Bitter almonds are the seed of Prunus amygdalus var. amara DC, a small tree belonging to the Rosaceae family. The bitter taste of these almonds is largely linked to the presence of amygdalin (2-4%), a cyanogenetic glucoside which, by hydrolysis, gives rise to prussic acid, better known as hydrogen cyanide. Hydrolysis takes place thanks to the presence of an enzyme, called emulsin, present inside the same bitter almonds, which breaks down the amygdalin into benzaldehyde, glucose and hydrogen cyanide. The same process occurs at the intestinal level, thanks to the B-glycosidase enzymes produced by the intestinal flora, which therefore make almonds bitter a potential and dangerous poison for humans.
Thus, the ingestion of a small number of bitter almonds can be fatal: it is estimated that 6-10 seeds are sufficient to cause a deadly poisoning in the child, while for an adult the lethal dose is around 50-60 units. Fortunately, the markedly bitter taste of these almonds, which is proportional to their content in amygdalin, strongly discourages their intake. Symptoms of hydrocyanic acid poisoning include headache, vomiting, confusion, increase in the frequency and depth of breathing, loss of consciousness, convulsions.
At sight, a bitter almond can be distinguished by a sweet almond for the wider base and the shorter length.
The rich lipid content of the seeds means that an oil used in perfumery and cosmetics (for the production of soaps) is extracted from bitter almonds, after rectification to remove the hydrocyanic acid. Unlike sweet almond, with laxative properties (20-30 ml), bitter almond oil is not used internally for medicinal purposes, although once rectified it can be used in pastry. The same goes for the outside, where sweet almond oil is more widely used, with its soothing, nourishing and anti-itching properties.
Bitter almonds and amygdalin are devoid of any medicinal utility, although on the internet it depopulates articles and groups in support of the antitumor activity of amygdalin; in this regard, see our in-depth article on the relationship between amygdalin, bitter almonds and tumors.
