You may need more Vitamin D than you think.

May 17, 2007 4:19 PM

New research suggests that taking vitamin D, preferably D3, may prevent up to half of the cases of breast cancer and two-thirds of the cases of colorectal cancer in the United States. Vitamin D3 is produced by your body when your skin is exposed to sunlight. (You can also get it from fatty fish, egg yolks, fortified milk and other products, and supplements. D3 supplements are usually produced from lanolin, so vegans will prefer D2.) This doesn't mean you should stop wearing sunscreen entirely - white people exposed to summer sunlight in a bathing suit will produce all the vitamin D they need in only 15 to 20 minutes, while darker-skinned people will need longer exposures (which might explain why black men have a higher incidence of prostate cancer). Health Canada now recommends all adults over the age of 50 take a daily vitamin D supplement of 10 micrograms (400 IU), and, because "vitamin D synthesis in the skin is absent during the winter months (October to March)," they note that Canadians (and, one assumes, other people in northern climates) must rely on dietary intake of vitamin D to maintain adequate levels of vitamin D in the body.
posted by joannemerriam (26 comments total)

But don't take too many vitamins.
posted by euphorb at 4:23 PM on May 17, 2007

Not exactly new information, although perhaps not widely publicized - the study's co-author, Cedric Garland, has been promoting vitamin D3 as a cancer-prevention method since at least 1990. He's done similar meta-analysis studies before, claiming similar results (for example, Garland CF, Garland FC, Gorham ED, Lipkin M, Newmark H, Mohr SB, Holick MF. The role of vitamin D in cancer prevention. Am J Public Health. 2006 Feb;96(2):252-61.)

I'm not really competent to judge how accurate his findings are, but among those who think them true, D3 is thought to fight cancer by increasing cancer cell apoptosis (the damaged cell self-destruct mechanism), reducing metastasis and proliferation, inducing cell differentiation, reducing angiogenesis (the growth of new blood vessels from pre-existing ones, a fundamental step in the transition of cancerous tumors from a dormant state to a malignant one), and enhancing calcium absorption and regulating parathyroid hormone (both of which protect against colon cancer specifically as part of a complex series of signaling events affecting the organization of colon cells.)

If you do take vitamin D supplements, though, be careful - vitamin D is fat soluble and you can overdose on it if you take it orally, which can have nasty effects. Vitamin D produced through sunlight exposure, I have heard, tends not to have that problem, because the sunlight starts destroying excess vitamin D after an equilibrium point is reached.
posted by kyrademon at 4:45 PM on May 17, 2007

Doctors promoting sun exposure have been ostracized, including losing hospital privileges, which is among the most severe punishments for a doctor. Yet, they are right. All things in moderation however. Really, the Earth is not flat and it does not revolve around the sun.
posted by caddis at 5:01 PM on May 17, 2007

Weston A Price has been pounding the Vitamin D table since the 1930s. His studies of healthy native diets around the world found D intakes 10 times or more greater than modern diets. Vitamin D plus Vitamin A and Vitamin K2 (K2 is called the "Price Factor" or "Vitamin X") are the main components of traditional native diets.
posted by stbalbach at 5:11 PM on May 17, 2007

Lanolin... like sheeps wool?
posted by ageispolis at 5:28 PM on May 17, 2007

I just had a full blood analysis done and was shocked to find that I had a mild Vitamin D deficiency, especially since I drink more milk (fortified, of course) than pretty much anyone else I know over the age of 18, I get regular sun exposure, and I take both fish oil and a multivitamin every day. I didn't know about the cancer connection though...now maybe I'll actually take the Vitamin D I was prescribed.
posted by nekton at 5:52 PM on May 17, 2007

Can I get the same health benefits by bathing in the glow of my CRT monitor for 16 hours a day, or am I fucked?
posted by BrotherCaine at 6:22 PM on May 17, 2007 [2 favorites has favorites]

I've heard that vitamin D, and folic acid, are the two big winners in terms of measurable benifits.
posted by StickyCarpet at 6:25 PM on May 17, 2007

First, we are warned about sun exposure. Then breast feeding mothers are told that their milk might not have enough vitamin D for their children, because they don't get enough sun to produce our own.

