Revisiting Vitamin D

I currently take 5000 IU’s of Vitamin D daily and my labs for this are in the upper end of normal range. Given this new study, does this concern anyone and should I stop supplementing with Vitamin D?

See Calcium, vitamin D supplements can affect women's risk of cancer.

I see little reason to supplement with Calcium. Have a healthy diet and you’ll be fine. Having Vitamin D in the higher range, but not over range is sensible, and furthermore adding vitamin K2 MK7 is reasonable in regard to decreasing osteoporosis risk.

There is some data that dairy decreases colorectal cancer, but it also increases risks of other disease (for example prostate cancer), and certainly doesn’t help osteoporosis. Consumption of dairy is inversely proportional to osteoporosis as a society.

This is probably a not useful article - apart from, no reason to take supplemental calcium as it hasn’t been consistently shown to help osteoporosis. Many countries use K2 MK7 for decreasing vascular disease and osteoporosis risk. The evidence seems reasonable.

I usually have folks on that combination, and unless someone has hypocalcemia due to a parathyroid disorder, I cannot recall ever prescribing calcium for outpatient care or routine supplementation and unless new evidence came forth wouldn’t think it a good idea.

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Would you recommend mk7 to someone on an anticoagulant?

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In general warfarin is being used a lot less, and it is only warfarin that we have this interaction with.
I do have patients on warfarin (whom have chosen not to go to a factor Xa inhibitor such as apixiban) who I have on K2-MK7.
However, this is nuanced, as should be the advice to avoid dietary vitamin K when on warfarin.
The important issue is that someone is consistent in what they do whether on vitamin K2 or not, in regard to dietary pattern (if taking vitamin K containing foods, which are generally healthy foods) and get into a steady state with their warfarin dosage with their dietary pattern and intake of vitamin K.

So long as their INR is monitored and warfarin dose adjusted, this is safe. Done blindly, whether suddenly stopping vitamin K containing foods or going on supplements and a higher vitamin K diet, all this needs to be measured and adjusted for. Someone can have a steady state on their INR with consistent behavior and a consistent intake of vitamin K, whether it be a zero intake or a modest intake.

In general, for individuals who have labile INR’s, switching to a newer agent is indicated. In general, a diet low in Vitamin K lacks a number of items with significant health benefits.

If you are on warfarin, obviously a chat with your physician if you were to change your intake of vitamin K whether dietary or supplement would be necessary to assure safety. I’m personally not a fan of the approach of avoidance of vitamin K in these patients - but this has been the dogma.

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If on Pradaxa for example, no INR monitoring involved, then there’s not a concern about vitamin K supplementation in that case?

No concern with direct thrombin inhibitors (like dabigatran - Pradaxa) or factor Xa inhibitors (apixiban/Eliquis or rivaroxaban/Xarelto). Vitamin K doesn’t impact these to any extent. No food-drug-vitamin K interactions are known. So fine to have at it if you are on these drugs!

Killifish vitamin D analog extends lifespan in that vertebrate species +21% males, +7% females.

https://www.science.org/doi/10.1126/sciadv.adi1621

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Yet another guideline saying don’t measure don’t treat

It is really frustrating to have specialty societies put forward yet another guideline saying vitamin D supplementation/testing is nonsense and don’t bother.

As much as I don’t have definitive evidence (due to poorly performed studies) that it is beneficial, there is a whole of evidence that points very strongly to that conclusion.

These specialty groups however, due to the same poorly designed studies, in no way can state that it is of no benefit to test or supplement. Yet, shockingly, they are doing exactly that. If they were sensible, they’d get a properly performed study, first finding people vitamin D deficient, then supplementing them to a therapeutic level based on blood levels and holding them there for years and seeing who happens compared to those on placebo who were deficient.

Not that hard to do - yet that study has never been done. The amount of publications and “studies” on this topic is huge, and yet a simple properly designed study like this hasn’t been done. Seems absurd … but it is true.

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They are for supplementation it seems, just that it should not go above the RDA for certain populations which is 600 IU RDA etc.

The RDA is controversial according to the Linus Pauling Institute and they recommend 2,000 IU a day, with a serum concentration according to observational studies. If we are eating healthy according to guidelines, I believe it would be logically inconsistent not to believe the observational data for Vitamin D and thus a higher RDA.

The Linus Pauling Institute recommends that generally healthy adults take 2,000 IU (50 μg) of supplemental vitamin D daily. Most multivitamins contain 400 IU (10 μg) of vitamin D, and single-ingredient vitamin D supplements are available for additional supplementation. Sun exposure, diet, skin color, and body mass index (BMI) have variable, substantial impact on body vitamin D levels. To adjust for individual differences and ensure adequate body vitamin D status, the Linus Pauling Institute recommends aiming for a serum 25-hydroxyvitamin D concentration of at least 30 ng/mL (75 nmol/L). Observational studies suggest that serum 25-hydroxyvitamin D concentrations between 30 ng/mL and 60 ng/mL are associated with lower risks of adverse health outcomes, including cancers and autoimmune diseases.

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If you take a look at my blog on this topic, the most important is looking at dosing vs. blood levels - here was my summary. A useful study is here - Target D

If you look through the details - 2,000 IU/day was still unlikely to meet targets in the majority of patients, let alone the US RDA. It is important to be aware that a high % of people are deficient - but this is the reason to test - and the figures below are for people deficient.

This trial looked at patients with a low vitamin D level <=20 ng/mL (50 nmol/L) and repetitively tested to understand what dose of vitamin D supplementation would get them to a minimal acceptable level for disease mitigation. The results are interesting. Note that USRDA recommendations at 600-800 IU/day. However, only 13.5% got to >40 ng/mL (100 nmol/L) on <2,000 IU/day, 20.8% did so on 3,000-4,000 IU/day, 51% needed 5,000-8,000 IU/day, and 14.6% required>10,000 IU/day. Additionally, on supplementation, <65% got to the target level by 3 months, and 25% still weren’t at target level after 6 months. So, there is a time factor, and also a need for testing and dose modification. None of these key items were done on prior published trials.
Looking at the studies that showed no effect on outcomes that UpToDate and others are relying on to say don’t supplement, supplemented at <=2,000 IU/day. They also didn’t separate out those deficient or monitor blood levels to show adequate response. It is thus no surprise that we have a lack of evidence for supplementation. The reason is self-evident.

My vitamin D level is 49 from just Florida sunshine and no vitamin D supplementation.

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