An Overview of Nutrition Chapter 1

Introduction Daily food choices Diet Benefit health Harm health Chronic disease Diet Foods and beverages

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

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

The Nutrients Water Minerals Vitamins Carbohydrates Proteins Hydrogen & oxygen Inorganic (no carbon) Minerals Simplest nutrient Inorganic Vitamins Organic (contains carbon) Carbohydrates Organic Proteins Contains nitrogen Lipids (fats)

Body Composition of Healthy-Weight Men and Women Figure 1-1 Body composition of healthy-weight men and women

The Six Classes of Nutrients Organic Inorganic Energy-yielding Macronutrient Micronutrient Carbohydrates ✓   Lipids (fats) Proteins Vitamins Minerals Water Table 1-1 The six classes of nutrients

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

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

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

The Vitamins Thirteen organic vitamins Facilitate energy release 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

The Minerals and Water Minerals Water 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

The Science of Nutrition Foundation in several other sciences Biology, biochemistry, physiology Tremendous growth Knowledge gained from sequencing the human genome Nutritional genomics

Conducting Research Use of scientific method Research studies Systematic process for conducting research Research studies Controls Randomization Sample size Placebos Double-blind experiments

The Scientific Method

Design a study and conduct the research to collect relevant data Identify a problem to be solved or ask a specific question to be answered OBSERVATION & QUESTION 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. Figure 1-3 The Scientific Method Research scientists follow the scientific method. Note that most research generates new questions, not final answers. Thus the sequence begins anew, and research continues in a somewhat cyclical way. HYPOTHESIS SUPPORTED HYPOTHESIS NOT SUPPORTED NEW OBSERVATIONS & QUESTIONS THEORY Develop a theory that integrates conclusions with those from numerous other studies Stepped Art

Types of Research Epidemiological studies Experimental studies Cross-sectional studies Case-control studies Cohort studies Experimental studies Laboratory-based animal studies Laboratory-based in vitro studies Human intervention (clinical) trials

Examples of Epidemiological Studies

Examples of Experimental Studies

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

Publishing Research Peer review Research has validity Findings are preliminary when published Not meaningful by themselves Findings need to be replicated

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). Table 1-3 Parts of a research article

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

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

EAR and RDA Compared

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

Inaccurate versus Accurate View of Nutrient Intakes 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. 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. If the usual intake falls below the EAR, it is probably inadequate. Figure 1-6 Inaccurate versus accurate view of nutrient intakes

Establishing Energy Recommendations Estimated Energy Requirement (EER) Average dietary energy intake to maintain energy balance Healthy body weight Physical activity No upper level

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

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

Nutrition Assessment Deficiency or excess over time leads to malnutrition Undernutrition and overnutrition Symptoms of malnutrition Diarrhea Skin rashes Fatigue Others

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

Stages in the Development of a Nutrient Deficiency Figure 1-7 Stages in the development of a nutrient deficiency

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

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 Table 1-4 Healthy people 2020 nutrition and weight status objectives (continues)

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 Table 1-4 Healthy people 2020 nutrition and weight status objectives (cont’d.)

Diet and Health Food plays vital role in supporting health   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 Food plays vital role in supporting health Chronic disease – epidemic levels Multiple factors over multiple years Table 1-5 Leading causes of death in the United States 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.

Chronic Disease Risk Factors Percentage of Deaths Tobacco 18 Poor diet/inactivity 15 Alcohol 4 Microbial agents 3 Toxic agents 2 Motor vehicles Firearms 1 Sexual behavior <1 Illicit drugs Risk factors Persist over time Cluster Prominence of risk factors Tobacco Diet and activity patterns Others Table 1-6 Factors contributing to deaths in the United States 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.

Nutrition Information and Misinformation Highlight 1

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?

Nutrition in the News News often tells lopsided story Testimonials Tight deadlines Limited understanding Current and controversial

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)

Credentials Identifying fake credentials College accreditation Diploma mills Fraudulent businesses Red flags of nutrition quackery Misinformation Consider the source Buyer beware

Red Flags of Nutrition Quackery Figure H1-2 Red flags of nutrition quackery