A positive report about vitamin D: Works a lot better than the low fat diet!


Vitamin D Appears to Cut Breast and Colorectal Cancer Risk


February 12, 2007 — Researchers say that raising vitamin D levels may prevent up to half of all breast and two thirds of colorectal cancer cases in the United States. Based on the results of 2 separate studies, the investigators recommend a daily intake of 2000 IU of vitamin D3 and, when possible, moderate sun exposure.

"The results are pretty straightforward," Karen Glanz, PhD, director of Emory University's Prevention Research Center at the Rollins School of Public Health in Atlanta, Georgia, said in a news release. However, changing behavior on the basis of these studies may be premature, she noted. The analyses found an association between vitamin D levels and lowered risk, not a definite link, Dr. Glanz said, but adding vitamin D to the diet or taking a supplement would probably not do much harm and there could be a benefit.

Lead author Cedric Garland, DrPH, of the University of California at San Diego, agreed that future consensus is needed, but he recommended no delay in raising vitamin D levels. "We shouldn't hold up implementation," he said. "Inadequate photosynthesis or oral intake of vitamin D is associated with high incidence and mortality rates of breast cancer."

Published in the January 30 Article in Press issue of the Journal of Steroid Biochemistry and Molecular Biology, the researchers pooled dose-response data from 2 previous studies — the Harvard Nurses Health Study and the St. George's Hospital Study. They found that patients with the highest blood levels of 25-hydroxyvitamin D had the lowest risk for breast cancer.

Dr. Garland and his team divided the more than 1700 records in the studies into 5 groups from the lowest blood levels of 25-hydroxyvitamin D (< 13 ng/mL) to the highest (approximately 52 ng/mL). These data also included whether the patient had developed cancer.

The investigators found that patients with serum 25-hydroxyvitamin D of approximately 52 ng/mL had a 50% lower risk for breast cancer than those with serum measuring less than 13 ng/mL. This level corresponds to a vitamin D intake of 4000 IU per day, which exceeds the National Academy of Sciences upper limit of 2000 IU per day. "Leading researchers are building a case to have this level increased," Dr. Garland said, "but in the meantime, we are recommending a daily intake of 2000 IU."

The group is also calling for an additional 10 to 15 minutes of daily sun exposure when appropriate — an amount estimated to be equivalent to an oral intake of 3000 IU of vitamin D3.

But What About the Risk for Skin Cancer?
The American Academy of Dermatology has voiced concern about the vitamin D literature prescribing the health benefits of sunlight. "While many health issues are complex and involve multiple factors, we know that ultraviolet light is the primary cause of skin cancer, and avoiding excessive exposure to the sun and other forms of ultraviolet radiation is the solution," Clay Cockerell, MD, president of the academy said in a news release.

Dr. Garland emphasized that his group is advocating prudence and moderation, including the use of a broad-brimmed hat. "I think most physicians will see this as a well-controlled and reasonable approach," he added.

The article points out that sun exposure is inadvisable for patients with primary photosensitivity disorders, people taking photosensitizing medications, and anyone with a personal or close family history of skin cancer or actinic keratosis.

Evidence Stacking in Favor of Vitamin D
Dr. Garland was also a coauthor of a second study examining the effect of vitamin D levels on colon cancer risk. Published in the February issue of the American Journal of Preventive Medicine, the researchers conducted a meta-analysis of 5 studies examining serum 25-hydroxyvitamin in colorectal cancer.

The investigators combined the findings of the 5 studies using standard methods for pooled analysis. There were 535 cases and 913 controls or 1448 participants in total. The researchers divided the results into quintiles with median 25-hydroxyvitamin values of 6, 16, 22, 27, and 37 ng/mL.

Previous studies had shown that lower blood levels of vitamin D did not protect against colorectal cancer, but in the current study, the researchers came to a different conclusion. "Through this meta-analysis we found that raising the serum level of 25-hydroxyvitamin D to 34 ng/mL would reduce the incidence rates of colorectal cancer by half," lead author Edward Gorham, MPH, PhD, a research epidemiologist with the Naval Health Research Center in San Diego told reporters. "We project a two-thirds reduction in incidence with serum levels of 46 ng/mL."

The amount of dietary vitamin D needed to reach the serum levels that appear to be protective against colorectal cancer — 1000 to 2000 IU per day — would not pose any risk, Dr. Gorham said. "The Institute of Medicine has set a 'No Adverse Effect Level' of 2000 IU per day for vitamin D intake, so this recommendation would be safe for most people."

J Steroid Biochem Mol Biol. Published online January 30, 2007.