It is my experience with Science and Medicine, that there are more than enough beloved pronouncements, to go around.

The Sun sets our internal clock, people all over the world, shut indoors have solar affective disorder. Now they see that cancer thrives without Sun generated Vitamin D.

So if a photo sensitive species such as ours, climbs under a rock and doesn't come out now and again, there are dire consequences.

The snake oil megacorporations abound, offering estrogen identical slather for children's skin to protect from Sun exposure, Vitamin D enriched milk, Vitamin D in pill form, anti depressants, infant formula, and countless lotions and other potions, to give us what 15 minutes of Sunlight would create, or prevent.

We need our Ozone, our sunlight, clean water and air, fruits and vegetables, whole grains, range fed red meat, and a host of things that are abundant and cheaper than drugs, and that add to a rich and lovely life.
posted by Oyéah at 7:33 PM on May 17, 2007

range fed red meat

I was with you until that... what's so great about red meat?
posted by phrontist at 7:48 PM on May 17, 2007

Man, fifteen to twenty minutes of sun exposure in the summertime here would make me toast. Burn time is generally ten minutes, and is not exaggerated. Still, I'm not in the US but instead the melanoma capital of the world.
posted by shelleycat at 7:48 PM on May 17, 2007

Really, the Earth is not flat and it does not revolve around the sun.

Noted.
posted by weapons-grade pandemonium at 8:28 PM on May 17, 2007

joannemerriam, Excellent, well researched and informative post. Thank you very much!

A year ago the head of Sloan Kettering came on morning TV news and stated how essential it is to prevent cancer to get additional vitamin D, especially for all the people who sit behind computers most of their lives.

It impressed me how serious he sounded about the importance of vitamin D. It's a rare experience for me hearing doctors telling people to take vitamins, especially because neither before, after chemo and radiation was I told to take any vitamins and warned not to take any not to take any vitamin other than the cheapest generic multi one during treatment.

Sometimes I feel swamped when I try to find stuff on Google and love it when somebody makes a post which condenses a lot of info into a manageable chunk of learning. Your post is the best researched and well organised collection of info on the subject of sun/sunscreen/vitamin D and cancer I've found. Much appreciated.
posted by nickyskye at 9:12 PM on May 17, 2007

Shelleycat, most sunbathing advocates stress that skin type, latitude, altitude, time of day, air pollution, and other factors all be taken into account when creating a sunbathing program. Depending on where you live, they would probably suggest that you try to get your sun early in the morning, when you are much less likely to burn, and stay out of it at least between about 10 AM and about 2 PM.
posted by kyrademon at 10:57 PM on May 17, 2007

Yeah, I was surprised these articles (caveat: I only read some some far) didn't mention that as they usually do. I guess this is cos they were aimed at the US. But even early morning sun burns in NZ in the summer, there is no safe exposure limit for us palefaces.
posted by shelleycat at 12:47 AM on May 18, 2007

nickyskye, thanks!

All, sorry, I should have noted the 15-20 min thing was from a US article.

One of the articles I read (but, of course, couldn't find again) noted that skin cancer is the most easily treatable of cancers and avoiding the sun to avoid it is counterproductive if it means the incidence of these other, harder-to-treat cancers goes up. But I think I'm going with the cancer society recommendation of continuing to be aware and wearing sunscreen when the sun's at its most direct, and I will probably start taking a vitamin D3 supplement (not a multivitamin though as I think I eat fine - just not enough of vitamin D-source foods to make up for living in New Hampshire and working indoors all day).
posted by joannemerriam at 3:27 AM on May 18, 2007

Lanolin... like sheeps wool?
posted by ageispolis at 8:28 PM on May 17

I was surprised too. Apparently they expose it to sunlight and then somehow chemically remove the D3 that the sheep's fat produces.
posted by joannemerriam at 3:29 AM on May 18, 2007

Man, I knew it.

