Conclusions and Lacunae
Death by apricot kernels appears to be rare, consuming more than 20 kernels at once can lead to serious negative reactions, but again, there are few recorded cases, and milder negative reactions can occur with eating about five to ten kernels at once.
The data triangulate well, but, as is obvious from table 1, the empirical basis of these summary statements is weak. We would eventually like to say with confidence what the lowest observed adverse effect level (LOAEL) is as well as what the no observed adverse effect level (NOAEL) is.
In addition, major mysteries remain.
Thousands of people have purchased and presumably have eaten apricot kernels. Young (1992), in fact, states that in the 1970's, apricot kernels were “in vogue,” and even today they are widely advertised on the internet. Why do reports of apricot pit toxicity appear so rarely in the professional literature or even anecdotally, especially when the anti-laetrile establishment is so eager to cite the few that do exist? Is apricotpit.com correct in stating that negative reactions appear in only a few cases?
Of course, such reactions could be common but simply not reported. More likely, serious negative reactions are in fact unusual.
A second mystery is how people are apparently able to accommodate to apricot kernels, having negative reactions at first but gradually building up to higher doses (see e.g. cgeordge's report, cited above).
One website gives the following advice: “If you do not have cancer and you want to prevent it, eat 7 to 10 apricots seeds daily (start out at a low dosage, such as 1 or 2 at a time and work up to 7 to 10) “ (http://www.1cure4cancer.com/continue_pp2.htm
How does accommodation occur, and what are the best schedules to follow in “getting used to” apricot kernels?
The third mystery is why there is so little research on the relationship between consuming apricot kernels and negative reactions.
I suspect that a major part of the problem is the widespread belief that Laetrile is useless against cancer. Anti-Laetrile writers have seized on the few studies of apricot pit toxicity and have cited them again and again, giving the false impression that apricot pits are dangerous and no further research is necessary.
But the case against Laetrile as an anti-cancer agent has not been made. It has been argued that studies “proving” that Laetrile is useless are deeply flawed (Griffin, 1997; Moss, 1966; Krashen, 2008, 2009). In addition, the professional literature contains a number of reports of patients who did well with Laetrile, reports written by professional physicians who reported the cases carefully, and are not in the business of selling apricot kernels (e.g. Morrone, 1962, Navarro, 1955, 1970, 1975; Navarro and Lagman, 1956; Navarro et. al, 1957, 1958). These cases cannot be ignored, and there are too many of them to attribute all to fraud, misdiagnoses or spontaneous remission.
Despite the pessimism of the medical establishment, people continue to consume apricot kernels, and if future studies on the efficacy of laetrile are positive, consumption will increase. It is essential that we improve the state of knowledge on the possible toxicity of apricot kernels.