Daily Archives: April 23, 2010

Vitamin D Supplementation and Cancer Prevention

Readers of this blog know that, in general, I’m in favor of healthcare professionals checking vitamin D levels as part of routine exams. I do this on all adolescents and adults. And, I’ve blogged more on the topic of vitamin D this year than any other topic. So, I’m trying to post less on the topic, but this and the next too blogs were too important not to mention to you.

The subject of this blog is based upon an abstract of an amazing study titled “Vitamin D Supplementation and Cancer Prevention.” It is authored by Thomas L. Lenz, PharmD, and published in the American Journal of Lifestyle Medicine (2009;3[5]:365-368):

It is estimated that approximately 1 billion people worldwide have blood concentrations of vitamin D that are considered suboptimal.

Much research has been conducted over the past 30 years linking low vitamin D serum concentrations to both skeletal and nonskeletal conditions, including several types of cancers, cardiovascular disease, diabetes, upper respiratory tract infections, all-cause mortality, and many others.

Several observational studies and a few prospectively randomized controlled trials have demonstrated that adequate levels of vitamin D can decrease the risk and improve survival rates for several types of cancers including breast, rectum, ovary, prostate, stomach, bladder, esophagus, kidney, lung, pancreas, uterus, non-Hodgkin lymphoma, and multiple myeloma.

Individuals with serum vitamin D concentrations less than 20 ng/mL are considered most at risk, whereas those who achieve levels of 32 to 100 ng/mL are considered to have sufficient serum vitamin D concentrations.

Vitamin D can be obtained from exposure to the sun, through dietary intake, and via supplementation.

Obtaining a total of approximately 4000 IU/d of vitamin D3 from all sources has been shown to achieve serum concentrations considered to be in the sufficient range. However, most individuals will require a dietary supplement of 2000 IU/d of vitamin D3 to achieve sufficient levels as up to 10,000 IU/d is considered safe.

Vitamin D3 is available as an over-the-counter product at most pharmacies and is relatively inexpensive, especially when compared with the demonstrated benefits.

What am I doing in my practice? As mentioned above, I check a vitamin D level as part of my annual exam. I do this on all adolescents and adults.

If the vitamin D level is below 50, I suggest supplementing with vitamin D and rechecking.

I give my patients two options:

  1. OTC vitamin D, 2000 IU per day, and recheck the level in 4-6 months, or
  2. Prescription vitamin D, 50,000 IU per week for 12 weeks and then recheck the level.

Vitamin D helps fend off flu and asthma attacks

In a recent study of Japanese schoolchildren, vitamin D supplements taken during the winter and early spring helped prevent seasonal flu and asthma attacks. Here’s more on the study from Reuters Health:

The idea for the study, study chief Dr. Mitsuyoshi Urashima, told Reuters Health, came from an earlier study looking at whether vitamin D could help prevent the bone-thinning disease osteoporosis. The researchers in that study noticed that people taking vitamin D were three times less likely to report cold and flu symptoms.

This led Urashima, of Jikei University School of Medicine, Tokyo, and colleagues to randomly assign a group of 6- to 15-year-old children to take vitamin D3 supplements (1,200 international units daily) or inactive placebo during a cold and flu season.

Vitamin D3, or cholecalciferol, is more readily absorbed by the body and more potent than vitamin D2, or ergocalciferol, the form often found in multivitamins.

During the study, conducted between December 2008 and March 2009, 31 of 167 children taking placebo caught influenza A, the most common form of the virus, compared with only 18 of 167 taking vitamin D.

The vitamin D group was 58 percent less likely to catch influenza A, the researchers report in the American Journal of Clinical Nutrition.

Vitamin D also appeared to suppress asthma attacks in children with a history of asthma.

Two children taking vitamin D had asthma attacks during the study, compared to 12 children taking placebo.

Urashima admitted to being a bit surprised by this finding and hopes to confirm it in a randomized trial targeting children with asthma.

Dr. Adit Ginde, of University of Colorado Denver School of Medicine, who was not involved in the study, told Reuters Health: “This is the first time a study has been done that rigorously shows that vitamin D supplementation can reduce a type of influenza in a dedicated clinical trial.”

Ginde and colleagues published a study a year ago showing that asthmatics with lower vitamin D levels were at five times the risk for colds and flu.

In the Japanese study, vitamin D supplementation did not prevent influenza type B, which tends to appear later in the flu season than the “A” flu variety.

Ginde said there is no solid explanation for why vitamin D prevented influenza A and not influenza B. “The immune system fights different viruses in different ways. This finding needs to be explored in more detail,” Ginde said.

Based on the current study, giving kids vitamin D supplements during the winter may help reduce cases of influenza A, the researchers conclude.

Urashima suggests that children could take 1,200 IU per day starting in September to prevent flu and asthma attacks during the flu season. This is three times the currently recommended intake, but well within safe limits for children.

Increasing vitamin D levels may cut heart disease risk

I may have blogged more on vitamin D this year than any other topic. And, now, the Los Angeles Times is reporting, “Raising the amount of vitamin D in the blood appears to help some people — at least those deficient in the vitamin — reduce their risk of heart disease by about 30%.” This is according to research presented at the American College of Cardiology annual meeting.

In the past, “researchers have been uncomfortable randomizing people with low vitamin D into a group that … does not” receive treatment, because deficiency “can contribute to weaker bones and” has “been associated with increased risks of several diseases, including several types of cancer.”

The Salt Lake Tribune reports that the researchers reported that “patients who increased their vitamin D levels to 43 nanograms per milliliter of blood or higher reduced their risks of the chronic diseases.” Currently, 30 nanograms is “considered ‘normal'” by some (although in our community, many of the specialists want vitamin D levels to be 50 or higher).

Meanwhile, researchers also found that “patients who raised their vitamin D levels were 33% less likely to have a heart attack, 20% less likely to develop heart failure, and 30% less likely to die between” visits to their physician, WebMD reported. HealthDay also covered the story.

What am I doing in my practice? Checking a vitamin D level as part of my annual exam. I do this on all adolescents and adults. If the vitamin D level is below 50, I suggest supplementing with vitamin D and rechecking. I give my patients two options. (1) OTC vitamin D, 2000 IU per day, and recheck the level in 4-6 months, or (2) Prescription vitamin D, 50,000 IU per week for 12 weeks and then recheck the level.