The journal is at http://www.elsevier.com/locate/jsbmb

The reference at the end of the initial post is not to the journal article but to a review at a location not stated. The article can be found by going to
http://dx.doi.org/10.1016/j.jsbmb.2006.09.014

Unfortunately, the abstract is totally missing what might be the most useful information, we don't know if it was even studied: what is the correlation between vitamin D levels in blood and *all* forms of cancer? What would be the effect of sun exposure to get vitamin D? Would one simply be trading breast or colorectal cancer risk for skin cancer?

As we see all too often, further study is needed, it would seem.

In the other direction, if most of us heed the advice to avoid direct sunlight, would we simply be trading cancer risk in the other direction.

Science does research and *somebody* jumps to conclusions and we get public recommendations that some years later turn out to be harmful. Like avoid saturated fats. And that advice is still continually repeated, even though there is no evidence, apparently, correlating butter intake with heart disease.... beyond the original defective epidemiological study that triggered it all.

From what I have read, and maybe Zuleikaa can add to this, it is NOT exposure to the sun that determines risk for melanoma, but it is the amount of DAMAGE to the skin from the sun. That is, people that have had lots of sun burn incidences have a greater risk than those that have longer exposures but do not allow themselves to get burned. Rather those people have taned gradually, allowing the skin to form the natural protection built into most of us. In those people, they also get the added protection of the natural Vitamin D their body is made to produce.

I don’t have the references, but there are some good studies that show a strong relationship with elevated Vitamin D and reduced prostate cancer.

Abd, I agree with your points. The sunlight risk seems to be a bit over-hyped, but tough to prove either way. Supplements may be safer, and a lot easier to study.

If vitamin D can really cut the risk of colon and breast cancer in half, with no risks, we all should be taking it. But who will do a good interventional long-term randomized placebo-controlled study of vitamin D? The NIH?

It's not as if the NIH isn't willing to spend money. The women's health initiative (which included vitamin D), has already wasted 1/2 billion dollars of taxpayer money, and is spending another 18 million on 12 new studies of the WHI population, looking at:

adipokines, exercise, estradiol and estrogen metabolism, proteomics, genomics, trans-fats!, NSAIDS, minority fracture rates, and ancestry informative markers (AIMS) in DNA samples-whatever they are.

http://www.eurekalert.org/pub_relea...a-na1012907.php

Vitamin D just isn't sexy and there's no money in it.

The original WHI showed no benefit to Vitamin D supplementation WRT colon cancer, but they only used 400 IU of vitamin D, in a population in which 70% of women were already taking vitamin D supplements.

The risk of melanoma actually has an inverse relationship with sun exposure.

The other skin cancers are caused by sun damage, i.e., burning from the sun. These cancers are not life threatening and can even be removed/healed by further safe exposure/vitamin D generated via the sun.

I get awfully depressed if I don't get enough sun exposure. I sunblock my face, neck and hands, i.e. the areas that receive most sun, but in winter have to let my arms and legs get sun every few days to ward off /treat depression.

I'll have to find it again, but they were showing that the rates of cancer that are prevented by adequate sun exposure well exceeds the very few cases of skin cancer.

Personally I can't take the sun exposure, I'm on a drug that makes me photosensitive (Sulfasalazine), so I take 4,000 iu of D a day, that's probably what... 5 minutes of full body sun exposure at noon for a person of scottish descent? Hopefully I can get off the drug someday and get back into the sun.

There's an awful lot of evidence building up that our minimum requirement is probably somewhere round 2000-4000 iu and our RDA falls way, way short of that. Combine that with the fact that probably a lot of people aren't properly absorbing dietary D, or are taking the wrong sort.

Maybe LC FD can answer a question for me. The sun is not out every day even in summer. So if one gets a good hit of sun on a particular day, but not on two other days, will Vit D average out overall? In other words, does one have to have daily input of D, or can one just take some sun one day, take some supplements on others and it all averages out?

I will take a try at answering your question. Vitamin D is a fat soluble vitamin so it will be stored in the fat cells when there is a excess. Then released as needed so it should average out.

That Vitamin D is stored in fat, is one of the reasons that Eskimos can survive in the Arctic where they could never get enough sun exposure on their skin to make what they need. So their Vitamin D comes from the fat of the animals they eat.

Here is a web page on fat soluble vitamins. http://www.faqs.org/nutrition/Smi-Z...at-Soluble.html
Not sure if it is totally accurate on the toxicity of Vitamin D.

I also question this statement;
“alpha-tocopherol is the only one to have vitamin-E activity in the human body” (It is the one most studied by researchers.)

But at least it gives the list of fat soluble vitamins and how they are stored in the body.

Here's a good lecture about D3 (warning long): http://www.insinc.com/onlinetv/dire...tvnetplayer.htm

I think he goes into the blood levels of D3 in N. America/Canada versus what is found in indiginous people near the equator.

Remember I'm a doctor and I don't know a dam#ed thing about nutrition.