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I have read in an article on the internet that cancer is caused due to deficiency of vitamin B17 which has been removed from our diets long ago in the western food. But some people say that vitamin B17 does not work. So, is it deficiency of vitamin B17 which causes cancer i.e. can this vitamin really be used to cure cancer?

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    $\begingroup$ It is mentioned as cancer quackery in this paper which you might find useful. $\endgroup$ – Kiritee Gak Jan 23 '17 at 8:14
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    $\begingroup$ @user39315 Please open new questions, and do not ask in the comments. $\endgroup$ – Chris Jan 23 '17 at 8:57
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    $\begingroup$ @david I would disagree with your last point. Since this is a conspiracy, it is indeed better to have an answer regarding why those claims are false and why amygdalin is indeed harmful rather than useful. For the question title, I agree that it could be framed better. $\endgroup$ – another 'Homo sapien' Apr 11 '17 at 12:50
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    $\begingroup$ Its not about the trolls. I meant it would be useful for the ones who don't know about this matter; if they read this post and get to know the truth behind the conspiracy, then how can't it be better? $\endgroup$ – another 'Homo sapien' Apr 11 '17 at 12:59
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    $\begingroup$ If you wish medical information or advice I would suggest you do not come here. The British, NHS Choices site (nhs.uk/Conditions/Pages/hub.aspx) or the US NIH Health Information (nih.gov/health-information) are reputable sources. If there is a conspiracy, of course, these sites will be part of it. But then, perhaps Elvis has really become a Tibetan monk. $\endgroup$ – David Apr 11 '17 at 13:25
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Short Answer: No.

Background: First of all, there is no such thing as vitamin B17. The compound, amygdalin or laetrile, which is referred to by this term, is not a vitamin1. Amygdalin is indeed a cyanogenic glycoside (like glucosinolates, see this answer) which is poisonous to organisms including humans, because it forms cyanide which is toxic2. See this image for its structure:

amygdalin

The notion that amygdalin is a vitamin started when Ernest Krebs Jr., inventor of 'laetrile' (a modified form of amygdalin), rebranded it as a vitamin to get around the new FDA drug regulations and get it approved as nutrient supplement instead of pharmaceutical3. Ernest Krebs Sr., in 1920s, formulated a theory that amygdalin could kill cancer cells4 and the notion was carried forward by his son, though Ernest Krebs Sr. himself considered amygdalin as too toxic for human consumption. This view received a huge uplift when, in 1973, a public relations officer at Sloan Kettering Hospital, which was given the task by the NIH of performing a series of laetrile trials, alleged a cover up of, and leaked, data that claimed potential for laetrile as an anti-cancer agent5, though nobody else was able to reproduce the same test results in a series of followups. Yet, perhaps the most prominent force which still keeps this myth alive is the book World Without Cancer: The Story of Vitamin B17 by G. E. Griffith (interestingly, reviewed by 'Dr.' Ernest Krebs Jr.). According to all these reports, laetrile might work in following ways6:

  • malignant cells have higher levels of $\beta$-glucuronidase and lesser levels of rhodanase, because of which they are more susceptible to effects of laetrile.

  • malignant cells have higher levels of $\beta$-glucosidase (different from $\beta$-glucuronidase) and lesser levels of rhodanase, because of which they are more susceptible to effects of laetrile.

  • cancer is due to deficiency of vitamin B17 (laetrile) and vitamin B17 is required by cells to restore health (though there is no evidence for this).

  • cyanide released by laetrile has a toxic effect beyond its interference with oxygen utilization by cells. According to this theory, cyanide increases the acid content of tumors and leads to the destruction of lysosomes. The injured lysosomes release their contents, thereby killing the cancer cells and arresting tumor growth.

Laetrile is even supposed to raise the red count in blood, be of value in treating sickle cell anemia, treat parasitic diseases, help regulate intestinal flora, cause lowering of blood pressure in cancer victims and provide relief from arthritis3.

However, all clinical tests have concluded that laetrile is poisonous to humans (and other organisms) due to cyanide poisoning and thus, its effect in cancer treatment is unambiguously negative6,7,8. In fact, use of laetrile has even led to a number of deaths9.

In reality, when amygdalin is ingested, the enzymes $\beta$-glucosidase, emulsin and amygdalase hydrolyze it into gentiobiose and L-mandelonitrile. Gentiobiose is further hydrolyzed to glucose, whereas L-mandelonitrile is converted into benzaldehyde and hydrogen cyanide, which causes cyanide poisoning2. The concerned process looks like10:

amygdalin metabolism

If the quantity of cyanide generated is under the acceptable daily intake limit (0.05 mg/kg body weight)11, then it can be handled easily by enzymes, like rhodanase which converts toxic CN- to non-toxic SCN- ion12. But this quantity is often beyond the limit; a single apricot seed contains about 0.5 mg cyanide13. Hence, it results in cyanide poisoning.

