Chapter 1: Nutrition and the Canadian Diet

Processed foods definition

Foods which have been specifically treated or changed from their natural state

What are processed foods usually high in?

• Saturated fat

• Sugar

• Salt

• Calories

Chronic disease

Non-communicable diseases that develop slowly over a lifetime and need continuing medical attention to manage and control

Information about the health and food intake of Canadians in obtained from:

The Canadian Community Health Survey (CCHS)

What is the Canadian Community Health Survey (CCHS)?

Comprehensive survey of all health-related issues (including eating habits)

The CCHS doesn’t include which measures which the CHMS does?

• Laboratory measurements

• Questionnaires

To date, around _____ nutrients have been determined to be essential to human life

45

How do essential nutrients support life?

By being applied to the diet

Criteria for the definition of essential nutrients:

• Cannot be made by the body, or

• Cannot be made in sufficient quantities to meet ends

True or False:

The only way to obtain essential nutrients is through a diet of foods which are naturally high in nutrients

False.

Some foods contain nutrients which have been added during processing (e.g., cereals, infant formula, plant-based milk, …)

Fortified foods

Foods to which nutrients have been added

What are fortified foods intended to do?

Restore nutrient losses caused by processing, or to prevent known inadequacies in peoples’ diets

The 2015-CCHS-Nutrition estimates that around ____% of Canadians use vitamin and mineral supplements

46

Phytochemicals

Substances which come from plants

Zoochemicals

Substances which come from animal foods

True or False:

If additional dietary intake of a substance is linked to health benefits, it’s considered an essential nutrient

False.

Example: Certain fatty acids aren’t essential (they can be synthesized in the body), but additional dietary intake has been linked to a reduced risk of death from cardiovascular disease

What are the six (chemical) classes of nutrients?

• Carbohydrates

• Lipids

• Proteins

• Water

• Vitamins

• Minerals

What are some ways in which the nutrient classes can be grouped?

• Whether they provide energy to the body

• How much is needed in the diet

• Their chemical structure

Carbs, lipids, and proteins provide energy and thus are referred to as:

Energy-yielding nutrients

If alcohol provides energy, why isn’t it considered a nutrient?

It isn’t needed to support life

Macronutrient requirements are measured in:

• Kilograms (kg)

• Grams (g)

Vitamins and minerals are classified as micronutrients because:

They’re needed in small amounts in the diet

Micronutrient requirements are measured in:

• Milligrams (mg)

• Micrograms (μg)

Structurally, carbs, proteins, lipids, and vitamins are organic molecules and are referred to as:

Organic nutrients

Minerals and water are inorganic molecules, and are referred to as:

Inorganic nutrients

The energy provided by carbohydrates, lipids, and proteins is measured in:

• Kilocalories (kcalories or kcals)

• Kilojoules (kjoules or kJs)

The common term, “calorie,” is technically _________ of a kcal

1/1000

One Calorie is ____/1000 of a kcal

1000/1000 = 1/1 (they are the same)

_________ provide a readily available source of energy to the body

Carbohydrates

Carbs contain _____ kcals/g

4

_______ is/are the simplest form of carbohydrate

Sugars

______ is/are more complex carbs made of many sugars linked together

Starches

True or False:

Most fibre is a carb

True

Lipids are ____ kcals/g

9

________ is/are a concentrated source of energy in food, and is a lightweight storage form of energy in the body

Lipids

Which lipid is most abundant in foods and the body?

Triglycerides

Which of the following fatty acid(s) may reduce the risk of heart disease?

a) Saturated

b) Monosaturated

c) Polyunsaturated

b) Monosaturated

c) Polyunsaturated

What makes up triglycerides?

Fatty acids

________ is/are needed for the growth and maintenance of body structures, and the regulation of body processes

Protein

Protein is ____ kcal/g

4

What makes up proteins?

Amino acids

True or False:

All amino acids are essential in the diet

False.

Some can be made by the body

Do animal proteins or plant proteins better match our needs for amino acids?

Animal proteins.

But, both can provide all necessary amino acids.

True or False:

Water is a nutrient in a class by itself

True

Water makes up for around ____% of human body weight

60

Vitamins are _________ organic/inorganic molecules

Organic

____ substances have been identified as vitamins

13

Minerals are __________ (organic/inorganic) molecules

Inorganic

Vitamins ______ (do/don’t) provide energy

Don’t

Minerals ______ (do/don’t) provide energy

Don’t

_________ (vitamins/minerals) are more stable

Minerals

Function of nutrients

• Providing energy

• Forming structures

• Regulating body processes

When the energy in carbs, lipids, and proteins consumed in the diet is not needed immediately, it:

Can be stored (mainly as fat)

What are 3 different ways that energy can be used in the body?

• Used to synthesize new compounds and maintain basic body functions.

• Used to fuel physical activity.

• Lost as heat.

Most of the weight of the human body is due to which 3 components?

• Water

• Protein

• Fat

What does protein form?

