Daily vitamin C linked to fewer adverse events in pre-leukemia trial
Key takeaways
- A clinical trial found that daily vitamin C supplementation may reduce adverse events among people with pre-cancerous blood disorders.
- One year of daily oral vitamin C supplementation restored nutrient levels and was linked with higher survival rates during three years of follow-up.
- The findings suggest vitamin C as a possible supportive approach for pre-cancerous blood disorders, but the authors stress that further trials are needed.

A study has found that vitamin C may benefit people with pre-cancer blood disorders. The nutrient is known for its immune support, wound healing, and ability to protect cells from molecular damage. Scientists found that restoring vitamin C levels in people with those blood disorders, which are often low, can bring health benefits for pre-cancerous blood disorders and early-stage blood cancer.
The participants took a daily supplement of 1,000 mg of vitamin C for one year and showed fewer adverse events during the trial and follow-up period compared with the participants taking a placebo.
Vitamin C was also found to positively alter the level of cytokines — inflammatory molecule signals — suggesting it may support regulation of inflammatory pathways linked to progression of pre-cancerous cells, the researchers note.
“We are excited and cautiously optimistic that our results could one day translate into a simple way to improve care and outcomes for people with pre-leukemia disorders,” says co-author of the study Peter Jones, Ph.D., D.Sc., a professor at Van Andel Institute, US, and co-leader of the Van Andel Institute-Stand Up To Cancer (VAI–SU2C) Epigenetics Dream Team.
“Our approach reflects a growing emphasis on cancer interception — intervening before cancer becomes established. We are working to build on the trial findings by exploring how exactly vitamin C interacts with pre-cancerous cells, including the idea that it may help restore normal epigenetic function in blood cells at risk of becoming leukemia.”
Need for treatment
Published in Cancer, the double-blind trial included 109 people diagnosed with blood disorders that may progress into acute myeloid leukemia — a tough-to-treat type of cancer. The diagnoses included clinical cytopenia of unknown significance (CCUS) or myelodysplastic syndrome (MDS), and none of the participants were undergoing treatment during the time of the trial.
Previous trials have included an intravenous vitamin C, while this trial used the same dose as an over-the-counter supplement.The study authors note that there are currently no available treatments to prevent CCUS from progressing to leukemia. MDS can be treated by cell transplantation. However, many people, and especially the older population, have other conditions that limit them from undergoing such a treatment.
The participants were randomly divided into groups, consuming either 1,000 mg daily of vitamin C or a placebo.
The researchers say that this was the first trial of its kind to evaluate oral supplementation of vitamin C in a pre-leukemia population and for people with lower-risk myeloid malignancies. Previous trials have included an intravenous vitamin C, while this study used the same dose as an over-the-counter supplement. The study authors add that it also focused on pre-cancer blood disorders and early-stage blood cancer in comparison to previous studies focusing on tumors.
The participants’ blood was checked for vitamin C levels, and more than half were deficient before the start of the trial. Oral supplementation helped bring those levels up to normal.
Vitamin C has been explored for cancer treatments for over 70 years, note the researchers, but many trials have ended with inconclusive results and methodological differences across studies. They say that thanks to technological advances, vitamin C’s role in gene regulation and cell development has grown in the last decade.
They explain that vitamin C has proven to be an “essential partner” to TET2 — an enzyme that suppresses cancer cell growth and regulates whether certain genes are on or off. TET2 mutations can boost malignant cells to proliferate, which are common features of leukemia and related disorders.
Measuring progression
The researchers also looked at the differences in growth rates of abnormal blood cells, which is a common measurement of the progression of leukemia. The researchers did not find a significant difference between the intervention and placebo groups.
The researchers also looked at the differences in growth rates of abnormal blood cells, which is a common measurement of the progression of leukemia.
Independent researcher Dr. John Riches, a clinical reader in Cancer Immuno-metabolism at Barts Cancer Institute, St Bartholomew’s Hospital, UK, says the trial is well designed. However, the main aim of the study was not achieved.
He explains: “Vitamin C did not significantly slow the growth of the abnormal blood-cell clones. The apparent improvement in survival is interesting, but this was an unexpected finding in a relatively small study that was not designed to test whether vitamin C helps people live longer.”
“The results are therefore interesting enough to justify a larger trial, but we do not yet have good enough evidence to say that vitamin C improves outcomes or should change clinical practice in these early-stage blood cancers,” he argues.
Study lead Kirsten Grønbæk, Ph.D., a hematologist, a member of the VAI–SU2C Epigenetics Dream Team, and a professor at the University of Copenhagen, Denmark, says these preliminary findings lay the groundwork for a larger clinical trial to explore vitamin C as a possible way to improve patient outcomes.
“It is too early to make definitive recommendations based on our results, but we are hopeful that a more expansive study will provide further insights.”














