The journey through a stem cell transplant is a monumental challenge for patients with blood cancers, but a recent pilot study suggests a familiar nutrient—vitamin C—could help rewrite the story.
For patients with certain blood cancers like myeloma and lymphoma, myeloablative chemotherapy and autologous haematopoietic stem cell transplantation represent a potential cure—but the path is grueling. This aggressive treatment intentionally destroys the bone marrow before replenishing it with the patient's own stem cells.
Alongside fighting cancer, patients battle severe side effects, with oral mucositis being one of the most common and distressing. This painful inflammation and ulceration of the mucous membranes lining the mouth and digestive tract can make eating, drinking, and even speaking unbearably painful, significantly compromising quality of life during an already difficult time 1 .
Emerging research is investigating whether a simple, natural compound could help change this narrative. At the center of this investigation is vitamin C—a potent antioxidant with anti-inflammatory properties that becomes severely depleted following intensive chemotherapy 1 .
A pioneering pilot study conducted at Christchurch Hospital, New Zealand, set out to determine if oral vitamin C supplementation could restore and maintain adequate levels of this vital nutrient, potentially mitigating some of chemotherapy's harshest effects 1 .
Vitamin C, or ascorbic acid, is an essential nutrient with pleiotropic immune supportive roles in the body. It functions as a potent antioxidant, scavenging a wide range of reactive oxygen species that would otherwise cause cellular damage. Additionally, it possesses significant anti-inflammatory properties that could theoretically help counteract the inflammatory cascades triggered by chemotherapy 1 .
The intense physiological stress of myeloablative chemotherapy rapidly depletes the body's vitamin C reserves. Patients with hematologic malignancies often have low baseline levels even before treatment begins, creating a perfect storm of deficiency precisely when the body most needs resources to repair and recover 1 2 .
This deficiency isn't benign. Research has shown that vitamin C depletion correlates with increased markers of inflammation and oxidative stress in transplant patients. Preliminary data even suggests that patients who develop more severe mucositis tend to have lower vitamin C status 1 .
Could restoring vitamin C levels help protect against these damaging side effects? 1
To answer this question, researchers in New Zealand designed a pilot randomized controlled trial—the gold standard for clinical investigation. Their study enrolled 20 patients with myeloma and lymphoma who were scheduled for autologous haematopoietic stem cell transplantation. The design was double-blinded, meaning neither patients nor clinical staff knew who was receiving the active treatment versus placebo, eliminating potential bias 1 .
Participants were randomly assigned to one of two groups using concealed allocation methods. This randomization ensured that the groups would be comparable in all respects except for the treatment received.
The study demonstrated remarkable adaptability when the first three participants receiving chewable tablets could not tolerate them due to nausea and vomiting post-transplantation. Researchers promptly switched to powder-filled capsules for subsequent participants, highlighting the importance of patient-centered design in clinical research 1 .
The study yielded clear, compelling, and somewhat unexpected results that provide important insights for future research.
The pretreatment phase was notably successful. By day 0 (the day of transplantation), pre-supplementation with oral vitamin C had doubled vitamin C concentrations relative to placebo, with median levels of 61 μmol/L versus 31 μmol/L in the placebo group. Importantly, 60% of participants in the vitamin C group achieved plasma concentrations considered "adequate" (≥50 μmol/L), compared to only 10% in the placebo group 1 .
However, the picture changed dramatically following chemotherapy and transplantation. The significant difference between groups was lost by day 7, with only 30% of patients in the vitamin C group maintaining adequate concentrations. This occurred despite continued supplementation according to protocol 1 .
The researchers identified a primary culprit for this decline: gastrointestinal intolerance. Approximately 40% of participants in both groups experienced nausea, vomiting, and diarrhea severe enough to interfere with taking the study medication. This highlights a critical challenge of oral supplementation in this patient population—when patients cannot keep pills down, they cannot benefit from them 1 .
| Time Point | Vitamin C Group (median μmol/L) | Placebo Group (median μmol/L) | % with Adequate Levels (≥50 μmol/L) in Vitamin C Group |
|---|---|---|---|
| Baseline | Similar between groups | Similar between groups | Comparable between groups |
| Day 0 (Transplant) | 61 | 31 | 60% |
| Day 7 Post-Transplant | Not significantly different from placebo | Not significantly different from vitamin C group | 30% |
| Outcome Measure | Vitamin C Group | Placebo Group |
|---|---|---|
| GI Intolerance | 40% | 40% |
| Oral Mucositis Incidence | 40% (at day 7 or 14) | 40% (at day 7 or 14) |
| Ability to Maintain Supplementation | Challenged post-transplant | Challenged post-transplant |
While the study was not powered to detect statistically significant differences in clinical outcomes due to its small sample size, the researchers gathered valuable preliminary data. Oral mucositis was observed in 40% of participants at day 7 or 14, with no statistically significant difference between groups. Similarly, quality of life metrics, while important to monitor, did not show dramatic differences between the vitamin C and placebo groups in this pilot investigation 1 .
