic • Proteins • Organic • Contains nitrogen • Lipids (fats) • Organic Body Composition of HealthyWeight Men and Women © 2016 Cengage Learning. All Rights Reserved. The Six Classes of Nutrients Nutrient Organic Inorganic Energy-yielding Macronutrient Carbohydrates ✓ ✓ ✓ Lipids (fats) ✓ ✓ ✓ Proteins ✓ ✓ ✓ Vitamins ✓ ✓ Minerals ✓ Water ✓ © 2016 Cengage Learning. All Rights Reserved. Micronutrient ✓ Macronutrients and Micronutrients • Macronutrients yield energy • Carbohydrate • Fat • Protein • Water and minerals do not yield energy • Micronutrients • Vitamins and minerals • Human body needs small amounts © 2016 Cengage Learning. All Rights Reserved. Energy-Yielding Nutrients • Macronutrients: source of kcalories • Carbohydrate = 4 kcal/g • Protein = 4 kcal/g • Fat = 9 kcal/g • Higher energy density • Alcohol • Not a nutrient • Yields energy – 7 kcal/g • Lower energy density foods • Contribute to weight loss © 2016 Cengage Learning. All Rights Reserved. Energy in the Body • Body uses macronutrients • Bonds between the nutrients’ atoms break • Energy is released • Can then be used or stored • Macronutrients • Provide raw material for building tissue and regulating body activities • Proteins regulate digestion and energy metabolism © 2016 Cengage Learning. All Rights Reserved. The Vitamins • Thirteen organic vitamins • Each has a special role to play • Facilitate energy release • Almost every bodily action requires assistance from vitamins • Vulnerable to destruction • Heat (as from cooking), light, and chemicals © 2016 Cengage Learning. All Rights Reserved. The Minerals and Water • Minerals • Do not yield energy • Sixteen essential minerals • Other minerals are environmental contaminants • Example: lead • Indestructible • But can be lost into cooking water, for example • Water • Environment for nearly all body processes © 2016 Cengage Learning. All Rights Reserved. The Science of Nutrition • Foundation in several other sciences • Biology, biochemistry, physiology • Tremendous growth • Knowledge gained from sequencing the human genome • Nutritional genomics © 2016 Cengage Learning. All Rights Reserved. Conducting Research • Use of scientific method • Systematic process for conducting research • Research studies • Controls • Randomization • Sample size • Placebos • Double-blind experiments © 2016 Cengage Learning. All Rights Reserved. The Scientific Method © 2016 Cengage Learning. All Rights Reserved. OBSERVATION & QUESTION Identify a problem to be solved or ask a specific question to be answered HYPOTHESIS & PREDICTION Formulate a hypothesis—a tentative solution to the problem or answer to the question—and make a prediction that can be tested EXPERIMENT Design a study and conduct the research to collect relevant data RESULTS & INTERPRETATIONS Summarize, analyze, and interpret the data; draw conclusions. HYPOTHESIS SUPPORTED THEORY Develop a theory that integrates conclusions with those from numerous other studies HYPOTHESIS NOT SUPPORTED NEW OBSERVATIONS & QUESTIONS Stepped Art Types of Research • Epidemiological studies • Cross-sectional studies • Case-control studies • Cohort studies • Experimental studies • Laboratory-based animal studies • Laboratory-based in vitro studies • Human intervention (clinical) trials © 2016 Cengage Learning. All Rights Reserved. Examples of Epidemiological Studies © 2016 Cengage Learning. All Rights Reserved. Examples of Experimental Studies © 2016 Cengage Learning. All Rights Reserved. Analyzing Research Findings • Correlations – only show association • Positive correlation • Not necessarily a desired outcome • Negative correlation • No correlation • Cautious interpretations and conclusions • Accumulation of evidence © 2016 Cengage Learning. All Rights Reserved. Publishing Research • Peer review • Research has validity • Findings are preliminary when published • Not meaningful by themselves • Findings need to be replicated © 2016 Cengage Learning. All Rights Reserved. Parts of a Research Article • Abstract. The abstract provides a brief overview of the article. • Introduction. The introduction clearly states the purpose of the current study and provides a comprehensive review of the relevant literature. • Review of literature. A comprehensive review of the literature reveals all that science has uncovered on the subject to date. • Methodology. The methodology