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Unit 1 Food Choices and Human Health Introduction Can what you eat really have an impact on your health? Have you ever wondered why you choose the foods you do? Have you ever read an ad in a magazine or online and wondered “could that weight loss product really work for me?” If you have ever asked yourself these questions, then this is the course for you. This is just a snapshot of what will be answered in the first unit of this course. Food plays an important role in everyone’s life—we depend on it for survival. It is important for everyone to have some basic nutrition knowledge, because the foods we choose have an effect on our body and our health. Unit 1 for this course is a general introduction to nutrition. There are lots of definitions and topics introduced, which will be discussed in more depth further along in the course.

Learning objectives Upon completion of this unit, you should be able to do the following: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

define the common terms in nutrition listed in the course notes; list the six classes of nutrients and their division into two subgroups; differentiate between essential, non essential and conditionally essential nutrients; define calorie and recall the food energy provided by carbohydrates, protein, fat and alcohol; describe the five characteristics of a healthy diet; describe the factors that play a role in food choices; discuss nutrient density differentiate between the different food types differentiate between the four research designs discussed; identify characteristics of valid nutrition information and nutrition quackery.

Assigned readings Read textbook chapter 1.

How to proceed 1. Read the instructional content in this unit. You should visit the links included in the course notes and the textbook. 2. Read the textbook chapter 1 (Food Choices and Human Health), following along with the instructional content, making notes as you read. (You only need to know the sections, figures and tables from the textbook that are covered/ mentioned in the instructional content). 3. At the end of the unit, test your knowledge of the material by trying the practice questions at the end of the chapter and/or on the textbook companion website CourseMate. 4. Complete the timed quiz for unit 1. 5. Read through and complete the Getting to Know Your Course Tools assignment. 6. Read through Assignment 1 and start looking for a nutrition article to critique.

Instructional content Chapter 1 Nutrition and healthy eating definitions In order to start developing an understanding of nutrition and healthy eating, you need to know the basic definitions.

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 when nutrition is an integral part of these efforts” (Health Canada)

Nutrition is the study of:

Diet

the nutrients in foods; how nutrients are used in the body; and human behaviours related to food.

the foods and beverages a person usually eats and drinks.

Food any substance that the body can take in and assimilate that will enable it to stay alive and healthy.

Nutrition and disease prevention Your choice of diet can profoundly affect your long term health prospects.

Chronic Disease audio file Many chronic diseases (e.g., diabetes, heart disease, some types of cancer, dental disease, adult bone loss, etc.) have a connection to poor diet. These diseases cannot necessarily be prevented by a good diet alone, as other factors like genetic and lifestyle play a role as well. For example, forms of heart disease can vary—some are nutrition related, others are not. Diet influences long-term health outlook, and genetics also plays important role. Genetics and nutrition affect health conditions in varying ways (See Figure in your textbook: “Nutrition and Disease”). Nutritional genomics or “Nutrigenomics” is a hot topic right now. This may be the reason behind the often conflicting nutrition claims. Nutritional genomics The science of how nutrients affect the activities of genes and how genes affect the activity of nutrients.

Nutrients Nutrients Components in food that are indispensable (or essential) to the functioning of the body.

Nutrients provide energy and building material used to help maintain or repair the body and support growth There are 6 classes of nutrients that can be divided into 2 groups: A. energy providing (meaning that the body can use the energy they contained) 1. carbohydrate 2. fat 3. protein B. other nutrients (or non-energy containing) 4. water 5. vitamins

6. minerals See Figure “Materials of Food and the Human Body” Within the 6 classes of nutrients, there are essential, conditionally essential and non-essential nutrients.

Essential nutrients Essential nutrients The nutrients that the body cannot make for itself from other raw materials.

There are 8 essential amino acids (TV TILL PM) Threonine Valine Tryptophan Isoleucine Leucine Lysine Phenylalanine Methionine 1. There are 2 essential fatty acids: linoleic acid, linolenic acid 2. Most of the vitamins are essential 3 fat soluble (A, D, E), 1 conditional (K) all water soluble 3. All minerals are essential

Conditionally essential nutrients Some nutrients are conditionally essential, meaning that the body can not make enough to meet the requirements for health (e.g., the amino acid histidine during periods of growth).

Non-essential nutrients These are nutrients that the body can make for itself, so does not have to rely on our food intake (e.g., some amino acids, some fatty acids).

Food energy Caloric definition audio file

Food energy is measured in calories Carbohydrate (CHO) provide us with 4 Cal/g (=kcal/g) Fat (lipid) provide us with 9 Cal/g Protein provide us with 4 Cal/g Alcohol provide us with 7 Cal/g Alcohol provides energy, but is not a nutrient Food quantity is measured in grams (so when you look at the Nutrition Facts panel on your food product, it lists carbohydrates, fat and protein in grams). We can use those known values to do different calculations to determine information about a food product. For example, if we wanted to calculate what percentage of total calories was coming from fat, we would take the grams of fat, multiply it by our known value of 9 calories per gram to determine the total calories that the fat in the food provides. We could then divide that number by the total calories in the food to determine what percentage of calories is coming from fat. Example:

“Crispers” 1.4 g protein, 5.5 g fat, 17 g CHO, and 123 Calories for 25 grams (~17 crackers) 5.5 g fat x 9 Calories/g = 49.5 Calories and 49.5/123 x 100 = 40% Calories from fat 17 g CHO x 4 Calories/g = 68 Calories and 68/123 x 100 = 55% Calories from CHO

Now that we have seen how to do this type of equation, practice with the information below to determine the %age of calories coming from fat and CHO. Potato Chips (small bag) 2 g protein, 15 g fat, 24 g CHO, and 239 Calories for 43 grams (~22 chips) % Calories from fat? % Calories from CHO?