Interactive chart showing vitamin C levels over time would appear here
Conducting rigorous nutritional science requires specialized tools and methodologies. The Christchurch study employed several key resources that represent the standard approach in this field:
| Research Tool | Function in the Study |
|---|---|
| High-Performance Liquid Chromatography (HPLC) | Precisely measured plasma vitamin C concentrations from blood samples |
| WHO Oral Toxicity Scale | Standardized assessment and grading of oral mucositis severity (Grade 0-4) |
| EORTC QLQ-C30 Questionnaire | Validated quality of life assessment covering physical, emotional, and social functioning |
| Randomized Placebo-Controlled Design | Gold standard methodology to minimize bias and establish causality |
| Chewable Tablets & Capsules | Initial and adapted delivery methods for the intervention; highlighted importance of formulation tolerance |
Precise measurement of vitamin C levels in blood samples
Standardized assessment of symptoms and quality of life
Modified delivery methods based on patient tolerance
The Christchurch findings resonate with broader research on vitamin C in critically ill patients. Recent investigations have explored similar questions in different clinical contexts:
A 2025 prospective study of 60 patients undergoing allogeneic hematopoietic cell transplantation found that 40% had hypovitaminosis C (<23 μmol/L) at hospital admission. Patients with high baseline inflammatory markers (C-reactive protein or CRP) had significantly worse outcomes, including higher rates of severe mucositis. This underscores the inverse relationship between inflammation and vitamin C status—when inflammation is high, vitamin C levels tend to be low 2 .
The absorption challenges identified in the Christchurch study point toward a potential solution: intravenous vitamin C administration. By bypassing the gastrointestinal system, IV delivery could overcome the intolerance issues that plagued the oral intervention. Pharmacokinetic studies show that intravenous administration achieves much higher peak plasma concentrations—up to 70-fold greater than oral intake—because it avoids the saturation of intestinal absorption mechanisms 1 6 .
This approach is already being investigated in other settings. A 2023 meta-analysis of 44 trials found that vitamin C monotherapy was associated with a 26% reduction in mortality risk in patients with sepsis, a condition sharing some pathological features with the inflammatory state following chemotherapy 7 .
Emerging laboratory research suggests vitamin C might play an even more direct role in cancer therapy beyond supportive care. Some studies indicate that pharmacological concentrations of vitamin C, particularly achieved through intravenous administration, can selectively target cancer stem cells (CSCs)—the resistant cells thought to drive cancer recurrence. Vitamin C appears to act as a pro-oxidant at high concentrations, generating hydrogen peroxide that creates cytotoxic reactive oxygen species specifically in cancer cells while sparing healthy cells 3 6 .
Protects healthy cells from oxidative damage
Selectively targets cancer cells through oxidative stress
The Christchurch pilot study, while small, provides valuable insights that will help shape future research. It demonstrates that while short-term oral vitamin C pre-supplementation can effectively restore adequate vitamin C status before transplantation, ongoing oral supplementation cannot maintain these levels following chemotherapy due to gastrointestinal intolerance and potentially altered metabolism.
The researchers concluded that intravenous vitamin C should be trialled in future studies as this method bypasses the gastrointestinal system, potentially overcoming the absorption and tolerance challenges observed with oral supplementation 1 .
For patients undergoing one of modern medicine's most challenging treatments, this research represents hope—that a simple, natural compound might eventually be optimized to reduce suffering and improve quality of life during stem cell transplantation.
Each study brings us closer to understanding how to best support the body's healing mechanisms during cancer treatment.
As research evolves, the goal remains constant: not just to survive cancer, but to preserve quality of life throughout the journey. The investigation into vitamin C's role in supportive cancer care continues to develop, offering promise for more tolerable treatments in the future.