section defines key terms and describes the study design, subjects, and procedures used in conducting the study. • Results. The results report the findings and may include tables and figures that summarize the information. • Discussion: The discussion draws tentative conclusions that are supported by the data and reflect the original purpose as stated in the introduction. Usually, it answers a few questions and raises several more. • References. The references reflect the investigator's knowledge of the subject and should include an extensive list of relevant studies (including key studies several years old as well as current ones). © 2016 Cengage Learning. All Rights Reserved. Dietary Reference Intakes • Standards defined for: • • • • Energy Nutrients Other dietary components Physical activity • Collaborative effort between United States and Canada • Recommendations apply to healthy people • May be different for specific groups © 2016 Cengage Learning. All Rights Reserved. EAR and RDA • Estimated Average Requirements (EAR) • Average amount sufficient for half of population • Recommended Dietary Allowances (RDA) • Recommendations to meet needs of most healthy people • Set near the top end of the range of EAR © 2016 Cengage Learning. All Rights Reserved. EAR and RDA Compared © 2016 Cengage Learning. All Rights Reserved. Adequate Intakes and Upper Intake Levels • Adequate Intakes (AI) • Insufficient scientific evidence to establish EAR • AI value set instead of RDA • Expected to exceed average requirements • Tolerable Upper Intake Levels (UL) • Point where nutrient is likely to be toxic • Helps protect against overconsumption © 2016 Cengage Learning. All Rights Reserved. Inaccurate versus Accurate View of Nutrient Intakes 1. If a person’s usual intake falls above the RDA, the intake is probably adequate because the RDA meets the needs of almost all people. 2. A usual intake that falls between the RDA and the EAR is more difficult to assess; the intake may be adequate, but the chances are greater or equal that it is inadequate. 3. If the usual intake falls below the EAR, it is probably inadequate. © 2016 Cengage Learning. All Rights Reserved. Establishing Energy Recommendations • Estimated Energy Requirement (EER) • Average dietary energy intake to maintain energy balance • Healthy body weight • Physical activity • No upper level © 2016 Cengage Learning. All Rights Reserved. Acceptable Macronutrient Distribution Ranges (AMDR) • Adequate energy and nutrients • Reduce risk of chronic diseases • Ranges • 45-65% kcalories from carbohydrate • 20-35% kcalories from fat • 10-35% kcalories from protein © 2016 Cengage Learning. All Rights Reserved. Using Nutrient Recommendations • Estimates apply to healthy people • Needs adjusting for medical problems, malnourishment, or other condition • Recommendations – not minimum levels nor optimal levels • Goals intended to be met through diet • Apply to average daily intakes • Each DRI category serves a unique purpose © 2016 Cengage Learning. All Rights Reserved. Nutrition Assessment • Deficiency or excess over time leads to malnutrition • Undernutrition and overnutrition • Symptoms of malnutrition • • • • Diarrhea Skin rashes Fatigue Others © 2016 Cengage Learning. All Rights Reserved. Creating a “Total Picture” of the Individual • Historical information • Health status, SES, drug use • Diet history – intake over several days; portion sizes; computer analysis • Anthropometric measurements • Height and weight – track to identify trends • Physical examinations • Laboratory tests © 2016 Cengage Learning. All Rights Reserved. Stages in the Development of a Nutrient Deficiency © 2016 Cengage Learning. All Rights Reserved. Nutrition Assessment of Populations • National nutrition surveys • Conducted by various agencies • One survey collects data on food types and amounts • Another collects data about people themselves • Oversample high-risk groups • National health goals • Healthy People program • National trends © 2016 Cengage Learning. All Rights Reserved. Healthy People 2020 Nutrition and Weight Status Objectives • • • • • • • • • • • • Increase the proportion of adults who are at a healthy weight Reduce the proportion of adults who are obese Reduce iron deficiency among young children and females of childbearing age Reduce iron deficiency among pregnant