Sunshine? Did they get it wrong?

[marko]

Most didn't live nearly that long in those days (graph below). Perhaps this impression exists because we know/have heard of only the "oldsters" who lived a long time.

My impression is likely flawed as I live near a cemetery from the early 1700's. Every other person buried there is 70 or 80 it seems.

I do know of one of my own ancestors from 1743 lived to be 84 and his wife was 89 but maybe they were aberrations.

 

[TromboneAl]

I always wondered how our species survived and got this far along without sunscreen.

Seems that after a couple million years we should have adapted to those harmful rays. I live in Florida half the year; never used sunscreen in all my life. I only get tan(ner) and have never had a sunburn...genes.

DW is a fair Irish, so.......I get that it's different.

If humans die of cancer only *after* their childbearing and childrearing ages, the species can't adapt.

 

[Boho]

People need to have more respect for well known, generally respected media and government agencies, not the two websites linked to in this thread. I didn't even click them. In articles I trusted that covered this issue over the last several years there were estimates of the amount of sun you should be getting to reduce the risk of cancer and they were pretty low. Like 10-20 minutes. I forgot whether that was per week or daily. If I had a history of skin cancer and my doctor said to use sun screen and a hat whenever I go out, I'd think that's reasonable unless I read something I found convincing that's to the contrary, and those websites wouldn't convince me of anything even if I visited them.

 

[GrayHare]

I never use sunscreen, I get a lot of sun, and I have had low vitamin D levels for years. Over the past 2 years, I've doubled the amount of vitamin D drops and my vitamin D levels haven't budged. I've increased sun exposure to no avail. None of my bloodwork benchmarks seem to be affected by diet, exercise or supplements.

The situation you describe can be caused by certain infections. I'd guess your 1,25D level is indeed responding but your doctor is mistakenly retesting 25D. Get 1,25D tested, after all that supplementation it might be dangerously high.

 

[Ronstar]

The situation you describe can be caused by certain infections. I'd guess your 1,25D level is indeed responding but your doctor is mistakenly retesting 25D. Get 1,25D tested, after all that supplementation it might be dangerously high.

Thanks - I’ll look into it.

 

[TromboneAl]

In articles I trusted that covered this issue over the last several years there were estimates of the amount of sun you should be getting to reduce the risk of cancer and they were pretty low. Like 10-20 minutes.

This site is fun and surprising:

https://fastrt.nilu.no/VitD-ez_quartMED.html

It calculates how much sun exposure you need for a healthy dose of Vitamin D.

 

[jollystomper]

This site is fun and surprising:

https://fastrt.nilu.no/VitD-ez_quartMED.html

It calculates how much sun exposure you need for a healthy dose of Vitamin D.

Neat! I just did early morning yardwork in the sun for 2.5 hours. This told me I needed 1.1 hours for my healthy dose. Now I can stay inside and goof off the rest of the day.

 

[RAE]

This site is fun and surprising:

https://fastrt.nilu.no/VitD-ez_quartMED.html

It calculates how much sun exposure you need for a healthy dose of Vitamin D.

According to Harvard Medical School, you basically can't get any Vitamin D from the sun above the 37th parallel, except during the summer months.

"Except during the summer months, the skin makes little if any vitamin D from the sun at latitudes above 37 degrees north (in the United States, the shaded region in the map) or below 37 degrees south of the equator. People who live in these areas are at relatively greater risk for vitamin D deficiency."

 

[braumeister]

According to Harvard Medical School, you basically can't get any Vitamin D from the sun above the 37th parallel, except during the summer months.

I am extremely skeptical of that statement.
Can you provide the source of it? I tried to look it up but found nothing besides that unsupported claim.

 

[RAE]

The chart and quote came from this Harvard Health newsletter:


https://www.health.harvard.edu/staying-healthy/time-for-more-vitamin-d

 

[braumeister]

The chart and quote came from this Harvard Health newsletter:
https://www.health.harvard.edu/staying-healthy/time-for-more-vitamin-d

Yes, I saw that, but it cited no published study or rationale for the claim. I want to know where they got that idea.

 

[MichaelB]

Yes, I saw that, but it cited no published study or rationale for the claim. I want to know where they got that idea.

A web search turned up this https://www.ncbi.nlm.nih.gov/pubmed/2839537 It looks like the original thesis, based on a model, not actual measurement.


Edit to add - not a thorough search, and I'd rather have a study that did actual measurements. We chuckle at many of the hypotheses of yesteryear.

 

[RAE]

Most peer-reviewed medical journal articles I have read seem to agree that it is best to keep your 25-hydroxyvitamin D blood level at or above 30 ng/mL, for optimum health. It's easy and inexpensive to get that blood test done........most insurance companies will cover it. Seems prudent to me to have this test done once in a while to see what your Vit. D status is........then you can go from there with regard to whether you should increase your sun exposure, and/or take a Vit. D supplement. Just my opinion, YMMV.

Here is one meta-analysis that looked at all-cause mortality and Vit. D blood levels.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103214/

 

[braumeister]

A web search turned up this https://www.ncbi.nlm.nih.gov/pubmed/2839537 It looks like the original thesis, based on a model, not actual measurement.

Even that says there is only a partial issue above 52 degrees (a long way from 37).

Also see https://www.westonaprice.org/vitamin-d-problems-with-the-latitude-hypothesis/

I'm not saying the claim is entirely wrong; just that it seems extremely far-fetched.

 

[RAE]

Even that says there is only a partial issue above 52 degrees (a long way from 37).

Also see https://www.westonaprice.org/vitamin-d-problems-with-the-latitude-hypothesis/

I'm not saying the claim is entirely wrong; just that it seems extremely far-fetched.

There is quite a bit of information online about the effect of latitude on Vitamin D absorbtion. Here is another article, and a passage from the article explaining why people in northern latitudes do not get much, if any Vitamin D from the sun during the winter months:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897598/


Factors that Influence Cutaneous Vitamin D3 Synthesis

Zenith Angle

Only about one percent of solar UVB radiation ever reaches the earth’s surface even in the summer at noon time.38 The reason is that all of the UV C (200–280 nm) and all of the UVB radiation up to approximately 290 nm is efficiently absorbed by the stratospheric ozone layer.38,39 In addition the ozone layer absorbs approximately 99% of the UVB radiation with wavelengths 291–320 nm. Therefore increasing the path length by which solar UVB has to travel through the ozone layer will result in a decrease in the number of UVB photons that reach the earth's surface (Fig. 22).40 This is the explanation for why during the winter when living above and below approximately 33° latitude very little if any vitamin D3 can be produced in the skin from sun exposure. People who live farther North and South often cannot make any vitamin D3 in their skin for up to 6 mo of the year.41 For example in Boston at 42° North essentially no vitamin D3 can be produced in the skin from November through February. Inhabitants living in Edmonton Canada at 52° North, Bergen Norway at 60° North, or Ushuaia Argentina at 55° South are unable to produce any significant vitamin D3 for about 6 mo of the year (Figs. 23 and ​and2424).2,39,41

 

[braumeister]

Except during the summer months, the skin makes little if any vitamin D from the sun at latitudes above 37 degrees north

in Boston at 42° North essentially no vitamin D3 can be produced in the skin from November through February.

Not quite the same thing.

 

[RAE]

Not quite the same thing.

True, but the basic point is that you are not going to get a whole lot of Vitamin D from the sun for several months of the year if you live in northern latitudes. If you are unsure just how much you are getting, have a Vit. D blood test done, and then you'll know where you stand, and whether you need to take any action to boost your levels.

 

[Boho]

Still, your chances of getting Nonmelanoma skin cancer (NMSC - the most commonly occurring cancer type in the Caucasian population) generally increase with latitude (according to the below article), despite the extra vitamin D you're getting. It sounds like only melanoma skin cancer (MSC) can be prevented with good vitamin D synthesis.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5431270/

An inverse association was observed between NMSC and latitude in males and females, as observed at 18°S in Arica and 36°S in Concepción (Fig. 2C); thus rates decreased as latitude increased...

It can be concluded from these studies that there is a direct correlation between NMSC rates and mortality with UVB radiation, meaning that this type of cancer would not depend on vitamin D synthesis and therefore on calcium uptake; by contrast, MSC rates increased with decreased levels of vitamin D and thus calcium uptake in all cities, with the only exception being Punta Arenas.

But:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689397/

Results: Recreational sun exposure was a risk factor for melanoma on the trunk (pOR = 1.7; 95% CI: 1.4–2.2) and limbs (pOR = 1.4; 95% CI: 1.1–1.7), but not head and neck (pOR = 1.1; 95% CI: 0.8–1.4), across latitudes. Occupational sun exposure was associated with risk of melanoma on the head and neck at low latitudes (pOR = 1.7; 95% CI: 1.0–3.0). Total sun exposure was associated with increased risk of melanoma on the limbs at low latitudes (pOR = 1.5; 95% CI: 1.0–2.2), but not at other body sites or other latitudes.

 

[Boho]

Still, your chances of getting Nonmelanoma skin cancer (NMSC - the most commonly occurring cancer type in the Caucasian population) generally increase with latitude (according to the below article), despite the extra vitamin D you're getting.

Wait, I think got part of that backwards...the article is what I mean, not my words.

 

[RAE]

Still, your chances of getting Nonmelanoma skin cancer (NMSC - the most commonly occurring cancer type in the Caucasian population) generally increase with latitude (according to the below article), despite the extra vitamin D you're getting. It sounds like only melanoma skin cancer (MSC) can be prevented with good vitamin D synthesis.

Yes, but nonmelanoma skin cancer is MUCH less life-threatening than melanoma. 75% of NMSC cases are basal cell carcinomas, which rarely if ever spread (metastasize) to other parts of the body. The other 25% are typically squamous cell carcinoma, which can infrequently metastasize, but it's still far less serious than melanoma. Melanoma is the skin cancer that is most likely to kill you, as it is much more likely to metastasize, making treatment difficult.

Of course, no one wants to develop either type of skin cancer, but since there is some evidence that getting adequate sun exposure (without burning the skin), and the Vitamin D you are getting from that sun exposure, actually decreases your chances of developing melanoma, I certainly have no concerns about getting a reasonable amount of sun exposure.

 

[daylatedollarshort]

I've always been wary of chemicals and wanted to get vitamin D naturally so avoided sunscreen most of my life. I'd only use it on myself and our kids when they were younger if we went some place like snorkeling in Hawaii in winter so so we could be out all day without getting burned.

 

[Jerry1]

I’m in the camp of using sun screen mainly to prevent burning. Main activity I use sunscreen for is golf. Otherwise, I just wear a hat and sometimes long sleeves. As for burning, being from Michigan, when I go to see my brother in Florida, I wear sunscreen most of the time. That sun is much different than our Michigan sun and I don’t want to ruin a trip by getting sunburn. I did that once. Once was more than enough.

 

[JoeWras]

According to Harvard Medical School, you basically can't get any Vitamin D from the sun above the 37th parallel, except during the summer months.

Thank goodness I'm at 36 degrees. I'm safe. Yippee!

 

[JoeWras]

Still, your chances of getting Nonmelanoma skin cancer (NMSC - the most commonly occurring cancer type in the Caucasian population) generally increase with latitude (according to the below article), despite the extra vitamin D you're getting. It sounds like only melanoma skin cancer (MSC) can be prevented with good vitamin D synthesis.

It's a balance, right? A balance between the good vitamin D, and the bad exposure. I made some fun about my current life at 36, but in all seriousness, I lived at 26 for a while and I can tell you it is brutal for a fair skinned person. I'm paying for it today with removals of AK lesions, and a constant awareness of my skin.

But here's the weird thing, FOOT melanoma is fairly common and deadly. Why? Why isn't "wrist" melanoma common? Most of the time our feet are covered. And dark skinned people get melanoma in the feet too (Bob Marley, for example).

I had a good friend die at age 50 from what they thought was foot melanoma. His first symptom was swelling in the groin. It was way too late by then. The pathologist said it was melanoma, yet he and his doctors never found the actual original lesion. They just assume it was his foot, because that is a fairly common hidden source.

 

[Music Lover]

Even that says there is only a partial issue above 52 degrees (a long way from 37).

Also see https://www.westonaprice.org/vitamin-d-problems-with-the-latitude-hypothesis/

I'm not saying the claim is entirely wrong; just that it seems extremely far-fetched.

And of course, many of us who live up north make up for the lack of sun exposure in winter by getting a lot of it in summer during our 14 - 16 hour days.

In the long run most of us probably get enough and it's likely not very different from those who avoid the sun during the brutally hot and humid summer months in the south.