Pancreatic Cancer Patients More Likely to Lack Vitamin D
Pancreatic cancer, on the rise in the United States, may be deterred by maintaining adequate vitamin D status. Researchers who compared 451 pancreatic-cancer patients with 1,167 healthy controls report that average blood levels of vitamin D were significantly lower in those with the cancer. Compared to participants with the lowest levels of vitamin D, people with sufficient or only slightly low levels were at 30% lower risk of pancreatic cancer.
Brian Wolpin, MD, of the Dana-Farber Cancer Institute, and colleagues compared cancer incidence in pooled data from five case-control studies. Levels of vitamin D were assessed by measuring the predominant form of the vitamin, 25-hydroxyvitamin D, that circulates in the blood and which the body uses to store the sunshine vitamin. Although low levels were associated with higher cancer risk, very high blood levels of vitamin D offered no additional risk-reduction benefits.
A possible protective effect of vitamin D against cancer, though unproven, has been suspected since the 1940s, when it was observed that people in lower latitudes with more sunshine-enabling their skin to make more vitamin D-tended to develop fewer cancers. Various studies have sought to establish a connection between vitamin D and lower risk of cancers including colorectal, breast and stomach cancers.
Dr. Wolpin and colleagues noted that studies have previously shown that vitamin D can slow the growth of pancreatic cancer cells in mice. Other laboratory studies have demonstrated that pancreatic cancer cells can convert the storage form of the vitamin to the active form.
Although pancreatic cancer is not as common as colon, breast or lung cancer, notes Joel B. Mason, MD, director of Tufts HNRCA Vitamins and Carcinogenesis Laboratory, its the fourth leading cause of cancer deaths in the United States. Because pancreatic cancer is difficult to detect and treat early in its progression, preventive lifestyle steps are especially important.
While cautioning that their new study was observational and thus cant prove cause and effect, Dr. Wolpin and colleagues concluded, In light of the high prevalence of vitamin D insufficiency in the population, further studies should examine whether increasing vitamin D levels impacts the incidence of this highly lethal malignancy.
TO LEARN MORE: Cancer Epidemiology, Biomarkers & Prevention, January 2012; abstract at dx.doi.org/10.1158/1055-9965.EPI-11-0836.
| Too Little-or Too Much-Vitamin D Bad for Your Heart |
A new study suggests that when it comes to vitamin D and your heart, there may be a Goldilocks relationship-youre healthiest when your vitamin D level is just right. Analyzing data on more than 15,000 adults, ages 18-85, researchers found that increasing blood levels of vitamin D are associated with decreasing amounts of C-reactive protein (CRP), a marker of inflammation linked to artery stiffness and greater risk of heart problems.
But that benefit held only up to a point: Any extra increase in vitamin D beyond 21 nanograms/milliliter (ng/mL)-in the low range of whats considered normal-actually was associated with CRP going up again.
Vitamin D appears to be important for your heart health, commented lead author Muhammad Amer, MD, of Johns Hopkins University, noting that adequate levels of the sunshine vitamin are associated with reduced cardiovascular inflammation and atherosclerosis. But it appears that at some point it can be too much of a good thing.
Dr. Amer and colleagues recommended having your blood levels tested if youre at risk of vitamin D deficiency, and checking with your doctor before taking vitamin D supplements.
TO LEARN MORE: American Journal of Cardiology, Jan. 15, 2012; abstract at dx.doi.org/10.1016/j.amjcard.2011.08.032.
| You and Vitamin D: What the Experts Say |
Are you getting enough vitamin D? In late 2010, the Institute of Medicine (IOM), which sets recommended daily levels for nutrients, increased its recommendation for children and adults under age 71 to 600 IU of vitamin D. Older adults, the IOM expert committee concluded, need 800 IU daily. That was an increase from levels set in 1997, which ranged from 200-600 IU daily, and from the 400 IU used to calculate percentages for nutrition labels on food.
Many vitamin D advocates argued for even higher recommended levels, citing possible health benefits for the sunshine vitamin beyond bone health, where its known that vitamin D is essential to the bodys use of calcium. But the IOM concluded the jury is still out on those benefits, such as fighting cancer or heart disease.
The IOM defined adequate blood levels of the vitamin using a target of 20 nanograms/milliliter (ng/mL). Bess Dawson-Hughes, MD, director of Tufts HNRCA Bone Metabolism Laboratory, points out that research at Tufts and other laboratories suggests 30 ng/mL of vitamin D is the optimum blood level for bone health.
People at risk for vitamin D deficiency include those with little effective sun exposure, osteoporosis patients, people with gastrointestinal disorders that affect vitamin D absorption, patients on medication that causes vitamin D to break down more rapidly, and people with a lot of body fat. Dr. Dawson-Hughes points out, A lot of people in the general public are at increased risk. If youre among them, she advises getting a blood test for vitamin D, then being re-tested after increasing your intake to make sure your level has been corrected.
If you dont get much sun exposure, Dr. Dawson-Hughes adds, the higher 30 ng/mL level is difficult to achieve from diet alone. So you may decide to take supplemental vitamin D as a little insurance-but check with your doctor first.