Thus, the so-called vitamin B17 cannot cure cancer.

References:

1. Lerner IJ (1981). "Laetrile: a lesson in cancer quackery". CA Cancer J Clin. 31 (2): 91–5

2. Wikipedia contributors. "Amygdalin." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 10 Mar. 2017. Web. 11 Apr. 2017.

3. United States, Food and Drug Administration. “Laetrile, the Commissioner’s decision” 1978

4. (1991), Unproven methods of cancer management: Laetrile. CA: A Cancer Journal for Clinicians, 41: 187–192. doi:10.3322/canjclin.41.3.187

5. WADE, NICHOLAS (1977). Laetrile at Sloan-Kettering: A Question of Ambiguity. Science, 198, 1231-1234.

6. Ellison NM, et al. “Special report on Laetrile: the NCI Laetrile Review. Results of the National Cancer Institute’s retrospective Laetrile analysis.” N Engl J Med. 7 September 1978.

7. Milazzo S, Horneber M. Laetrile treatment for cancer. Cochrane Database of Systematic Reviews 2015, Issue 4. Art. No.: CD005476. DOI: 10.1002/14651858.CD005476.pub4.

8. Milazzo S, Ernst E, Lejeune S, Boehm K, Horneber M (2011). "Laetrile treatment for cancer". Cochrane Database Syst Rev (Systematic review) (11): CD005476. doi:10.1002/14651858.CD005476.pub3. PMID 22071824.

9. Editors of Consumer Reports Books (1980). "Laetrile: the Political Success of a Scientific Failure". Health Quackery. Vernon, New York: Consumers Union. pp. 16–40. ISBN 0-89043-014-4

10. Amygdalin - TradMPD

11. FAO Meeting Report No. PL/1965/10/2; WHO/Food Add/28.65; Evaluation of the hazards to Consumers resulting from the use of Fumigants in the protection of foods

12. Cipollone R, Ascenzi P, Tomao P, Imperi F, Visca P (2008). "Enzymatic detoxification of cyanide: clues from Pseudomonas aeruginosa Rhodanese". J. Mol. Microbiol. Biotechnol. 15 (2-3): 199–211.

13. S Krashen. Are Apricot Kernels Toxic?. The Internet Journal of Health. 2008 Volume 9 Number 2.

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    $\begingroup$ +1 Great answer. It's cool how your answer and my answer here are actually saying the same thing in terms of how laetrile/amygdalin is useless as cancer medication, but with slightly different narratives and lines of evidence (and also references). $\endgroup$ – AlexDeLarge Apr 11 '17 at 12:43
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    $\begingroup$ @AlexDeLarge thanks for appreciation! I first thought of answering that question, but then I saw this question and thought it would be better to answer this one ;) $\endgroup$ – another 'Homo sapien' Apr 11 '17 at 12:45
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Short version: This is nonsense, cancer does not arise from nutritional deficiencies.

Long version: The substance is called Amygdalin, a poisonous cyanogenic glycoside. It can be found in higher concentration in the kernels of several plants including apricots, plums, bitter almonds, peach, plum. The semisynthetic, modified form is called Laetrile. Taking up this substances with the oral route can lead to cyanide poisoning up to death due to the release of cyanide from the molecules.

There is nothing like a vitamin B17 (which suggests that the substance is an essential vitamin to the human body), this has been invented by cancer quacks. None of the two substances have shown any activity in clinical cancer trials. See references 1 and 2 for details. The second is a systematic review of the Cochrane Foundation which analyses all available articles on this topic.

References:

  1. Laetrile: A lesson in cancer quackery
  2. Laetrile treatment for cancer
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As far as toxicity of laterite is concerned, all currently approved neoplastic agents have enough toxicity and patients succumb to the effects of such more than the disease itself. Not to mention the extravagant cost. There definitely needs more in depth analysis on the disease process to find a simple cure. This disease appears to go beyond genetics alone. A few viral and bacterial variants have been discovered hpv and h. Pylori when earlier it was denied that it is caused by any microorganism.

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Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.

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    $\begingroup$ Welcome to Biology.SE! Please add some references to your answer. $\endgroup$ – another 'Homo sapien' May 24 '17 at 16:01
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    $\begingroup$ Cancer is not a simple disease and there won't be a simple (meaning always working) cure. There has been quite a lot of success lately with targeted and immune therapies - cancer treatment is by far not only chemotherapy. $\endgroup$ – Chris May 24 '17 at 16:10

protected by Chris Nov 24 '17 at 15:22

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