15 Common Cancer Symptoms Can Food Prevent Cancer? Colon Cancer: What To Know Lung Cancer: Visual Guide Hodgkin Lymphoma: Learn More IV Vitamin C Boosts Chemo's Cancer-Fighting Power? Lab study found it also left healthy cells unharmed, but experts say more research needed WEDNESDAY, Feb. 5, 2014 (HealthDay News) -- Large doses of intravenous vitamin C have the potential to boost chemotherapy's ability to kill cancer cells, according to new laboratory research involving human cells and mice. Vitamin C delivered directly to human and mouse ovarian cancer cells helped kill off those cells while leaving normal cells unharmed, University of Kansas researchers report. "In cell tissue and animal models of cancer, we saw when you add IV vitamin C it seems to augment the killing effect of chemotherapy drugs on cancer cells," said study co-author Dr. Jeanne Drisko, director of integrative medicine at the University of Kansas Medical Center. In follow-up human trials, a handful of cervical cancer patients given intravenous vitamin C along with their chemotherapy reported fewer toxic side effects from their cancer treatment, according to the study published in the Feb. 5 issue of Science Translational Medicine.
"In those patients, we didn't see any ill effects and we noticed they had fewer effects from the chemotherapy," Drisko said. "It seemed to be protecting the healthy cells while killing the cancer cells." Intravenous vitamin C has been considered an integrative medical therapy for cancer since the 1970s, Drisko noted. But vitamin C's cancer-killing potential hasn't been taken seriously by mainstream medicine ever since clinical trials performed by the Mayo Clinic with oral vitamin C in the late 1970s and early 1980s found no anti-cancer effects, she explained. Researchers have since argued that those trials were flawed because vitamin C taken orally is absorbed by the gut and excreted by the kidneys before its levels can build up in the bloodstream. But it's been hard to attract funding for further research. There's no reason for pharmaceutical companies to fund vitamin C research, and federal officials have been uninterested in plowing research dollars into the effort since the Mayo research was published, Drisko said.
This latest investigation began with researchers exposing human ovarian cancer cells to vitamin C in the lab. They found that the cells suffered DNA damage and died off, while normal cells were left unharmed. The researchers then tested vitamin C on mice with induced ovarian cancer. The vitamin appeared to help chemotherapy drugs either inhibit the growth of tumors or help shrink them. Finally, the team conducted a pilot phase clinical trial involving 27 patients with stage III or stage IV ovarian cancer. The patients who received intravenous vitamin C along with their chemotherapy reported less toxicity of the brain, bone marrow and major organs, the investigators found. These patients also appeared to add nearly 8.75 months to the time before their disease relapsed and progressed, compared with people who only received chemotherapy. The researchers did note that the study was not designed to test the statistical significance of that finding. Vitamin C in the bloodstream helps kill cancer cells because it chemically converts into hydrogen peroxide when it interacts with tumors, Drisko said.
"If you can get your blood levels of vitamin C very high, it gets driven into the space around the cancer cells," she explained. "In that space, it's converted into hydrogen peroxide. It's very similar to what our white blood cells do. They create hydrogen peroxide to fight infection." Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City, said intravenous vitamin C therapy is not unheard of among cancer doctors. "I've had patients come in and say they were doing vitamin C intravenous therapy," Bernik said. "I always tell them we don't know enough to know whether it is good or bad." This new research raises interesting possibilities, but until larger clinical trials are conducted Bernik says her advice to patients will not change. "You have to do a bigger study with patients and look at outcomes. You also have to make sure these treatments don't interfere with the treatments we're giving currently," she said. "There may be some efficacy in what they're doing.
It just needs to be proven. This is just the start of more studies looking at this in-depth." Dr. Michael Seiden, chief medical officer for The US Oncology Network, agreed. "It is important to emphasize that many vitamin therapies have shown interesting results when applied to cancer cells in test tubes yet, to date, these approaches typically are not effective and occasionally prove harmful in human studies," he said. "At this time, there is still no evidence that high-dose vitamin C should be part of the treatment for women with ovarian cancer." While she agreed that larger trials need to be conducted, Drisko was not as hesitant.There's a plausible mechanism we're investigating for why it works," she said. "We should be using this in patients, rather than dragging our feet and worrying about using it at all."THANK YOU FOR YOUR SUPPORT! YOUR PATRONAGE ALLOWS US TO SUPPORT THESE CHARITIES & MOREVolume 1, January 2016, Pages 10–12 Vitamin C (ascorbic acid, ascorbate) is a basic compound that is of great importance with its role in various enzymatic reactions including the synthesis of collagen, as well as with its redox functions.
Vitamin C has become the center of interest in cancer studies, in consequence of the facts that connective tissue changes and vitamin C deficiency were first alleged to be associated with cancer in the 1950s; and that high doses of vitamin C was asserted to be cytotoxic for cancer cells, later on. The results of the first study carried out in the 1970s were promising; but afterwards, the studies were ascertained to be faulty. Despite the positive results achieved from some laboratory and animal experiments, randomized clinical trials did not verify those findings, and no clear benefit of vitamin C for cancer treatment could be demonstrated. As for studies, where its use in combination with other cancer treatment regimens was assessed, conflicting results were obtained. Although intake of high doses of vitamin C is alleged to be harmless, based on that it is in the group of water soluble vitamins and is not stored in the body, there are many side effects and drug interactions reported in the literature.
