CHAPTER 1: The Role of Nutrition in Our Health
Nutrition: The science that studies food & how food nourishes our bodies and influences our
Energy and Vitality
Historically| Vitamin C deficiency lead to Scurvy; diet was a means to cure criminal behavior
and cast out devils.
WHO definition of health: “ A state of complete physical, mental and social well-being and not
merely the absence of disease or infirmity.”
Nutrient Deficiencies can lead to life threatening illnesses such as scurvy, goiter and rickets.
Diseases in which nutrition plays Osteoporosis
some role Osteoarthritis
Some forms of Cancer
Disease with a strong nutritional Type 2 Diabetes
component Heart disease
High Blood Pressure
Disease caused by nutritional Pellagra
Undernutrition: A diet that lacks energy or specific essential nutrients
Essential nutrients: Nutrients that must come from food or nutrient supplements because
they are not manufactured by the body at all or not in amounts sufficient to meet body’s
Overnutrition: A diet that has an imbalance of fats, carbohydrates and proteins or simply
too much energy.
Malnutrition: Any condition associated with undernutrition or overnutrition. 6 Classes of nutrients
Carbohydrates Only classes of nutrients that
Lipids All macronutrients and organic
Vitamins Inorganic nutrients
Organic: A substance or nutrient that contains the element carbon.
Inorganic: A substance or nutrient that does not contain the element carbon.
Macronutrients: Nutrients that our bodies need in relatively large amount to support
normal function and health; Carbs, Fats, and Proteins are macronutrients.
Carbohydrates: The primary fuel source for our bodies, particularly for our brain and for
physical exercise. (Carbo- carbon; hydrates- water)
What is a Calorie:
Energy: defined as the capacity to do work.
A Kilocalorie (Kcal, or calorie): The amount of heat required to raise the
temperature of 1 kilogram of water by 1 degree Celsius. It is a unit of measurement
we use to quantify the amount of energy in food that can be supplied to the body.
(i.e. 1 gram of carbohydrate is equal to 4 kcal/calories.
Conversion: 1 kcal = 4.184 (or 4.2) kilojoules
Lipids: An important energy source for our bodies at rest and during low-intensity exercise.
Insoluble in water; but also provide fat-soluble vitamins and essential fatty acids
Include triglycerides (fats), phospholipids, and sterols.
Contain Carbon; as well as hydrogen and oxygen (at lower levels than Carbs)
Yield more energy per gram than either carbohydrates or proteins. Solid fats: Butter, lard, margarine
Liquid fats: oils (olive, vegetable, canola oils)
Cholesterol: A form of lipid that is synthesized in our bodies, and it can also be consumed in
Proteins: The only macronutrients that contains nitrogen; the basic building blocks of
proteins are amino-acids.
The elements of proteins assemble into building blocks known as amino acids.
(Carbon, hydrogen, oxygen, and nitrogen; may also contain sulphur)
We break down dietary proteins into amino acids and reassemble them to build our
own body proteins – for instance, the proteins in our muscles and blood.
Supports tissue growth, repair, and maintenance. (metabolism and fluid balance)
Vitamins: Organic compounds that assist us in regulating our bodies’ processes.
Fat-soluble A, D, E, and K Soluble in fat
Stored in the human
Toxicity can occur
excess amount, which
accumulate in the
Water-soluble C, B vitamins (thiamin, Soluble in fat
riboflavin, niacin, Not stored to any
vitamin B12, extent in the human
pantothenic acid, body
bioton, and folate. Excess excreted in
occurs only as a result
Their solubility in water or fat affects how vitamins are absorbed, transported, and stored in
our bodies Contrary to belief, vitamins do not contain energy; however, vitamins do play an important
role in helping our bodies to release and use the energy found in carbohydrates, fats, and
Micronutrients: Nutrients needed in relatively small amounts to support normal health and
body functions. Vitamins and some minerals are micronutrients.
