Vitamin D and Cancer

A report issued earlier this year (available on Medscape once you register) on Vitamin D levels in breast cancer, identified low levels of this nutritional factor as a risk for breast cancer. Dr. Kristin Skinner reported at the American Association of Breast Surgeons, that the most aggressive forms of breast cancer (i.e. ER negative, triple negative or basal-like) were associated with lower blood levels of vitamin D.

This is one of many reports associating vitamin D levels with disease. Indeed, so many reports on this topic have been published that vitamin D consumption in the U.S. has exploded. While some physicians have made careers promoting the concept, the science of vitamin D is indeed credible and very interesting.

What is vitamin D? Well, although we refer to it as a vitamin, it is, in fact, a hormone. It is obtained from the diet or from exposure to sun. The most potent form of vitamin D is that associated with sunlight exposure. Once in the body, vitamin D interacts with cells at very specific receptors. The term receptor reflects the role of these “landing sites” contained within the cell’s nucleus. As the vitamin D molecule traverses the cell membrane and enters the cell nucleus, it binds with the vitamin D receptor, which connects to the chromosome at a hormone response element and drives the cell machinery forward.

The vitamin D receptor is part of a large collection of genes called the steroid super gene family. These include receptors for estrogen, progesterone, testosterone, and, yes, vitamin D.

What makes the field so interesting is the interaction between these factors. Inside the nucleus are a large variety of receptors. Vitamin D and the other molecules are known as ligands. When the ligands enter the nucleus, they must compete for receptors. This leads to a complicated collection of down-stream events that are unique to the individual. If, for example, your nucleus has a number of orphan receptors (receptors with unclear ligand associations) and these orphan receptors have some binding affinity for the vitamin D, then the down-stream signaling will reflect this new biology.

Many studies have associated vitamin D levels with disease. Prostate cancer, colon cancer, even blood-born tumors may, in part, arise in vitamin D deficient states. But, the most compelling evidence in several analyses supports its protective effect against colon cancer. In one study there was a 15 percent risk reduction for every 10 ug/ml increase in circulating blood levels of calciferol (Gandini S, Int J Cancer. March 11, 2011). What is interesting about the report from the University of Rochester is that it was the most aggressive forms of breast cancer that were found to be associated with Vitamin D deficiency. To date, the correlations with the more common forms of breast cancer have been less positive.

Cardiovascular disease and musculoskeletal diseases are also associated with vitamin D levels. So critical is vitamin D to the well-being of the human that mankind could not easily migrate far north from the equator until he found a source of vitamin D unrelated to the skin synthesis. This source proved to be fish and animals that survived by eating fish. Older readers will remember cod liver oil as a remedy doled out by grandparents. It is ironic that cod liver oil is an excellent source of vitamin D.

While deficiencies of vitamin D are likely to be deleterious, substantially exceeding the normal levels of 30 micrograms/ml have not been shown to further enhance health. It is prudent for patients to monitor their vitamin D levels and highly appropriate for physicians to recommend replacement. Interestingly, a scientific colleague recently commented that sun exposure, by providing active vitamin D, is greatly under appreciated as a healthful activity. He wondered whether the broad use of sunscreens would ultimately save or cost more lives when the aggregate impact of vitamin D levels upon cancer and health is finally understood.

About Dr. Robert A. Nagourney
Dr. Nagourney received his undergraduate degree in chemistry from Boston University and his doctor of medicine at McGill University in Montreal, where he was a University Scholar. After a residency in internal medicine at the University of California, Irvine, he went on to complete fellowship training in medical oncology at Georgetown University, as well as in hematology at the Scripps Institute in La Jolla. During his fellowship at Georgetown University, Dr. Nagourney confronted aggressive malignancies for which the standard therapies remained mostly ineffective. No matter what he did, all of his patients died. While he found this “standard of care” to be unacceptable, it inspired him to return to the laboratory where he eventually developed “personalized cancer therapy.” In 1986, Dr. Nagourney, along with colleague Larry Weisenthal, MD, PhD, received a Phase I grant from a federally funded program and launched Oncotech, Inc. They began conducting experiments to prove that human tumors resistant to chemotherapeutics could be re-sensitized by pre-incubation with calcium channel blockers, glutathione depletors and protein kinase C inhibitors. The original research was a success. Oncotech grew with financial backing from investors who ultimately changed the direction of the company’s research. The changes proved untenable to Dr. Nagourney and in 1991, he left the company he co-founded. He then returned to the laboratory, and developed the Ex-vivo Analysis - Programmed Cell Death ® (EVA-PCD) test to identify the treatments that would induce programmed cell death, or “apoptosis.” He soon took a position as Director of Experimental Therapeutics at the Cancer Institute of Long Beach Memorial Medical Center. His primary research project during this time was chronic lymphocytic leukemia. He remained in this position until the basic research program funding was cut, at which time he founded Rational Therapeutics in 1995. It is here where the EVA-PCD test is used to identity the drug, combinations of drugs or targeted therapies that will kill a patient's tumor - thus providing patients with truly personalized cancer treatment plans. With the desire to change how cancer care is delivered, he became Medical Director of the Todd Cancer Institute at Long Beach Memorial in 2003. In 2008, he returned to Rational Therapeutics full time to rededicate his time and expertise to expand the research opportunities available through the laboratory. He is a frequently invited lecturer for numerous professional organizations and universities, and has served as a reviewer and on the editorial boards of several journals including Clinical Cancer Research, British Journal of Cancer, Gynecologic Oncology, Cancer Research and the Journal of Medicinal Food.

4 Responses to Vitamin D and Cancer

  1. Elaine L. says:

    I had ER/PR- BC, 23 years ago and now have OC. I had my GP check my vitamin D levels. She said that everyone’s Vitamin D levels are coming out low. She has me taking a supplement and wants me to have my level checked, again in a month. She definitely seems to think that Vitamin D needs to be monitored and that too much isn’t good.

  2. Very true.

    Too much of a good thing is indeed bad in this case. Chronic overexposure to vitamin D can lead to hyperclacemia (too much calcium), kidney stones and arthritic symptoms.

    Levels above 30 have not been shown to be better but levels below 30 are worth treating with supplements.

  3. Vitamin D receptor binding to its partner, Retinoid X receptor has been visualized by the french research team for the first time, which could lead to possible enlightening of mode of action of this nuclear receptor and for possible cures for many ailments.

    dr prem raj pushpakaran
    http://www.incredb.org/investigator.php?incredb_id=373

  4. Sarah Hill says:

    I take these vitamin D supplements once daily and try to get 20mins of sun. Thoughts? http://www.purematters.com/Product.aspx?p=816116010662

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