Answers: % cals from fat = 56.5% % cals from CHO = 40%

We can also use our known values to calculate the number of calories in a food based on the grams of CHO, protein and fat the food provides. Quaker Crispy Mini’s 14g CHO, 1g PRO, 3g fat per 20g serving (approx 12 rice chips) Total calories? (14g CHO x 4 cal/g) + (1g PRO x 4 cal/g) + (3g fat x 9 cal/g) = (56)+(4) + (27) Total calories = 87

Healthy diets We often think that we know everything there is to know about choosing foods, but with the high number of choices available, it is easy to lose track of what individual foods contain, and how to put them together into a health promoting diet. There are five characteristics of a healthy diet. Adequate in essential nutrients, fiber and energy Balance in nutrients and food types Calorie control: foods provide amount of energy to maintain healthy body weight Moderation in fat, salt, sugar or other unwanted constituents Variety: choose different foods each day Characteristics of a Healthy Diet audio file

Many factors play a role in the foods that we choose: Availability, cost, convenience Emotional, social, cultural factors Media advertising Habit, positive association Weight, nutritional value Factors that Affect Food Choices audio file

See table “Glossary of Food Types”

Dietary guidelines and nutrition objectives Nutrition research can help countries establish nutrition guidelines and health objectives. These are set to help guide people in what to eat to stay healthy. Dietary Guidelines audio file The 3 dietary guides that we are going to review in this course are: 1. Eating Well with Canada’s Food Guide 2. Nutrition Recommendations for Canadians (Appendix A) 3. Dietary Reference Intakes We will look at these in detail in Unit 2.

Nutrient density: Food Feature Nutrient density A measure of nutrients provided per calorie of food.

“Getting the most nutrients for your calories,” (e.g., calcium) 1 c. skim milk: 85 calories, 301 mg calcium 1 c. ice cream: 350 calories, 173 mg calcium Milk has more calcium per calorie, therefore, a higher nutrient density for calcium. Nutrient density: Food Feature audio file See Figure: “A Way to Assess Which Foods Are the Most Nutritious”.

Nutrition research Scientists uncover nutrition facts by experimenting and asking questions, following the scientific method (see Figure: “The Scientific Method”). There are four common research designs used in nutrition research (See Figure: “Examples of Research Design”): 1. 2. 3. 4.

case studies–individuals epidemiological study–populations intervention study–populations with manipulation laboratory study–tightly controlled conditions

Nutrient Research audio file

One experiment does not prove/disprove anything. It must be replicated many times before findings are confirmed. Even then, science is more “theories” than “facts”. Theories can always be challenged and revised. This process is a slow path and contrasts to the media’s desire for the latest news.

Consumer corner: Reading nutrition news with an educated eye. Can we trust the

media to deliver nutrition news? Media audio file

Controversy 1: Separating the imposters from the real nutrition experts Everywhere you look, there is nutrition information being spewed to the public (newspapers, magazines, infomercials, internet…). Nutrition fraud/quackery is a $27 billion dollar a year industry. So how can you tell if a claim is legitimate? Valid nutrition information is derived from scientific research, conducted by scientists who follow specific characteristics. They: Test ideas through properly designed scientific experiments Recognize inadequacies of anecdotal evidence / testimonials Do not apply research findings from animals to humans Do not generalize findings to all population groups Report their findings in respected scientific journals that are peer reviewed There are many tools in your textbook to help you identifying valid nutrition information. See Table: “Misinformation Terms” See Table: “Credible Sources of Nutrition Information” (also see course outline) See Table: “Is This Site Reliable?” See Figure: “Earmarks of Nutrition Quackery” Controversy 1: Separating the imposters from the real nutrition experts audio

Who can you trust for accurate nutrition information? Nutritionist This term is not regulated. The individual may have a university degree in nutrition, however may not have formal training, may be selftaught, and may have a variable degree of nutrition information. Your pet can even get a nutrition diploma from a diploma mill! So the information received from a nutritionist may or may not be accurate.

Registered Dietitian (R.D.) This term is regulated by law. To use the term R.D., an individual must be a member of their provincial regulatory body (in Manitoba, this is College of Dietitians of Manitoba [CDM]) who ensure continued competency. To become a registered dietitian you must complete a 4 year undergraduate degree plus an 8–12 month internship (practical experience) in health care setting. So the information you receive from a registered dietitian will be accurate. See Table: “Credentials of Canadian Dietitians” See Table: “Terms Associated with Nutrition Advice” See Table: “Responsibilities of a Clinical Dietian” Go to top...