Vitamin D prevents cancer: American Journal of Clinical Nutrition
- 06-10-2007, 04:18 PM
Vitamin D prevents cancer: American Journal of Clinical Nutrition
Vitamin D prevents cancer
By Ben Wasserman-foodconsumer.org
Jun 10, 2007 - 9:37:28 AM
Taking vitamin D supplements may drastically reduce risk of a number of non-skin cancers including breast cancer, colon cancer and lung cancer in older women; suggests a new study, which appears in the June 8, 2007 online edition of the American Journal of Clinical Nutrition.
The study, conducted between 2000 and 2005 by researchers from Creighton University School of medicine in Nebraska, found that women who used both high doses of calcium and vitamin D3 were actually 60 percent less likely to acquire a non-skin cancer than those who did not get the vitamin.
"The findings are very exciting. They confirm what a number of vitamin D proponents have suspected for some time but that, until now, have not been substantiated through clinical trial," said Joan Lappe, Ph.D., R.N., principal investigator of the trial, professor of medicine at Creighton. "Vitamin D is a critical tool in fighting cancer as well as many other diseases."
In the study, researchers followed 1,179 healthy, postmenopausal white women age 55 or older from rural eastern Nebraska. They were assigned into three groups with one given 1400 to 1500 mg of calcium per day, second one given 1400 to 1500 mg of calcium plus 1100 international units of vitamin D3 and the third one a placebo.
During the course of the study, 50 participants developed nonskin cancers, including breast, colon, lung and other cancers.
The women had been cancer-free for at least ten years before entering the study. Considering that women may have undiagnosed cancer one year before the study, the researchers considered only the data derived after the first 12 months of the study and found that the reduction in cancer risk was even more significant, 77 percent, compared to those who were not given vitamin D3.
The three-year analysis also showed that there was no statistically significant difference in cancer incidence between women on placebo and those taking calcium supplements only, suggesting calcium does not have an effect of cancer prevention.
It is not known if the findings resulting from a group of Caucasian women age 55 or older are applicable to other groups with a different sex, age, and or ethnic background. Lappe said further studies are needed to clarify.
The current findings differ from some early studies. In a recent study, Jennifer Lin, Ph.D. from Brigham and Women's Hospital and Harvard Medical School, Boston and colleagues followed 10,578 pre-menopausal and 20,909 postmenopausal women age 45 and older who were enrolled in the Women's Health Study. They found those who had highest intake of vitamin D were 34 percent less likely to develop breast cancer in the pre-menopausal women, but no association between the two was found among postmenopausal women.
The researchers explained that "Calcium and vitamin D exert anticarcinogenic effects on breast cancer cells expressing high levels of IGF-1 and IGF binding protein 3. Calcium, vitamin D and IGF binding protein 3 have been shown in vitro to interact with each other in promoting growth inhibition in breast cancer cells." The postmenopausal women were not affected by vitamin D because production of IGF-1 and IGF binding protein 3 declines as women get older.
The results, published in the May 28, 2006 issue of Archives of Internal Medicine, were observational and should be considered less reliable than what was found in the current trial.
Early studies have found that high vitamin D in the blood seems important when it comes to cancer prevention. A study, led by Dr. Carlo Palmieri, of Cancer Research UK Laboratories and Imperial College, London and colleagues and published in the Oct. 2006 issue of the Journal of Clinical Pathology, found that women with early stage breast cancer had higher levels of vitamin D in their blood than those who had advanced breast cancer.
Another study by Edward Giovannucci from Harvard School of Public Health and colleagues who followed up black Americans for an association between vitamin D status in the body and the incidence of cancer showed the total cancer incidence among African Americans with a poor vitamin D status was 57 percent higher, and total cancer mortality 127 percent higher. The results were published in the Dec. 2006 issue of the journal Cancer Epidemiology Biomarkers & Prevention.
The current trial has drawn some attention from organizations that have high stakes in the cancer business. Some experts, as claimed, said the study is not big enough to have a reliable result. Some who praised the study disagreed, however, saying that the size of the study could be big enough to win FDA approval of a drug for marketing in the U. S.
Len Lichtenfeld of the American Cancer Society, a group that is close liaison with the medical industry as critics has alleged, was cited by webmd.com as saying in a statement that the society "is not recommending that individuals routinely increase their vitamin D intake based on this report."
He explained, as quoted, “Past experience has shown that, despite studies that suggest a particular vitamin or drug may be effective in reducing cancer risk, once that theory is subjected to a well-designed clinical trial the results frequently do not hold up.”
Dr. Michael Holick, a long time vitamin D researcher and professor of Medicine, physiology and biophysics at the Boston University, was quoted by healthday.com as saying of the Lappe study that "It's very clear the data are significant."
A scientist affiliated with foodconsumer.org, who did not want to be named, said that it could be unwise not to use vitamin D as a huge body of evidence has merged to say this vitamin not only protects against cancer, but many other diseases as well.
To say the least, this nutrient is a safe vitamin as recognized by health authorities who agree that the upper tolerance of this vitamin for adults is 2000 international units or IU. Harvard University professor Edward Giovannucci earlier suggested that to have an anti-cancer effect, one should use about 1500 IU of vitamin D daily.
Some researchers who spent much of their lifetime studying vitamin D have said that the current recommended daily allowance (RDA) by the government is dangerously low, 200 IUs for people age 50 or younger, 400 IUs for those aged between 51 and 70 inclusive and 600 IUs for those who are older than 70 . They recommend the government to raise the RDA for vitamin D to at least 1000 IU.
