Chapter 1 - The Science of Nutrition - Comstock PDF

CHAPTER 1 – THE SCIENCE OF NUTRITION CHRIS COMSTOCK MS, RD, LN TIPS FOR SUCCESS IN THIS COURSE  In-person sections:  Come to class - I will discuss information in class that is not found in your notes. Pay attention to the items I repeat or write on the board  Online sections:...

CHAPTER 1 – THE SCIENCE OF NUTRITION CHRIS COMSTOCK MS, RD, LN TIPS FOR SUCCESS IN THIS COURSE  In-person sections:  Come to class - I will discuss information in class that is not found in your notes. Pay attention to the items I repeat or write on the board  Online sections:  Review the news section regularly and read over the commentary I provide in the PowerPoint “Notes” section  Pay attention to concepts and terms that are asterisked (“*”) in the notes. These are things I feel you should know as we progress through the chapters  Repetition, repetition, repetition!!!  Look at the information several times and try to apply what you’re learning to real life  We cover a lot of material, so don’t try to cram everything in right before the exam.  Study with your friends, classmates, etc.  Read your textbook and utilize my office hours TIPS FOR SUCCESS IN THIS COURSE  Because this is a 300-level course, you will need to spend quite a bit of time preparing for the exams.  Application questions are common on board and licensing exams, so they will be included in my tests as well. Application questions can be challenging if you’ve never encountered them before, and sometimes it takes a little practice to learn how to approach them.  If you're comfortable teaching the material to someone else, then you probably have a firm grasp on it. TIPS FOR PREPARING FOR THE EXAMS  Read the chapter in the textbook before reviewing the corresponding PowerPoint notes.  Review the PowerPoint slides.  If anything is confusing, go back to the textbook first, then reach out to me for clarification.  Go through the PowerPoints notes once again, filling out the study guide(s) as you progress through the material.  Now that you've seen this material several times, try to think actively about it:  How does this information apply to everyday life?  What are some potential multiple-choice questions I could ask? Being able to apply this material to your life and future career is very important  Review the supporting material (e.g., videos, websites, and diagrams) I've linked on D2L. If you're a visual learner, these resources will be really helpful.  As the test approaches, focus on the information within the study guides and pay attention to items in the notes that are bolded, underlined, asterisked, or repeated several times.  Keep in mind that I won't ask any questions on the exam about information and material that isn't covered in your notes or book. WHY STUDY NUTRITION?  2 out of 3 U.S. deaths can be linked to a poor diet and/or a sedentary lifestyle  Taxpayer dollars, morbidity, obesity as a disability  Obesity is the 2nd leading cause of preventable death in the US (smoking is #1)  Consuming too much or too little of a nutrient can lead to disease and death, even years later  What you eat in your childhood/teen/young adult years influences health later in life  We know this is true of Calcium/Vitamin D and bones!  Reach peak bone mass between 25 and 30 years of age. Poor diet at a young age could lead to osteoporosis.  To pass this course! CHAPTER OUTLINE  Nutrition Overview  Energy Sources and Uses  The North American Diet  Nutritional Health Status  Genetics and Nutrition  Using Scientific Research to Determine Needs  Evaluating Nutrition Claims and Products INTRODUCTION TO CHAPTER 1  Research shows what we eat has a profound influence on our health and longevity!  Poor diet is a known risk factor for malnutrition, chronic disease, and nutrient deficiency diseases  Overweight and obesity, cardiovascular disease, type 2 diabetes and certain forms of cancer  Plant-based diets with adequate fruits, vegetables, and whole grains are known to be protective against disease NUTRITION OVERVIEW  Nutrition – The science of food; the nutrients and the substances therein; their action, interaction, and balance in relation to health and disease; and the process by which the organism ingests, digests, absorbs, transports, utilizes, and excretes food substances  Nutrients** – Substances essential for health that the body cannot make OR that the body makes in quantities too small to support life  Not all foods provide all nutrients  A nutrient is essential** if:  It has a specific biological function  Removal from diet leads to decline in human biological function  Returning the nutrient to the diet before permanent damage occurs restores impaired biological functions  Essential nutrients MUST come from the diet; their absence will lead to sickness and disease NUTRITION OVERVIEW  Six main classes of nutrients**  Carbohydrates, lipids, proteins, water, vitamins, minerals  Nutrients can be categorized by function or needs  Function  Nutrients that provide energy (Carbohydrates, proteins, lipids)  Nutrients that promote growth and development (Proteins, lipids, some vitamins, some minerals, water)  Nutrients that regulate body processes (proteins, some lipids, some vitamins, some minerals, water)  Needs  Macronutrients** – Needed in large quantities (grams)  Includes carbohydrate, lipids, protein, and water  Note: Water is sometimes classified as a micronutrient because of its structure  Micronutrients** – Needed in small quantities (mcg or mg)  Includes vitamins, minerals MICRONUTRIENT DEFICIENCIES  When we eat, we need to focus on more than just the macros!  