Concordia University
BIOL 203 Class & Textbook Notes
“WHAT IS FOOD?”
Chapter 1: The Essentials
Food -- a substance that nourishes the body containing varying amounts of macronutrients
(carbohydrates, lipids and proteins), micronutrients (vitamins and minerals), fibre,
phytochemicals (e.g. antioxidants) and water.
Essential nutrients –substances that must be obtained from the diet because the body cannot
synthesize or make them in sufficient quantities
- In the absence of an essential nutrient, cell function is irreparably compromised and
deficiency diseases manifest
Non-essential nutrients -- compounds in food that promote health but without the same sense
of urgency as the essential nutrients. (Eg. fibres and phytochemicals)
Essential Nutrients:
2 Main Types:
1) Energy yielding (Macronutrients -- require large amounts)
2) Non-energy yielding (Micronutrients -- require small amounts)
● Exception = Water
○ The most important essential nutrient is a non-energy yielding nutrient that is
required in large amounts
● Agriculture = macronutrient-driven technology
○ Higher need for macro than micro
○ Mass production of macronutrients -- carbohydrates (e.g. wheat, rice, oats,
millet), lipids (e.g.rapeseed/canola, oil palm) and proteins (e.g. soybean, lentils)
Six Discrete Categories:
1) Carbohydrates (Macro)
2) Lipids (Macro)
3) Protein
4) Vitamins
5) Minerals
6) Water
,Macronutrients:
- Glucose (carbohydrate) – an energy-yielding macronutrient
- It can be synthesized by the cells of the body, BUT only in limited quantities
- Is also the product of photosynthesis and serves as a source of energy for most
living organisms
- As an important source of fuel for red blood cells and neurons in addition to
fuelling rapid burst of physical activity, glucose must also be supplied by the diet
- Both carbohydrates and proteins can be transformed into lipids (fat) and stored as
fuel for later use
- Fat = go-to molecule for energy storage in animals and plants (eg. olives, walnuts and
avocados)
- Fat can store more than 2x the energy per gram than carbohydrates or proteins
- Some fats that must be supplied by the diet because our species cannot build them
- Including: alpha-linolenic (omega-3) and linoleic acids (-6 fatty acids)
- Only essential our species (others animals/plants either don't need them or can
synthesize them)
- Some organisms ability to synthesize specific fat molecules allows
researchers to deduce their diet by looking at the variety of fatty acids
from their tissues (called the fatty acid signature)
- For example: seals can synthesize omega-7 fatty acids, whereas bears
cannot. The presence of omega-7 fatty acids in polar bears becomes
incontestable evidence they’ve been eating seal (Thiemann et al. 2008)
- Amino acids are the building blocks of protein
- 20 total amino acids
- 9 are essential and must be supplied by the diet (eg. fish)
- Remaining 11 can be built endogenously (cells in liver)
Micronutrients:
- 2 types: Vitamins and Minerals
- Non-energy yielding -- meaning they don’t serve as fuel and are required in very small
amounts.
- Micronutrients keep cells, and by extension the body, functioning.
- Their absence lead to deficiency diseases → sometimes even life-threatening
situations
IMPORTANT: focus on the life-threatening situations associated with a depletion of sodium and
blood calcium in the body and the long-term health benefits of potassium- and magnesium-rich
diets
,Non-Essential Nutrients
● 2 Types: Fibre and phytochemicals
Fibres:
- It never reaches the autonomously working body cells, interacting instead only with gut
microbes as it travels in and out of the alimentary canal
- This interaction has impacts on whole organ systems– including the nervous
(e.g. Borre et al., 2014) and circulatory (e.g. Sonnenburg & Bäckhed, 2016)
systems
Phytochemicals:
- Include pigments like carotenoids and flavonoids
- Can play important roles in protecting tissues from damage by free radicals but remain
the least researched of any nutrient
REQUIRED READING OUTSIDE TEXTBOOK
https://food-guide.canada.ca/en/
https://globalnews.ca/news/4873598/new-canada-food-guide-2019/
, Chapter 2: Illuminating Standards and food
DRIs Pros and Cons:
Cons:
● Very complicated -- several thousand reported intake values
○ Difficult to implement into daily life
● Easy to fall into the DRI rabbit hole
● Is it necessary? → Millions of people (& other organisms) live long into old age without it
Pros:
● It reduced debilitating congenital deficiency diseases like spina bida through the
mandated fortification of grain products (e.g. breads and pasta)
● Very informed -- very effective if at some point you’re faced with an illness that requires
you to monitor your diet up close
Food Guides:
● While it is a well-intentioned educational initiative, it lacks instruction on the botanical
and animal origin of the foods we eat
What are Nutrition Standards?
The DRIs -- a set of six standards aimed for healthy people that quantitatively capture the
recommended intake of essential nutrients and set limits of safe intake
DRIs Group 1 (nutrients):
1) The estimated average requirement (EAR)
2) recommended dietary allowance (RDA)
3) Adequate intake (AI)
4) The tolerable upper intake level (UL)
These were developed with the goal of staving off deficiency diseases (e.g. sugar , scurvy,
rickets) which were all too common once upon a time.
DRIs Group 2 (energy & macronutrients):
5) The estimated energy requirement (EER)
6) Acceptable macronutrient distribution ranges (AMDR)
Target excesses (chronic diseases)