Chapter 1: Recaps
Nutrition is the science that studies food and how food affects our body and our health. Nutrition
is an important component of health and is strongly associated with physical activity. One goal
of a nutritious diet is to prevent nutrient-deficiency diseases, such as scurvy and pellagra; a
second goal is to lower the risk for chronic diseases, such as type 2 diabetes and heart diseases.
Both nutrient-deficiency diseases and chronic disease linked to over nutrition are types of
malnutrition found in developed and developing nations.
The six classes of nutrients found in food are carbohydrates, lipids or fats, proteins, vitamins,
minerals and water. Carbohydrates, lipids and proteins are referred to as energy-yielding
nutrients, as they provide our bodies with the energy necessary to thrive. Carbohydrates are the
primary energy source for our bodies; fats are a source of fat-soluble vitamins and essential fatty
acids and act as energy storage molecules; and proteins support tissue growth, repair and
Vitamins are organic compounds that assist with regulating many body processes. Fat-soluble
vitamins are soluble in fat and including vitamins A, D, E, and K. We can store fat-soluble
vitamins in our liver and in adipose and other fatty tissues. Water-soluble vitamins are soluble in
water and include vitamin C and the B vitamins (thiamin, riboflavin, niacin, vitamin B6 and B12,
pantothenic acid, biotin and folate). We excrete excess amounts of water-soluble vitamins in our
Minerals are inorganic elements that maintain their structure throughout the processes of
digestion, absorption and metabolism. Major minerals are needed in amounts greater than 100mg
per day, and the total amount found in our bodies is at least 5 grams (or 5000 mg). Trace
minerals are needed in amounts less than 100mg per day, and the total amount found in our
bodies is less than 5 grams (or 5000 mg). Minerals play critical roles in virtually all aspects of
human health and function. Water is critical for our survival and is important for regulating
nervous impulses, muscle contractions, nutrient transport and excretion of water products.
The dietary reference intakes (DRIs) are dietary standards for nutrients established for healthy
people in a particular life stage and gender group. The estimated average requirement (EAR)
represents the nutrient intake levels that meet the requirement of half the healthy individuals in a
group. The recommended dietary allowances (RDA) represent the nutrient intake level that
meets the requirements of 97% to 98% of healthy individuals in a group. The adequate intake
(AI) is a recommended nutrient intake level based on estimates of nutrient intake of group of
healthy people when not enough information is available to set an RDA. The tolerable upper
intake level (UL) is the highest daily nutrient intake level that likely poses no risk of adverse
health effects to almost all individuals in a group.
The estimated energy requirement (EER) is the average daily energy intake that is predicted to
maintain energy balance in a healthy adult. The EER is defined by a person’s age, gender,
weight, height and physical activity level. The acceptance macronutrient distribution ranges
(AMDR) are ranges of intakes for particular energy sources that are associated with reduced risk
of chronic disease while also providing adequate intakes of essential nutrients. The DRI values
can be used to plan diets that are nutritionally adequate and healthful.
Registered dietitians are professionals who have completed an accredited undergraduate program
and dietetic internship or comparable practical experience. Look for the professional designation RD, PDt, or RDt (or french equivalent Dt.P) to ensure an individual is qualified to provide
nutrition advice. Dietitians of Canada, and other professional associations, such as the American
Dietetic Association and the society for nutrition education, are excellent sources of reliable
nutrition information. Health Canada is lead federal agency responsible for protecting people’s
health. If affiliated agencies include the Canadian Food Inspection Agency and the Public Health
Agency of Canada.
Nutrition is the science of food and how food nourishes the body and affects health.
Nutrition is an important component of health, and nutrition plays a critical role in
eliminating nutrient-deficiency diseases and can help reduce our risks for various chronic
Nutrients are chemicals found in food that are critical to human growth and function.
The six classes of nutrients found in the foods we eat are carbohydrates, fats, proteins,
vitamins, minerals and water.
