Vitamin D and Cancer

What do you think of vitamin D as a cancer treatment?

Here’s a link to a Science Daily article.

Vitamin D is well established as an anti-cancer (preventive) treatment, but not yet as an cancer treatment.  In cell cultures, some cancer cell lines respond to increased D levels, but clinical responses have been highly equivocal in humans with cancer (and animals with cancer).

Vitamin D’s effect appears not to be as simple as a switch being thrown.  It takes about two years for the cancer-prevention effects of vitamin D to maximize.  As far as I know, nobody has yet studied massive D loading (50,000IU daily for a month or two) to see if it can be done in 1 year, or 6 months.

In general advice, the Science Daily articles sucks:

1.  “The body not only obtains vitamin D from food, especially milk and fish oils, but also manufactures it from exposure to sunlight.”

Only fortified milk contains a modicum of D.  But to reach 5000 IU dosages, you’d be drowning in milk.  You’d suffer serious osteoporosis and cancer before you’d reach D levels roughly comparable to sun-exposed humans (like lifeguards).   At 400 IU (the dose that the Food and Nutrition Board figures will prevent gross deficiency symptoms), you’d need ten daily doses to reach the level I believe is sufficient for anti-cancer effects.  For people who do not avoid the sun, that’s 4000 IU for white folk, 5000 IU for tanned and slightly darker skinned people, and 6000 IU for dark skinned people, and 7000-8000 IU for well tanned dark-skinned people.  This will result in vitamin D levels of a minimum of 40 ng/dl (?) and more likely 60-90 ng/dl.  (There is also a manomole-units measurement scale which is 2.5 times higher.)

Only raw or low-processed fish oils contain D.  Cod liver oils and filtered fish oils contain D, but distilled fish oils do not.  They contain the fatty acid but not the cholesterol and D components.

It is only the UV-B component of sunlight that results in appreciable D3 synthesis.  In our area, sunlight often is missing its UV-B component.

2.  “Prolonged exposure is not necessary; just 10 minutes in the sun every day when it is not at its peak is sufficient to stimulate its production.”

This is ridiculously optimistic.  The greater thickness of the atmosphere at sea level filters out more UV-B, air pollution components also absorb UV-B, and the increased angle of the sun through the atmosphere also filters out more UV-B (the winter at northern latitudes effect).  But even during the summer, UV-B cannot be detected in the streets of downtown Oakland at high noon on half the days of the summer.  (Not so in San Francisco.)  I think it highly likely that this effect also applies to Silicon Valley, unless you live in the surrounding hills at above the 1000-2000 foot level (depending on whether you are downwind of the valley, or not).  Sun exposure is an unreliable source for vitamin D in most places that Americans live.  And assuming you have pristine sunlight, and near-full nudity, ten minutes is only enough to generate moderate levels of vitamin D3.  To reach protective levels (the highest quartile), you need at least a half hour in a bathing suit.

Synthesis if vitamin D3 is not linear.  The UV not only initiates D synthesis, it destroys D, too.  So the D effect of sunlight is self limiting.

The not-peak comment is baffling.  The UV-B is highest at noon.  So is the UV-A and UV-C, but avoiding the other UV components also avoids UV-B.  So if you are four hours off peak, your chances of getting D are much lower.  Ten minutes at 9AM or 5PM would be a joke.

I suspect that this comment is a misguided attempt to placate dermatologists, who made the wrong call in advising people that sun exposure causes skin cancer and that minimizing sun exposure prevents skin cancer).  In actuality, regular sun exposure decreases your risks of the vast majority of skin cancers, and the most virulent skin cancers.  See for further info if you are interested in digging.  It is only irregular sun exposure that constitutes the risk, especially overt sunburn.  Same with ionizing radiation.  Dental and mammogram x-rays are much more dangerous than living in Denver, despite the massively greater radiation exposure in Denver.

3.  “During the summer, when we are more likely to sunbathe, it is important to use the appropriate protective measures against sunburn to avoid future sun damage.  Use high-factor solar protection products and do not expose the skin to the sun in the middle of the day to protect against skin cancers.”

Oops!  The dermatologists also blew it in recommending sunscreens, which use UV-absorbing organic chemicals (e.g., organic PABA and cinnamate derivatives)  that fragment, rearrange and decompose after absorbing UV to produce strong carcinogens.  These are absorbed through the skin into the underlying dermis to increase (!) skin cancer risks.  The politics surrounding this finding is an interesting example of the bias and corruption in the federal grant system.  BTW, zinc oxide does not have this carcinogenic effect.

I suggest you use clothing (and tanning) to regulate your sun exposure to avoid sunburn.  —Steve

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