Vitamin D Deficiency and Cancer
Medical News Today recently reported on a study from the University of California-San Diego School of Medicine, which suggests a link between vitamin D deficiency and premature death. Now, new research published in the BMJ links vitamin D deficiency to increased risk of death from all causes - including cardiovascular disease and cancer - and it may even play a part in cancer prognosis.
Vitamin D is essential to our bodies. It helps regulate the absorption of calcium and phosphorus in our bones, strengthens the immune system and helps cell communication.
The main source of vitamin D is from the sun (and don't believe the LIE about sunlight causing cancer!), and some foods - such as fatty fish (tuna, mackerel), cheese and fortified cereals - contain the vitamin. Vitamin D supplements can also boost levels in the body.
Vitamin D deficiency can be caused by low exposure to sunlight, low consumption of dietary vitamin D over a period of time, problems with kidney or digestive tract function and obesity.
Low levels of the vitamin have been associated with numerous health problems, such as increased risk of death from cardiovascular disease (CVD), higher risk of cognitive impairment in later life, increased risk of asthma among children and cancer.
But the researchers of this latest study say that so far, it has been unclear how vitamin D production in the body influences death.
Findings 'remarkably consistent'
The team set out to determine whether there was an association between vitamin D deficiency and deaths from all-causes, CVD and cancer.
They analyzed data from eight population-based studies from Europe and the US involving 26,018 participants between the ages of 50 and 79. Subjects were followed for 16 years.
Researchers found an association between low vitamin D levels and all-cause mortality - including CVD and cancer.
During follow-up, 6,695 deaths occurred. Of these, 2,624 were from CVD and 2,227 were from cancer.
The team found a link between participants with the lowest vitamin D levels - as determined by 25-hydroxyvitamin D (25(OH)D) concentrations in blood - and death from CVD. This association was found in participants with and without a history of the disease.
The team also found an association between low vitamin D levels and death from cancer among participants with a history of the disease. However, no such association was found among participants without a history of cancer, the researchers say, which indicates that vitamin D may be important in cancer prognosis.
But the team points out that they "cannot exclude reverse causality, that is, that the cancer might have led to low 25(OH)D levels."
"Furthermore," they add, "our study with the endpoint cancer mortality cannot make assumptions about a potential role of vitamin D in early phases of the carcinogenic process."
The researchers note that the findings were consistent across difference study populations, sexes, age groups and the time of year when blood tests were conducted "even though 25(OH)D cut-off values varied."
How Much is Enough?
Getting a simple blood test to measure Vitamin D levels is an easy thing to do. However, most labs list normal high levels of 80 ng/ml which just isn't true. I like to see my patients have Vitamin D levels in the 80-150 range!
When supplementing Vitamin D, make sure that the source either contains Vitamin K or that you are getting Vitamin K in another source (usually in a fish oil).
Most children need 1-3,000 iu extra per day if they don't get outside in the sun very often (depending on size and weight of child). Most adults need 5-10,000 iu/day. Those with cancer or the chronic disorder may need 10-20,000 iu/day D3 supplementation.