The nutrients that provide energy for our bodies are the macronutrients: carbohydrates,
fats and proteins.
Carbohydrates are composed of carbon, hydrogen and oxygen. Carbohydrates are the
primary energy source for our bodies, particularly our brains.
Fats provide us with fat-soluble vitamins and essential fatty acids in addition to storing
large quantities of energy.
Proteins can provide energy if needed, but they are not a primary fuel source. Proteins
support tissue growth, repair and maintenance.
Vitamins assist with the regulation of body processes.
Fat-soluble vitamins can be stored in our tissues; these include vitamins A, D, E, and K.
Water-soluble vitamins are soluble in water, and we excrete excess amounts in our urine.
These include vitamin C and the B vitamins (thiamin, riboflavin, niacin, vitamin B6 and
B12, pantothenic acid, biotin and folate).
Minerals are inorganic substances that are not changed by digestion or other metabolic
Major minerals are found in our bodies in amounts greater than 5 grams (or 5000 mg),
and we need to consume at least 100 mg of these minerals each day.
Trace minerals are found in our bodies in amounts less than 5 grams (or 5000 mg), and
we need to consume less than 100 mg of these minerals each day.
Water is critical to support numerous body functions, including fluid balance, conduction
of nervous impulses and muscle contraction.
The dietary references intakes (DRIs) are reference standards for nutrients intakes for
healthy people in Canada and the United States.
The DRIs can be used for dietary planning for individuals and groups.
The DRIs include the estimated average requirement, the recommended dietary
allowance, the adequate intake, and the tolerable upper intake level.
Potentially good sources of reliable nutrition information include individuals who are
registered dietitians or those who hold an advanced degree in nutrition.
Health Canada is the lead federal agency that protects the health and safety of Canadians.
When looking for information on the internet, be wary of websites addresses ending in
.com. Look for .org (organization), .edu (educational institution), or .gov (government)
for dependable sources of information. Chapter 2: Recaps
A nutritious diet provides adequate nutrients and energy, and it includes only moderate amounts
of foods that are less nutritious. It also includes an appropriate balance of foods and a wide
variety of foods to ensure that many different nutrients are provided.
Reading food labels is a necessary skill when planning a nutritious diet. Food labels must list the
ingredients in a food, in descending order by weight, and include a Nutrition Facts table, the
Nutrition Fact table provides specific information about Calories (kJ), macronutrients, and select
vitamins, minerals, and other components (such as dietary fibre). The % DV is useful to compare
food products or to tell whether the product contains a little or a lot of specific nutrient. Nutrient
content claims, five specific health claims, and product-specific health claims are also allowed.
Eating well with Canada’s Food Guide can be used to plan a nutritious diet – one that provides
adequate nutrients and energy and includes only moderate amounts of foods that are less
nutritious. Following the advice in Canada’s Food Guide will ensure your diet has a wide variety
of foods and an appropriate balance of foods from the four food groups – vegetables and fruits,
grain products; milk and alternatives; and meat and alternatives- depends on your age and sex.
The serving sizes of foods listed Canada’s Food Guide may be smaller than the amounts we
normally eat or are served. Use the interactive tool provided on Health Canada’s website to
create your own customized My Food Guide.
The 5 to 10 a day for better health program and the DASH diet are two examples of healthy food
plans. High fruit and vegetable consumption has been linked to cancer prevention and reduced
risk of heart disease. The DASH diet was designed to reduce blood pressure in people with
hypertension. It is similar to Canada’s Food Guide with an emphasis on vegetables and fruit; it
also is designed to keep sodium intakes to 3000 mg or less each day. The DASH diet has been
shown to significantly decrease blood pressure.
Healthy ways to eat out include choosing menu items that are smaller in size, ordering meats that
are grilled or broiled, avoiding fried foods, choosing items with steamed vegetables, avoiding
energy-rich appetizers and desserts, and eating less than half the food you are served.