Fat-soluble vitamins are absorbed in our intestines along with dietary fat. They are then
transported to the liver or other organs, where they are either used or stored for later use.
(in our liver, and in adipose, & other fatty tissues)
Storing fat-soluble vitamins can be bad; toxicity symptoms include damage to our hair, skin,
bone, eyes, and nervous system.
Water Soluble vitamins are absorbed through the intestinal wall directly into the
bloodstream; or kidneys filter out any excess water-soluble vitamins we consume, and we
excrete this excess in our urine.
Minerals are inorganic substances that are not broken down during digestion and absorption
and are not destroyed by heat or light. Minerals assist in the regulation of many body process
and are classified as major minerals or trace minerals.
Major Minerals Calcium, phosphorus, Needed in amounts
magnesium, sodium, greater than 100mg/day
potassium, chloride, in our diets.
sulphur Amount present in the
human body is greater
Trace Minerals Iron, zinc copper, Needed in amounts less
manganese, selenium, than 100 mg/day in our
iodine, fluoride, diets.
chromium, molybdenum. Amount present in the
human body is less than
Water is an inorganic nutrient that is vital for our survival. Adequate water intake ensured
the proper balance of fluid both inside and outside our cells; it assist in the regulation of
nerve impulses, muscle contractions, nutrient transport, and excretion of waste products.
See page 17. DIETARY REFERENCE INTAKES (DRI) The DRIs for most nutrients consist of 4 values:
Important 2: RNI and RDA
The Estimated Average Requirements (EAR)
The average daily nutrient intake level estimated to meet the requirement of half of the
healthy individuals in a particular life stage and gender group.
Recommended Dietary Allowance (RDA)
The average daily nutrient intake level that meets the nutrient requirements of 97% to 98%
of healthy individuals in a particular life stage and gender group.
Adequate Intake (AI)
A recommended average daily nutrient intake level based on observed or experimentally
determined estimates of nutrient intake by a group of healthy people.
Tolerable Upper Intake Level (UL)
The highest average daily nutrient intake level likely to pose no risk of adverse health effects
to almost all individuals in a particular life stage and gender 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 Acceptable 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.
Nutrients and AMDR
Protein 10%-35% CHAPTER 2: Planning a Nutritious diet
Nutritious diet: A diet that provides the proper combination of energy and nutrients and is
adequate, moderate, balanced, and varied.
What is a Nutritious Diet?
Adequate diet: A diet that provides enough of the energy, nutrients, and fibre to maintain a
Nutrient density: The relative amount of nutrients per amount of energy (or number of
Moderation: Eating the right amounts of foods to maintain a healthy weight and to optimize
the body’s metabolic processes.
Balanced diet: A diet that contains the combinations of foods that provides the proper
balance of nutrients.
Food Labels can have 4 Main Components:
1. Ingredient list: listed in descending order by weight. (1 ingredient on list is the
predominant ingredient) It is essential for people with food allergies.
2. Nutrition Facts table: the table on a food package label that gives the amount of energy
and a minimum of 13 key nutrients in 1 serving of the food.
3. Nutrient content claims: These claims are about the amount of a nutrient in a food; i.e.
“high in fibre”
4. Health claims: “statements that link a food or food component with reduced risk of
disease or a condition (i.e. cancer) in the context of a total diet.”
Health Canada permits 5 health claims: (i.e. suggests adequate source or low sodium
that may reduce an illness) Chapter 3: What happens to the food we eat?
Much of our ability to taste foods actually comes from our sense of smell. Our sense of smell
is so distinct that newborn babies can distinguish the scent of their own mother’s breast
4 factors interact to motivate us to eat: sight, smell, taste and texture.
Appetite: A psychological desire to consume specific foods
Hunger: A physiological sensation that prompts us to eat.
The region of brain tissue that is responsible for prompting us to seek food is called the
hypothalamus. It triggers hunger by integrating signals from nerve cells throughout our
bodies. One important signal comes from specialized cells lining the stomach and small