BIOL 203 FINAL EXAM NOTES Lesson1- Lesson 11 all what covered in a short time Concordia University
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BIOL 203 FINAL EXAM NOTES Lesson1- Lesson 11 all what covered in a short time Concordia University
Lesson1- Intro to Nutrition
Nutrition: how an organism acquires food & uses food to support all processes required for its existence
Plant nutrition:
• Plants are anchored by roots to the grou...
BIOL 203 FINAL EXAM NOTES
Lesson1- Lesson 11 all what
covered in a short time Concordia
University
Lesson1- Intro to Nutrition
Nutrition: how an organism acquires food & uses food to support all processes required for
its existence
Plant nutrition:
• Plants are anchored by roots to the ground
• Absorb nutrients from the soil solution
• & Directed upwards towards the leaves
• Developing leaf buds & flower buds pick up the bulk of the nutrients
• Together w/ photosynthesis, the plant now has all it needs to grow into a tree
towering more than 30 m high
Roundworm nutrition:
• A biologist studying the nutrition of a roundworm. For ex: C-elegans would be
interested in its locomotion during the time it’s foraging for food
• Once food has been located, the worm biologist would be interested in the type &
rate of digestion in each compartment of the worm’s elementary canal
• Next, they may question how the nutrients are absorbed, stored & metabolized by
the cells that make up the organism
• They also study the neurobiology of feeding in simpler animals like roundworms.
Roundworms are great model organisms b/c of their neurological simplicity
• Only 309 nerve cells make up the full organism
Human nutrition
• The science of nutrition is the study of the nutrients & other substances in food & the
body’s handling of them
• It’s a young science
• More recently, it has a sister discipline called nutritional genomics: science for how
nutrients affect gene expression
What’s Food?
• There’s drawbacks to the advances made in the field of nutrition
• The science of nutrition is partly to blame for anyone of these being considered as
food: milkshakes, pop tarts, granola bars
• Nutritionists broke down food into an amalgam of nutrients & offer the advice that we
need X amount of these nutrients every day
• Food is more than just a collection of vitamins, minerals & macronutrients
,• Organs of the digestive system communicate w/ the brain & vice versa to offer a
feeling of wellness & satisfaction
• Food provides us w/ essential nutrients that must be supplied by the diet b/c the body
can’t synthesize them. It can, but not in sufficient quantities hence we eat food to get an
adequate amount of the essential nutrients to promote optimal health
• Absence of an essential nutrient would lead to a deficiency disease like scurvy &
eventual death
• It also matters the proportion of essential nutrients consumed
• Too much can lead to chronic diseases like cardio disease, Type 2 diabetes or sudden
death as in overdosing on supplements
• Energy-yielding nutrients= carbs, lipids & proteins
• Non-energy yielding nutrients= vitamins, minerals & water
• Food also contains non-nutrients like fiber & phytochemicals, which stave off chronic
diseases
• Fiber: promotes bowel health; food waste is quickly & effortlessly eliminated, helping
to reduce the risk of colon cancer
• Phytochemicals: function as anti-oxidants to help reduce the risk of chronic diet-
related diseases
, • Many types of compounds found in plants are now studied for their curative powers.