A nutritious diet provides adequate energy, nutrients, and fibre to maintain health.
A nutritious diet is moderate in the amounts of foods eaten. Foods that contain a lot of fat
and sugar should be eaten only in moderation to maintain a healthy weight.
A nutritious diet contains the proper balance of food groups and nutrients to maintain
A nutritious diet provides a variety of foods every day.
The nutrition facts table on the food label contains important nutrition information about
serving size, serving per package, total calories per serving, a list of various
macronutrients, vitamins, and minerals, and the % daily values (% DV) for the nutrients
Eating well with Canada’s Food Guide is the major tool for consumers to use to plan
nutritious diets. It was developed by Health Canada to be consistent with the DRIs. It is
available in 10 languages in addition to English and French.
Eating well with Canada’s Food Guide has four food groups: vegetable and fruit, milk
and alternative, meat and alternative and grain products.
Eating well with Canada’s Food Guide contains the recommended number of servings for
each food group in nine age and sex categories. Specific serving sizes are given for foods in each food group of Canada’s Food Guide.
There is no standard definition for a serving size, and the serving sizes listed in Canada’s
Food Guide are generally smaller than those listed on food labels and what most of us
The U.S Department of Agriculture’s MyPyramid: Steps to a Healthier You (USDA
2005) has six sections that represent five food groups plus oils and includes a stylized
figure climbing stairs to represent the importance of daily physical activity.
Some researchers recommend that people follow a traditional Mediterranean Diet, which
contains less red meat and dairy products and more legumes, healthy fats and wine than
the traditional North American diet. This diet, and daily physical activity, may help
protect against heart attacks and some cancers.
The 5 to 10 a day for better health program is a major public health initiative promoting
the intake of a combination of 5 to 10 servings of fruit and vegetables every day to reduce
the risk for cancer and other chronic diseases.
The DASH diet is high in fibre, low in fat, and moderate in sodium, and includes 8 to 10
serving sizes of fruit and vegetables each day. Eating DASH diet can significantly
decrease blood pressure, a benefit to people with high blood pressure.
Eating out is challenging because of the high fat content and large serving sizes of many
fast food and sit down restaurant menu items.
Behaviors that can improve the quality of your diet when eating out include choosing
lower fat meats that are grilled or broiled, eating vegetables and salads as side or main
dishes, asking for low-fat salad dressing on the side, skipping high fat desserts and
appetizers, and drinking low or non caloric beverages.
Chapter 3: Recaps
A number of factors stimulate us to eat. Our senses of sight, smell, and taste are stimulated by
foods. The texture of foods can also stimulate us to eat or may cause some foods to be
unappealing. These four factors interact to motivate us to eat.
Appetite is thought to be a psychological desire to consume certain foods and is generally
related to pleasant sensations associated with food. Appetite typically involves cravings for foods
in the absence of hunger. Environments and moods contribute to appetite. For people trying to
lose weight, it is important to ignore the cues of appetite to avoid overeating.
In contrast to appetite, hunger is a physiologic sensation triggered by the hypothalamus in
response to cues about stomach and intestinal distension, levels of energy substances in the
blood, and the release of certain hormones and hormone like substances. High-protein and high-
fat foods make us feel satiated for longer periods, and bulky meals fill us quickly, causing the
distension that signals us to stop eating.
Our bodies are made up of atoms, which are small units of matter. Atoms group together to form
molecules. The food we eat is composed of molecules. The ultimate goal of digestion is to break
food into molecules small enough to be passed through the gastrointestinal tract walls and easily
transported to the cells as needed.
Cells are the smallest unit of life. They perform all critical body functions, such as reproducing
new cells, utilizing nutrients, transmitting nervous impulses, and excreting waste products. Cells are encased in a cell membrane that acts as a gatekeeper for the cell. Cells contain organelles,
which are tiny structures that perform many functions, such as making proteins, storing nutrients,
and producing energy.
