Vitamin D3 may reduce risk of developing advanced cancer, but not for obese adults
20 Nov 2020 --- Vitamin D3 may reduce the risk of developing advanced cancer among adults over the age of 50 without a diagnosis of cancer at baseline.
In a paper published in JAMA Network Open, researchers reported that vitamin D was associated with an overall 17 percent risk reduction for advanced cancer.
“No other treatment or supplement has been identified that is associated with an almost 20 percent reduction in advanced total cancer risk,” corresponding study author Dr. Paulette Chandler tells NutritionInsight.
Her findings suggest that vitamin D supplementation may be operating through general mechanisms – such as inflammation – rather than site-specific mechanisms to reduce the risk of advanced cancer.
“Vitamin D may reduce inflammation through a variety of pathways since many cells have vitamin D receptors,” Chandler explains.
However, vitamin D supplementation did not yield statistically significant results on reducing cancer risk in overweight and obese adults.
“Obesity and associated inflammation may decrease the effectiveness of vitamin D, possibly by reducing vitamin D receptor sensitivity or altering vitamin D signaling,” she outlines.
The study findings support a “biologically plausible” connection between vitamin D and preventing metastatic cancer.VITAL research round two
The current study findings are a continuation of the Vitamin D and Omega-3 Trial (VITAL), which concluded in 2018. At the time, Chandler’s research team found that vitamin D did not reduce the overall incidence of cancer, but hinted at a decreased risk of cancer deaths.
Now, in a secondary analysis of VITAL, the researchers at Brigham and Women’s Hospital narrowed in on the connection between taking vitamin D supplements and the risk of metastatic or fatal cancer.
Among 25,871 randomized VITAL elderly participants, over 1,600 were diagnosed with invasive cancer in the next five years. This included breast, prostate, colorectal and lung cancer.
Of the almost 13,000 participants who took 2,000 IU of vitamin D daily, 226 were diagnosed with advanced cancer compared to 274 who received the placebo.
Notably, of the 7,843 participants with a body mass index lower than 25 taking vitamin D, only 58 were diagnosed with advanced cancer compared with 96 taking the placebo.
Randomization took place from November 2011 through March 2014, and study medication ended on December 31, 2017.
Unlocking doors with the vitamin D-key
A dynamic interplay between obesity, inflammation and immune system activation may contribute to the differential response to vitamin D3, says Chandler.
“Vitamin D receptors are on the surfaces of many cells in the immune system. Receptors are like a lock in a door that is opened with the right key. Opening the lock may start a cascade of actions that changes how a cell behaves,” she explains.
While vitamin D is traditionally known as a stalwart in supporting bone and joint health, it is now coming to the fore as a means of tackling COVID-19.
“The potential broad influences of vitamin D on immune function may result in it being important for a variety of conditions related to inflammation, including COVID-19,” Chandler adds.
Vitamin D did not reduce the risk of developing advanced cancer among adults with a BMI higher than 25.Standard recommendations?
Chandler maintains that her findings support the ongoing evaluation of vitamin D supplementation for preventing metastatic cancer – a connection that is “biologically plausible,” she argues.
Other facilitating factors for more widespread vitamin D supplementation recommendations are that it is readily available, cheap and has a long clinical research history.
However, she flags that additional studies – focusing on cancer patients and investigating the role of BMI, for example – are needed before vitamin D3 could become a standard recommendation for cancer prevention.
Vitamin D supplementation has become a hot topic, ranging from the vitamin falsely being perceived as medicine in elderly patients to interest from the UK government.
Some members of Chandler’s research group are currently conducting the Vitamin D for COVID-19 (VIVID) trial that aims to determine the effect of vitamin D supplementation at higher doses on disease progression and post-exposure prophylaxis for COVID-19 infection.
By Anni Schleicher
