Lecture 10 Flashcards
What are Vitamins?
Organic compounds that are required in small quantities within the diet.
Why are Vitamins important?
They are essential for most metabolic reactions.
What are the fat soluble Vitamins?
A, D, E, K
What are the water soluble vitamins?
Vitamin B and C
Compare fat soluble and water soluble vitamins:
- Fat soluble stored in the body whereas water-soluble is not
- Fat soluble has a much higher risk of toxicity, water soluble is a much lower toxicity risk
What are Vitamers?
These are members of the same Vitamin family and they have very similar metabolic roles. They are compounds that play similar roles.
Most vitamin concentrations are measured in mg/day. Vitamins A, D and E are all expressed as ________
“potency” IU. The potency units are related to activity.
What three factors influence the stability of a vitamin within a ration?
- Environment
- Processing
- Time
What are minerals and why are they important?
They are inorganic and essential for life. They have catalytic functions, physiological functions and regulatory functions.
Why with minerals is an “imbalance of elements as important as a deficiency”?
some elements can interfere with the absorption, transport, function, storage or excretion of other elements.
What are the two different classifications of minerals?
- Macrominerals (g/kg)
2. Trace elements (mg/kg)
What requirements must a mineral meet in order to be considered essential?
- Deficiency = impairment of body function
- Deficiency = consistent pattern of biochemical and pathological changes
- All signs of deficiency = prevented/reversed by supplementation
- Clearly defined biochemical/physiological role in metabolism
Compare the terms supplementation and requirement for minerals:
Supplementation: diets are often supplemented at levels greater than requirements to allow for uncertainties.
Requirement: least amount of a nutrient that will prevent clinical signs of deficiency or support a well defined biochemical response.
What are the three methods that can be used to determine the Vitamin or mineral requirement in a diet?
- Supplement and monitor
- Feed a deficient diet and measure the response to supplementation
- Factorial analysis
What Is the formula for factorial analysis?
Dietary requirement = (E+G+P+L)/A
- E = amount of endogenous losses
- G = amount required per unit of growth
- P = amount required for pregnancy
- L = amount that is lost in milk lactation
A = co-efficient of absorption for that mineral or vitamin
What is the recommended daily allowance?
Dietary concentration needed to achieve optimum enzyme activity/tissue stores in a population.
Describe the sequence of events that occurs during the depletion of a mineral:
- Plasma (transport) first
- Tissue enzyme function
- Onset of the clinical signs
Where is calcium in the body?
- 99% is in skeleton/teeth
2. 1% in cells and the ECF
What is the effect of Vitamin D (calcitriol)?
- Increases calcium absorption from the gut
2. Increase the calcium absorption from the bone
What is the effect of parathyroid hormone (PTH)?
- Increases the conversion of Vitamin D to active calcitriol
- Increase calcium reabsorption from the kidney
- Increases calcium reabsorption from the bone
What is the effect of calcitonin?
- Decreases bone reabsorption
What is the effect of 24,25-Dihydroxy-D3?
- Increases mineralisation from the bone
For Egrocalciferol (D2) state:
a) The pro-vitamin
b) The source
c) Who it can be used by
a) Ergosterol
b) Plants
c) Mammals
For cholecalciferol (D3) state:
a) The provitamin
b) The source
c) Who it can be used by
a) 7-DHC
b) Animal tissues with UV
c) Birds and mammals
