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Scientists Find Vitamin C Kills Drug-Resistant Tuberculosis
AndyKrish writes "A BBC story reports that scientists at Albert Einstein College of Medicine at Yeshiva University found Vitamin C kills drug resistant tuberculosis (abstract). Though results are preliminary — the lead investigator of the study said, 'We have only been able to demonstrate this in a test tube, and we don't know if it will work in humans and in animals' — this is an exciting development in the fight against drug-resistant TB."
No context given in the article, but here's the abstract:
"Drugs that kill tuberculosis more quickly could shorten chemotherapy significantly. In Escherichia coli, a common mechanism of cell death by bactericidal antibiotics involves the generation of highly reactive hydroxyl radicals via the Fenton reaction. Here we show that vitamin C, a compound known to drive the Fenton reaction, sterilizes cultures of drug-susceptible and drug-resistant Mycobacterium tuberculosis, the causative agent of tuberculosis. While M. tuberculosis is highly susceptible to killing by vitamin C, other Gram-positive and Gram-negative pathogens are not. The bactericidal activity of vitamin C against M. tuberculosis is dependent on high ferrous ion levels and reactive oxygen species production, and causes a pleiotropic effect affecting several biological processes. This study enlightens the possible benefits of adding vitamin C to an anti-tuberculosis regimen and suggests that the development of drugs that generate high oxidative burst could be of great use in tuberculosis treatment."
So you need ferrous ions as well. Interesting things to have in your lungs, but it's a start.
So.. Did someone just catch up on the later seasons?
Well, to be fair, most organisms in a test tube can be killed by putting in a lot of acid (vitamin C being ascorbic acid). The key thing is that you can't significantly change the pH of the blood / body without causing problems in the host. It is easy to kill shit in a test tube.
In case other readers didn't understand the humor, Alfred Nobel invented dynamite and other explosives. That's why a peace prize in his name may sound funny and contradictory.
no, we're talking of a foreign acidic solution in unnatural concentration being harmful to certain bacteria
But he didn't invent it for warfare, he invented it to make mining easier, once he saw that people would use his invention for warfare he was horrified and thus invented the peace price.
Actually, just vitamin C is Ascorbate.
Ascorbate by itself is relatively unstable. Adding a hydrogen atom stabilizes it and makes it Ascorbic Acid which is probably the most common form of vitamin C.
But you can add other atoms to it like Calcium, Sodium or Magnesium, which would make non-acidic, but still bioactive, forms of vitamin C.
Large doses, particularly ascorbic acid, may promote diarrhea. Non-acidic forms like calcium ascorbate, sodium ascorbate, and ascorbyl palmitate, are more tolerable. YMMV.
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Mtb is an intracellular pathogen. It invades our cells, the very same cells that are supposed to kill bacteria (the macrophages). This is why treatment of TB takes six months. Vitamin C, at a dosage lethal for Mtb as described in the article, cannot be used to kill the bacteria in our cells. The importance of the article is that it identifies a potentially intereseting difference between Mtb and other bacteria.
As for vitamin C, this is not some kind of a miraculous drug; it is just a co-enzyme required for a few particular reactions in our metabolic pathways. We, humans, are mutants, we lack the ability to synthetise vitamin C -- along with our cousins, the monkeys, although most animals do synthetise it on their own. Lack of vitamin C impedes the metabolism. However, only little of the co-enzyme is needed, and once vitamin C is no longer a limiting factor, it has barely an effect.
Think about that in terms of a network. If your wireless router is extremely slow, buying a new one will increase the speed of your connection. But what good is a super fast wifi router, if the outgoing connection runs at 10Mbit?
Vitamin C is also an antioxidant, and this is why some people (quite incorrectly) think that taking large doses of vitamin C are beneficial. However, there are two forms of this compound, L-ascorbate (vitamin C) and D-ascorbate; both are antioxidative, but only one is a co-enzyme. D-ascorbate, however, shows no beneficial effects.
Big pharma has not much interest in preventing the use of vitamin C in Mtb treatment. Mtb drugs are cheap, generic, and effective; the main reason why Mtb is a problem for much of the world is lack of fast and cheap diagnostic tools. You see, 2 billions (2e9, one third of worlds population) are infected with Mtb, and of these, only 10% will develop tuberculosis during their lifetime. However, we don't know which, why, and when. Also, when a person falls ill, it is not a quick process like a flu; rather than that, a person starts feeling unwell, caughing and becomes infectious over weeks before she finally decides to see a doctor. Here is a review article I wrote on TB and biomarkers: http://www.ncbi.nlm.nih.gov/pubmed/23181737 (full text behind a paywall, unfortunately).
Pauling believed that taking large doses of vitamines will prevent cancer and took large amounts of vitamin C throughout his life. In 1994, he died of prostate cancer.
6000 mg vitamin C daily, not counting vitamin C in the food? That is a lot. Consult your physician and be very, very cautious about suggesting medical advice if you are not prepared to take moral and financial responsibility for it. Yes, vitamin C is important. Yes, increased intake of vitamin C has been show to have several health benefits, including reduced stroke and cardiovascular disease risks, especially in smokers. However, "increased intake" means "well below 1g/day".
6000 is 30-100 times the recommended daily dose. Although studies indicate that vitamin C intake at 2-4 g/day may not have large adverse effects (1), one has to be extremely cautious when recommending supplementing your diet by a 100x of a daily dose. The fact that you don't experience any adverse effects such as kidney stones (at least yet) does not mean that a person reading your comment will not suffer from that either.
Apart from the problems with the digestive tract, vitamin C can hamper endurance in physical exercises (2). Moreover, vitamin C not used by the organism (which requires as little as 100-200mg / day) is excreted (3). For that, it is metabolised to oxalic acid, which in turn can cause kidney stones (4 and the references therein). So yes, although problems with vit. C overdose do not seem to be common and are not comparable to overdoses of some other vitamins, at 6g/d saying that "C can't hurt" is very risky (especially as supplements can contain other vitamins as well, and the fat soluble vitamins A, D, E and K can cause severe adverse effects -- vitamine poisoning -- when overdosed).
The highest risk-free level of daily intake for vitamine C has been recently proposed to be 1000 mg (1g) (5, 6). People, before you install some shady software someone recommends at a biology-oriented website, ask your IT friend for advice. Before your follow medical advice from Slashdot, consult your physician.
"Rational by choice."
Prove it. Read the evidence based medical studies rather than trusting and spreading anecdotes.
(1) http://onlinelibrary.wiley.com/doi/10.1111/j.1753-4887.1999.tb06926.x/abstract
(2) http://ajcn.nutrition.org/content/87/1/142.short
(3) http://ajcn.nutrition.org/content/69/6/1086.short
(4) http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2362.1998.00349.x/full
(5) http://jama.jamanetwork.com/article.aspx?articleid=189543
(6) http://www.pnas.org/content/93/8/3704.short