Major Minerals Flashcards
Source and intake of calcium?
main source is dairy products and it is added to fortified foods.
Average intake is 1000 mg per day for adults between 19-50 and the average intake does not increase during pregnancy due to increased absorption efficiency. Also the average intake is increased during lactation because of the excretion of calcium in the milk. It can be found in small fish, legumes, and some green vegetables.
Where is calcium found in the body?
It makes 1-2 % of the human body weight and over 99% is found in bones and teeth. The remaining one percent is in intracellular and extracellular fluid.
Roles of calcium?
1.) cell signaling: nerve trasnmission and muscle contraction, release of hormones (inulin)
2.) needed for the coagulation cascade involving vitamin K
3.) regulating glucose degradative pathway
Bone calcium can be mobilised to mainatain this.
How is calcium absorbed ?
It is absorbed by both active transport (vitamin D dependant ) and passive diffusion. Its bioavailability decreases by tannins, fiber, phytates and oxalates and the absorption rates varies with life stage.
How is blood calcium regulated ?
Constantly the ICF and ECF concentrations must be monitored and the important hormones involved with this are parathyroid hormone (PTH) and calcitonin.
What happens if there is a calcium deficiency and its toxicity?
Deficiency:
in the short term there are no symtoms from the loss of calcium in the bones, however, low intake during bone formation results in a lower peak bone mass and low intake in the adult years increases the rate of bone loss.
Toxicity: the excess are usually due to supplements and it may cause the formation of kidney stones, and interferes with the bioavailability of other minerals and causes hypercalcemia and renal insufficiency.
What is osteoporosis?
It is the loss of bone density that is accelerated by the deficiency of calcium. More specifically, it is caused by a loss of the protein matrix and mineral deposits of bone. It is a particular issue with women as oestrogen regulate bone formation.
Where is phosphorus found?
85 % found in bones and teeth and it makes up 1 % of the human body weight. It is also widely distributedd and also found in dairy products.
Role of phosphorus?
- ) major constiuent of DNA and RNA and also ATP and other high energy compounds.
- ) it is involved in the regulatory process of the body
- ) part of the phosphate buffer system
How is phosphorus maintained and controlled?
It is maintained in aration to calcium that allows bone mineralisation. Ratio is 2/1 (2 calcium). It is controlled by vitamin D and PTH which increase and decrease the serum levels of phosphorus.
What is the RDA and how is effected in stages of life?
RDA: 700 mg per day for adults
This requirement doesnt increase:
in pregnancy: increased absorption efficiency
lactation: increase bone resorption and decrease in urinary excretion.
Phosphorus deficiency and toxicity?
Deficiency: Rare and most common in premature infants, vegans, alcoholics, elederly and people who have chronic diarrhea and overuse antacids. It can lead to bone loss, muscle weakness and loss of appetite.
Toxicity: rare and primarily caused by decreased PTH. Excessive intake can lead to bone resorption. Excess can also form crystal deposit of soft tissue with calcium and the increased use of phosphorus containing food addiditives my be a concern. (4 g a day)
What are the electrolytes and what are they for?
They are sodium, chloride, and pottasium. They are important for balancing body fluids and they are essential for nerve conduction and muscle contraction. Na and Cl are found from NaCl which is common in modern diet but pottasium is under ingested in wester diets which can lead to cardiac arythmia and muscle weakness.
Hypertension and electrolytes?
Diets high in salt increase water retention and increase plasma volume and increase blood pressure. Diets high in pottasium, calcium, and magnesium lower the risk of hypertension and increase the Na excretion.