The consequences of micronutrient deficiencies can be severe  Micronutrient deficiencies can:  Lead to fatigue  Increase an individual’s susceptibility to infection  Lead to birth defects  Impair wound healing  Impair cognitive development  Damage eyesight and cause blindness  Lead to premature mortality  Iron, iodine, and vitamin A** are the three most common nutrient deficiencies seen worldwide  Iron deficiency can lead to anemia, fatigue, shortness of breath, hair loss, brittle nails, pale skin, increased susceptibility to cold and infection, restless leg syndrome, pica, depression, anxiety disorders, and impaired mental development MICRONUTRIENT DEFICIENCY EXAMPLES Vitamin A Deficiency Iodine Deficiency  Can lead to nyctalopia**  Can lead to goiter** and cretinism**  Why don’t we see goiter in America? CARBOHYDRATES  Composed of Carbon, Hydrogen and Oxygen in a ratio of 1:2:1 (AKA CH 20)  “Hydrated carbons”  C6H12O6 = Glucose  Sometimes abbreviated “CHOs”  Major fuel source for the body  Provide 4 kcal/g CARBOHYDRATES  Can be divided into “simple” and “complex”  Simple carbohydrates*  AKA “sugars”  Single sugars are called monosaccharides**  __________  __________  __________  Double sugars are called disaccharides.** They contain 2 monosaccharide units.  __________ = Glucose + Glucose**  __________ = Glucose + Fructose**  __________ = Glucose + Galactose** CARBOHYDRATES  Can be divided into “simple” and “complex”  Complex carbohydrates*  Oligosaccharides** = Typically 3-10 monosaccharides linked together  Polysaccharides** = Many monosaccharides linked together  Examples include Cellulose, Glycogen, and Starch  __________ = the storage form of glucose in plants**  __________ = the storage form of glucose in humans**  Found in the muscle and the liver!  The body uses Glucose as a main energy source  The body can make glucose from the other mono- and disaccharides, and can even make it from certain amino acids DIGESTIBLE VS. INDIGESTIBLE CARBOHYDRATES  Digestible Carbohydrates – Carbohydrates that can be broken down by the human body  Supply energy  Indigestible Carbohydrates (AKA Fibers) – Carbohydrates that cannot be broken down by the human body  Important for gut health! (More later)  Fibers are naturally present in fruits, vegetables, whole grains, nuts, seeds, and legumes  Soluble fiber**  May reduce blood cholesterol levels and blood glucose levels**  Examples include the gums, pectins, and mucilages found in beans, fruits, oats, etc.  Insoluble fiber**  Adds bulk to the stool, promotes bowel health and regularity**  Examples include the cellulose, hemicellulose, and lignin found in whole grains and vegetables  You can learn more about soluble and insoluble fiber here: https://www.healthline.com/health/soluble-vs-insoluble-fiber LIPIDS  Includes both fats (solid at room temp) and oils (liquid at room temp)  Composed of Carbon, Hydrogen, and Oxygen  Provide 9 kcal/g  Insoluble in water  Think about what happens when you mix water and oil!  Glycerol plus 3 Fatty Acid (FA) molecules  Triglyceride (TG)*  TGs are the major form of fat in foods*  TGs are the major form for energy storage in the body* FATTY ACIDS – SATURATED VS UNSATURATED  Saturated fatty acids**  Every bond on every carbon in the chain is filled  Solid at room temperature  Primarily come from animal sources  Exceptions include palm oil and coconut oil  Unsaturated fatty acids**  Contain double bonds  Monounsaturated Fatty Acids** – Contain one double bond  Polyunsaturated Fatty Acids** – Contain more than one double bond  Liquid at room temperature  Primarily come from plant sources  Note: Many foods contain a mixture of saturated and unsaturated fats TRANS FATS  Unsaturated fats that have been processed to change their structure from the cis form to the trans form  Trans fats cause inflammation and significantly increase your risk for heart disease  Partially hydrogenated vegetable oils were the #1 source of trans fats in the American diet  Found primarily in:  Deep-fried foods  Baked goods and deserts  Fast foods  FYI: Trans fats are naturally found in beef and dairy products, but do not exert the same effects within the body as artificial trans fats PROTEIN  Contain C, H, O + N (Nitrogen)  Provide 4 kcal/g  Proteins are made up of chains of Amino Acids*  20 different Amino Acids exist in foods**  9 are essential**  Proteins are the main structural material in the body and also have many functional roles.  Bone, muscle, blood, cell membranes, enzymes, antibodies, etc. SIDE NOTE ON ESSENTIAL NUTRIENTS  There are “essential” vitamins, minerals, fats, and proteins, but NOT essential carbohydrates…why?  2 Essential Fatty Acids (EFAs)**  Linoleic Acid (LA)** – Omega __ Fatty Acid  Alpha-Linolenic Acid (ALA)** – Omega __ Fatty Acid  9 Essential Amino Acids (EAAs)**  Mnemonic – PVT TIM H(A)LL  Arginine = Conditionally Essential  Valine, Leucine, and Isoleucine = BCAAs Essential Amino Acids P= V= T= T= I= M= H= L= L= VITAMINS  Main Function: Enable chemical reactions in the body**  Provide no energy (calories) directly, but help release energy trapped in carbohydrates, lipids, and proteins.  This is why micronutrient deficiencies often lead to fatigue!  