Nutrition for Healthy Hormones Flashcards
why do we need to advise feeding/diet for hormonal health?
maintain hormonal responses within normal physiological levels
glycaemic response measures what?
measures blood glucose levels
what is the glycaemic response?
a normal physiological process in man and animals
it is simply a rise in blood glucose over time
increase in glucose and the duration of that increase
what causes the glycaemic response?
glucose in the small intestine
what causes glucose in the small intestine?
a meal of easily digestible carbs
what removes glucose from the small intestine?
insulin (hormone secreted from pancreas)
if glycaemic response is not maintained at normal physiological levels - what happens?
will lead to insulin resistance
how do we keep the endocrine response to diet within normal physiological parameters?
meal size: to maintain insulin within normal physiological levels
processing: to increase small intestine digestion of starch
in order to maintain healthy hormones - what do we need to minimise?
minimise changes in glucose and insulin
sources of easily digested carbs are?
cereals (starch)
molasses and syrups (sugar)
what happens to raw/large meals of starch or resistant starch?
it bypasses enzymic digestion and is fermented in large intestine/hind gut
where are cooked/small meals of starch absorbed?
in small intestine
safe starch feeding for preventative nutrition?
maximise glycogen replacement
maximise small intestine digestion
provide some instant energy
keep insulin within normal physiological limits
advise feeding separately to fibre
high glycaemic response?
small intestine digestion of starch is maximised
this is the most efficient uptake of starch into the small intestine
low glycaemic response?
large intestine fermentation of starch
cows - what do minerals influence to do with PTH?
they influence the control of calcium mobilisation before and during lactation
start of lactation - massive demand for?
calcium
can’t increase absorption from the intestine fast enough
cannot mobilise Ca from the bones
we tell farmers to stop feeding calcium three weeks before lactation - no calcium in diet?
cows respond to decreased plasma Ca concentrations by increasing PTH
so cows will improve their ability to absorb Ca as it is not in their diet
increases resoprtion (release) of Ca from bone and renal tubular reabsorption
what does vitamin D help w/ to do with Ca?
increases intestinal absorption of Ca
what affect does PTH have on Ca?
parathyroid hormone increases Ca released from bone
Calcitonin - decreases Ca released from bone
principles of mineral feeding to help calcium mobilisation?
acidify diet
reduce potassium intake
increase magnesium intake
what diet thing increases the incidence of milk fever?
diets high in sodium and potassium
and low in chlorine and sulphur
grass - benefit?
high in potassium
maintains healthy bones and decreases calcium available for lactation
if we reduce potassium - what happens?
grass are the cow equivalent of fruit and veg as high in K
potassium maintains bone health and keeps calcium in bones
needs opposing effect to reduce milk fever
in cows, high K reduces Mg absorption from rumen
increase magnesium in diet - what happens?
protective role of Mg in the pathogeneses of milk fever
Mg is critical for release of PTH
Hypomagnesaemia (low Mg) reduces functionality of PTH
Mg and phosphorus play an important role in Ca in homeostasis
kidney and bone are < repsonsive to PTH
impairs the release of PTH
reduces Ca mobilisation from the bone
on the farm - How do we manipulate diet to maximise mobilisation of calcium to maintain health of the dry cow?
calcium adjustments
acidification of diet
balance minerals
Why do you NOT increase dietary calcium before lactation?
increased dietary intake of Ca means: decrease in the efficiency of intestinal absorption
decrease in Ca mobilisation from bone
need to advise reduction in Ca to maximise absorption and mobilisation of calcium before lactation
uptake is maximised at lactation when dietary Ca is increased
how do we ensure max absorption of calcium after birth
increase Ca in diet AFTER birth to ensure maximum absorption
why do we acidify diet to change the structure of the parathyroid hormone?
improve calcium mobilisation
adjust dietary cation and anion balance (DCAB)
in order to check levels of Na and K - what do we need to do?
need to calculate the balance between acid and base using the equation below:
* (Na+ + K+) - (Cl-+ S2-) meq/100g DM
* Cations – anions
what do you need to do in order to balance minerals in diet?