Different cells types give rise to different tissue types and ultimately to different kinds of organs.
Body systems, such as the gastrointestinal system, depend on many different organs to carry out
all the varied functions they perform.
Digestion is the process by which foods are broken down into molecules. Absorption is the
process of taking the products of digestion across the GI track wall and into the body.
Elimination is the process by which undigested food, unabsorbed nutrients, and waste products
are excreted from the body. These processes take place in the gastrointestinal tract. The organs of
the GI tract include the mouth, esophagus, stomach, small intestine, and large intestine (also
called the colon or large bowel). Accessory organs, such as the pancreas, gallbladder and liver
assist with digestion and absorption of nutrients.
The cephalic phase of digestion involves hunger and appetite working together to prepare the
GI tract for digestion and absorption before you take your first bite of food. Chewing initiates
mechanical digestion of food by breaking it into smaller components and mixing all nutrients
together. Chewing also stimulates chemical digestion through the secretion of digestive juices,
such as saliva. Saliva moistens food and starts the process of carbohydrate digestion through the
action of the enzyme salivary amylase. This action continues during transport of food through
the esophagus and stops when food mixes with the stomach acid.
Swallowing causes our nasal passages to close and the epiglottis to cover our trachea to prevent
food from entering our sinuses and lungs. The esophagus opens as the trachea closes. The
esophagus is a muscular tube that transports food from the mouth to the stomach. The rhythmic
waves of muscles surrounding the esophagus, called peristalsis, push food toward the stomach.
Gravity helps move food toward the stomach to lesser extent. Once food reaches the stomach,
the lower esophageal sphincter (or cardiac sphincter) opens to allow food into the stomach.
The stomach prepares itself for digestion by secreting gastric juice. Gastric juice contains
substances that assist in digestion, including hydrochloric acid and the enzymes pepsin and
gastric lipase. The stomach wall also secretes mucus to protect the stomach’s lining from
digestion by HCL and enzymes. Digestion of proteins and minimal digestion of fats begins in
the stomach. The stomach mixes food into a liquid substance called chime, which is more easily
digested than solid food. The stomach holds the acidic chime and releases it periodically into
small intestine through the pyloric sphincter in very small amounts.
Most digestion and absorption occurs in the small intestine. The small intestine comprises
three sections: the duodenum, the jejunum, and the ileum. The gallbladder concentrates and
stores bile, which is produced by the liver. Bile emulsifies fat into pieces that are more easily
digested. The pancreas synthesizes and secretes digestive enzymes that break down
carbohydrates, fats and proteins into their basic building blocks: sugars, fatty acids and amino
acids. The lining of the small intestine is heavily folded, with the surface area expanded by villi
and microvilli. Nutrients are absorbed across the mucosal membrane by various processes and
enter either the lymph or the bloodstream. The liver processes all nutrients absorbed from the
small intestine and stores and regulates monosaccharides, fatty acids and amino acids.
The large intestine comprises seven sections: the cecum, ascending colon, transverse colon,
descending colon, sigmoid colon, rectum, and the anal canal. Small amounts of undigested
food, indigestible food material, bacteria, and water enter the large intestine from the small intestine. The bacteria assist with final fermentation of any remaining digestible food
products; this fermentation causes some gas production. The main functions of the large intestine
are to hold the digestive mass and absorb any remaining nutrients and water over a 12 to 24
hour period. The remaining substance, a semisolid mass called feces, is then eliminated from
the body through the anus.
The coordination and regulation of digestion is directed by the neuromuscular system. The
muscles of the GI tract mix food and move it from the mouth to the anus. Voluntary muscles,
which are under our conscious control, assist us with chewing and swallowing and with
expelling waste from our bodies. Once our food is swallowed, the involuntary muscles along the
entire length of the GI tract function together so that materials are moved in one direction in a
coordinated manner. The enteric nerves of the GI tract wo