There are 13 vitamins  9 water-soluble vitamins  Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Vitamin B6 (Pyridoxine), Biotin, Folate (B9), and Vitamin B-12  4 fat-soluble vitamins  Vitamins A, D, E, K**  In certain areas, vitamin D might not be essential. Why? MINERALS  Simple, inorganic structures  Unlike vitamins, minerals are not easily destroyed by cooking  Can leach out into the cooking water  Provide 0 kcal  Play many important roles in the body (e.g., body system function, water balance, nutrient absorption and transport, etc.)  Minerals are divided into two groups: Major and trace  Major Minerals** – Needed daily in gram amounts  Examples include:  Trace Minerals** – Need less than 100 mg daily  Examples include: WATER  Macronutrient needed in largest amounts by the body  Composed of (2) H and (1) O  H2O  Besides being a nutrient, water acts as a solvent in the body (dissolving substances), a lubricant, a transport medium, a temperature regulation medium, and a medium for chemical reactions  The human body is at least ½ water (more later) FYI: ARE YOU DRINKING ENOUGH WATER?  You can estimate your fluid needs by multiplying your weight in kg by 30 mL/kg  You can find your weight in kg by dividing your weight in lbs by 2.2  Example: 200 lb male  200 lbs/2.2 = 90.9 kg  90.9 kg x 30 mL of water per kg of body weight = 2,727 mL  30 mL = 1 fluid ounce, so 2,727 mL = 90.9 ounces of water FYI: A PERSPECTIVE ON AMOUNTS  Sally is on a 2000 calorie per day diet. She gets 50% of her calories from CHOs. How many grams of CHOs per day does she eat?  To answer this question, you first need to understand how many calories are in a gram of carbohydrate.  1 gram of CHO = 4 kcal  If she is on a 2000 kcal diet, and 50% of her calories are coming from CHO, then we know that Sally is consuming 1000 kcal from CHOs.  1000 kcal from CHO divided by 4 kcal/g = 250 grams  Answer: Sally eats 250 grams of CHOs each day  Approximately how many ounces of CHOs does she eat per day?  To convert grams to ounces, multiply by.035 ounces/gram  250 grams x 0.035 ounces/gram = 8.75 ounces from CHOs  To compare, how many ounces of water should she consume per day?  There are 8 ounces in a cup. If we use the recommendation that much of the general public is familiar with, you will see that humans consume much more water than carbohydrate!  8 cups x 8 ounces per cup = 64 ounces of water NUTRIENT SUMMARY  At this point, you should consider making a chart detailing the 6 major classes of nutrients. Your rows/columns could include:  Basic components  What elements are they made of?  Structure notes (Chains/structures of “___”)  Do they provide energy? If so, how many kcal/g are provided?  What else is this nutrient used for in the body?  Do they have structural roles or functional roles or both?  Are there essential nutrients in this class?  What are they?  Other misc. notes about this class of nutrients WE SHOULD ALL TRY TO ADOPT A FOOD FIRST APPROACH  There are THOUSANDS of bioactive compounds in our foods  You can’t make up for a poor diet with supplements!  Your diet should be colorful and include a variety of foods.  Functional foods  Phytochemicals**  Physiologically active compounds found in plant foods (fruits, vegetables, legumes, and whole grains)  Provide many health benefits; reduce inflammation, improve immunity, may protect against diseases like cancer  Zoochemicals**  Physiologically active compounds found in animal foods  Examples: Omega-3 fatty acids, probiotics, etc. Study link: ENERGY SOURCES, USES OF ENERGY  Carbs, lipids, proteins and alcohol all provide calories  Considered “energy-yielding” nutrients  Most foods contain more than one of these energy sources  Energy is used for:  Making new compounds in the body  Examples include hormones, enzymes, cells and cell parts  Performing muscular movements  Including smooth muscle in blood vessels and gut, cardiac muscle in heart, and skeletal muscles to move the body  Promoting nerve transmissions  Nerves are firing somewhere in the body 24/7!  Maintaining ion balance within the cells  Cells must constantly maintain balance across the cell membranes to avoid bursting or shriveling ENERGY IN FOODS  Expressed as # of Calories*  1 calorie = the amount of heat energy required to raise the temperature of 1 g of water 1 degree C  1 Calorie = 1 Kilocalorie = the amount of heat energy required to raise the temperature of 1 Kg of water 1 degree C  1 Calorie = 1000 calories  Food energy is expressed in “kilocalories” because 1 calorie is very small  Kilocalorie = kcal = 1000 calories  To Review:  Carbohydrates = 4 kcal/g  Fats = 9 kcal/g  Proteins = 4 kcal/g  Alcohol = 7 kcal/g PRACTICE CALCULATIONS – BE ABLE TO DO THIS FOR THE EXAM! Calculate how many Calories are in a food with 30 grams of carbohydrate, 16 grams of fat, and 20 grams of protein. Carbohydrate: 30 g x 4 kcal/g = 120 kcal 120 kcal/344 kcal = 34.8% of total calories from carbohydrate Fat: 16 g x 9 kcal/g = 144 kcal 144 kcal/344 kcal = 41.9% of total calories from fat Protein: 20 g x 4 kcal/g = 80 kcal 80 kcal/344 kcal = 23.3% of total calories from protein Total Calories: 120 + 144 + 80 = 344 kcal Calculate the percent energy intake from CHO, Pro, and Fat using the following information: A meal you consume contains 285 g of CHO, 55 g fat, 70 g protein, and 8 g alcohol. What percent of calories come from each of the aforementioned nutrients? Carbohydrate: 285 g x 4 kcal/g = 1140 kcal 1140/1971 = 57.8% Fat: 55 g x 9 kcal/g = 495 kcal 495/1971 = 25.1% Protein: 70 g x 4 kcal/g = 280 kcal 280/1971 = 14.2% Alcohol: 8 g x 7 kcal/g = 56 kcal 56/1971 = 2.8% TOTAL = 1971 kcal THE NORTH AMERICAN DIET  Only 1 in 10 adults consume enough fruits and vegetables!  