Vitamin D and prostate cancer are connected. Here is some of the latest research on vitamin D as it applies to prostate cancer and prostate health as well as heart disease, bone health, diabetes, and colon cancer.
Vitamin D is a substance that functions like a vitamin (as a fat-soluble vitamin it is stored in fat tissue in the body), but it is also a hormone. Its many activities include regulating bone health, muscle health, immune system response, insulin and blood sugar levels, and calcium and phosphorus metabolism.
Vitamin D (in the form of D3) is manufactured by the body through exposure to sunlight and it can also be obtained from a limited number of foods, and through supplements. The body also needs co-factors in order to properly utilize vitamin D. These include magnesium, zinc, vitamin K, boron, and small amounts of vitamin A.
Vitamin D and Prostate Health
Although the connection of vitamin D and prostate cancer remains controversial, some researchers have found evidence that a vitamin D deficiency increases the risk of developing prostate cancer. In the British Journal of Urology International, investigators reported that men with prostate cancer were more likely to have low levels of vitamin D compared with men who did not have the disease. (Trump 2009)
Also, in a smaller study published in BJU International in November 2009, 26 men who had prostate cancer were given a daily dose of vitamin D. The PSA levels in five men declined: two by more than 50 percent, two by 25 to 50 percent, and in one by less than 25 percent. In the remaining patients, their PSA levels stabilized after treatment with vitamin D for up to 36 months. (Newsom-Davis 2009)
Vitamin D may also impact the prostate in another way. At least one study has reported that a low level of vitamin D circulating in the blood is linked to a greater risk of having an enlarged prostate. (Galic 2008)
Getting Vitamin D
Vitamin D can be gotten through sun exposure or diet. Most people have insufficient or deficient levels of vitamin D. One reason for this deficiency is that the main and most efficient way to get enough vitamin D is through exposure to sunlight. According to the Vitamin D Council, the skin produces about 10,000 International Units (IUs) of vitamin D in response to 20 to 30 minutes of summer sun exposure. That’s 50 times more than the US government’s (Institute of Medicine’s) recommendation of only 200 IU.
Unfortunately, modern lifestyles often are not conducive to regular sun exposure for a great number of people. Most people work and spend much of their time indoors, children do not play outside as much as they used to, and older adults are often homebound or have limited access to sunlight. Also, there is a widespread campaign to “cover up” when in the sun that may be another reason for the widespread deficiency.
Dietary sources of vitamin D are limited. The healthiest and richest food sources of vitamin D are salmon and sardines and, to a lesser extent, 2% cow’s milk. However, eating normal amounts of these foods will generally not provide sufficient amounts of vitamin D. Also, food is not the best way to meet the body’s requirements for this vitamin, which is why sunlight exposure and supplements are so important.
How Much Vitamin D Do You Need?
The Food and Nutrition Board (FNB) at the Institute of Medicine (IOM) at the National Academies currently recommends 200 IU of vitamin D daily for adults younger than age 50, a dose of 400 IU for adults 50 to 70, and 600 IU for adults ages 71 and older. (These doses are currently under review by the FNB at the IOM, and a report is expected in September 2010, with an anticipated increase in vitamin D recommendations.) Among conventional American medical circles, 30 ng/mL is considered a “normal” blood level of vitamin D. However, many experts from different disciplines believe both these doses and the blood level are much too low and result in deficiency and associated health problems.
For example, a statement released by the International Osteoporosis Foundation on May 11, 2010, noted that adults age 65 and older need up to twice the amount of vitamin D that is generally recommended in the United States, and recommends 800 to 1,000 mg for this age group. The International Osteoporosis Foundation also warned that people who are obese, have osteoporosis, have limited exposure to the sun, or have difficulty absorbing vitamin D should take 50 micrograms (2,000 IU) daily. Dr. Bess Dawson-Hughes of Tufts University, who was the lead author of the Foundation’s statement, noted that the “high prevalence of suboptimal levels [of vitamin D] raises the possibility that many falls and fractures can be prevented with vitamin D supplementation.”
Higher doses are also recommended by Harvard School of Public Health (HSPH). In a recent article, HSPH recommended that everyone older than one year of age take up to 2,000 IU of vitamin D daily, and that some people may need 3,000 to 4,000 IU to reach adequate blood levels, especially individuals who have darker skin, those who spend winters at higher latitudes, and anyone who gets little exposure to direct sunlight. (HSPH 2010)
According to the Vitamin D Council and other experts, the ideal blood level of vitamin D is between 50 and 80 ng/mL. Because the majority of people are deficient (at 30 ng/mL or lower), the Council recommends that people take 5,000 IU daily for 2 to 3 months, then ask their healthcare provider for a 25-hydroxyvitamin D (25[OH]D) test to check their levels. Home test kits are also available and may be a more economic choice if you don’t have health insurance or if your insurance does not cover the test. In either case, the test requires just a few drops of blood from a finger or heel, which is then sent to a lab for analysis. Once you know your body’s level of vitamin D, you can adjust your supplement intake until your blood levels are between 50 and 80 ng/mL year round.
