An Overview of Nutrition Chapter 1 PDF

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 Learn...

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 Carbohydrates Hydrogen & oxygen Organic Inorganic (no carbon) Proteins Minerals Organic Simplest nutrient Contains nitrogen Inorganic Lipids (fats) Vitamins Organic Organic (contains carbon) © 2016 Cengage Learning. All Rights Reserved. Body Composition of Healthy- Weight Men and Women The human body is made of compounds similar to those found in foods water (60 percent) fat (18 to 21 % for men) (23 to 26 % for women) the remaining carbohydrate, protein, vitamins, minerals, and other minor constituents make up the remainder. © 2016 Cengage Learning. All Rights Reserved.  The Six Classes of Nutrients Nutrient Organic Inorganic Energy-yielding Macronutrient Micronutrient Carbohydrates ✓ ✓ ✓ Lipids (fats) ✓ ✓ ✓ Proteins ✓ ✓ ✓ Vitamins ✓ ✓ Minerals ✓ ✓ Water ✓ © 2016 Cengage Learning. All Rights Reserved.  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 ✓The science of nutrition : is the study of the nutrients and other substances in foods and the body’s handling of them. ✓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 (a process of choosing the members of the experimental and control groups Randomization helps to 1. eliminate bias 2. Ensure that the two groups are “equal” and that observed differences reflect the treatment and not other factors © 2016 Cengage Learning. All Rights Reserved.  Conducting Research ❖Sample size ✓ Sample Size Importance: ▪ Ensures that chance variation between groups does not influence results. ▪ Larger groups reduce the impact of individual anomalies ( ‫( (شذوذ‬e.g., one person in a group catching a cold) ✓ Effect of Sample Size: In small groups (e.g., 5 people), one person's condition (like catching a cold) significantly affects the group's average. In large groups (e.g., 500 people), individual conditions have a minimal impact on the overall group average. ✓ Statistical Methods: Used to determine if differences between groups of various sizes are significant and support a hypothesis. ❖Placebos ❖Double-blind experiments © 2016 Cengage Learning. All Rights Reserved.  Conducting Research ❖Sample size ✓ Sample Size Importance: ▪ Ensures that chance variation between groups does not influence results. ▪ Larger groups reduce the impact of individual anomalies ( ‫( (شذوذ‬e.g., one person in a group catching a cold) ✓ Effect of Sample Size: In small groups (e.g., 5 people), one person's condition (like catching a cold) significantly affects the group's average. In large groups (e.g., 500 people), individual conditions have a minimal impact on the overall group average. ✓ Statistical Methods: Used to determine if differences between groups of various sizes are significant and support a hypothesis. ❖Placebos ❖Double-blind experiments © 2016 Cengage Learning. All Rights Reserved.  Conducting Research ❖Placebos Placebo Effect: Belief in the effectiveness of treatment (e.g., vitamin C for colds) can improve recovery chances. Taking perceived beneficial pills can reduce illness duration and severity, regardless of active ingredients. Mind-Body Influence: The placebo effect stems from expectations impacting recovery. Experiments on vitamin C's effects must control this phenomenon due to the subjective nature of symptom severity. Controlling the Placebo Effect: All participants receive pills; the experimental group gets vitamin C, while the control group receives placebos. Placebos match in appearance and taste but contain inactive ingredients to balance expectations between groups. Study Design: Participants do not need to believe they are receiving vitamin C, but belief levels must be consistent across groups. Such studies are "blind experiments," where subjects are unaware of their group assignment (experimental vs. control). © 2016 Cengage Learning. All Rights Reserved.  Conducting Research ❖Double-blind experiments Double-Blind Experiment: Both subjects and researchers are unaware of group assignments (experimental or control). Reason for Double-Blind Design: Prevents researcher bias in recording and interpreting results. Researchers might have emotional or financial interests in the outcome, leading to biased results. Implementation: Pills are coded by a third party. The coding ensures neither researchers nor subjects know group assignments until after data collection is complete. © 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 HYPOTHESIS NOT SUPPORTED THEORY NEW OBSERVATIONS Develop a theory that integrates conclusions & QUESTIONS Stepped Art with those from numerous other studies  Types of Research Epidemiological studies Cross-sectional studies Case-control studies Cohort studies Experimental studies Laboratory-based animal studies Laboratory-based in vitro studies (microorganisms or human or animal cells in culture.) 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.  