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Currently, there are many studies on intravenous injection of high doses of vitamin C that have the ability to attack cancer cells without harming health. However, these studies have mostly been done in test tubes or in mice, but very few studies have been done in humans.
1. Some problems related to vitamin C and cancer
Interest in using high doses of vitamin C as a cancer treatment dates back to the 1970s, when it was discovered that certain properties of the vitamin could make it become toxic to cancer cells. Early human studies showed promising results with cancer infusion of vitamin C, but these studies were later found to be flawed.
Subsequent well-designed randomized, controlled trials of vitamin C in pill form found no such benefit for people with cancer. Despite the lack of evidence, some alternative medicine practitioners continue to recommend high doses of vitamin C to treat cancer.
Recently, vitamin C given intravenously (intravenously) has been found to have different effects than vitamin C in pill form. This has spurred renewed interest in the use of vitamin C as a cancer treatment. However, there is still no evidence that vitamin C alone can cure cancer, but researchers are studying whether it can increase the effectiveness of other cancer treatments, such as: chemotherapy and radiation therapy or reduce the side effects of the treatment.
There are still no large, controlled clinical trials showing a significant effect of vitamin C on cancer, but some preliminary research suggests there may be a benefit to the combination of treatments standards with high-dose vitamin C until clinical trials are completed, it is too early to determine the role of vitamin C in cancer treatment.
Truyền vitamin C cho bệnh nhân ung thư vẫn đang là vấn đề gây nhiều tranh cãi
2. Studies determining the role of vitamin C in cancer treatment
Based on the known role of vitamin C in collagen synthesis, about six decades ago, William J. McCormick hypothesized that cancer metastasis could be related to vitamin C deficiency, due to poor collagen formation and connective tissue degeneration. Therefore, maintaining optimal collagen synthesis using vitamin C is suggested to limit metastasis. From this hypothesis, author Ewan Cameron proposed that vitamin C inhibits the enzyme hyaluronidase reducing the breakdown and proliferation of cancer cells. He performed the first clinical studies analyzing the anticancer effects of ascorbate. When the authors performed a retrospective study, they also suggested the effectiveness of high-dose vitamin C treatment for patients with advanced cancer. The patient will be given intravenous injection, then oral ascorbate. The results showed an increase in survival time and symptom reduction compared with the control group.
The National Institutes of Health (NIH) has established dietary recommendations for cancer patients. Physiological analysis in young, healthy subjects showed that the pharmacokinetics of the acid varied depending on the way it was used. When subjects received oral doses, plasma concentrations of ascorbate were low (approximately 100–200 μM), whereas intravenous doses resulted in concentrations 100 times higher than those obtained orally (approximately 15 mM). This is a consequence of limited intestinal absorption, renal reabsorption and oral excretion. Unlike oral administration, intravenous administration removes this tight control and produces high plasmatic concentrations that are safe or tolerable for humans. Therefore, high (“pharmacological”) concentrations of AA are achieved only by intravenous administration, not by oral (“physiological”). Based on this evidence, it was proposed that only pharmacological concentrations of ascorbate could act as a drug, and interest in the use of vitamin C as an anticancer agent reemerged.
Trắc nghiệm: Thử hiểu biết của bạn về bệnh ung thư
Ung thư là nguyên nhân gây tử vong hàng thứ 2 trên thế giới. Thử sức cùng bài trắc nghiệm sau đây sẽ giúp bạn có thêm kiến thức về yếu tố nguy cơ cũng như cách phòng ngừa bệnh ung thư.
Bài dịch từ: webmd.com
3. Pharmacological effects of vitamin C in cancer cells
Since the basic knowledge of vitamin C pharmacokinetics was established, several studies analyzing the effects of pharmacological ascorbate in cancer cells have been reported. Initially, in vitro studies in several human and mouse cancer cell lines showed that ascorbic acid at concentrations of about 20 mM selectively killed cancer cells, with no effect on cell lines. normal cells. In addition, the authors proposed that the mechanism of cancer cell death depends on the formation of hydrogen peroxide (H2O2) with an ascorbate moiety as an intermediate. The same research group then confirmed in mice that pharmacologically induced ascorbic acid, obtained by infusion of vitamin C into cancer patients or intravenously, induces the formation of ascorbate radicals and H2O2 in the external environment. cell.
Experimental study showed that intraperitoneal pharmacological administration of ascorbate reduced the growth rate of human ovarian tumors, rat pancreas and rat glioblastoma induced prooxidant effects. The intraperitoneal administration of ascorbate reduces the growth rate of liver tumors in mice based on a cytotoxic mechanism involving extracellular H2O2 production and involving intracellular transition metals.
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References: mayoclinic.org, ncbi.nlm.nih.gov
