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Full course notes for Introduction to Nutrition (NUTR1010)
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- University Of Guelph (U Of G )
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NUTR 1010 Full Course NotesCHAPTER 1-Nutrition: Food for health
1.1 Nutrition and the Canadian Diet
• Nutrition: A science that studies the interactions that occur between living organisms and food.
• Nutrients: Chemical substances in foods that provide energy and structure and help regulate body
processes.
The Modern Canadian Food Supply
• includes an endless assortment of eating options.
o fresh fruits and vegetables, meats, and grains
o frozen vegetables, canned soups, packaged meats, frozen prepared meals, and snack foods.
• processed foods: Foods that have been specially treated or changed from their natural state.
o can be microwaved in minutes rather than meals prepared from basic ingredients
o Snack foods such as potato chips, nachos, sugar-sweetened beverages are readily available
o usually high in saturated fat, sugar, and/or salt, which increase the risk of chronic disease
How Healthy Is the Canadian Diet?
• Not very healthy. Many Canadians are overweight or obese due to the overconsumption of
calories
• Need to eat more fruits and veggies and plat based proteins
• chronic disease Non-communicable diseases that develop slowly over a lifetime and need
continuing medical attention to manage and control
• Canadian Community Health Survey: This is a comprehensive survey of health-related issues,
including the eating habits of Canadians, that was begun in 2000 and continues to collect data
annually.
• Canadian Health Measures Survey (CHMS): conducted every two years, includes useful food and
nutrition data, but differs from the CCHS as it includes laboratory measurements as well as
questionnaires
1.2 Food Provides Nutrients
• Essential nutrients: Nutrients that must be provided in the diet because the body either cannot
make them or cannot make them in sufficient quantities to satisfy its needs.
o 45 nutrients have been determined to be essential to life
o Must be supplied by diet
o Ex. our bodies cannot synthesize vitamin C, but we need it to stay healthy. If we do not
consume vitamin C in the foods we eat, we will begin to show signs of vitamin C deficiency.
• fortified foods: Foods to which one or more nutrients have been added, typically to replace
nutrient losses during processing or to prevent known inadequacies in the Canadian diet.
o Added to numerous foods such as flour, cereal, milks etc
• natural health products: Natural health products are a category of products regulated by Health
Canada that include vitamin and mineral supplements, amino acids, fatty acids, probiotics, herbal
remedies, and homeopathic and other traditional medicines. They occupy a middle ground
between food and drugs.
• phytochemicals Substances found in plant foods (phyto means plant) that are not essential
nutrients but may have health-promoting properties.
o Ex. a phytochemical found in broccoli called sulforaphane is not essential in the diet but has
effects in the body that may help reduce the risk of cancer
, • zoochemicals Substances found in animal foods (zoo means animal) that are not essential
nutrients but may have health-promoting properties.
o Ex. Certain fatty acids found in fish oils
Classes of Nutrients
• 6 classes of nutrients:
o Carbohydrates, lipids, proteins, water, vitamins, and minerals
o Grouped by whether they provide energy to the body, by how much is needed in the diet,
and by their chemical structure
• energy-yielding nutrients: Nutrients that can be metabolized to provide energy in the body.
o Carbohydrates, lipids, and proteins
o Alcohol also provides energy but is not considered a nutrient
o Measured in kilocalories
• The unit of heat that is used to express the amount of energy provided by foods. It is
the amount of heat required to raise the temperature of 1 kilogram of water 1 degree
Celsius (1 kcalorie = 4.18 KJ).
• “calorie,” is technically 1/1000 of a kilocalorie, but when it is spelled with a capital “C,”
it indicates kilocalories. “Calories” on food labels actually refers to kilocalories but in
the popular press, the term “calorie” (small “c”) is often used to express the kcalorie
content of a food or diet.
• Macronutrients: Nutrients needed by the body in large amounts.
o include water and the energy-yielding nutrients: carbohydrates, lipids, and proteins.
• Micronutrients: Nutrients needed by the body in small amounts. These include vitamins and
minerals.
• organic molecules: Those containing carbon bonded to hydrogen.
o carbohydrates, proteins, lipids, and vitamins
• inorganic molecules: Those containing no carbon–hydrogen bonds.
o Minerals and water
• Carbohydrates: provide a readily available source of energy to the body. They contain four
kcalories per gram
o include sugars in table sugar, fruit, and milk, and starches such as those in vegetables and
grains.
o legumes : The starchy seeds of plants belonging to the pea family; includes peas, peanuts,
beans, soybeans, and lentils. Contains lots of fibre.
• Lipids: (fats and oils) provide nine kcalories per gram. They are a concentrated source of energy in
food and a lightweight storage form of energy in the body.
o Triglycerides are the type that is most abundant in foods and in the body. The fat on the
outside of a steak, the butter and oil that is added to food during cooking, made up of fatty
acids
o Diets high in saturated fatty acids increase the risk of heart disease
o Diets high in monounsaturated and polyunsaturated fatty acids may reduce risks.
o Cholesterol is another type of lipid; high levels in the blood can increase heart disease risk.
