Minerals Flashcards
Name the macronutrients:
- Carbohydrates
- Proteins
- Fat
Name the micronutrients:
- vitamins
- minerals (macrominerals = major; microminerals = trace)
What is the % of children less than 5yo that are stunted? - WHO
20%
How do you access the adequacy of a population’s…. lets say… Zn intake?
- Take into account the physiological requirements for absorbed Zn
- Account for an estimate of % of absorbable dietary Zn (to calculate EAR)
- Account for an estimate of coefficient of variation (CV) of usual intakes of zinc in the population
What is the result of calcium deficiency?
- Rickets
- Osteomalacia
- Osteoporosis
- Tetany
What is the result of Magnesium deficiency?
- Neuromuscular hyperexcitability
- muscle weakness
- tetany
What is the result of phosphorus deficiency?
- neuromuscular, skeletal, haematological, and cardiac manifestations
- rickets
- osteomalacia
What is the result of sulfur deficiency?
(unknown.. hahaha)
What are the ‘functions’ of calcium?
- Bone structure
- muscle contraction
- nerve impulse transmission
- wound healing
- cellular metabolism
In lifetime, when is absorption in great levels?
childhood and pregnancy
What are the % levels of absorption at childhood and adulthood respectively?
childhood = 75% adulthood = 30%
What facilitates absorption?
lactose
What reduces absorption?
Phytates, NSP and oxalates
Is absorption energy-dependant?
Yes
In what way can vitamin deficiency develop?
- lack of exposure to sunlight
- inadequate dietary intake
(or both)
What is reduced in vitamin deficiency?
- efficiency of intestinal Ca2+ absorption
- decreased serum ionized calcium
From animal studies, what happens in excessive Ca2+ intake?
Can impair Fe, Zn and Mg nutritional status
From Human studies, what happens in excessive Ca2+ intake?
- Ca2+ interacts and reduces absorption of Mg and P
- inhibits absorption of Fe in a dose-dependent and dose-saturable fashion
- reduces absorption of Zn and Zn balance = increase Zn requirement
- NO EVIDENCE that it’s associated with nutrient deficiencies
Does calcium deficiency exist?
No. (at least not as a nutritional disorder)
What does inadequate intake/poor intestinal absorption of Ca2+ cause?
- circulating ionized calcium concentration declines acutely
- triggers increase in PTH synthesis and release
- restores the circulating calcium concentration to normal via targeting 3 organs
How fast does it take for plasma calcium concentration levels to be restored?
within minutes to hours
Circulating Ca2+ concentration is maintain largely at the expense of?
Skeletal mass
In regard to bones, what happens from vitamin D deficiency?
- increased rate of bone resorption
- over years, reduced bone mass and osteoporosis
What is tetany?
Muscle pain, spasm, numbness in hands and feet
What are the outcomes in terms of the link between calcium deficiency and osteoporosis?
- affects post-menopausal women
- loss of trabecular bone
- public health significance
- evidence for oestrogen, vit D and low PA
What are the 3 main outcomes from calcium toxicity?
- Kidney stone formation (nephrolithiasis)
- Syndrome of hypercalcaemia and renal insufficiency (with or w/out alkalosis)
- Effects on absorption of other essential minerals (Fe, Zn, Mg, P)
What is alkalosis?
- historically referred as milk alkali syndrome
- associated with peptic ulcer, dyspepsia, osteoporosis treatments
What is the tolerable upper intake level (UL) of calcium?
2500mg/day
What is genetic hypocalcaemia?
Inborn erros of metabolism associated with hypocalcaemia that can impair the bone calcification process
What are the 2 outcomes of genetic hypocalcaemia?
- Vitamin D-dependent rickets (type I and II)
2. Familial benign hypercalcaemia (type I and III)
What causes vit. D-dependent rickets and what is its treatment?
- mutation in enzyme enzyme 25(OH)D3-1α-hydroxylase
- changes in the vitamin D receptor molecule
Treatment = daily vitamin D3 administration
What causes familial benign hypercalcaemia?
- mutation in the gene encoding the calcium-sensing receptor
- renal tubular defect in calcium reabsorption
What substance enhances intestinal phosphorus absorption?
Vitamin D
What substances inhibit intestinal phosphorus absorption?
- Phytic acid
- excessive intakes of: Mg, Al, Ca
What are the functions of phosphorus?
- Bone mineralisation
- Nucleotide/nucleoside phosphates
- Phosphoproteins and phosphorylated forms of vitamins (e.g. B6)
- Phospholipids
- Acid-base balance
- Oxygen availability
What does phosphorus inhibit?
polyphosphates in food additives can interfere with the absorption of Fe, Cu and Zn
What are the roles of nucleotide/nucleoside phosphates?
- Structural role
- Energy storage and transfer
- Intracellular second messenger
Is phosphorus ubiquitous in various food?
Yes
What is hypophosphataemia?
Limited P stored within cells, tissue depend on ECF inorganic P for their metabolic phosphate (ECF P < 0.3 mmol/l)
What does hypophosphataemia cause?
- cellular dysfunction
- severe manifestations
What are some symptoms of hypophosphataemia?
- anorexia, anaemia, muscle weakness, bone pain, rickets and osteomalacia
- general dibility
- increased susceptibility to infection, paresthesia, ataxia, confusion and even death
- skeleton will exibit either rickets in childern or osteomalacia in adults
What happens in rickets and osteomalacia?
- failure of bone mineralisation
- impairment of chondroblasts and osteoblast function
State the bioavailability % of different sources of P:
Plant P (phytates) = absorption rate 40-50%
Animal P (casein) = Absorp. rate 60-70%
Inorganic P (food additives) = Absorp. rate 100%
In what way is inorganic P helping patients with advanced CKD?
can measurably elevate the serum P concentration
high absorp. rate = 100%
What are the effects of hyperphosphotaemia?
- Adjustments in hormonal control system regulating Ca economy
- Ectopic calcification, particularly of kidney
- Increased porosity of skeleton (in some animal models)
- May decrease Ca calcium absorption by complexing calcium (limited evidence)
What are the 3 phosphorus-related genetic diseases?
- X-linked hypophosphataemia
- Hypophosphatemic bone disease
- Fanconi’s syndrome
What is X-linked hypophosphataemia?
Primary inborn error of phosphate transport, probably located in the proximal nephron (Xp22.2-p.22.1)