Only 9% of adults ate the recommended amount of vegetables and 12% of adults ate the recommended amount of fruit  https://www.cdc.gov/nccdphp/dnpao/division-information/media-tools/adults-fruits-vegetables.html  Macronutrient distribution for the average  Acceptable Macronutrient Distribution North American diet: Ranges (AMDRs)**:  50% of total calories comes from CHO  45 – 65% of total calories should come from CHOs  33% of total calories comes from fat  20 – 35% of total calories should come from  16% of total calories comes from protein fat  10 – 35% of total calories should come from protein NORTH AMERICAN DIET  Issues with the North American diet**  Too many calories are being consumed  Too much protein and fat from animal sources; too little from plants  Too many carbohydrates from simple sugars; too few from complex carbohydrates  Diet is too high in sodium  Recommendations for Improvement**  Eat more fruits, vegetables, whole-grains, and reduced-fat dairy  Increase intake of fiber, vitamin A, vitamin E, iron, potassium, and calcium  Decrease intake of sodium (Consume fewer fast food and ultra processed food)  Moderate intake of sugary soft drinks and fatty foods WHAT INFLUENCES OUR FOOD CHOICES? HUNGER VS. APPETITE THREE GENERAL CATEGORIES OF NUTRITIONAL STATUS  Undernutrition (malnutrition)**  Subclinical nutrient deficiency* – Nutrient stores are depleted, but person exhibits no overt signs or symptoms of deficiency  Clinical nutrient deficiency* – Signs and symptoms of nutrient deficiency become outwardly apparent  Desirable (“optimal”) nutrition  The body tissues have enough of a nutrient to support normal functions and enough to build and maintain body stores that can be used in times of need.  Overnutrition (malnutrition)**  Consumption of more nutrients or calories than the body needs  Some nutrients are easily stored in the body and can lead to toxicity! NATIONAL HEALTH OBJECTIVES  Healthy People 2030  10-year plan for addressing our nation’s most critical public health priorities and challenges.  Many of the goals/objectives of Healthy People are nutrition-related!  Overarching goals of Healthy People 2030:  Attain healthy, thriving lives and well-being, free of preventable disease, disability, injury, and premature death.  Eliminate health disparities, achieve health equity, and attain health literacy to improve the health and well-being of all  Create social, physical, and economic environments that promote attaining full potential for health and well-being for all  Promote healthy development, healthy behaviors, and well-being across all life stages  Engage leadership, key constituents, and the public across multiple sectors to take action and design policies that improve the health and well-being of all. NATIONAL HEALTH OBJECTIVES ASSESSING NUTRITIONAL STATUS  Assessing nutritional status using the ABCDEs  Anthropometric (Body) Measurements*  Height, weight, arm/waist/hip circumferences, skinfold measurements  Biochemical Labs*  Measurement of concentrations of nutrients and nutrient by-products in the blood, urine, feces, and hair  Clinical Assessments*  Medical history and family history  Looks for physical evidence of diet-related disease in the skin, eyes, nails. Examines blood pressure, neurological symptoms, etc.  Dietary Assessments*  Assesses food intake, identifies food allergies and intolerances, religious/cultural influences on eating, etc.  Environmental Assessments*  Socioeconomic status factors that might influence nutrition - Education, housing, marital status, income LIMITATIONS OF NUTRITIONAL ASSESSMENT  Many signs and symptoms of nutritional problems are vague and hard to diagnose  Signs and symptoms of nutritional problems can take a long time to develop and an even longer time to show up clinically!  Examples: Cholesterol building up in the arteries, osteoporosis  Nutrition research is challenging to conduct NUTRITION AND GENETICS  “Nutrigenomics” is a new area of nutrition!  Studies are beginning to show that food can impact gene expression  Some studies also indicate that you may be able to pass on those changes to your kids!  Your genes may impact the way in which your body utilizes specific nutrients  Family history is considered one of the most important risk factors in the development of many nutrition-related diseases:  Diabetes (type 1 and 2), cancer (e.g., colon, prostate, breast), osteoporosis, cardiovascular disease, obesity, etc.  Heredity ≠ destiny COLLECTING SCIENCE-BASED EVIDENCE  Scientific method – Process of inquiry used to answer questions about natural and physical observations 1. Make an observation (Observe a natural phenomena) 2. Ask a question and develop a hypothesis 3. Conduct research/scientific experiments to test that hypothesis  Safety and ethical concerns  Controlled experiments are conducted before human research 4. Collect information (Data) 5. Evaluate the results (Analyze the data using statistics) 6. Form conclusions based on the findings 7. Share the results (Publish the study in a Peer-Reviewed Journal) and have them scrutinized and evaluated 8. Other scientists conduct more studies to confirm or refute the findings! TERMS TO KNOW  Experimental studies*  Researchers introduce an intervention and study the effects. Experimental studies are usually randomized, meaning the subjects are grouped by chance.  Observational studies*  Can be prospective (forward-looking) or retrospective (backward-looking).  Prospective studies* – Observe a group of people (or compare different groups, or cohorts, over time) to look for relationships between lifestyle factors or environmental exposures and the development of conditions or diseases.  