females Reduce the proportion of children and adolescents who are overweight or obese Increase the contribution of fruits to the diets of the population aged 2 years and older Increase the variety and contribution of vegetables to the diets of the population aged 2 years and older Increase the contribution of whole grains to the diets of the population aged 2 years and older Reduce consumption of saturated fat in the population aged 2 years and older Reduce consumption of sodium in the population aged 2 years and older Increase consumption of calcium in the population aged 2 years and older Increase the proportion of worksites that offer nutrition or weight management classes or counseling © 2016 Cengage Learning. All Rights Reserved. Healthy Weight Objectives (Cont’d.) • • • • • • • • Increase the proportion of physician office visits that include counseling or education related to nutrition or weight Eliminate very low food security among children in US households Prevent inappropriate weight gain in youth and adults Increase the proportion of primary care physicians who regularly measure the body mass index of their patients Reduce consumption of kcalories from solid fats and added sugars in the population aged 2 years and older Increase the number of states that have state-level policies that incentivize food retail outlets to provide foods that are encouraged by the Dietary Guidelines Increase the number of states with nutrition standards for foods and beverages provided to preschool-aged children in childcare Increase the percentage of schools that offer nutritious foods and beverages outside of school meals NOTE: Nutrition and Weight Status is one of 38 topic areas, each with numerous objectives. Several of the other topic areas have nutrition-related objectives, and these are presented in Appendix J. SOURCE: www.healthypeople.gov © 2016 Cengage Learning. All Rights Reserved. Diet and Health • Food plays vital role in supporting health • Chronic disease – epidemic levels • Multiple factors over multiple years Percentage of Total Deaths 1. Heart disease 23.7 2. Cancers 22.9 3. Chronic lung diseases 5.7 4. Strokes 5.1 5. Accidents 4.9 6. Alzheimer's disease 3.4 7. Diabetes mellitus 2.9 8. Pneumonia and influenza 2.1 9. Kidney disease 1.8 10. Suicide 1.5 NOTE: The diseases highlighted in bold have relationships with diet SOURCE: Deaths: Preliminary data for 2011, National Vital Statistics Reports. October 10, 2012. Centers for Disease Control and Prevention, www.cdc.gov/nchs. © 2016 Cengage Learning. All Rights Reserved. Chronic Disease Risk Factors • Risk factors • Persist over time • Cluster • Prominence of risk factors • Tobacco • Diet and activity patterns • Others Factors Percentage of Deaths Tobacco 18 Poor diet/inactivity 15 Alcohol 4 Microbial agents 3 Toxic agents 2 Motor vehicles 2 Firearms 1 Sexual behavior <1 Illicit drugs <1 SOURCE: A. H. Mokdad and coauthors, Actual causes of death in the United States. 2000. Journal of the American Medical Association 291 (2004): 1238-1245, with corrections from Journal of the American Medical Association 293 (2005): 298. © 2016 Cengage Learning. All Rights Reserved. Nutrition Information and Misinformation Highlight 1 © 2016 Cengage Learning. All Rights Reserved. Nutrition on the Internet • Validity of information • Who is providing information? • Qualifications • Internet • Anyone can publish anything • No guarantees of accuracy • Evaluate websites • Who, when, where, why, and what? © 2016 Cengage Learning. All Rights Reserved. Nutrition in the News • News often tells lopsided story • • • • Testimonials Tight deadlines Limited understanding Current and controversial © 2016 Cengage Learning. All Rights Reserved. Identifying Nutrition Experts • Physicians and other health-care professionals • Training in nutrition is limited • Registered dietitian (RD) • Degree and clinical internship • National exam • Maintain up-to-date knowledge • Dietetic technician registered (DTR) © 2016 Cengage Learning. All Rights Reserved. Credentials • Identifying fake credentials • College accreditation • Diploma mills • Fraudulent businesses • Red flags of nutrition quackery • Misinformation • Consider the source • Buyer beware © 2016 Cengage Learning. All Rights Reserved. Red Flags of Nutrition Quackery © 2016 Cengage Learning. All Rights Reserved.
