Minerals and Bone Health Flashcards
minerals are inorganic elements. t or f
t
can minerals be destroyed?
NO, they are very stable, cannot be destroyed by heat, oxygen or acid
what is the main difference between minerals and trace elements?
minerals are needed in amounts greater than 100mg/day (make up more than 0.01% of body wt), whereas trace elements are needed in a much smaller amount of less than 100 mg/day (make up less than 0.01% of body wt)
can minerals be lost?
yes (ex, if you remove skin from a veggie, minerals in the skin will be lost”
what do supplements provide?
a source of single or multiple minerals
can minerals prevent the absorption of others?
yes (ex, calcium can prevent absorption of iron)
can minerals serve as cofactors for enzymes and help stabilize molecules?
yes (don’t change just stabilize)
minerals provide structure and support such as bone and teeth. t or f
t
can also serve a regulatory function in the body
what is the process of mineral cofactors binding?
- the mineral cofactor combines with the incomplete enzyme to form the active enzyme
- the active enzyme binds to the molecules involved in the chemical reaction (compounds A an B) and accelerates their transformation into the final products (products A an B)
- The final products are released, while the enzyme remains unchanged
what are all the main minerals in the diet?
calcium, phosphorus, magnesium and sulfer
what food products are good sources of calcium?
canned fish, fruits, veggies and plant based proteins
when does passive transport occur in calcium?
primarily when calcium intake is high
(does not require ATP)
when happens in active transport of calcium?
-vitamin D triggers expression of a calcium transporter in the mucosal cells
-leads to more calcium absorbed from dietary intake
(requires ATP)
what is the process of vitamin D brings more calcium into bloodstream?
- vitamin D turns on the synthesis of calcium transport proteins
- calcium transport proteins shuttle calcium across the mucosal cell
- a calcium pump that requires energy moves calcium from the mucosal cells to the bloodstream
what percentage of calcium do infants absorb?
60%, they absorb extra
what percentage of calcium do young adults absorb?
25%
why do older adults have decreased calcium absorption?
low levels of vitamin D
why is calcium absorption decreased in women post menopause?
because of low estrogen levels
how much calcium is absorbed in pregnancy?
50% because estrogen levels are higher
what is the main function of calcium?
necessary in promoting blood clotting
where is most calcium in the body stored?
99% in the bone, 1% in the rest of the body is critical
what are the main functions of calcium?
-regulates muscle contraction
-important for BP - decreased BP (regulating contraction of blood vessels)
-regulates enzyme activity
what are the 2 hormones that regulate blood calcium levels?
calcitonin and parathyroid hormone
which hormone is expressed when blood calcium levels are high?
thyroid gland releases calcitonin, this triggers storage of calcium
- deposits calcium and rebuilds bone structure
calcitonin acts on the kidneys to do what?
prevent them from retaining calcium allowing it to be excreted
which hormone is expressed when blood calcium levels are low?
parathyroid gland releases the parathyroid hormone
- breaks down the bone to bring calcium back into the blood
- results in activation of vitamin D, can increase absorption in the kidneys
what happens to calcium absorption without vitamin D?
increase reuptake in kidneys and increase breakdown of bone
what is the purpose of osteoblasts?
bone deposition, builds the bone
what is the purpose of osteoclasts?
break down bone tissue to release calcium (bone resorption)
bones are broken down overtime and re build to maintain calcium levels. t or f
t
which bone does calcium mainly get stored?
trabecular bone (spongy)
- high SA
what does calcium deficiency result in?
loss of bone mass/density
what can occur with calcium toxicity?
-kidney stones (formed from calcium oxalate or calcium phosphate)
-can interfere with iron, zinc, magnesium and phosphorus absorption
how does osteoporosis occur?
results from loss in the protein matrix and calcium deposits in the bone
which bone is most likely to develop osteoporosis?
trabecular bone
- at higher risk to lose density and fracture later in life
osteoporosis is responsible for what percentage of fractures in ppl over age of 60?
80%
what influences osteoporosis?
-age
-gender
-hormone levels
-genetics
-exercise
-smoking an alcohol use
-diet
are men or women more susceptible to osteoporosis?
women
- men have better bone mass
- bone loss is accelerated 5 years post menopause
where is most phosphorus stored?
85% of phosphorus is in bone and teeth
phosphorus makes up 1% of human body weight
what is phosphorus typically found as?
found bound to O2 as phosphate
is it common or rare to be deficient in phosphorus?
rare
where is phosphorus readily available?
GI tract
- 60-70% of dietary phosphate is absorbed
Phosphate is part of which molecules in the body
-Phospholipids (cell membrane)
-ATP (adenosine triphosphate, energy)
-Creatine phosphate (energy)
-Phosphorylation of proteins (activates/deactivates proteins)
-RNA/DNA
-Regulation pH within a cell
deficiency in phosphorus is rare but can lead to what?
bone loss (bone is broken down to maintain blood levels)
Toxicity is also rare in phosphorus but can lead to:
increased bone resorption
how many g of magnesium is in an adult human?
25 g
magnesium is a component of what? and is mainly found in which food?
chlorophyll
leafy greens (and whole grains and seeds)
what percentage of magnesium is absorbed in the diet?
50%
can vitamin D increase magnesium absorption?
yes, slightly
high dietary calcium can decrease magnesium absorption. t or f
t
what percentage of magnesium is in the bone?
65%
- helps to maintain structure
Magnesium help stabilize structures in molecules such as
ATP
magnesium is a cofactors for how many enzymes?
> 300 enzymes including the sodium-potassium ATPase pump
magnesium is important for which processes?
DNA, RNA and protein synthesis
how do kidneys regulate magnesium levels?
by controlling excretion in the urine
what are magnesium deficiencies linked to?
osteoporosis, heart disease
how can toxicity occur with magnesium?
from supplementation or in those with impaired kidney function
how is sulfer obtained?
from organic molecules such as sulfur containing amino acids and vitamins and some inorganic food additives
when is there a deficiency with surfer?
when protein needs are not being met
What are the sulfer containing amino acids
Methionine, cystine
What are the sulfer containing vitamins
Thiamine, biotin
