Your takeaway summary would be appreciated...

A place to get your questions answered from McDougall staff dietitian, Jeff Novick, MS, RDN.

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Your takeaway summary would be appreciated...

Postby Doug_ » Wed Feb 03, 2021 10:21 am

Jeff,

Years ago I looked over your analysis of some of the more controversial issues, and I spent the time to look at the body of studies in question, to parse through what was meaningful, significant, and relevant to already-healthy people eating and living well. I did so to determine if you could be someone I could generally trust, since I do not usually have the time to go as in depth in a field that is not my expertise. For many reasons you established yourself as the least biased, most thorough, most realistic and level headed dietary and lifestyle research expert.

Could you give me your take on something that I am having trouble coming to my own conclusions on?

I've followed the thread on the vitamin D consensus now and then without studying it too hard. But I know that you have. I'm a little confused. It seems like the consensus is that vitamin D supplementation does not seem to help anyone in any way except maybe some extreme edge cases. At the same time, it seems that keeping vitamin D to a certain level is best. I seem to recall that achieving that adequate level (20 ng/ml if i remember) though, even primarily via supplementation, might be advisable. If supplementation is the primary route someone wants to go to assure that level, is that going to do any good for them, or no?

I know that adequate but minimal midday sun exposure is your typical preference, but I want to ask about that confusion about supplementing.
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Re: Your takeaway summary would be appreciated...

Postby JeffN » Wed Feb 03, 2021 1:16 pm

Good question. I do not have an answer for you but I will mention some things from the thread for you to think about...


1) First issue is testing...

- I am not sure why we have such widespread testing or that it is even good. Most who are being tested are not in an “at risk” group, which is an issue I raised long ago with my supplement recommendations

https://jeffnovick.com/RD/Q_%26_As/Entr ... ments.html

- There are also some serious concerns about the Vitamin D testing/supplement industry in general

viewtopic.php?f=22&t=20770&#p587796

viewtopic.php?f=22&t=20770&#p587803



2) Second issue is recommended blood levels...

- it seems that 20-30 may be the goal, with going over 35 a concern and that as low as 12-15 may be fine.

viewtopic.php?f=22&t=20770&#p370369

viewtopic.php?f=22&t=20770&#p299916

(there are more references to these values in my thread but these 2 will get you going.)



3) Third issues is sources...

- sunlight is the best source, it doesn't take much and has many other benefits. We can also store it and don’t have to have it year round.

- If sunlight is not available, there is a FDA approved Vitamin D lamp by Sperti.

- if those are not enough, and a need exists, then any other recommendation would be individualized based on current level, desired level and source of vitamin D. If supplementing is chosen, then one must monitor blood levels and we get back to issue number 2. Also, while supplementing can raise blood levels, we really don't know if it is effective as sunlight.


When we consider the first two issues, the third becomes almost moot.

In Health
Jeff
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Re: Your takeaway summary would be appreciated...

Postby Doug_ » Wed Feb 03, 2021 2:33 pm

Thanks very much Jeff. This is very helpful.

JeffN wrote:while supplementing can raise blood levels, we really don't know if it is effective as sunlight.


It's almost as if we don't have the full picture of everything involved in human metabolism and supplementing a single hormone might not stand in well for all the known and unknown ways sunlight gets taken advantage of by the body ;)

As you know, the concern for many is that different types of ionizing radiation in sun rays do a lot of DNA damage, including double strand breaks, which can raise concern about the risk/benefit, and whether we can get the same benefits without the risks.

But as you said, it doesn't take much.

For anyone else reading, cells are equipped to handle constant DNA damage from many sources, and only seem to run into trouble when it becomes too much too quickly to repair well. Surely the damage from brief exposure over a sufficient amount of skin to minimize the time needed to be adequate is something the DNA repair mechanisms can handle. Nothing is perfect, you can't eliminate risk, and sunshine is far from the only source of damage. Contrasting with typical radon exposure and other sources of DNA damage though, at least we know sunshine is good for us in many ways.
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