We're all gonna die.
posted by chillmost at 3:41 AM on May 18, 2007

I was with you until that... what's so great about red meat?
Red meat's blood is good for your blood.
posted by joecacti at 4:20 AM on May 18, 2007

First, we are warned about sun exposure. Then breast feeding mothers are told that their milk might not have enough vitamin D for their children, because they don't get enough sun to produce our own.

People like to over-react. What? I shouldn't bask in the sun until I turn the color of liver? Oh. I better stay in this cave then.
posted by Kid Charlemagne at 5:39 AM on May 18, 2007

exposed to summer sunlight in a bathing suit

Swimsuits are for Republicans, dude.
posted by ZenMasterThis at 6:34 AM on May 18, 2007

NIH Vitamin D Fact Sheet.
List of all NIH fact sheets.
posted by joecacti at 11:12 AM on May 18, 2007

I've heard that vitamin D, and folic acid, are the two big winners in terms of measurable benifits.

There is a problem with getting health information through hearsay and innuendo. joecacti's link to the NIH fact sheet pretty well sums the state of knowledge up (note the last sentence):

Vitamin D and cancer:
Laboratory, animal, and epidemiologic evidence suggests that vitamin D may be protective against some cancers. Epidemiologic studies suggest that a higher dietary intake of calcium and vitamin D, and/or sunlight-induced vitamin D synthesis, correlates with lower incidence of cancer [44-51]. In fact, for over 60 years researchers have observed an inverse association between sun exposure and cancer mortality [33]. The inverse relationship between higher vitamin D levels in blood and lower cancer risk in humans is best documented for colon and colorectal cancers [44-50]. Vitamin D emerged as a protective factor in a study of over 3,000 adults (96% of whom were men) who underwent a colonoscopy between 1994 and 1997 to look for polyps or lesions in the colon. About 10% of the group was found to have at least one advanced neoplastic (cancerous) lesion in the colon. There was a significantly lower risk of advanced cancerous lesions among those with the highest vitamin D intake [52].

Additional well-designed clinical trials need to be conducted to determine whether vitamin D deficiency increases cancer risk, or if an increased intake of vitamin D is protective against some cancers. Until such trials are conducted, it is premature to advise anyone to take vitamin D supplements for cancer prevention.

My own research involves randomized trials of both folate and vitamin D in colorectal cancer, and so far neither has been shown to reduce it. Folate may actually accelerate the promotion phase of carcinogenesis, so be wary of supplementation that hasn't been rigorously proven to be effective.
posted by Mental Wimp at 4:48 PM on May 18, 2007

One of the articles I read (but, of course, couldn't find again) noted that skin cancer is the most easily treatable of cancers and avoiding the sun to avoid it is counterproductive if it means the incidence of these other, harder-to-treat cancers goes up.

My recent post grad lecturers, world renowned experts in melanoma treatment, would be very surprised to hear that. Cos, yeah, bullshit. Or at the least a gross over simplification (as per usual from the media). If it's caught in time then sure, you can treat it easily enough. But that's difficult to do and you don't know if it was caught in time straight away, and by the time you do know (or by the time it's caught not in time) then a not-very-slow, painful death is your next option.

Again,. things are different here. The damage to the ozone done world over migrates here, plus some other climatological stuff happens to make sure our UV levels are high. So basically, make sure the advice you're taking is aimed at your location and listen to your local experts rather than random stuff from the internet.
posted by shelleycat at 1:00 AM on May 19, 2007

shelleycat

Although melanoma is as deadly as your lecturers indicate, it is pretty rare compared to basal and squamous cell skin cancer, both very easy to treat and slow growing. I've had the latter, (on an unexposed portion of my skin) and it was simply cut out after I had had it for three years.

To the point, the choice between sun-based vitamin D and no skin cancer is a false dichotomy. Moderate amounts of sun exposure are not going to noticeably raise the risk of melanoma but will increase vitamin D levels significantly.
posted by Mental Wimp at 8:21 AM on May 19, 2007

First Reaction: Michael Moore’s Sicko is “brilliant and uplifting”
posted by homunculus at 11:51 AM on May 19, 2007