Calcium-Phosphorus ratio

[dime]

Just to clarify something - most phosphorus in nuts is bound in phytic acid and is not very available as I know.
It's a similar case with egg yolks; around 80% of the P is bound to phosvitin.
Maybe bananas are not good according to that ratio but on the other hand they contain valuable magnesium and other nutrients.
It's not smart to rule in or out foods based on some single measure.
So the food that may be "bad" regarding this ratio is meat, which on this diet is not something you consume in huge quantities.

[dime]

I'm trying to understand why is meat/fish high in phosphorus.
One important process is phosphorylation, which adds/removes phosphate from proteins in order to turn them on or off.
I guess this is the main reason for P in meat, and why liver is so high in P, because it contains so many enzymes.

In order to understand what would be the perfect ratio of Ca/P that you should get from foods
- first you need to know how much you actually digest and absorb into the blood
- and then you need to know the rates of use of both Ca and P
- finally you need to know the threshold of serum levels of Ca, Mg and P that will trigger PTH release
- probably a bunch of other stuff in between

So it's complicated and probably impossible to figure out. What we're doing here is just speculating and guessing..
What we do know is that P is easily excreted in urine, so unless you have kidney problems it doesn't make sense to waste time on this.

[dime]

So why is excessive PTH bad?

Of importance to us I guess is secondary hyperparathyroidism.

The most common causes are vitamin D deficiency (caused by lack of sunlight, diet or malabsorption) and chronic renal failure.

Lack of vitamin D leads to reduced calcium absorption by the intestine leading to hypocalcaemia and increased parathyroid hormone secretion. This increases bone resorption. In chronic renal failure the problem is more specifically failure to convert vitamin D to its active form in the kidney.
..
Symptoms: In secondary hyperparathyroidism the parathyroid gland is behaving normally; clinical problems are due to bone resorption and manifest as bone syndromes such as rickets, osteomalacia and renal osteodystrophy.

[Kasper]

So why is excessive PTH bad?

Well, this is speculation (or maybe not), I don't know much about PTH, but for what I've read, PTH causes a lot of trouble.
In my (maybe simplistic) view, everything that causes mast cell degranulation is a bad thing.
The only reason when they may have a positive role is when the body is attacked by parasites.
But besides that, it only causes hair loss, chronic inflammation, lack of energy, allergy etc. etc. etc.

These results demonstrate that elevated levels of PTH can induce mast cell secretion in vitro and in vivo and suggest a possible role for mast cells in the pathophysiology of non-allergic disease states.

Serum PTH level, but not 25-OH-vit D, is an independent predictor of chronic inflammation. Elevated serum PTH may be associated with increased risk of cardiovascular morbidity in obese adolescents. Further, African American adolescents have an increase in serum PTH at a lower 25-OH-vit D level than other ethnic groups implying negative cardiometabolic risks of higher PTH levels.

Thus, PTH and PTHrP may play an important role in the normal physiology of skin, and their agonists and antagonists have potentially wide therapeutic applications in the treatment of hyperproliferative skin disorders and aging skin and could also be effective in stimulating and maintaining hair growth.

Of importance to us I guess is secondary hyperparathyroidism.

Yes. But secondary hyperparathyroidism is chronic PTH elevation right? I doubt that acute PTH elevation doesn't cause trouble.
Vitamin D is shown to lower PTH, but I think there is more too PTH then only vitamin D.
In a study I read about females (12-18 years), high PTH was rare at vitamin D levels higher than 80 nmol/L.
Still one individual had a PTH of 170 ng/L (normal 10-60) at 80nmol/L vitamin D.
https://docs.google.com/viewer?a=v&q=ca ... oJmKMFDtIg

Another question, what is the optimal PTH level ? Danny Roddy thinks that for hair loss you want PTH as low as possible. I haven't studied the effects of too low PTH tough.

[dime]

This is interesting about the hair connection, I've added to the wiki: http://www.waiwiki.org/index.php/Male_P ... ldness#PTH

It would be interesting to figure out why are there PTH receptors at all in the skin..
How is the emergency to increase calcium levels in the blood (primary role of PTH) related to hair? Is calcium required to make hair?

I think getting a good picture of your PTH levels would be pretty hard, because the hormone has only 4 minutes half life.

[RRM]

I don't know much about PTH, but for what I've read, PTH causes a lot of trouble.
In my (maybe simplistic) view, everything that causes mast cell degranulation is a bad thing.

Thats quite simplistic, indeed.
Its a hormone, which means it has essential functions.
Maybe its most important function is making sure that the blood-calcium level never gets to low,
because that would be lethal. (preventing all muscle functioning)
There are not just PTH receptors in the bones (which acts as a spare calcium depot) and the kidney,
to make sure the right amount of calcium and phosphorus is excreted,
but also in the central nervous system (calcium is essential in neurotransmitter signalling) and the pancreas.
Calcium and phosphate absorption rates in the intestines are also co-regulated by PTH (and vitamin D).

It would be interesting to figure out why are there PTH receptors at all in the skin.

Because its also important to regulate serum calcium levels in the skin.
These receptors are part of that control system.

Is calcium required to make hair?

The scalp is just a part of skin. And the skin needs blood, which needs to contain the right amount of calcium,
for proper cell functioning. Hence the PTH receptors (registration of calcium levels).

[Kasper]

I don't know much about PTH, but for what I've read, PTH causes a lot of trouble.
In my (maybe simplistic) view, everything that causes mast cell degranulation is a bad thing.

Thats quite simplistic, indeed.
Its a hormone, which means it has essential functions.
Maybe its most important function is making sure that the blood-calcium level never gets to low,
because that would be lethal. (preventing all muscle functioning)
There are not just PTH receptors in the bones (which acts as a spare calcium depot) and the kidney,
to make sure the right amount of calcium and phosphorus is excreted,
but also in the central nervous system (calcium is essential in neurotransmitter signalling) and the pancreas.
Calcium and phosphate absorption rates in the intestines are also co-regulated by PTH (and vitamin D).

Okay, I completely agree, I don't think it is wise to suppress PTH when PTH is needed.
My strategy would be to have a diet which make sure your body doesn't need to elevate PTH.
And therefore your body doesn't get the side effects associated with elevated PTH levels.

[RRM]

You mean similar to minimizing insulin secretion,
by eating very small meals very frequently?
That way still insulin is secreted, but minimally.
The same (minimally required secretion) is obtained (regarding PTH)
by consuming lots of juices / fruits and little animal food,
and by not consuming all animal food in one meal if its a more substantial amount.

[Kasper]

What would be a healthy ratio of Calcium:Phosphorus?