Retrospective studies* – Compare study subjects who have already been diagnosed with a condition or disease (these are the cases), with study subjects who do not have the condition or disease (these are the controls). Cases and controls are then asked about past exposures to identify associations between exposure and disease. TERMS TO KNOW  Epidemiology* - The study of disease across populations  Animal model-based studies  Used under certain conditions when studying humans would be unsafe, unethical, or impractical  Human model-based studies  Require informed consent from the participants  The study must be approved by the human subjects committee before researchers can proceed MAKE SURE YOU TAKE TIME TO REVIEW THE “IDENTIFYING REPUTABLE SOURCES” TAB ON D2L.. TERMS TO KNOW  Meta-Analysis** – A statistical analysis that combines the data/results from multiple scientific studies  The studies that are combined were all focused on addressing the same question  The conclusion drawn from a meta-analysis is statistically stronger than the conclusion drawn from a single study  Systematic Review** – A study that provides a summary of the available literature on a specific topic.  Researchers use an organized method of locating, assembling, and evaluating a body of literature on a particular topic using a specific set of criteria  Randomized Controlled Trial (RCT)** – A study design that randomly assigns participants into an experimental group or a control group.  Considered the “gold standard” for studying causal relationships between interventions and outcomes  Randomization eliminates much of the bias inherent with other study designs. TERMS TO KNOW  Cohort Study** – An observational study in which a cohort (a large group of study participants) is followed prospectively for a long period of time (usually many years).  Expensive, does not prove cause and effect  Commonly done with nurses and doctors as licensed professionals are an easy population to track  Framingham Heart Study** is an example  Case Control Study** – An observational study that compares patients who have a disease or outcome of interest (the case group) with patients who do not have the disease or outcome (the control group)  There is no randomization  Researchers look retrospectively at past exposures to see if exposure to a risk factor is related to the development of a disease.  Can be used to identify factors that differ between the two groups but does NOT prove a cause-and- effect relationship! TERMS TO KNOW  Cross-Sectional Study** – Observational study that analyzes data from a population at one specific point in time  Case Report** – An article that describes and interprets an individual case, often written in the form of a detailed story.  If multiple case reports show something similar, the next step might be a case-control study to determine if there is a relationship between the relevant variables.  Migrant Study** – Look at changes in health in people who move from one country to another  Does not prove cause and effect, but may provide clues into what should be explored next TERMS TO KNOW  Double-Blind Study**  After a hypothesis is developed about what might be causing the disease/condition, a research group is chosen, and participants are randomly assigned to the experimental group or the control group  A placebo is given to the control group, while the intervention is given to the experimental group  Need to watch for “the placebo effect”  Note: Double-blind studies are very difficult to conduct in nutrition because it’s hard to disguise food ADDITIONAL THINGS TO NOTE  Correlation vs. Causation**  When reading published studies, it is important to understand that correlation is not equivalent to causation.  While observational studies can suggest relationships between certain exposures and diseases, they cannot prove cause and effect.  Only randomized, controlled trials comparing intervention and control groups can definitively confirm causation.  An example highlighting why correlation ≠ causation: https://www.instagram.com/p/CM4rUB0B3uR/?utm_source=ig_web_copy_link  Peer-Review** – evaluation of scientific, academic, or professional work by others working in the same field.  Prior to publishing, other scientists review study to ensure most unbiased, objective findings are published  Essential to the integrity of science; used to maintain scientific rigor and standards, and provide credibility  The best research is published in peer-reviewed journals*  Peer-Reviewed Journal Examples: the Journal of the American Medical Association (JAMA), American Journal of Clinical Nutrition (AJCN), New England Journal of Medicine, Journal of the Academy of Nutrition and Dietetics ACTIVITY – TAKE 5 MINUTES TO CONDUCT RESEARCH TO CONFIRM OR DENY THE FOLLOWING STATEMENT: “RED MEAT IS BAD FOR YOU”  The meat from mammals such as cows and calves, sheep, lamb and pigs is considered red.  The meat from chicken, turkey and rabbits is considered white.  Things to consider while conducting your research:  What’s the link between red meat consumption and disease (i.e., cardiovascular disease, cancer, and diabetes)? Does red meat consumption increase your risk of CVD, cancer, and diabetes?  What’s the link between red meat consumption and mortality? In other words, does red meat consumption increase your risk of death? ACTIVITY – TAKE 5 MINUTES TO CONDUCT RESEARCH TO CONFIRM OR DENY THE FOLLOWING STATEMENT: “RED MEAT IS BAD FOR YOU”  Was 5 minutes enough time to confirm or deny the statement?  