By Editor
Daily vitamin C supplements have been linked to fewer deaths and some favourable biological changes among people with precancerous blood disorders or low-risk blood cancers, offering an unexpected potential clue for preventing progression to more serious disease.
The finding emerged from the EVITA phase 2 clinical trial, in which researchers tested whether vitamin C could influence the development of abnormal blood cells in people at increased risk of blood cancer.
The 109 participants, recruited in Denmark and the United States, were randomly assigned to receive either 1,000 milligrams of oral vitamin C daily or a placebo for 12 months.
The trial, published online by Wiley in CANCER the peer-reviewed journal of the American Cancer Society, found that vitamin C did not slow the growth of abnormal or cancerous blood cells, the study’s primary endpoint.
But researchers observed several unexpected signals that they say warrant further investigation—including an apparent survival advantage among participants who received vitamin C.
Fewer deaths during follow-up
At a median follow-up of 33.6 months, nearly three years, 35 participants had died.
Of those deaths, 24 occurred among participants assigned to placebo, compared with 11 among those assigned to vitamin C.
An exploratory analysis found that people assigned to vitamin C were more likely to survive during the follow-up period than those who received placebo.
Researchers, however, stressed that the survival finding was exploratory and was not the primary endpoint of the trial.
It therefore cannot yet establish that vitamin C reduces the risk of death in people with early-stage blood disorders.
The researchers say the apparent survival benefit will need to be tested in a larger, phase 3 clinical trial.
Vitamin C and blood cancer risk
The scientific rationale behind the study lies in vitamin C’s ability to influence TET enzymes, proteins involved in regulating gene activity.
Reduced activity of TET enzymes is a common feature of some blood cancers. Scientists have therefore been investigating whether increasing vitamin C levels could restore or enhance the activity of these enzymes and potentially influence the biological processes involved in cancer development.
The EVITA trial was designed to test that possibility in people who already had either a blood disorder with the potential to become cancerous or a low-risk blood cancer.
Of the 109 participants, 55 received vitamin C while 54 received placebo.
Although vitamin C did not produce the expected reduction in abnormal cell growth, researchers found changes in inflammatory signalling that were associated with potentially better outcomes.
Participants receiving vitamin C also experienced fewer cases of anaemia, pneumonia, acute aseptic arthritis and internal bleeding.
However, gastrointestinal problems were reported more frequently among people receiving vitamin C.
Researchers urge caution
Peter A. Jones, PhD, DSc (hon), of Van Andel Institute and co-senior author of the study, said the findings provide a reason to continue investigating vitamin C as a possible strategy for intercepting blood cancers before they become more aggressive.
“The EVITA trial gives us a strong rationale to continue exploring if and how vitamin C might benefit people with certain pre-cancer or early-stage blood cancers,” Jones said.
“More work is needed but we are cautiously optimistic that these findings could inform future strategies to intercept leukemia development.”
The researchers emphasised that the results should not be interpreted as evidence that people with blood disorders should begin taking high-dose vitamin C supplements as a cancer treatment.
The study did not demonstrate that vitamin C stopped or slowed the growth of abnormal blood cells, and its survival findings require confirmation.
A larger trial could provide answer
Kirsten Grønbæk, MD, PhD, of Rigshospitalet, Copenhagen University Hospital, and co-senior author, said the findings were encouraging but not yet sufficient to change clinical practice.
“We are encouraged by our findings and what they ultimately could mean for people with these early-stage blood disorders,” Grønbæk said.
“Although it is too soon to make recommendations based on our results, we are hopeful that a larger study will give us more definitive answers.”
For now, the EVITA findings add an intriguing new dimension to research into blood cancer prevention. While vitamin C did not deliver the expected effect on abnormal cell growth, the lower number of deaths, favourable inflammatory changes and fewer serious complications observed in the vitamin C group have given researchers a new question to investigate.
The next step, scientists say, is to determine whether the apparent survival signal is real and whether vitamin C could eventually become part of a strategy to prevent or delay the progression of certain blood cancers.
