A daily dose of 1 – 1.5 g vitamin C [structural formula shown below] may protect steroids users against prostate cancer. Lower doses may protect the prostate of non-users, conclude researchers at Seoul National University College of Medicine after doing tests on rats. Their article will be published soon in the Journal of Nutritional Biochemistry.
The reason that the Koreans examined whether vitamin C cancels out the undesirable effect of testosterone on the prostate is a theoretical one. According to recent research, the prostate grows because cells that are influenced by androgens produce more of the transcription factor HIF-1alpha. This leads to an increase in the production of VEGF, a hormone that stimulates the creation of new blood vessels. If the prostate grows and prostate cells start to divide, the risk of errors occurring in the genetic material of the cells increases. And if that happens, cancer cells may start to form.
HIF-1alpha is deactivated by HIF-1-prolylhydroxylases. And the more vitamin C there is in the cells, the harder these enzymes work.
But the proof of the pudding is in the eating. So the researchers injected rats with testosterone [T]. The dose was 10 mg/kg/day. Some of the rats were also given a dose of vitamin C [T+VC]. A control group was given nothing at all [C]. The figure below shows that testosterone increases the production of the prostate cancer protein PSA, and that vitamin C reduces this. The more PSA men have in their blood, the greater the chance of them developing prostate cancer.
After four weeks of supplementation, the researchers observed that the vitamin had reduced the growth of the prostate. The effect was noticeable but somewhat disappointing. The left-hand prostate in the photo below is from a C rat, the one in the centre is from a T rat, and the right-hand prostate comes from a T+VC rat. The researchers suspect that a longer course of vitamin C than the four weeks of the experiment would have had a greater inhibitory effect.
The rats in the T group, exactly as the theory predicted, started to produce more HIF-1alpha. The addition of vitamin C reduced this effect.
Vitamin C works primarily through the enzyme PHD2, the Koreans discovered during the experiment.
They believe that their discovery explains why, in epidemiological studies, men who consume large quantities of fruit and vegetables in their diet develop prostate cancer less often. They also think that their study will be of interest to doctors who treat prostate cancer, as it shows that high doses of vitamin C administered through a drip can help fight prostate cancer. We at Ergo-log thought of those of our readers who, for whatever reason, have higher levels of androgens in their bodies.
Vitamin C supplementation prevents testosterone-induced hyperplasia of rat prostate by down-regulating HIF-1alpha.
Benign prostatic hyperplasia (BPH) is a disease that impairs the well-being of many aged men. To alleviate BPH symptoms or to find a cure for this disease, key molecules should be identified that control prostate cell proliferation. Recently, HIF-1alpha has attracted attention in this context, because it is highly expressed in hyperplasic prostates and prevents prostate cell death. Thus, given that vitamin C inhibits HIF-1alpha expression in several malignant tumors, we examined its therapeutic potential in BPH. HIF-1alpha was noticeably induced by testosterone in prostate cells, and this HIF-1alpha induction was abolished by vitamin C. Vascular endothelial growth factor (VEGF) promoter activity reporter assays and semi-quantitative RT-PCR revealed that vitamin C inhibited HIF-1-dependent VEGF expression. Furthermore, HIF-1alpha suppression by vitamin C was rescued by knocking down HIF-prolyl hydroxylase-2, suggesting that vitamin C destabilizes HIF-1alpha via prolyl hydroxylation. Moreover, vitamin C treatment abolished cell proliferation induced by testosterone treatment to the control level. These results suggest that vitamin C inhibits testosterone-induced HIF-1alpha expression and by so doing effectively prevents prostate hyperplasia. In male rats, testosterone treatment for 4 weeks induced prostate hyperplasia. Furthermore, HIF-1alpha and VEGF levels were significantly elevated in hyperplasic prostates. In vitamin C-treated rats, however, most prostate hyperplasia parameters and prostrate HIF-1alpha/VEGF levels were markedly reduced. Accordingly, our findings indicate that vitamin C could be further developed clinically for use as an anti-BPH agent.
PMID: 19716283 [PubMed – indexed for MEDLINE]