Natural Health Blog | Laetrile, B17, Detoxing, Supplements

Date: 10/25/2006    Written by: Jon Barron

How Laetrile Works, B17


Like clockwork, every month or so, I receive a question on laetrile. Does it work? Does it cure cancer? I can't answer that question; the evidence is decidedly mixed. Depending on how you look at the studies, you can come to completely different conclusions. What I am willing to say is that most people don't understand what laetrile is, or how it works. Once you do understand though, you can make a very strong case for why it should at least be considered by anyone who has cancer.

The presence of cyanogenic glycosides in the diet is normally not a big deal. Any vague possibility of problems is directly related to the dosage and to the overall nutritional status of the person consuming the food. Many, many foods (not just apricot pits) contain cyanogenic glycosides. They are used by the plants as a natural insectiside. Flax seed meal, for example, contains two cyanogenic glycosides, linustatin and neolinustatin. But as I mentioned, MANY foods are slightly cyanogenic (e.g. wheat, barley, lima beans, apples, almonds, blackberries, blueberries, strawberries, etc -- not to mention vitamin B12 (cyanocobalamin)). But as a result of evolutionary adaptation (so we can eat these foods), our bodies have developed a capacity to detoxify low concentrations of cyanide through the addition of sulfur (from amino acids) to form thiocyanate or through a reaction with cysteine to form beta-cyanoalanine.

If the dietary levels of sulfur-containing amino acids are adequate, the body is designed to accommodate a low intake of cyanide; but if the diet is low in protein, or it is low in the sulfur containing amino acids as a result of imbalances in the vegetarian proteins consumed, then these foods can exhibit toxicity. The bottom line is that few people are likely to consume anywhere close to enough foods containing cyanogenic glycosides to present a problem.

But, and this is very important to understand, there is no "free" hydrogen cyanide in apricot pits, or any of the other foods I just mentioned.

It is only when these foods come in contact with the enzyme beta-glucosidase that the cyanogenic glycosides are broken down to form two molecules of glucose, one molecule of benzaldehyde, and one molecule of hydrogen cyanide (HCN). Within the body, the cancer cell - and only the cancer cell - contains that enzyme. And this, of course, has profound positive health implications - potentially.




One final thought to keep in mind is that in most documented cases in which any benefits were associated with laetrile, the laetrile was used as part of a comprehensive protocol that included detoxing, an extremely clean raw diet, and a high level of supplementation.

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    Submitted by Mark on
    June 18, 2007 - 9:55pm

    To allow calculation of the amounts of amino acids, vitamins and minerals you are consuming in your diet, you can order a new software program called a Nutrient Calculator. You can view details on it at:

    Submitted by Guest on
    March 7, 2012 - 1:16pm

    Dear Sir,
    here is a link to scientific paper:;2-6/pdf

    which proves that the evidence for the claims that laetrile (amygdalin) can prevent or control cancers has been reviewed and proves it doesn't work. The β-glucosidase content of cancer tissues is low compared to that of normal liver and small intestine. Cancer tissues contain the enzyme rhodanese in amounts comparable to that of liver and kidney and hence, cannot be attacked selectively by cyanide release through β-glucosidase action on amygdalin.
    Besr Regards

    Submitted by BaselineFoundation on
    March 13, 2012 - 12:35pm

    You use the word “proof” a bit loosely – based on a paper that “selectively” chooses to reference only negative studies and not include the positive studies. Understand, the paper researched nothing itself. It merely assembled a report that referenced only negative studies. I’m not sure that actually qualifies as proof. You could pretty much have done the same thing proving the benefits of hormone replacement therapy(and in fact, many papers did exactly that) – at least before the Women’s Health Initiative and the Million Women Study proved it tended to kill you. As for laetrile, there are in fact numerous studies, including one extensive five year study at Sloan Kettering, that came to exactly the opposite conclusion vs the paper you cite. For some historical perspective on the positive research on amygdalin, check out:

    Again, we’re not saying that laetrile works, only that the case for it working is still open – despite the “proof” you offer.

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