Why is this level important? Research shows that the body does not begin to adequately store vitamin D until the nutrient reaches a level of 50 nanograms per milliliter (ng/mL). Below 50 ng/mL, the body uses up the vitamin as fast as it can produce it or take it in. Therefore, people who have “normal” vitamin D levels by American standards are deficient. It can take many months of taking high doses of vitamin D to make up the deficiency. According to the Vitamin D Council, that amount may be 5,000 IU daily, although you should consult your healthcare provider to determine the best dose for your situation.
Results of an study around “super-dosing” of vitamin D were just published, and they serve as an example of “too much of a good thing”. Two scientists commented on the results of the study, in which a single dose of vitamin D (500,000 IU) given to older women increased rather than decreased their risk of falls and fractures. (Dawson-Hughes 2010) The two scientists noted that while this single dose did not provide the hoped-for response (i.e., less falls and related fractures), “there is no evidence that adverse effects of more frequent, lower-dose regimens, so daily, weekly, or monthly dosing with vitamin D3 appears to be the best option for clinicians at this time.” One reason for the increase in fractures was the possibility that the older women actually were feeling “too” good and may have increased their mobility too much as a result of the effects of the vitamin. I doubt whether the researchers had this potential effect in mind when they started their research!
Vitamin D and Colon Cancer
Besides the studies on vitamin D and prostate cancer, vitamin D has been researched with other cancers as well, such as colon cancer. A study conducted by cancer prevention experts at the Moores Cancer Center at the University of California revealed that high intake of vitamin D could cut the rates of colorectal cancer by two-thirds. In a study performed by the International Agency for Research on Cancer, the authors reported that high levels of vitamin D reduce the risk of developing colon cancer by nearly 40 percent. (Jenab 2010)
In an April 2010 published study from Brigham and Women’s Hospital and Harvard Medical School, the investigators noted that “all lines of inquiry from observational studies indicate that an association between better vitamin D status and lower colorectal cancer risk exists.” Therefore, improving intake of vitamin D could protect against colorectal cancer incidence and mortality. (Giovannucci 2010) Another study also published in April 2010, this one from Loma Linda University, pointed out that vitamin D insufficiency and colorectal cancer are common among the elderly, and that daily intake of 1,000 IU of vitamin D can increase serum levels of the vitamin sufficiently in most older persons which may substantially lower the incidence of this type of cancer. (Rheem 2010)
Vitamin D and Heart Disease
At Intermountain Medical Center in Salt Lake City, Utah, cardiologist J.B. Muhlestein, MD, recently found that patients who raised their blood levels of vitamin D after they had been diagnosed as being deficient reduced their risk of having a heart attack by 33 percent, their risk of heart failure by 20 percent, and their chances of dying from any cause by 30 percent. His results prompted him to encourage physicians to recommend vitamin D supplements to patients who have low vitamin D levels, as he believes it may lower their risk of cardiovascular disease. Dr. Muhlestein presented his findings at the American College of Cardiology in Atlanta in March 2010.
In an earlier study, also by Dr. Muhlestein and presented at the American Heart Association’s Scientific Conference in Orlando, Florida, in November 2009, he reported that low levels of vitamin D can significantly increase a person’s risk of heart disease, stroke, and death, even among people who do not have a history of heart disease. Muhlestein and his colleagues followed 27,686 people age 50 and older who had no prior history of cardiovascular disease. Vitamin D levels were measured in all the participants. The researchers found that participants who had very low vitamin D levels (<15 ng/mL) were 78 percent more likely to have a stroke, 77 percent more likely to die, and 45 percent more likely to develop coronary artery disease than people who had normal levels (>30 ng/mL). Individuals who had very low levels were also twice as likely to develop heart failure as participants who had normal vitamin D levels. (Muhlestein 2009)
Researchers at the University of Genova found that nearly all 90 elderly patients who had chronic heart failure had vitamin D deficiency. (Ameri 2010) In a review of 17 prospective studies and randomized trials, investigators from Brigham and Women’s Hospital and Harvard School of Public Health found consistent reductions in cardiovascular disease mortality among adults who took vitamin D supplements at moderate to high doses (about 1,000 IU daily). (Wang 2010)
Vitamin D and Diabetes
Vitamin D may also improve insulin resistance and sensitivity, which are risk factors for diabetes. In a double-blind, controlled study conducted in New Zealand, researchers studied 81 South Asian women ages 23 to 68 who had insulin resistance. (von Hurst 2010) Half of the women were given 4,000 IU vitamin D3 daily for six months and the other half were given placebo. At the end of the six months, the women who had taken vitamin D had significant improvement in both insulin resistance and sensitivity compared with women in the placebo group. The best results were seen in women who had blood levels of vitamin D in the range of 80 to 119 nmol/L. The Vitamin D Council notes that the optimal blood levels is at least 125 nmol/L (50 ng/mL), yet most Americans have levels less than 30 ng/mL.