reduce potassium
ensure adequate magnesium intake
how do we minimise risk of milk fever and hypocalcaemia?
increase magnesium - supplement with 40g Mg (or 70-80g MgCl)
decrease potassium - replace grass with maize silage, wholecrop or straw
limit Ca to 30-50g in last 3 wks before calving
what is milk fever caused by?
caused by abrupt increase in Ca requirements at start of lactation
needs 10x more calcium for milk than is in serum
blood calcium moves into milk
low blood calcium (hypocalcaemia) takes place in the days around calving
for what percentage of lactating are dairy cows pregnant for? (unique to dairy cows)
70% of the time lactating
describe the mammary gland of a dairy cow for the last two months of pregnancy?
mammary gland remains nearly fully developed during the last 2 months of pregnancy when the cow is not milked (dry cow)
due to genetic engineering, dairy cows produce more milk than needed in order to?
to feed her offspring
twice-a-day milking removes how much milk?
removes large volume of milk in a short time frame ( -10 min) in a cow whereas other animals (incl. humans) lose small amount frequently - so steady rather abrupt loss
how do you reassure that calcium deficit is short term?
cows remain in negative Ca balance for the first 6-8 weeks of lactation
as lactation continues: feed intake of the cow increases, so intestinal tract increases in size compared to non-lactating cow, elevated 1,25(OH)2D3
Cow can now absorb enough Ca to meet her needs for lactation and replace skeletal Ca lost during early lactation
when cows remain in negative Ca balance for the first 6-8 weeks of lactation - what happens to the skeleton of the cow?
skeleton loses roughly 13% of its total Ca content during this period
summarise what needs to be done in order to mobilise calcium - help with calcium absorption:
Increase PTH release
reduce urinary Ca losses
Stimulate bone Ca reabsorption
Increase 1,25(OH)2D3 synthesis
Enhance the active transport of Ca in the intestine
how can we mobilise calcium? - give brief answer
by manipulating the diet at specific times during the lactation cycle
what is 1,25(OH)2D3?
it is the active form of vitamin D
what is 1,25(OH)2D3 important for?
it is an important regulator of bone metabolism, calcium + phosphate homeostasis
how does potassium affect PTH receptor?
high potassium (K) increases alkalinity so changes shape of PTH receptor
high K reduces Mg absorption from rumen
how does Mg affect PTH?
Low Mg reduces functionality of PTH
what does DCAB stand for?
dietary cation anion balance
other than potassium and magnesium, what else has an effect on PTH?
DCAB - dietary cation anion balance
In normal Mg acidotic conditions - what happens (with cAMP, PTH etc.)?
PTH released in response to hypocalcaemia and interacts with its receptor (found on surface of bone + kidney cells) in a lock and key fashion
What happens (with cAMP, PTH etc.) in normal Mg alkalotic conditions (high K)?
high potassium diets indue a change in the shape of the PTH receptor protein so that it is less able to recognise and bind PTH
what happens (with cAMP, PTH etc.) in a low Mg environment?
Mg is required for full function of the adenylate cyclase complex
low Mg (hypomagnesaemia) reduces ability of PTH stimulated cells to produce cyclic AMP resulting in failure to activate the cell
what two minerals play an important role in Ca homeostasis?
magnesium and phosphorus
protective role of Mg in the pathogeneses of milk fever?
Mg is critical for release of PTH & synthesis of 1,25(OH)2D3
what does hypomagnesaemia (low Mg) result in?
in reduced functionality of PTH
kidney and bone are less responsive to PTH
impairs the release of PTH and reduces Ca mobilisation from the bone
Acidification changes the balance between dietary cations and anions (DCAB) - what does this mean?
it increases mobilisation of Ca from bone
and increases absorption of dietary Ca by increasing plasma 1,25(OH)2D3 concentrations
if you manipulate diets by increasing anions, what does this result in?
results in an increase Cl and S anions (chlorine and sulphur)
Decrease of Na and K in order to maintain health and reduce/prevent the risk of milk fever disease
mobilise calcium from bones
high protein diets induce…
induce metabolic acidosis
what influences parathyroid hormone control of calcium mobilisation before and during lactation?
minerals