The low RDA for vitamin D has drawn criticism. Mike Adams, a noted natural health advocate affiliated with newstarget.com, said in a latest article on vitamin D and cancer that the recommendation of low doses of vitamin D indicates that the government does not want people to get protected against cancer and other diseases.
Regardless, the evidence on the protective effect of vitamin D against cancer is strong enough for people to take action. Both animal and epidemiological studies suggest that high intake of vitamin D may help prevent or even treat cancers including lymphoma, colon, prostate, skin, and lung cancer, in addition to a wide spectrum of other conditions including high blood pressure, fibromyalgua, diabetes mellitus, multiple sclerosis, and rheumatoid arthritis.
One early study of 456 patients with early stage lung cancer treated between 1992 and 2000 found that among those who received surgery during the summer, the 5-year survival rate was 70 percent, compared to 54 and 56 percent for those who received surgery in the winter and spring (or fall), respectively. The researchers suggested the apparent protective effect may come from high levels of vitamin D in the blood, which resulted from high exposure to sunshine during the summer.
The cancer survival rate was 83 percent among those who had the high vitamin D intake and received surgery during the summer, compared to 46 percent for patients who had low vitamin D intake and received surgery in the winter.
The study was conducted by David Christiani, M.D. and colleagues from Harvard University, Massachusetts General Hospital, Dana-Farber Cancer Institute, Brigham and Women’s Hospital and Harvard Medical School. The results were presented April 18, 2005 at the 96th Annual Meeting of the American Association for Cancer Research in Anaheim, California.
Scientists have now known that there is a physiological basis for the protective effect of vitamin D against cancer. In the case of vitamin D versus prostate cancer, one study by Yi-Fen Lee, Ph.D., an assistant professor of Urology at University of Rochester Medical Center has already found that vitamin D suppresses the progression of prostate cancer by reducing the activity of two enzymes, proteases called matric metalloproteinease and cathepsin, which would otherwise help cancer cells invade healthy cells. The results were published in the January 2006 issue of Carcinogenesis.
Not all studies lead to discovery of a positive association between use of vitamin D and reduced risk of cancer. In the Women's Health Initiative Calcium with Vitamin D trial involving 36,000 healthy postmenopausal women age 62 or older who either received 1,000 milligrams of calcium carbonate along with 400 IU of vitamin D3 or a placebo, researchers found that overall there was no association between taking the vitamin D/calcium supplements and incidence of colorectal cancer. The results were reported in the Feb.16 2006 issue of the New England Journal of Medicine.
But some factors may affect the outcome of the study. For instance, the 7-year follow-up is not long enough to follow up risk of colorectal cancer as it takes ten to 20 years to develop colorectal cancer. One most possible reason for the negative association is that the dose of vitamin D used in the study is way too low, as pointed out by some critics. In addition, about 20 percent of subjects did not take the supplements regularly and participants were allowed to use bisphosphonates and calcitonin during the study, and half of the subjects were taking hormone therapy, all these would have an impact on the risk of colorectal cancer.
When it comes to prevention of colorectal cancer, one previous five-year study involving more than 120,000 people, conducted by McCullough ML, Robertson AS, Rodriguez C, et al. and published in Cancer Causes Control 2003;14(1):1-12, found that men with the highest vitamin D intakes had a risk of colorectal cancer that was 29% lower than men with the lowest vitamin D intakes.
Previous studies have also found the serum level of 25(OH)D level- an active form of vitamin D, which reflects vitamin D intake and vitamin D synthesis, was inversely associated with the risk of potentially precancerous colorectal polyps, according to a study published in Cancer Epidemiol Biomarkers Prev. 2001;10(12):1267-1274, and indices of colonic epithelial cell proliferation, which are considered biomarkers for colon cancer risk, according to another study published in Cancer Epidemiol Biomarkers Prev. 2002;11(1):113-119.
In spite of some inconsistency, there is no doubt that vitamin D is more than likely to play a significant role in the cancer prevention. Those who are concerned about their health should pay attention to this long-ignored vitamin. The best way to have vitamin D is exposure to sunshine. Fatty fish is also a good source for vitamin D. Vitamin D supplemented foods such as milk and juices can be considered, but less desirable.
- 06-11-2007, 09:35 AM
I hope somone can chime in here, but in any way can this imply that high IGF-1 and IGF binding protien 3 expression increase the risk of cancer in men??
06-11-2007, 09:58 AM
06-11-2007, 10:19 AM
06-11-2007, 01:53 PM
Thanks for clearing that up man, i guess i just freaked when i read that little bit... My father just passed away a month ago from cancer..it was sudden, so cancer is a big enemy of mine at the moment.
06-11-2007, 02:04 PM
Basicallly, they are saying that D3 interacts with IGF-1 and IGFBP to inhibit cancer, but yes..IGF-1 as well as HGH will grow tumors faster but they are not mutagenic in and of themselves.
Interestingly, on the whole, those who have higher levels of testosterone, DHEA and IGF-1 have longer lives. If you have a deficiency in one of those hormones..it ups your risk or mortality by a lot. A deficiency in two of the above ups your risk of death by lots and lots...so they are are not to be feared, but monitored and balanced out if necessary.
06-11-2007, 06:18 PM
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