2

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Maximizing vitamin D production while getting sun (e.g. dietary cholesterol?)

Answered on August 19, 2014
Created July 23, 2013 at 9:09 PM

I've been getting some sunshine lately, enjoying those vitamin D making rays, but I've been curious if there's any way to make more vitamin D from the same amount of sun exposure.

One possibility that occurred to me is the availability of vitamin D's precursor, 7-dehydrocholesterol (not cholesterol itself as is often stated) might have an effect. I don't know if increasing 7-dehydrocholesterol in the skin would allow for greater vitamin D production, but it makes sense that it might. Because 7-dehydrocholesterol is the last product of the cholesterol synthesis (mevelonate) pathway before cholesterol, it's production is likely lowered the more cholesterol we consume (through a well established ability to induce feedback inhibition). This is the same reason people like Chris Masterjohn have suggested statins (mevelonate inhibitors) might decrease the efficiency of vitamin D synthesis. If we can make 7-DHC from cholesterol itself this doesn't matter, but I haven't seen much to suggest this reverse reaction is very significant.

So could eating a lot of dietary cholesterol lower the rate of vitamin D synthesis by lowering 7-dehydrocholesterol? What else might effect the availability of 7-dehydrocholesterol in the skin? And does 7-DHC in the skin even have a significant effect on vitamin D synthesis?

Moreover, what can be done to maximize vitamin D synthesis when out in the sunshine?

It's a lot of questions, sorry! Thanks in advance for any answers.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on July 25, 2013
at 06:27 PM

Thanks for sharing Dragonfly. I agree with the first article that higher protein diet clearly increase calcium absorption (with plenty of studies showing this), which can help one avoid rickets and hyperparathyroidism, but is it affecting vitamin D levels I wonder? It seems like there are a number of effects of vitamin D, some of which you discuss in your blog post, that might remain unaffected by protein intake. Anyway, interesting stuff.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on July 25, 2013
at 06:16 PM

Interesting NB&S, looks like there could be something to that: http://www.vitamindcouncil.org/blog/washing-away-vitamin-d/

211d4075d68b24cd0aa7ebfa94262bb9

on July 24, 2013
at 02:39 PM

I read somewhere that not washing/rinsing after sun exposure helps to improve vitamin D synthesis.

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on July 24, 2013
at 06:14 AM

Axial- yeah it's why dietary cholesterol generally doesn't affect blood cholesterol (in most people, but not everyone). It's thought to inhibit HMG-CoA reductase, which is well before 7-DHC synthesis (http://www.ncbi.nlm.nih.gov/pubmed/8857917) But statins also inhibit HMG-CoA and I found some studies saying they don't inhibit vitamin D synthesis, so maybe you can make 7-DHC quite easily from cholesterol.

56c28e3654d4dd8a8abdb2c1f525202e

(1822)

on July 24, 2013
at 02:11 AM

You are right. But it is still a small effect, whereas the Vit.D production at midday right now (summer) is orders of magnitude greater than later in the evening.

72cf727474b8bf815fdc505e58cadfea

on July 24, 2013
at 12:39 AM

Is it actually established that consuming more cholesterol causes your body to use that cholesterol, rather than synthesizing its own? If so, then the second question is where in the cholesterol synthesis process the inhibition is applied. If it's applied early on, then there will be less 7-DHC available. If it happens to be applied at the final step, then there will be much more.

72cf727474b8bf815fdc505e58cadfea

on July 24, 2013
at 12:34 AM

The hypothesis is not that dietary cholesterol will increase your blood cholesterol, but rather that eating more cholesterol will cause your body to maintain its proper level using the cholesterol you eat rather than making its own.

782d92f4127823bdfb2ddfcbcf961d0e

(5231)

on July 23, 2013
at 10:26 PM

Interesting question. If 7-DHC does have a significant effect on Vit D synthesis does it matter what latitude you're at?

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2 Answers

1
Ce41c230e8c2a4295db31aec3ef4b2ab

(32564)

on July 23, 2013
at 10:27 PM

Interesting question! I suspect that protein may play a role from reading this article:

http://high-fat-nutrition.blogspot.com/2009/12/vitamin-d-and-uv-fluctuations-2.html

And here's a blog post I wrote on the general topic of optimizing sun exposure:

http://www.sondrarose.com/sun-neglected-nourishment

A2c38be4c54c91a15071f82f14cac0b3

(12682)

on July 25, 2013
at 06:27 PM

Thanks for sharing Dragonfly. I agree with the first article that higher protein diet clearly increase calcium absorption (with plenty of studies showing this), which can help one avoid rickets and hyperparathyroidism, but is it affecting vitamin D levels I wonder? It seems like there are a number of effects of vitamin D, some of which you discuss in your blog post, that might remain unaffected by protein intake. Anyway, interesting stuff.

0
56c28e3654d4dd8a8abdb2c1f525202e

(1822)

on July 23, 2013
at 09:43 PM

I don't see it. Cholesterol is a scam in part because most of it comes naturally from your on liver. Any increase from food is going to be marginal. The only thing that helps is to be out in mid day. You are not making any vitamin if you are sunbathing at 6pm, the rays are absorbed by the much greater travel through the atmosphere.

56c28e3654d4dd8a8abdb2c1f525202e

(1822)

on July 24, 2013
at 02:11 AM

You are right. But it is still a small effect, whereas the Vit.D production at midday right now (summer) is orders of magnitude greater than later in the evening.

72cf727474b8bf815fdc505e58cadfea

on July 24, 2013
at 12:34 AM

The hypothesis is not that dietary cholesterol will increase your blood cholesterol, but rather that eating more cholesterol will cause your body to maintain its proper level using the cholesterol you eat rather than making its own.

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