Did your upbringing or previous beliefs influence your search? In other words, did you decide red meat was good or bad before you read any studies or articles?  Do you think you examined all the evidence that’s been published on this topic? Do you think you might have missed something while conducting your research?  Did you use reputable sources to find your answers? Or did you use Google and click on the first few links/options that agreed with your viewpoint?  If you looked at peer-reviewed studies, did you assess the study design? Did you look at who the authors were? Was the study conducted on humans or animals? How long was it conducted for? What variables were monitored or controlled?  We’ll come back to this statement in a bit…but it’s important to remember that not everything with nutrition is black and white! Sometimes things are gray!  One enemy of robust science is our humanity – our appetite for being right, and our tendency to find patterns in noise, to see supporting evidence for what we already believe is true, and to ignore the facts that do not fit. FYI: A SIDE NOTE ON COGNITIVE BIASES  When evaluating information, it’s important that you’re aware of your cognitive biases.  Cognitive bias – A flaw or error in your thinking or reasoning that leads you to misinterpret information from the world around you and to come to an inaccurate conclusion.  Confirmation Bias – Favoring or seeking out information that confirms your pre-existing beliefs  Makes people ignore or invalidate information that contradicts what they believe  The Backfire Effect  Anchoring Bias – The tendency to rely heavily on the first information you learn when you are evaluating something.  Dunning-Kruger Effect – The less you know, the more confident you are.  “The whole problem with the world is that fools and fanatics are so certain of themselves, yet wiser people so full of doubts.” - Bertrand Russell  Don’t mistake the cautiousness of experts as a lack of understanding, nor to give much credence to lay-people who appear confident but have only superficial knowledge.  False Consensus – Overestimating the proportion of people who agree with an idea  “Everyone I know believes _________ so it must be true.”  Groupthink – Conforming to a widely held world view in order to fit in and minimize conflict  Bandwagon Effect – Ideas, fads, and beliefs grow as more people adopt them  This is VERY common in nutrition  Blind-spot Bias – Failing to recognize our own cognitive biases is a bias  Base Rate Fallacy – Occurs when a person misjudges the likelihood of an event because he or she doesn’t take into account other relevant base rate information (Example: https://study.com/academy/lesson/base-rate- fallacy-definition-example.html) DON’T FORGET – IT’S OKAY TO CHANGE YOUR MIND!  Science is a systematic method of pursuing the truth.  It's not perfect, but it is a rigorous process that can be used to discard inaccurate ideas and move towards more accurate ideas.  Far too often, people search for data, evidence, and information AFTER they’ve reached a conclusion on a topic.  As a society, we need to do better job evaluating the totality of evidence before we commit to an idea. And when the evidence contradicts our current beliefs, we need to be open to changing our mind. BACK TO OUR STATEMENT – “RED MEAT IS BAD FOR YOU” I searched PubMed (https://pubmed.ncbi.nlm.nih.gov/) using the following search terms: “Red meat and health” – 3,660 results “Red meat and disease” – 2,364 results It’s okay to trust the experts! Most people in the “Red meat and cancer” – 1,892 results general public don’t have “Red meat and cardiovascular disease” – 679 results time to read and evaluate 8,595 studies.  “Doing research is being familiar with an entire field, with scientific methodology, limitations, nuances, conclusions, and what an entire body of evidence, including the part that disagrees with your viewpoint, says. In an age of misinformation, it’s important to remember that it takes training, not just a free search engine, to be able to [conduct research]. While we all should have access to science, we should also seek out experts in that field and listen to what they say about the things they’ve spent their lives studying. Changing our minds based on new data is how we make progress. That’s part of thinking like a scientist and following the scientific method.” – Stephanie Compton BACK TO OUR STATEMENT – “RED MEAT IS BAD FOR YOU”  Red Meat Consumption and Mortality: Results from Two Prospective Cohort Studies – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3712342/  The authors prospectively followed 37698 men from the Health Professionals Follow-up Study (1986-2008) and 83644 women from the Nurses' Health Study (1980-2008), who were free of cardiovascular disease (CVD) and cancer at baseline. Diet was assessed by validated food-frequency questionnaires and updated every four years.  The researchers documented 23,926 deaths (including 5910 CVD and 9464 cancer deaths) during 2.96 million person-years of follow-up. After multivariate adjustment for major lifestyle and dietary risk factors, they concluded that a higher intake of red meat was associated with a significantly elevated risk of total, CVD and cancer mortality, and this association was observed for both unprocessed and processed red meat, with a relatively greater risk for processed red meat. Substitution of fish, poultry, nuts, legumes, low-fat dairy products, and whole grains for red meat was associated with a significantly lower risk of mortality.  