|Prunus dulcis, var amara, near Perpignan, 29th September 2016|
We spotted this almond tree growing wild beside a lane, and (as usual) stopped to break open a few kernels and get a wild snack.
YEUCCH!!! They turned out to be bitter almonds, so we spent the next twenty minutes rinsing and spitting trying to clear every bit of that appalling taste out of our mouths.
We each probably ate no more than 0.1 of an almond.
Prunus dulcis is native to the Middle East, India and perhaps N. Africa. Wild almonds in the native regions are variously bitter and toxic. The sweet variety lacks these toxins and is cultivated all over the world in appropriate climates.
Almonds have been cultivated in places like France and Spain for so long that they are now a characteristic part of the wild flora of those regions. A proportion of the wild trees, like the one we sampled, revert to producing amygdalin and are known as "bitter almond" (Prunus dulcis var amara).
Apparently we might have been forewarned, if we'd known what to look for, by the shorter and broader fruits of the bitter variety, compared to the sweet one.
Bitter almonds are toxic to some degree. Individual fruits vary widely in their potency and it therefore isn't possible to give a recommended daily limit, as acknowledged in this Committee on Toxicity statement on bitter apricot kernels (which contain the same substance, amygdalin or laetrile, as bitter almonds). The authors limit themselves to saying that if you eat no more than one kernel per day you are probably safe, but if you consume 10 per day it puts you in the hazardous range as set by the WHO and the Council of Europe.
The following article, from the WHO Food Additives Series (30), drafted by Dr G. Speijers
has this to say:
"In a case-study a 67-year-old woman collapsed after ingestion of a slurry of 12 bitter almonds ground up and mixed with water. She recovered after treatment in the hospital. The average cyanide content was 6.2 mg HCN/bitter almond (Shragg et al., 1982).
The consumption of 60 bitter almonds is deadly for an adult. For young children, however 5-10 almonds or 10 droplets of bitter almond oil are fatal (Askar & Moral, 1983)."
The following article by Nadia Chaouali et al has more to say on the matter.
This is in a Tunisian context. In Tunisia bitter almonds are used in the production of some widely popular foods, especially orgeat syrup aka almond syrup.
These discussions also take place against the background of claims made in the 1970s-1980s that amygdalin, aka laetrile or B17, is effective in the natural prevention of and dissolution of cancerous tumours. The general idea is that it selectively attacks cancerous cells more than healthy ones. (I should emphasize that amygdalin's medical history goes back a lot further than the 1970s; centuries if not millennia...)
Selling B17 health products is now banned in the USA and in the EU.
You'll find a lot of polarized debate about this on the internet, but mostly it quotes the conclusions of others and interprets without any real authority. Do we have here an absurd, unsubstantiated and dangerous claim by a bunch of quacks; or the sinister suppression of a valuable and simple natural remedy in order to preserve Big Pharma's rip-roaring profits from even more dangerous chemotherapies?
Here are two articles from opposite sides of the debate that, though I can't claim either as authoritative, seem informed, detailed and temperate.