For now, it is better to abstain from this treatment, until the benefit of the treatment (if any) is clearly demonstrated, considering the potential side effects and interactions.Vitamin C, also known as ascorbic acid and ascorbate, is a basic compound that belongs to the group of water-soluble vitamins. It has l- and -enantiomer, but d-enantiomer is not available in nature and has no physiological significance; therefore, it always refers to the l-enantiomer of ascorbic acid and ascorbate, unless written otherwise.1 Vitamin C can be produced by most animals and plants from d-glucose and d-galactose, whereas it is not produced in humans due to the lack of l-gulonolactone oxidase enzyme; and therefore, it should be taken externally.2 The World Health Organization (WHO) recommends a daily intake of 45 mg C per day for healthy adults.3The biological importance of vitamin C is that it plays a cofactor role, as a reducing agent, in various enzymatic reactions. Because it has a low redox potential of 280 mV, it has the potential to react with almost all other oxidized free radicals.
Therefore, it is used as an antioxidant. Vitamin C is also a compound that plays an important role in collagen synthesis.2 Vitamin C is also responsible in the synthesis of carnitine and various neurotransmitters as well as tyrosine metabolism and microsomal metabolism.4 Because it is available in high concentrations in the immune cells, and is rapidly consumed in the body in case of any infection, it is thought to be associated with the immune systemHowever, its mechanism has yet to be clearly elucidated.5 Severe vitamin C deficiency leads to gum recession, weakness, lethargy, and scurvy characterized by easy bleeding and bruising. The symptoms of scurvy develop as a result of weakened connective tissue in the body, and vitamin C is given to patients with scurvy for strengthening their connective tissues.6Some alternative medicine proponents assert that high doses of vitamin C can be used in the treatment of cancer. But although promising results have been achieved from some laboratory and animal studies, these assertions have not been supported by clinical studies on humans.
In some studies, when it has been combined with other treatment regimens, some effects have been observed but specific contribution of high-dose vitamin C to those results could not be shown.7, 8, 9 and 10For the first time in 1753, citrus fruits were asserted to prevent scurvy; and upon that, the way of the path to the discovery of vitamin C was opened. In 1912, the scientist Casimir Funk coined the term “antiscorbutic vitamin” to refer this compound contained in fruits and vegetables. In 1920, the British biochemist Jack Drummond used the term “vitamin C” to refer this compound.11, 12 and 13 For the first time in a study conducted in 1959, it was asserted that cancer could be associated with connective tissue changes, and such a condition could be associated with a deficiency in vitamin C. Upon this assertion, the use of vitamin C in cancer treatment became a topic of conversation.14 High-dose vitamin C began to be tried by the Scottish surgeon Ewan Cameron for the first time in 1970, in his studies on cancer patients.
Afterward, the studies attracted greater interest upon the participation of the Nobel Prize winner Linus Pauling. As a result of their studies on patients with advanced cancer, Cameron and Pauling asserted that high-dose ascorbic acid can enhance the body resistance and can be a potential therapy agent for cancer, but those studies were then found to be faulty.15, 16, 17, 18 and 19The general consensus among practitioners is that high-dose intravenous vitamin C (HDIVC) is greater than 10 g/infusion and low-dose intravenous vitamin C (LDIVC) is less than 10 g/infusion.Although intake of high doses of vitamin C is alleged to be harmless, based on that it is a water soluble vitamin and is not stored in the body, there are many side effects and drug interactions reported in the literature. It has been reported that high-dose vitamin C could increase hemolytic anemia in those who have Glucose-6-phosphate dehydrogenase deficiency; and the risk of renal failure in those who have renal disorders.20 and 21 In addition, because vitamin C may increase the bioavailability of iron, its use in hemochromatosis patients is not recommended.22 Furthermore, vitamin B12 and copper absorption can be reduced, as well.23 Because vitamin C acidifies the urine, it can cause the formation of kidney stones;
and on the other hand, a case of hyperoxaluria may emerge due to oxalic acid formed as a result of vitamin C metabolism.24 In a study published in 2000, the tolerable upper limit of vitamin C was determined—for the first time—to be 2 g, and amounts exceeding this limit were reported to have a laxative effect. Diarrhea is already the most common side effect of high-doses vitamin C.25In the literature, there are studies showing that the use of high-dose vitamin C in combination with certain chemotherapy drugs increases the toxicity. It has been shown that the use of high-dose vitamin C in combination with arsenic trioxide in acute myeloid leukemia, refractory metastatic colon cancer, and metastatic melanoma causes serious side effects and leads to the disease's progression.9, 10 and 26 And in some studies, researchers had to discontinue their studies due to unexpected effects.27 and 28In some laboratory studies, pharmacological doses of vitamin C (0.1–100 mM) were shown to reduce proliferation in cell lines in various types of cancer.
The potential mechanism of this effect of vitamin C was investigated in laboratory studies, as well; and high-dose-vitamin C was shown to create cytotoxic effect on cancer cells, by means of chemical reactions that produce hydrogen peroxide.29, 30, 31 and 32 In laboratory studies again, pharmacological doses of ascorbic acid increased the effect of arsenic trioxide in ovarian cancer cells; gemcitabine in pancreatic cancer cells; and the combination of gemcitabine and epigallocatechin-3-gallate (EGCG) in mesothelioma cells.33, 34 and 35 In a study conducted in 2012, high-dose ascorbate was reported to increase the radiosensitivity of glioblastoma multiforme cells.36 But in some studies, it was reported to reduce the effect of the drug, when used in combination with certain chemotherapy drugs such as doxorubicin, methotrexate, and cisplatin.37The first clinical studies on the effects of high-dose vitamin C were carried out in the 1970s, by Linus Pauling and Ewan Cameron. Dr. Cameron and the chemist Pauling asserted, as a result of their studies, that IV (intravenous) administration of high-dose vitamin C significantly prolongs the survival of advanced-stage cancer patients.15, 16 and 19 However, when their studies were evaluated by the National Cancer Institute later on, they were concluded to be poorly designed and inaccurate.