The authors estimated that substitutions of 1-serving per day of other foods (including fish, poultry, nuts, legumes, low-fat dairy, and whole grains) for 1-serving per day of red meat were associated with a 7%-19% lower mortality risk.  Meat consumption and mortality - results from the European Prospective Investigation into Cancer and Nutrition – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599112/  Included in the analysis were 448,568 men and women without prevalent cancer, stroke, or myocardial infarction, and with complete information on diet, smoking, physical activity and body mass index, who were between 35 and 69 years old at baseline.  After multivariate adjustment, a high consumption of red meat was related to higher all-cause mortality, and the association was stronger for processed meat. After correction for measurement error, higher all-cause mortality remained significant only for processed meat. We estimated that 3.3% (95% CI 1.5% to 5.0%) of deaths could be prevented if all participants had a processed meat consumption of less than 20 g/day. Significant associations with processed meat intake were observed for cardiovascular diseases, cancer, and 'other causes of death'. The consumption of poultry was not related to all-cause mortality.  Meat intake and mortality: a prospective study of over half a million people – https://pubmed.ncbi.nlm.nih.gov/19307518/  Men and women in the highest vs lowest quintile of red and processed meat intakes had elevated risks for overall mortality. Regarding cause-specific mortality, men and women had elevated risks for cancer mortality for red and processed meat intakes. Furthermore, cardiovascular disease risk was elevated for men and women in the highest quintile of red and processed meat intakes. BACK TO OUR STATEMENT – “RED MEAT IS BAD FOR YOU”  Health Risks Associated with Meat Consumption: A Review of Epidemiological Studies – https://pubmed.ncbi.nlm.nih.gov/26780279/  Recent evidence from large prospective US and European cohort studies and from meta-analyses of epidemiological studies indicates that the long-term consumption of increasing amounts of red meat and particularly of processed meat is associated with an increased risk of total mortality, cardiovascular disease, colorectal cancer and type 2 diabetes, in both men and women. The association persists after inclusion of known confounding factors, such as age, race, BMI, history, smoking, blood pressure, lipids, physical activity and multiple nutritional parameters in multivariate analysis.  Association between total, processed, red and white meat consumption and all-cause, CVD and IHD mortality: a meta- analysis of cohort studies – https://pubmed.ncbi.nlm.nih.gov/24932617/  Subjects in the highest category of processed meat consumption had 22 and 18 % higher risk of mortality from any cause and CVD, respectively. Red meat consumption was found to be associated with a 16 % higher risk of CVD mortality, while no association was found for total and white meat consumption. In the dose-response meta-analysis, an increase of 50 g/d in processed meat intake was found to be positively associated with all-cause and CVD mortality, while an increase of 100 g/d in red meat intake was found to be positively associated with CVD mortality. No significant associations were observed between consumption of any type of meat and IHD mortality. The results of the present meta-analysis indicate that processed meat consumption could increase the risk of mortality from any cause and CVD, while red meat consumption is positively but weakly associated with CVD mortality. These results should be interpreted with caution due to the high heterogeneity observed in most of the analyses as well as the possibility of residual confounding.  Associations of Processed Meat, Unprocessed Red Meat, Poultry, or Fish Intake With Incident Cardiovascular Disease and All-Cause Mortality – https://pubmed.ncbi.nlm.nih.gov/32011623/  Although the associations between processed meat intake and cardiovascular disease (CVD) and all-cause mortality have been established, the associations of unprocessed red meat, poultry, or fish consumption with CVD and all-cause mortality are still uncertain.  These findings suggest that, among US adults, higher intake of processed meat, unprocessed red meat, or poultry, but not fish, was significantly associated with a small increased risk of incident CVD, whereas higher intake of processed meat or unprocessed red meat, but not poultry or fish, was significantly associated with a small increased risk of all-cause mortality. BACK TO OUR STATEMENT – “RED MEAT IS BAD FOR YOU”  Red and processed meat consumption and mortality: dose-response meta-analysis of prospective cohort studies – https://pubmed.ncbi.nlm.nih.gov/26143683/  The present meta-analysis indicates that higher consumption of total red meat and processed meat is associated with an increased risk of total, cardiovascular and cancer mortality.  Meta-Analysis of Randomized Controlled Trials of Red Meat Consumption in Comparison With Various Comparison Diets on Cardiovascular Risk Factors – https://pubmed.ncbi.nlm.nih.gov/30958719/  Findings among randomized controlled trials evaluating the effect of red meat on cardiovascular disease risk factors are inconsistent. We provide an updated meta-analysis of randomized controlled trials on red meat and cardiovascular risk factors and determine whether the relationship depends on the composition of the comparison diet, hypothesizing that plant sources would be relatively beneficial.  