• Protein: is needed for growth and maintenance of body structures and regulation of body
processes. It can also be used to provide energy—four kcalories per gram.
o Meat, fish, poultry, milk, grains, vegetables, and legumes all provide protein.
o There are thousands of different proteins made up of amino acids. Different combinations
of amino acids are linked together to form different types of proteins
, o Some amino acids can be made by the body, and others are essential in the diet. The
proteins in animal products better match our need for amino acids than do plant proteins,
but both plant and animal proteins can provide all the amino acids we need.
• Water: macronutrient that does not provide energy. makes up about 60% of the human body by
weight and is required in kilogram amounts in the daily diet.
o acts as a lubricant, a transport fluid, and a regulator of body temperature. Water can be
obtained from the beverages we drink and also from food
• Vitamins: organic molecules, micronutrients are needed in small amounts.needed to regulate
body processes.
o 13 substances have been identified as vitamins.
o helping the body use the energy from carbohydrates, lipids, and proteins; others function in
processes such as bone growth, vision, blood clotting, oxygen transport, and tissue growth
and development.
• Minerals: are inorganic molecules, micronutrients
o They are needed for bone strength, the transport of oxygen, the transmission of nerve
impulses, and numerous other functions.
• Vitamins and minerals: Fresh foods are a good, natural source and many processed foods are
fortified with micronutrients.
o Food processing can cause vitamin losses because some are destroyed by exposure to light,
heat, and oxygen.
Functions of Nutrients
• Metabolism: macronutrients and micronutrients provide energy, structure, and regulation, which
are needed for growth, maintenance and repair, and reproduction. Each nutrient provides specific
functions, but all nutrients together are needed to maintain health.
o The sum of all the chemical reactions that take place in a living organism
• Providing Energy: biochemical reactions release the energy contained in carbohydrates, lipids, and
proteins.
o used to synthesize new compounds, maintain basic body functions, fuel physical activity, is
lost as heat.
o Energy in food is not needed immediately, it can be stored, primarily as fat which provide
energy when dietary sources are unavailable.
o if more energy is consumed than is needed, body stores get larger, and body weight
increases.
o If less energy is consumed than is needed, the body will burn its stores, and body weight will
decrease.
• Forming Structures: Most of the weight of the human body is due to water, protein, and fat
o Proteins form the ligaments and tendons that hold bones together and attach muscles to
bones and the framework of bones and teeth that is hardened by mineral deposits, and the
overall structure of muscles.
o At the cellular level, lipids and proteins make up the membranes that surround cells.
• Homeostasis: A physiological state in which a stable internal body environment is maintained.
Metabolic processes must be regulated to maintain this stable environment.
o enzymes that catalyze the chemical reactions of metabolism are made up of proteins.
o proteins combine with vitamins and minerals to speed up or slow down the reactions as
needed to maintain homeostasis.
o water is the solvent for metabolism, most of these reactions occur in the watery component
of the cells. also helps to regulate body temperature. When body temperature increases,
water lost through sweat helps to cool the body.
, • Examples of Nutrient Functions in the Body
Function Nutrient Example
Energy Carbohydrate Glucose is a carbohydrate that provides energy to body cells.
Lipid Fat is the most plentiful source of stored fuel in the body.
Protein Protein consumed in excess of protein needs will be used for
energy.
Structure Lipid Lipids are the principal component of the membranes that
surround each cell.
Protein Protein in connective tissue holds bones together and holds
muscles to bones. Protein in muscles defines their shape.
Minerals Calcium and phosphorus are minerals that harden teeth and
bones.
Regulation Lipid Estrogen is a lipid hormone that helps regulate the female
reproductive cycle.
Protein Leptin is a protein that helps regulate the size of body fat stores.
Carbohydrate Sugar chains attached to proteins circulating in the blood signal
whether the protein should remain in the blood or be removed by
the liver.
Water Water in sweat helps cool the body to regulate body temperature.
Vitamins B vitamins regulate the use of macronutrients for energy.
Minerals Sodium is a mineral that helps regulate blood volume.
Nutrition and Health
• What we eat has an enormous impact on how much we weigh, how healthy we are now, and how
likely we are to develop chronic diseases like heart disease and diabetes in the future.
• Malnutrition: Any condition resulting from an energy or nutrient intake either above or below that
which is optimal.
o can affect our health today and can impact on our health 20, 30, or 40 years from now.
• Undernutrition: is a form of malnutrition caused by a deficiency of energy or nutrients. It may be
caused by a deficient intake, increased requirements, or an inability to absorb or use nutrients.
o Starvation: the most severe form of undernutrition, is a deficiency of energy that causes
weight loss, poor growth, the inability to reproduce, and if severe enough, death
o Ex, vitamin A is necessary for vision; a deficiency of vitamin A can result in blindness.
o Some nutrient deficiencies cause symptoms quickly. Others may take weeks, months, or
even years to become apparent.
• Overnutrition, an excess of nutrients, is also a form of malnutrition. When excesses of specific
nutrients are consumed, an adverse or toxic reaction may occur.
o Ex, a single excessive dose of iron can cause liver failure, and too much vitamin B6 over a
few weeks or months can cause nerve damage.
o Most nutrient toxicities are due to excessive intakes of vitamin and mineral supplements
o Most overnutrition do not have immediate toxic effects but contribute to the development
of chronic diseases, such as heart disease, type 2 diabetes, and some types of cancer
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