• Ligaments

• Tendons

• Framework of bones and teeth (hardened by mineral deposits)

• Overall muscle structure

What do lipids and proteins make up at the cellular level?

The membranes which surround cells

Metabolism

The sum of all chemical reactions in the body

The enzymes that catalyze the chemical reactions of metabolism are made up of:

Proteins

How can proteins speed up/slow down reactions in the body in order to maintain homeostasis?

By combining with different vitamins and minerals

Why do most body reactions occur in the watery component of cells?

Because water is the solvent for metabolism

________ is the solvent for metabolism

Water

True or False:

Malnutrition is defined as the underconsumption of certain nutrients

False.

Malnutrition can also occur from overconsuming nutrients.

Undernutrition can be caused by:

• A deficient intake

• Increased requirements

• Inability to absorb/use nutrients

What is the most severe form of undernutrition?

Starvation

Most nutrient toxicities result from:

Excessive intakes of vitamin and mineral supplements

(Foods generally don’t contain high enough concentrations of nutrients to cause toxic reactions)

Nutritional genomics/nutrigenomics

The study of how diet affects our genes, and how individual genetic variation can affect the impact of nutrients or other food components on health

Factors that affect food choice:

• Availability

• Cultural and family background

• Social acceptability

• Personal preference

• Psychological and emotional factors

• Health concerns

• Media

A healthy/adequate diet is defined by:

• Providing the right amount of energy to keep weight in the desirable range.

  • The proper types and amounts of carbs, proteins, and fats

  • Plenty of water

  • Sufficient, but not excessive amounts of vitamins and minerals

Nutrient density

• A measure of the nutrients a food provides compared to its energy content.

• Nutrient-dense foods contain substantial amounts of nutrients per kcal.

True or False:

No food can provide all the nutrients the body needs for optimal health

True

Why is it important to eat a variety of foods?

• Ensures adequate nutrient intake.

• There are interactions between different foods and nutrients.

• Choosing a variety of foods avoids an excess of unwanted substances, such as natural toxins, pesticides, and fertilizers.

What is a phenomenon that can make eating in moderation difficult?

Portion distortion

Portion distortion

The increase in portion sizes for typical restaurant and snack foods (over the last 40 years)

Subpackaging

In recent years, the food industry has introduced smaller portion sizes (e.g., 100-kcal snacks)

Kcalorie control

The specific aspects of balance and moderation that are related to energy intake

The scientific method:

Provides a systematic, unbiased approach to evaluating the relationship among food, nutrients, and health

3 main steps of the scientific method

1. Make an observation and ask questions about it.

2. Propose a hypothesis or explanation for the observation.

3. Design experiments to test the hypothesis.

Scientific theories are only accepted as long as:

• They have been reproduced (rendering them theories and not hypotheses).

• They cannot be disproved.

• They continue to be supported by all the new evidence that accumulates.

Features of a well-designed nutrition experiment include:

• Quantifiable data

• An appropriate experimental population

• Appropriate number of subjects

• Suitable study duration

• Statistical analysis of results.

• Publication after a peer-review process.

Quantifiable data

Data can be measured in a way that provides numerical results, and uses methods that can be repeated by others

Biomarkers

Features of future disease development

In order to be useful in science, anecdotes must:

Be quantified using standardized questionnaires and compared, when possible, to a quantifiable biomarker

True or False:

a P of 0 and/or a P of 1 is possible

False.

Calculated probability (P) is expressed as a decimal between 0 or 1.

P < 0.05 is considered a _______ (high/low) value

Low

P < _____ is considered a statistically significant difference

0.05

True or False:

If P is less than 0.05 (P<0.05), it’s certain that there’s a meaningful difference between the study groups

False.

This is likely, but it isn’t certain.

If P is equal to or higher than 0.05, then it suggests (but doesn’t confirm) that:

There’s no difference between the groups

Before scientists publish their results in a scientific journal, the experiment is usually peer-reviewed by around how many other experts?

2 or 3

True or False:

Peer reviewers of a study/experiment must not have taken part in the evaluated research

True

Nutritional epidemiology

The study of dietary exposures (e.g., the intake of a certain nutrient, food, or overall diet and outcomes) which are usually health-related (e.g., the incidence of disease)

True or False:

Most epidemiological studies are observational studies

True

In observational studies, which 3 relationships are common?

1. There’s no association between the nutrient intake and the occurrence of the disease.

2. As nutrient intake increases, the disease declines (inverse association).

3. As nutrient intake increases, the diseases increases (direct association).

Scientists have found a(n) __________ (direct/inverse) association between fibre and colon cancer

Inverse

Association definition

• 2+ factors occurring together

  • Can be direct (positive) or inverse (negative)

Causation

A relationship between two factors where one factor causes the second factor to occur

Confounding factors

Factors associated with both the dietary intake of interest and the disease

Residual confounding arises because:

No adjustment is perfect, and there may be unmeasured/unknown confounders still influencing the results

Which phenomenon is one of the main reasons that we describe results as indicating an association, but not proving causation?

Residual confounding

Of all observational studies, which is most important?

Cohort studies