Do dietary calcium and vitamin D matter?

[pjoshea13]

New French study below.

There are "convincing" studies going back at least 20 years that associate excess calcium intake with aggressive PCa. "Convincing" in the sense that avoidance of high levels of calcium from dairy &/or supplements has become common PCa advice.

Perhaps less known is the mechanism by which excess calcium might increase risk.

25-D, the inactive form of vitamin D, is converted to the active form, as needed, by various tissues in the body, including those of the prostate. In that context, the active (hormonal) form, 1,25-D, is subject to autocrine control - the conversion of 25,D to 1,25-D by one enzyme, triggers the production of a second enzyme that will clear 1,25-D from the cell. There is thus a window of opportunity for the hormone to do its stuff.

PCa down-regulates the first enzyme & upregulates the second, so that cancer cells make less (or no) 1,25-D & clear it faster.

Fortunately, the kidneys create 1,25-D & put it into the circulation where PCa cells have access to it. The kidneys do this in response to a dip in serum calcium. They do not do this when calcium levels are elevated.

From the new paper: "the results of a preclinical study from our own group demonstrate that a diet high in calcium dose-dependently accelerated the progression of early-stage prostate tumours and that dietary vitamin D prevented this effect."

1,25-D has several roles in calcium homeostastis, with the basic sequence being (a) osteoclastic activity releases calcium from bone, (b) calcium uptake from the gut is increased, & (c) calcium is drawn from the blood as osteoblastic activity rebuilds bone.

The French study suggests that chronic elevation of blood calcium only happens with 25-D insufficiency coupled with high calcium intake.

{Not mentioned is the importance of vitamin K to calcium transport to bone.}

The term "dietary calcium" is a little vague. What is an unsafe level with poor 25-D status? What is the upper safe level with good 25-D status?

How much "dietary vitamin D" was required to negate risk?

I have often wondered why a high intake of calcium would lead to high blood levels? Blood calcium is otherwise highly regulated. Might more calcium be taken up when there is osteopenia or osteoporosis? Perhaps low 25-D levels can be sufficient to get calcium into the blood in those conditions, but not into bone?

-Patrick

ncbi.nlm.nih.gov/pubmed/297...

Nat Rev Urol. 2018 May 15. doi: 10.1038/s41585-018-0015-z. [Epub ahead of print]

Do dietary calcium and vitamin D matter in men with prostate cancer?

Capiod T1, Barry Delongchamps N1,2, Pigat N1, Souberbielle JC1,3, Goffin V4.

Author information

1

Inserm Unit 1151, Institut Necker-Enfants Malades (INEM), Université Paris Descartes, Paris, France.

2

Urology Department, Hôpital Cochin, Assistance Publique Hôpitaux de Paris, Paris, France.

3

Physiology Department, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, Paris, France.

4

Inserm Unit 1151, Institut Necker-Enfants Malades (INEM), Université Paris Descartes, Paris, France. [e-mail].

Abstract

Active surveillance (AS) is an attractive alternative to immediate treatment for men with low-risk prostate cancer. Thus, the identification of environmental factors that promote the progression of indolent disease towards aggressive stages is critical to optimize clinical management. Epidemiological studies suggest that calcium-rich diets contribute to an increased risk of developing prostate cancer and that vitamin D reduces this risk. However, the potential effect of these nutrients on the progression of early-stage prostate tumours is uncertain, as studies in this setting are scarce and have not provided unambiguous conclusions. By contrast, the results of a preclinical study from our own group demonstrate that a diet high in calcium dose-dependently accelerated the progression of early-stage prostate tumours and that dietary vitamin D prevented this effect. The extent to which the conclusions of preclinical and epidemiological studies support a role for calcium and vitamin D and the relevance of monitoring and adjustment of calcium and/or vitamin D intake in patients on AS require further investigation.

PMID: 29765146 DOI: 10.1038/s41585-018-0015-z

[RJ-MN]

I wonder if there is a difference between early stage and late stage as to the influence of calcium on CPa. When mine went metastatic to the bones in 2009 my excellent primary care doc put me on 2 large calcium tablets a day (morning/evening) that contained Vit D3 as well. He also added a monthly Vit D2 @ 50,000 units. I've stayed with this regime, and no Mayo or NIH oncologist has questioned it. Somewhere along the line I was given the idea that the dairy ban had more to do with growth hormones and epithelial stimulants of some sort rather than fear of calcium.

Living with these mets for 9 years now, which have always continued to glow in their uptakes but no (yet) spread, I'm hesitant to change standing routine. But maybe I've been feeding them all along?

[pjoshea13 in reply to RJ-MN]

The knee-jerk reaction to bone loss is to load the patient up with calcium - as though the patient must have a calcium-deficient diet. At least doctors now realize that vitamin D is essential too. & maybe vitamin K will soon get the same recognition.

My understanding is that the only prescription form of vitamin D in the U.S. is D2 - mushroom D. It is not bioidentical to D3 nor is it as bioavailable. The Vitamin D Council considers it to be undesirable. You might consider taking the human form, which might even save you some money:

lifeextension.com/Vitamins-...

(2 month supply).

It is true that IGF-I in dairy makes it very undesirable. However, its contribution to total calcium intake is also significant.

[1] (2001)

"At baseline, men who consumed >600 mg Ca/d from skim milk had lower plasma 1,25(OH)(2)D(3) concentrations than did those consuming < or =150 mg Ca/d"

"1,25(OH)(2)D(3)" ... i.e. lower 1,25-D

[2] (2006)

"Our findings suggest that calcium intakes exceeding 1,500 mg/d may be associated with a decrease in differentiation in prostate cancer and ultimately with a higher risk of advanced and fatal prostate cancer but not with well-differentiated, organ-confined cancers."

...

The new French study suggests that a sufficiency of vitamin D removes the apparent risk from high calcium intake, so I wouldn't be overly concerned. However, there is no need to take more calcium than the body needs.

And, as covered in an earlier post, there is PCa benefit in combining with magnesium.

& Nalakrats will maybe remind us of his mineral combination for bone health ...

-Patrick

[1] ncbi.nlm.nih.gov/pubmed/115...

[2] ncbi.nlm.nih.gov/pubmed/164...