Thursday, May 04, 2017

Vitamin C: Snake Oil or Valid Cancer Therapy? Public Lecture 2nd May

Hello! Apologies, once again for the radio silence. It's not you, it's me, and my dodgy shoulder.

The main reason the blog is growing weeds is that the overuse syndrome in my right shoulder flares if I type too much.  And, as I'm in the heavy writing phase of my degree, I can't really escape that! I'm slowly mastering the voice dictation software but it's still much slower than typing at the moment. The frustration level is quite high, although I'm sure it's good for my brain to articulate my thoughts directly into an easily readable format! The only social media I'm really doing is Instagram because the voice recognition on my phone is pretty good, so please catch me there. Have any of you readers battled with OOS? Do you have any tips for me?

Ok! A few nights ago I attended a lecture at the med school here in Christchurch and a few people have asked me for a summary, so here are my minimally tidied actual notes with a few low quality phone pics :)

The lecture was Vitamin C: Snake oil or valid cancer therapy? but the first part primarily dealt with infections.

Part one: Dr Anitra Carr - Vitamin C and infectious disease

A vitamin is a substance which is 'vital' for life. Most animals can produce their own vitamin C (ascorbic acid) from glucose, however humans, guinea pigs and monkeys can't due to a mutation of the GULO gene causing lack of the GULO enzyme.

The body maintain a level of 50 to 70 mmol/L, through intestinal absorption at vitamin C receptors, and renal reabsorption

Vitamin C levels peak 2 to 3 hours after consumption

Vitamin C accumulates in the brain, adrenals and pituitary gland. It is a co-enzyme for collagen synthesis

There appears to be no difference in uptake between vitamin C from foods and vitamin C from supplements, however foods also contained bioflavonoids which can stabilise vitamin C through reducing its oxidation

Vitamin C tissue saturation occurs at intakes greater than 200 mg a day: this is the Ministry of Health target for reduction of disease risk [Anitra then showed a slide of the new USDA MyPlate which now encourages half the plate to be filled with fruits and vegetables, rather than having grains, which are low in vitamin C, as the basis of meals]

The RDI in New Zealand (45mg/ day) is based on scurvy prevention and is undoubtedly too low. Other countries have increased their recommended daily intakes

Vitamin C requirements increase greatly with stress. Even animals that make their own vitamin C increase their intake during times of stress or illness to maintain tissue saturation

Severe infections can cause low plasma vitamin C, however this is not routinely measured. Sepsis correlates with levels around 20 mmol/L

Deficiency and insufficient levels are rampant in hospitals, and probably not helped by hospital food! The suggestion was to replace the traditional hospital gift of flowers with kiwi fruit

When critically ill,vitamin C intake may not raise serum vitamin C as much as expected. I made some indecipherable note here that I think says that 3000 mg a day oral intake is needed to restore levels if someone is sick and has a level of 23 ┬Ámol/L

Here are some links to studies and cases mentioned:

Alan Smith, recovery from swine flu
Cochrane review on vitamin C and the common cold (may help if you are stressed or an athlete)
I.V Vitamin C for lung infections
I.V Vitamin C reducing mortality and kidney injury in sepsis, and a similar study here which showed a huge reduction in mortality.

Part two: Associate Prof Gabi Dachs - Vitamin C and cancer

This talk started with a discussion around the hallmarks of cancer. You can read about those here. Basically, they are the things that make cancer deadly, such as its ability to hide from the immune system, to use glucose like crazy and to infiltrate other tissues

HIF-1 is a transcription factor which could be considered the master regulator (mafia boss "Al") of many of the hallmarks of cancer. It is a target for cancer therapy and there are currently 41 novel HIF-1 inhibitor patents registered or pending. An example given was that HIF-1 inhibition decreases the cancer's ability to use glucose

Ascorbic acid also seems to act as a HIF-1 inhibitor

There is a 200 fold difference between vitamin C administered by I.V. and that taken orally (I assume difference in serum ascorbic acid levels attained, although I didn't write that down), however the peak level obtained after injection is short lived

There is a high incidence of inadequate intake in cancer patients and a higher percentage show measured deficiency. A figure mentioned was that three quarters of cancer patients have either inadequate or deficient measured ascorbic acid levels

Samples from the Cancer Society tissue bank of bowel, uterus, kidney and breast cancer were tested. It was found that increased vitamin C in the tissue correlated with decreased levels of HIF-1

Another study (reference here) found increased six year survival time and decreased HIF-1 in those with tumours higher in vitamin C

A big question is how to get the vitamin C into the tumour. Early studies by Linus Pauling showed no effect with oral vitamin C

However, a recent study (forgot to record the reference, sorry - it might have been as yet unpublished data) using very high doses of intravenous vitamin C (70 g a day in bowel cancer patients for the four days immediately before their surgeries to remove the cancer) resulted in very high levels of vitamin C at the centre of the tumour and in the surrounding tissue. In the control group the centre of the tumour contained little to no vitamin C, and the tissue surrounding it was also deficient. This study did not look at HIF-1

There are a number of promising studies showing that higher vitamin C levels results in a less aggressive cancer. More studies are warranted in this area

The take-home message was that vitamin C intake is important, and that many people do not consume enough. The best thing you can do for your long-term health is to get your intake up above 200 mg a day and keep it there for the rest of your life.

So there you have it! If you were there and have anything to add please let me know. And if you are wondering like I was whether it's the gold was a green kiwi fruit that have more vitamin C, the correct answer is, the gold ones (somebody had to ask…).

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