calcium Flashcards
how many g of calcium is in the bones, rest of body and in total
bones - 1185g
rest- 15g - 7 in teeth, 7 outside, 1 inside cells
total - 1200g
how many g of phosphorus is in bones, rest of body and total in body
bones - 600g
rest - 100g
total - 700g
how many g of magnesium is in bones, rest of body and total in body
bones - 15g
rest - 12g
total - 27g
what form does calcium occur in, in the environment and body
occurs as calcium carbonate in the environment ; occurs as calcium phosphate in the body.
what does regulation mean in terms of calcium
that plasma Ca cannot be used as a measure of calcium status.
calcium is required for the homeostatic control of what
of the absorption, excretion, secretion, and deposition – parathyroid hormone (PTH); 1,25 (OH)2 D3; calcitonin
To ascertain nutritional status requires what
complex measurements of bone mineral content and/or density
explain relationship between calcium intake and absorption
The efficiency of absorption of Ca is higher at low intakes
At low intakes, more Ca is lost in the faeces than is taken in the food; calcium is secreted in the intestinal juices.
on a typical diet the net proportion of calcium absorbed is
25-30% of the intake.
what are the 2 routes that calcium can be absorbed by in the intestine
Transcellular – active, calbindin-dependent, vit D regulated
Paracellular – passive, concentration-dependent.
what can calcium absorption be improved by
– lactose
– amino acids
– casein
– low Ca intake
– ingestion with a meal
– pregnancy
– lactation
what can calcium absorption be reduced by
– long chain fatty acids but only with fat malabsorption
– phosphate but only in excess
– phytate from bran
– oxalate
– vit D deficiency
– menopause, old age
– intestinal disease
in bones and teeth the calcium and phosphorus form crystals of what with what kind of structure
crystals of hydroxyapatite, Ca10(PO4)6(OH)2, form the rigid structure.
from 15mg/kg/d of calcium in food how much is lost as waste
11mg/kg/d as feaces
4mg/kg/d as urine
explain the process of calcium secretion
15mg/kg/d is in taken of calcium in food, this goes to intestine where 7mg/kg/d is absorbed to a calcium pool. 4mg/kg/d is used in bones which is turnover (so same come out of bones). 3mg/kg/d of the calcium in the calcium pool goes into digestive juices back into the intestine. the calcium pool then moves to the kidney where 4mg/kg/d of calcium is lost in urine
and 11mg/kg/d of calcium is lost from the intestine through faeces
explain the relationship between growth rate and calcium
Higher the rate of growth the higher need of calcium
so is why very young children/ babys need lost calcium
explain bone mineral content and calcium between men and women
Bone mineral density peaks between 25-30years. From this point, it’s a progressive decline from that peak
Males are more muscular and are bigger so bigger bones and so their bone mineral density peaks higher than the peak for females.
Males calc doesn’t decline at same rate as women
Osteoporosis is more common in elderly females than males. Stopping them from possibly being able to walk without bones breaking.
Physical activity and diet prevent this rapid bone mineralisation decline
in Britain how much calcium on average is lost from urine and skin
daily urinary losses of 150 mg are found
with 10 mg/d lost from the skin.
Assuming that 30% of calcium is absorbed from mixed British diets, it is suggested that about how many mg/d is needed on average, with no allowance for difference in sex.
525 mg/d
what are the RNI in UK for adults, male and females between ages (11-18) and during lactation
Adult RNI: 700 mg/d
higher levels are set for 11-18 year olds:
Male RNI: 1000 mg/d
Female RNI: 800 mg/d
(Lactation: +550 mg/d)
can we get calcium from sources other than dairy and calcium
yes
but where low intake of milk calcium theres also a low intake of total calcium
does skimming milk take away calcium content
no
describe calcium content in soft and hard cheese
Softer the cheese the less calcium , so harder cheeses have more calcium. But is variable
name some high calcium sources that are dairy products
cows milk,
human milk
skimmed milk
cheddar cheese(made with rennet)
yoghurt
butter
cottage cheese
name some high calcium sources that are non dairy
baking powder
self raising flour
white flour
wholemeal flour
meat, offal
fish
hard water- found more in south england
Hard water can form a scum on the top , due to its high levels of calcium
Amount of calc in water varies massively and depends on its location
the USA has tolerable upper intake of calcium why
Because of high Ca intakes from supplements can lead to
nephrolithiasis (kidney stones)
hypercalcaemia
renal insufficiency
reduced absorption of Fe, Zn, Mg, & P
what is the safe upper intake value for calcium
2500 mg/d