Ex: Flavanoids found in tea & blueberries are thought to decrease risk of some forms
of cancer & even improve memory
Challenge of Food
• We split our choices into a dichotomy of processed foods + whole foods
(unprocessed or minimally processed)
• Phytochemicals clearly promote consuming whole foods for optimal health yet we
continuously make poor food choices
• Factors that drive food choices:
o Convenience
o Advertising
o Economy
o Emotional comfort
o Social network
o Beliefs
• At the end of the day, it comes down to cooking skill & hardware
• Learn about nutrition (cognitive fix) & learn how to cook (non-cognitive fix)= vital life
skills
Cooking
• This skill is disappearing from our society
• Cooking, being physically active in the kitchen, it now incompatible w/ achieving
professional success
• Cooking can teach us:
o How to be organized
o How to socialize
o How to love
o Food chemistry
• Food rules: food safety, discipline & stay away from kitchen gadgets
Lesson 2- Nutritional Standards & Guidelines
Dietary Reference Intakes (DRIs)
• Reference values that are quantitative estimates of nutrient intakes to be used for
planning & assessing diets for healthy ppl
• It’s an umbrella term/group name. Group includes a set of 6 nutrient intake standards
aimed for healthy ppl
• Based on these standards, dieticians can plan or assess someone’s diet
• In the past, the sole purpose of DRIs was to reduce risk of deficiency diseases
• Today, in developed countries, deficiency diseases are rare. Chronic diet related
diseases replaced them
• Majority of population over 40 begin to worry about cardio disease & type 2 diabetes
• DRIs now have 3 objectives:
o 1) Prevent deficiency diseases
o 2) Reduce risk of chronic diseases w/ recommendations
o 3) Establish the upper safety for nutrient intake for supplement use &
fortification
6 Nutrient Intake Standards
1) Estimated Average Requirement (EAR)
2) Recommended Daily Allowance (RDA)
3) Adequate Intake (AI)
4) Tolerable Upper Intake Level (UL)
5) Estimated Energy Requirement (EER)
6) Acceptable Macronutrient Distribution Ranges (AMDR)
, - All essential nutrients have 1 or more of these DRIs (between standards 1-4)
- 1-3 target deficiency diseases
- 4 targets supplement use
- 5 & 6 are diff b/c they deal w/ calorie intake
- Nutrient standards differ by gender & life stage
- Men= 10 life stages; women= 16 life stages (includes periods of preggo & lactation)
- Pregnancy & lactation are so taxing on the female body that nutrient intakes must
increase during this period. Ex: recommended intake of iron for women…
o 13 yrs old= 8 mg
o 14-50 yrs= 15 mg
o 50+ yrs= 8 mg
o Pregnancy= 27 mg
- Average daily requirement for each nutrient expressed as mg/day, g/day or μg/day
- Most Canadians & Americans consume 3,400 mg/day of Na. AI for Na = 1500 mg/day
DRIs: Most Nutrients
1. Estimated Average Requirement (EAR)
• Average daily intake level of a nutrient to meet the needs of ½ the healthy ppl in a life
stage or gender population
• 2 key features:
o a) It’s based on a diagnostic test that can measure adequate amounts in the
body. Some nutrients lack a diagnostic test, thus an EAR cannot be
established
o It’s a requirement, NOT a recommendation
2. Recommended Dietary Allowance (RDA)
• The average daily nutrient intake level that meets the needs of 98% of healthy ppl in a
life stage or gender group
• Gold standard in DRIs
• Known in other countries as: Required Nutrient Intake (RNI) or Required Dietary
Intake (RDI)
• EAR x X (some factor) = RDA
• W/o EAR, an RDA cannot be established
3. Adequate Intake (AI)
• The average daily amount of a nutrient that appears sufficient to maintain a specified
criterion
• For nutrients where there’s no EAR or RDA established, we play a guessing game that
results into this nutrient standard
• Based on the intake levels of a healthy group of ppl in a population
• We find a relatively healthy population & examine their intake level & base the AI on
that #
• It’s the equivalent of looking at the intake level of a friend & basing your nutrient
intake on their diet
• Given that the AI is based on the nutrient intake level of a healthy group of ppl, we
assume that it’s higher than the EAR & lies somewhere near or below the RDA,
but below the UL
4. Tolerable Upper Intake Level (UL)
• Max daily amount of a nutrient intake that appears safe for most healthy ppl
• Above this level, there’s an increased risk of adverse health effects, toxicity &
eventual death
• Ex: UL for Selenium in men= 400 μ/day. More than this can lead to Selenium toxicity
& sudden death
• UL is meant to avoid excesses especially when using supplements
How to know what your intake level is?
• Nutrient recommendations are averages meant for a population- your requirement
can be above or below
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