As part of the Health Nuts Project, the skeptical cardiologist has been evaluating walnuts, hazelnuts and almonds which he plans to put in packets and distribute to patients and readers.
Consequently, after considerable searching, I purchased raw organic almonds from a company called NutsinBulk. These turn out to be from Spain (where pasteurization of almonds is not required) and are quite tasty.
As I was munching on one of these almonds I suddenly noticed an incredibly bitter taste causing me to spit the chewed almond out. My first thought was that this almond had gone “bad” in some way. Perhaps a mold had crept into it. Looking at the pieces I had spit out, however, I could see no discoloration or other visible difference from the “normal” almonds.
Subsequent experimentation has revealed that about one in ten of these almonds is incredibly bitter and there is no way to predict this from the external appearance of the almond.
The Source of Bitter Almonds
The sweet almond that we are used to eating in the US is produced from one type of almond tree (Prunus amygdalus var. dulcis) and does not contain poisonous chemicals. However, the bitter almond that I encountered comes from a different type of almond tree (Prunus amygdalus var. amara).
Prunus amara trees were likely the original almond trees but over time the sweet almond trees have been selected for and now dominate. According to the LA Times and Paul Schrade, who provides bitter almonds to restaurants:
Until recent decades, most Mediterranean almond orchards were grown from seed, and the shuffling of genes resulted in a mix of bitter almond trees among the sweet. Growers liked to keep a few bitter trees around because they helped to pollinize the sweet varieties. The inclusion of bitter nuts gave snackers occasional unpleasant surprises, but they deepened the flavor of marzipan, almond milk and glazes for cakes. In Italy, bitter almond paste was traditionally used to make crisp amaretti cookies, and bitter almond extract flavored amaretto liqueur. In Greece, bitter almonds are used in soumada, a sweet syrup. (apparently cooking or adding alcohol eliminates the toxic cyanide)
There’s little large-scale cultivation of bitter almonds left in Spain and Italy, mostly just scattered trees remain, but it is still possible to buy raw bitter almonds at European specialty markets. Morocco and Iran now lead in commercial production of bitter almonds.
What Makes The Almonds Bitter: Amygdalin
The source of the bitterness is amygdalin:
A recessive gene causes bitter almond trees to produce in their shoots, leaves and kernels a toxic compound called amygdalin, which serves as a chemical defense against being eaten. When amygdalin is moistened, it splits into edible benzaldehyde, which provides an intense almond aroma and flavor, and deadly hydrocyanic acid, a fast-acting inhibitor of the respiratory system.
A variety of sources confirm that:
The lethal dose of raw bitter almonds depends on the size of the nuts, their concentration of amygdalin and the consumer’s sensitivity. But scientists estimate that a 150-pound adult might die from eating between 10 and 70 raw nuts, and a child from ingesting just a few.
YIKES!!!When I read this I was shocked. Could it be that consuming 10 of these raw biter almonds would kill me.? How could I distribute these potentially lethal edibles to my patients?
Amygdalin (Laetrile) , Alternative Cancer Therapy and Quackery
In addition to bitter almonds, significant amounts of amygdalin are found in the stone fruit kernels of apricots, peaches and plums. A synthetic form of amygdalin called Laetrile achieved great notoriety in the 1980s as a cancer treatment. Although research had shown the chemical to be ineffective, it was embraced by “alternative” healers who claimed it was a “natural” cure for cancer which was being suppressed by a conspiracy between the US FDA, big pharma, and the the medical community.
Steve McQueen, suffering from pleural mesothelioma sought the care of a delisted American holistic orthodontist practicing in Mexico, William Kelley. The NY Times reported:
In July 1980, McQueen secretly traveled to Rosarita Beach, Mexico, to be treated by Mexican and American doctors using Dr. Kelley’s regimen. He received not only pancreatic enzymes but 50 daily vitamins and minerals, massages, prayer sessions, psychotherapy, coffee enemas and injections of a cell preparation made from sheep and cattle fetuses. McQueen was also given laetrile, a controversial alternative treatment made from apricot pits.
Although we hear little about Laetrile these days, like most snake oil it is still promoted by alternative medicine. For example, The notorious quack Dr. Mercola still promotes the idea that laetrile is a safe and effective treatment of cancer on his web site with a post that has been viewed over 700,000 times.
You Can Die From Eating Bitter Almonds