Lecture 1 Flashcards
What is the modern goal of understanding in the field of nutrition?
Understanding optimal levels of nutrients required for health and well-being
What are essential nutrients?
Chemical/substance that is required for metabolism but cannot be synthesized or cannot be synthesized rapidly by the body to meet the needs for the physiological functions of the body
What are the two rules to determine if a nutrient is essential?
- Removing the nutrient causes a deficiency and decline in health
- Putting the nutrient back into the diet corrects the problem and health will return
How do nutritional deficiencies occur?
When a persons nutrient intake consistently falls below the recommended requirement
Do the amount of nutrients stay the same as the different stages of life progress?
No, they vary
What is the difference between deficiency and nutritional requirements?
Deficiency is the prevention of diseases
Nutritional requirements ensure optimal health
What prompted the understanding of nutritional requirements?
WW1 and food rations, but age, gender, body size, physical activity were not considered which was an issue as these are important
What is used to establish nutrient requirements?
Nutrient research and statistics
What are daily values based on?
2,000 calorie a day diet, this is a simple way for governments to provide consumers with information about the daily requirement for each nutrient
How are daily values made?
Using dietary reference intakes (DRIs)
How are DRIs established?
National Academy of Sciences
What is Dietary Reference Intake?
Umbrella term that refers to a set of reference values for nutrients
DRI
Dietary Reference Intake
What are the 4 reference values under the umbrella term DRIs?
Estimated Average Requirement (EAR)
Recommended Dietary Allowance (RDA)
Adequate Intake (AI)
Tolerable Upper Limit (UL)
What is Estimated Average Requirement?
Nutrient requirement that meets the needs of 50% of the population (on a normal dist. EAR is in the middle)
What is Recommended Dietary Allowance?
Nutrient requirement that meets the needs of 97% of the population (3% deficient)
Do we aim for EAR or RDA?
RDA!!!!
What is the formula of RDA?
RDA = EAR + 2 S.D.
What is Tolerable Upper Limit?
The highest level of continuous daily nutrient intake that causes no risk of adverse effects (toxicity of over intake)
EAR
Estimated Average Requirement
RDA
Recommended Dietary Allowance
UL
Tolerable Upper Limit
What is Adequate Intake?
When sufficient evidence is not available to establish an EAR and RDA, then an AI is proposed (based on less scientific data), AI is expected to meet or exceed the needs of most individuals (the gap between RDA and UL)
AI
Adequate Intake
How is AI determined?
Based on intake in healthy people who are assumed to have Ana equate nutritional status
What is prospective vs retrospective human studies
Prospective - Following subjects for period of time (moving forward)
Retrospective - Follow backwards (e.g. cancer and figuring out the cause of it by working backwards)
What are the three classes of macronutrients?
Carbohydrates/Fibre, Lipids, Proteins (all organic)
What are the two classes of Micronutrients?
Vitamins (organic), and minerals (inorganic)
What is the stand alone nutrient class?
Water
What are the organic and inorganic nutrient classes?
Organic: Carbohydrates/Fibre, Lipids, Proteins, Vitamins
Inorganic: Minerals, Water
What is the average water intake by adult humans per day?
2.7-3.7 L
What percentage of the average water intake by an adult human is from food?
20% of water comes from foods
Why is water important for the body?
- Solvent in biochemical rxns
- Catabolism (hydrolysis)
- Maintains vascular volume
- Nutrient transport
- By-product of metabolic rxns
- Temperature regulation
What is water toxicity?
When the amount of water taken in is larger that the kidneys ability to process the water (0.9L/h), causes the electrolytes to become diluted
What is Hyponatremia?
Low electrolytes (sodium)
What is the formula for Hyponatremia?
Water/sodium imbalance
How can Hyponatremia occur?
Can occur from excessive fluid intake, under-replacement of sodium or both, typically avoided with urination
