Multiple studies have been conducted to better understand the differences in how oral and intravenous vitamin C administration affects the human body – more specifically, in patients with cancer.
Vitamin C, or ascorbic acid, is essential to the human body. It is required for numerous bodily functions including:
Strengthening the immune system
Acting as an antioxidant – which protects cells from being damaged by free radicals
Helping collagen production – which is a necessary protein in the healing process
Research has shown vitamin C deficiency is relatively common in cancer patients. Some causes associated with low vitamin C levels include low dietary intake, high CRP level, and high platelet count.
Studies involving oral administration of vitamin C have been unsuccessful in demonstrating any benefit in addressing cancer. Additionally, administrating high-dose ORAL vitamin C has adverse effects such as loose stool, or diarrhea.
Because the body limits plasma vitamin C levels from exceeding a certain point via oral consumption, oral administration of vitamin C affects the body differently than intravenous (IV) administration.
Intravenous Vitamin C
Commonly used as an adjunct therapy in treating cancer, IV vitamin C has demonstrated diverse effects in the body – the results depend on the dosage levels. Let’s take a closer look at the different effects associated with low doses and high doses:
Low Dose IV Vitamin C Effects
Unfortunately, very few concrete results have been demonstrated by low dose vitamin C trials due to uncontrolled studies.
High Dose IV Vitamin C Effects
Significant hydrogen peroxide production in tumors – this creates oxidative stress which selectively targets cancer cells
Stimulates the 2-OGDD (2-oxoglutarate-dependent dioxygenase) enzyme family – including the hydroxylases that control the hypoxic response (an important driver of tumor continuation)
Some adverse treatment effects of high dose IV vitamin C therapy include:
Studies and Trials
In vivo trials exhibit vitamin C’s efficacy in addressing cancer/cancer-related symptomatology and pathology. Here are some results from studies conducted on patients with various forms of cancer:
Patients with Tumors
These patients had a variety of tumors including liver, pancreatic, breast, skin, lung, and colorectal.
Treatment – dose-escalation design – 50 > 70 > 90 > 110g – of IV vitamin C four times a week for four weeks
Results – quality of life (as measured by EORTC QLQ-C30, or the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Cancer) remained stable for the initial two weeks and improved over the following two weeks
Stages III to IV Ovarian Cancer Patients
These patients had undergone debulking surgery.
Treatment – IV vitamin C two times weekly for six months (with chemo) and for six more months (post-chemo)
Results – FIVE FOLD FEWER adverse effects, including infection, myelosuppression, neurotoxicity, pancreatic/hepatobiliary toxicity, and toxicities of the pulmonary, gastrointestinal, and renal systems
Stage IV Pancreatic Cancer Patients
Terminally Ill Cancer Patients
Treatment – 10g of vitamin C two times with a three-day interval and an oral intake of 4g a day for one week
Results – (quality of life evaluated using the EORTC QLQ-C30) global health score improvements from 36±18 to 55±16 – patients reported improvement in pain, fatigue, loss of appetite, and nausea
This trial was of short duration and uncontrolled by yielded findings that suggest IV vitamin C may be an effective (and safe) therapy for improving the quality of life in terminally ill cancer patients.
Though administering vitamin C orally may not be largely beneficial when addressing cancer, IV administration appears to be beneficial in the following ways: