Mounting research on vitamin C's role in cancer and infection may change treatment methods

Scientists and doctors in APAC, North America and Europe have been conducting trials on the effects of vitamin C on tumours, as well as patients undergoing chemotherapy.

According to Otago University's Professor Margreet Vissers, this coincides with an improved understanding of vitamin C over the last 10 years, especially with regards to pharmacokinetics (the metabolic process) of how it works in the body, as well as its potential in treating cancer, and infectious diseases like pneumonia and sepsis.

C for cancer

Vissers' colleague, Associate Professor Anitra Carr, told NutraIngredients-Asia​: "Over the last 10 years, there's been a real renaissance in the world of vitamin C, with major discoveries being made in relation to its mechanisms and how we can use it to treat patients.​

"There's still a lot of ongoing research into vitamin C’s effects on cancer. What people are starting to focus on now is vitamin C's role in epigenetics, which is how our genes express themselves in the body.​

"Vitamin C has recently been discovered to regulate enzymes that control our epigenetics, which means it can upregulate or downregulate specific cancers that may respond to vitamin C depending on their epigenetic mechanisms."​

She further explained that this meant doctors would soon be able to develop more targeted treatments and screen people to determine who is more likely to respond to vitamin C. That way, they can focus on treating them rather than giving vitamin C to just any cancer patient, including non-responders who may need something else for their condition.

Carr added that vitamin C also helps improve the quality of life of patients undergoing chemotherapy, primarily by decreasing the toxicity of the treatment in the organs.

"Patients feel less pain, sleep better and have better appetites when they take vitamin C in higher, intravenous doses concurrently with chemotherapy."​

While Vissers acknowledges that using high doses of vitamin C to aid cancer treatment is still a controversial method — mainly because solid evidence of its efficacy is scant and reliable clinical studies are non-existent — she also believes attitudes towards vitamin C's therapeutic properties are slowly changing.

With an increasing number of researchers discussing appropriate clinical use and identifying the types of clinical trials, she said, it would become easier to identify which patients would benefit from vitamin C treatment and how best to treat them.

Her research trials are funded by the Canterbury Medical Research Foundation, Health Research Commission, and NZ Breast Cancer Foundation.

Infection intervention

In terms of vitamin C's effects against infectious diseases, Carr said: "This field has definitely exploded in the last one to three years. Studies are starting to show that giving vitamin C to critically ill patients can potentially decrease their mortality rate and improve their chances of survival."​

She further said that without vitamin C treatment, about 50% of septic shock patients would die. However, vitamin C in intravenous doses of approximately 7g a day has been found to improve organ function even in cases of organ failure, and to increase a patient’s chances of survival.

Carr added: "These are observations from some of some small initial studies that have been conducted so far. There are over a dozen clinical trials going on around the world now that are trying to confirm these findings."​

Gathering of the greats

Carr was speaking to NutraIngredients-Asia​ shortly after a recent symposium, called Vitamin C for Cancer and Infection — from Bench to Bedside​, at which she and Vissers were co-conveners.

The symposium — held in Auckland on February 15 and 16 and endorsed by the Royal New Zealand College of General Practitioners (RNZCGP) — featured prominent doctors and scientists from New Zealand, Europe and the US, who had been investigating vitamin C's potential against cancer and infectious diseases.

Among the guest speakers were Professor Jeanne Drisko from the University of Kansas, and US Critical Care physician and researcher, Dr Michael Hooper.

The delegates shared results from the latest international trials, and intensive care nurses discussed their experiences with patients who had received treatment using a novel vitamin C protocol for serious infection.

New information on vitamin C's effects on four main areas were also discussed: slowing cancer growth by controlling tumour hypoxia, restricting the spread of tumours through high-dose vitamin C infusions to kill cancer cells, controlling enzymes that regulate cancer cell epigenetics, and improving quality of life for cancer patients.

The symposium also included a special open session on the second day, which allowed members of the general public the opportunity to find out more about the latest research.

Carr said: "Some of our speakers told us about their personal experiences with their patients and how they responded to treatment involving vitamin C — instead of having to turn off life support, more patients are leaving the ICU alive and well, so it's a really exciting area of research.​

"We're hoping for these larger trials to come up with positive findings, so that vitamin C treatment will become routine practice for cancer patients and patients with infectious diseases."​

Trials and future targets

Carr also revealed her involvement in an ongoing trial and an upcoming study, both on the effects of vitamin C on critically ill patients.

"We've set up the first clinical trial in an intensive care unit in New Zealand and we’ve recruited half the participants so far. Hopefully, we'll finish recruitment by the end of the year."​

The researchers are recruiting 40 patients with severe sepsis at the Christchurch Hospital ICU, and will be given either IV vitamin C or placebo over the course of four days.

They will then measure the patients vitamin C levels, as well as selected biomarkers of inflammation and organ function, in order to determine whether the severity of sepsis has been lowered in the intervention group.

Carr added: "We're also in the process of setting up another trial for patients with community-acquired pneumonia (CAP). They'll be administered intravenous and oral vitamin C, and we'll see if this improves the outcome of their sickness and treatment."​

CAP, which results in over 14,000 hospital admissions and more than 1,000 deaths in New Zealand annually, requires vitamin C for immune response, tissue protection and antioxidant action.

The aim of the upcoming study is to determine the feasibility of a clinical trial involving early vitamin C administration (intravenous while on IV antimicrobial therapy, followed by oral administration while on oral antibiotics), in combination with standard antimicrobial therapy and supportive care, on the outcome of moderate to severe CAP.