Inconsistencies regarding the effects of red meat on cardiovascular disease risk factors are attributable, in part, to the composition of the comparison diet. Substituting red meat with high-quality plant protein sources, but not with fish or low-quality carbohydrates, leads to more favorable changes in blood lipids and lipoproteins.  Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: a systematic review and meta-analysis – https://pubmed.ncbi.nlm.nih.gov/20479151/  Consumption of processed meats, but not red meats, is associated with higher incidence of CHD and diabetes mellitus.  Red and Processed Meat Consumption and Risk for All-Cause Mortality and Cardiometabolic Outcomes: A Systematic Review and Meta-analysis of Cohort Studies – https://pubmed.ncbi.nlm.nih.gov/31569213/  The magnitude of association between red and processed meat consumption and all-cause mortality and adverse cardiometabolic outcomes is very small, and the evidence is of low certainty. BACK TO OUR STATEMENT – “RED MEAT IS BAD FOR YOU”  Reduction of Red and Processed Meat Intake and Cancer Mortality and Incidence: A Systematic Review and Meta-analysis of Cohort Studies – https://pubmed.ncbi.nlm.nih.gov/31569214/  The possible absolute effects of red and processed meat consumption on cancer mortality and incidence are very small, and the certainty of evidence is low to very low.  Limitation: Limited causal inferences due to residual confounding in observational studies, risk of bias due to limitations in diet assessment and adjustment for confounders, recall bias in dietary assessment, and insufficient data for planned subgroup analyses.  Patterns of Red and Processed Meat Consumption and Risk for Cardiometabolic and Cancer Outcomes: A Systematic Review and Meta-analysis of Cohort Studies – https://pubmed.ncbi.nlm.nih.gov/31569217/  Observational studies are prone to residual confounding, and these studies provide low- or very-low-certainty evidence according to the GRADE criteria. Low- or very-low-certainty evidence suggests that dietary patterns with less red and processed meat intake may result in very small reductions in adverse cardiometabolic and cancer outcomes.  Red and processed meat consumption and colorectal cancer risk: a systematic review and meta- analysis – https://pubmed.ncbi.nlm.nih.gov/29137344/  In a systematic review and meta-analysis, we found consumption of red and processed meat was associated with the risk of overall colorectal cancer but not rectal cancer. Additionally, there were no associations between the consumption of red meat and distal colon cancer risk and between the consumption of processed meat and proximal colon cancer risk. IS RED MEAT GOOD OR BAD FOR YOU?  It depends! Remember, not everything is black and white! Sometimes things are gray. When it comes to nutrition, nuance is okay.  Processed red meat and unprocessed red meat likely have different impacts on health.  Lean red meat is better for you than fatty red meat…  Fish, poultry, and plant-based proteins might be a better choice for some than red meat.  Sat. fat, fiber, omega-3 fatty acids, Magnesium, Potassium, etc.  Cooking methods matter!  Cooking red meat, poultry, and fish at high temperatures can generate compounds (e.g., heterocyclic amines (HAs), polycyclic aromatic hydrocarbons (PAHs) and advanced glycation end-products (AGEs)) that are carcinogenic/cancer causing.  Beneficial nutrients found in red meat  Good source of protein, vitamin B3, vitamin B6, vitamin B12, bioavailable iron, creatine, and zinc  If someone is deficient in these nutrients, then they might benefit from eating more red meat  Overall: Most Americans would benefit from eating LESS red meat and MORE Meme courtesy of @kcklatt on plants (e.g., fruits, vegetables, whole grains) and plant-based protein sources Instagram (e.g., nuts, seeds, beans, etc.). EVALUATING NUTRITION CLAIMS AND PRODUCTS  Read the 5 points for evaluating nutritional claims in your book!  Read and be aware of the current laws regarding nutritional supplements  Be careful with supplements, they can be dangerous!  The Dietary Supplement and Health Education Act (DSHEA) of 1994 classified vitamins, minerals, amino acids, herbal remedies, and many other supplements as “foods” – this prevents the FDA from regulating them as rigorously as food additives and drugs.  Unlike drugs which must be proven safe and effective for their intended use before marketing, the FDA must prove a supplement is UNsafe before it can remove the product from the marketplace or take action to restrict its use.  We’ll discuss this in greater detail in Unit 3! EVALUATING NUTRITION CLAIMS AND PRODUCTS  Be wary of claims that:  Only discuss advantages and ignore possible disadvantages  New or “secret” breakthrough  Claims to “cure” a disease  Sounds too good to be true – If a nutrition/supplement claim seems too good to be true, it probably is!  Demonstrate extreme bias against the medical or health community  Contain testimonials which show dramatic results  ONE STUDY DOES NOT PROVIDE ENOUGH EVIDENCE TO MAKE A DEFINITIVE CONCLUSION.  The media pulls conclusions from one study ALL the time  Misinformation and confusion  Pay attention to the source of the information, who financed the study, and if there are any conflicts of interest  There is no single ingredient or nutrient that will allow you to lose weight or gain muscle. There are no miracle foods Meme courtesy of @kcklatt on Instagram