Clinical Trials In clinical trials, an intervention’s effect on a certain disease or health condition is tested using two groups: the experimental group and the control group Randomized trials Single- and double-blind experiments Placebo: an imitation treatment that has no effect, given to the control group in placebo-controlled double-blind randomized clinical trials © 2016 Cengage Learning. All Rights Reserved. © 2018 Pearson Education, Inc.  Analyzing Research Findings Correlations – only show association Positive correlation Not necessarily a desired outcome Negative correlation No correlation © 2016 Cengage Learning. All Rights Reserved.  Analyzing Research Findings Researching Relationships: Researchers examine connections between variables (e.g., vitamin C intake and cold frequency/severity). Variables must be observable, measurable, or verifiable. Types of Correlations: No Correlation: No relationship between variables (e.g., vitamin C doesn't affect cold frequency). Positive Correlation: Both variables move in the same direction (e.g., more vitamin C, more colds; or less vitamin C, fewer colds). Negative Correlation: Variables move in opposite directions (e.g., more vitamin C, fewer colds; or less vitamin C, more colds). Understanding Correlations: Positive correlations aren't always beneficial; negative ones aren't always harmful. Correlations indicate association, not causation. Proving Causation: Correlational evidence alone can't prove one variable causes another. Scientists need a mechanism explaining how one variable causes the other to establish causation. © 2016 Cengage Learning. All Rights Reserved.  Analyzing Research Findings Cautious interpretations and conclusions Accumulation of evidence © 2016 Cengage Learning. All Rights Reserved.  Publishing Research ✓ Peer review (Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (peers). to ensure that the scientific method was followed in the study. ✓ The reviewers critique the study’s hypothesis, methodology, statistical significance, and conclusions ✓Research has validity If the reviewers consider the conclusions to be well supported by the evidence—that is, if the research has validity they endorse the work for publication in a scientific journal where others can read it. Findings are preliminary when published Not meaningful by themselves Findings need to be replicated © 2016 Cengage Learning. All Rights Reserved.  Publishing Research Findings are preliminary when published Not meaningful by themselves Findings need to be replicated New nutrition findings are only preliminary and need more testing. Other scientists must confirm them by doing repeated experiments. Accepted knowledge in nutrition comes from lots of studies over time. It can be hard to share new findings accurately. Review articles in journals can help understand nutrition topics. Meta-analysis combines results from many studies to give an average, but may not fit everyone. © 2016 Cengage Learning. All Rights Reserved.  Analyzing Research Findings Cautious interpretations and conclusions Accumulation of evidence -full Interpretation**: - Researchers must be cautious in interpreting experiment results. Avoid overgeneralizing findings to broader populations not studied. ✓ Specific Populations**: - For example, results from studying men aged 18-30 shouldn't be applied to all genders and ages. - Animal research findings need cautious application to humans. ✓ Tentative Conclusions**: Findings from a single study are considered preliminary. Researchers compare with other studies before making recommendations. © 2016 Cengage Learning. All Rights Reserved.  Analyzing Research Findings Cautious interpretations and conclusions ✓ Cautious Recommendations**: Even when evidence accumulates, wording remains careful (e.g., "A diet high in fruits and vegetables may protect against some cancers"). ✓ Continuous Inquiry**: Answering one question often leads to new questions. Future research may explore specifics, like identifying protective substances in fruits and vegetables. **Further Investigation**: Questions arise about the specific substances in produce and their protective mechanisms. Research continues into how vitamins might act, such as through antioxidant properties or other mechanisms. © 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 Percentage of Food plays vital role Total Deaths 1. Heart disease 23.7 in supporting health 2. Cancers 22.9 Chronic disease – 3. Chronic lung diseases 5.7 epidemic levels 4. Strokes 5.1 5. Accidents 4.9 Multiple factors over 6. Alzheimer's disease 3.4 multiple years 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 Factors Percentage of Risk factors Deaths Persist over time Tobacco 18 Cluster Poor diet/inactivity 15 Alcohol 4 Prominence of risk Microbial agents 3 factors Toxic agents 2 Tobacco Motor vehicles 2 Firearms 1 Diet and activity Sexual behavior