In another study, conducted at Warwick Medical School in the United Kingdom, researchers evaluated 28 studies that included nearly 100,000 men and women from various ethnic groups. (Parker 2010) They found that adults who had the highest blood levels of vitamin D reduced their risk of developing type 2 diabetes by 55 percent and their risk of cardiovascular disease by 33 percent.
Bone Health and Vitamin D
Vitamin D and calcium work in tandem to improve bone density and reduce the risk of hip and other fractures, and numerous studies have shown this relationship. Vitamin D alone is also essential for promoting calcium absorption and maintaining adequate concentrations of calcium and phosphate to allow normal mineralization of bone. It is also necessary for bone growth and bone repair. Without sufficient intake of vitamin D, bones can become thin, brittle, or misshapen. Sufficient levels of vitamin D prevent rickets in children, osteomalacia in adults, and along with calcium, protects individuals from development of osteoporosis. (National Institutes of Health)
Recent studies in Scotland find that 98 percent of people who had suffered fractures were deficient in vitamin D. Stephen Gallacher, a physician who heads the South Glasgow fracture liaison service, noted that taking a vitamin D supplement can increase bone density by 20 percent in a few months if patients take enough of the vitamin. Dr. Gallacher found that nearly all of the more than 500 older patients with broken hips that he researched had a vitamin D deficiency. (Gallacher 2010)
In a recent (May 2010) meta-analysis from the Netherlands, investigators evaluated data that included 12,658 postmenopausal women, 6,089 of whom received 800 IU vitamin D3 with or without calcium, and 6,569 who received placebo with or without calcium. They found that vitamin D showed a 70 percent probability of being better treatment than placebo for prevention of nonvertebral fractures, hip fractures, and nonvertebral, nonhip fractures. (Bergman 2010)
The Osteoporosis Risk Factor and Prevention-Fracture Prevention Study (OSTPRE-FPS) just published its results in the March 2010 issue of Osteoporosis International. The study included 593 ambulatory postmenopausal women who received either 800 IU vitamin D plus 1,000 mg calcium daily for three years (287 women) or 306 who received no supplement. Investigators found that total body bone mineral density increased significantly more in the women who took the supplements than those in the control group. (Karkkainen 2010)
Results of a 20-study meta-analysis of the efficacy of vitamin D supplements in preventing nonvertebral and hip fractures among individuals age 65 and older was recently published in the Archives of Internal Medicine. More than 83,000 people participated in the studies, which compared oral vitamin D with and without calcium, and vitamin D with calcium or placebo. Although the amount of vitamin D used in the studies varied, the investigators determined that prevention of nonvertebral fractures with vitamin D depends on the dose, and that a higher dose (482 to 770 IU daily) reduced nonvertebral fracture risk by 20 percent when compared with lower doses. (Bischoff-Ferrari 2009)
In yet another study, the authors of a review of both vitamin D and calcium concluded that supplements of these nutrients (700-800 IU/day of vitamin D; 500-1,200 mg/day of calcium) decreased the risk of falls, fractures, and bone loss in people aged 62 to 85. (Cranney 2007)
The Bottom Line
The list of health issues associated with vitamin D (such as vitamin D and prostate cancer) posted here does not even provide the whole story. Research indicates that low levels of vitamin D may be associated with the risk of depression, rheumatoid arthritis, multiple sclerosis, Crohn’s disease, obesity, high blood pressure, and schizophrenia, and may improve physical performance, reduce chronic pain, and improve mood in older adults.
A vitamin D insufficiency or deficiency is easily remedied: some sunlight and a good vitamin D3 supplement taken on a daily basis, followed up with a vitamin D test to ensure you are on the right track. Proper vitamin D levels help not only your prostate, but your overall health as well.
