Xiao Chi (Tony) Zhang, MD, MS
Jason Hack MD
Brown University, Medical Toxicology
“Food poisoning,” a term that may often be uttered after a skeptical potluck event, is defined by the National Institute of Health as a condition “…when you swallow food or water that contains bacteria, parasites, viruses, or the toxins made by these germs. “ Common food poisoning toxidromes often conjure up gastrointestinal symptoms from consuming fruits, vegetables, meats and dairy products of uncertain freshness and contamination from soil and/or pesticides. The media has a tendency to fixate on notorious food poisoning such as Listeria outbreaks from cantaloupes, salmonella from peanut butter; however, limited network time is devoted to common and devious poisonous foods, many of which can be found in a local grocery store, or commonly consumed by the international patients. The purpose of this article is to enlighten its viewers, whether you are consumers, foodies, patients or physicians to be aware of easily-available poisonous foods, include them as a differential diagnosis, and how to prepare them for safe, consumptive pleasures.
Stone fruit seeds – why does it smell like bitter almonds?
Stone fruits (drupes) are shelled, hardened endocarp with a fleshy and tasty exterior; common North American supermarket varieties include cherries, plums, apples, pears, peaches, apricots. While the fleshy fruits are delectable and excellent alternatives to the artificial sugary rush affiliated with the upcoming spooky holiday season, the consumption of the pits/seeds may result in unsuspected cyanide poisoning. The stone fruit kernels contain a compound called amygdalin, which can be degraded to hydrogen cyanide when metabolized by beta-glucosidase (found in human intestines). Of note, cyanide can occasionally smell like bitter almonds, hence the title.
Cyanide is particularly worrisome as it inhibits the final step of oxidative phosphorylation and causes the victim to rely on anaerobic metabolism, and resulting in cellular hypoxia and anion gap acidosis. Important diagnostic tools include assessing for potential co-ingestion (ASA, Acetaminophen), in addition to carboxyhemoglobin and methemoglobin for potential carbon monoxide exposure. Treatment options include stabilization, decontamination with activated charcoal (within 1 hour of consumption), and binding of cyanide via hydroxycobalamin and sodium thiosulfate for renal excretion. Nitrite kits, while considered as an acceptable alternative, should be used with extreme caution as it can worsen methemoglobinemia – which is commonly associated with cyanide toxicity in the setting of enclosed fires.
Amygdalin (synthetic or natural) may have been used in the past for cancer treatments; however, recent NIH and Cochrane review of these literature have concluded that the risk–benefit balance of laetrile (synthetic amygdalin) or amygdalin as a treatment for cancer is unambiguously negative, due to lack of sound clinical data in addition to the risk of serious adverse effects from oral ingestions of these cyanogenic compounds.
Rhubarb – sweet and tart, just not for your kidneys
Rhubarb and strawberry pie may be as iconic as the American Flag, PB&J, or the even the apple pie; however, this delicious, rubor celery impersonator can be as devastating to your kidneys as a nightly binge on an unappetizing and not-recommended ethylene glycol, commonly found in antifreeze. The rhubarb stalk, when consumed raw, can likely be used as a home remedy for sialolithiasis with its gritty texture and incredibly sour taste; the triangular LEAF blade, however, “leaves” more than just a sour face after consumption. Rhubarb leaves contain citric and oxalic acids that form oxalate crystals and may result in acute kidney injury while causing a constellation of unflattering GI symptoms, such as nausea, vomiting and diarrhea. Rhubarb leaves were originally recommended during World War I as a vegetable until a number of deaths occurred and the advice was withdrawn. Eat the stalks, AVOID the leaves! Treatment: supportive care.
Tomatoes, “tomahtoes,” potatoes, “potahtoes,” Let’s talk about glycol..alkaloid…off?
Roasted Provencal heirloom tomato and potato gratin can add a culinary and nutritious complement to many hearty meat dishes, however if prepared incorrectly, it may cause your guests to thank you from both ends of their gastrointestinal tracts. Tomatoes vines and potato sprouts (especially green potatoes) contain elevated levels of glycoalkaloids, which, if consumed at high quantities can cause a bitter tasting, burning irritation in back of mouth and tongue, in addition to gastrointestinal irritation, headache, diarrhea, and fatigue. Sweet potatoes and yams, however, do not produce toxic glycoalkaloids, contain more fiber with a lower glycemic index and high levels of carotenoids (precursor Vitamin A) and can be used as an alternative to the brown tuber cousin. Treatment: cut off the tomato vines and potato sprouts before cooking + supportive care.
Ink Cap Mushroom – a tastier alternative to Antabus
The coprinopsis atramentaria, also known as the common ink cap, is found in Europe and North America, with a mild taste with a soft flesh that pairs well in soups and omelets, can also result in a uncomfortable flushing reaction when consumed with a little bit of Bloody Mary on a Sunday Brunch. The ink cap mushroom contains coprine, a compound that blocks acetaldehyde dehydrogenase, resulting in a disulfiram-like reaction, commonly associated with the famed “HANGOVER,” with tachycardia, nausea, vomiting, headache, and facial flushing. This phenomenon has been coined as the “Tippler’s Bane” given its symptoms when consumed in conjunction with alcohol. Treatment: avoid alcohol.
Ackee – Not an FDA-approved treatment for DKA
The Ackee fruit is the national fruit of Jamaica and is a member of Sapindaceae (soapberry family), similar to lychee and longan berries. It is native to tropical West Africa, and imported to Jamaica in 18th century, where it is the national fruit of Jamaica, with the Ackee and codfish considered as the #2 national dishes by National Geographic Magazine. The Ackee fruit, when consumed immaturely, contain hypoglycin in the seeds that is converted to methylenecyclopropyl acetic acid (MCPA) that inhibits the breakdown of acyl CoA and ultimately inhibits the formation of ATP, NADH, and acetyl CoA. The result is severe depletion of glucose and hypoglycemia, also known as the “Jamaican vomiting sickness.” Treatment: supportive care and D50.
Cassava – Cyanide revisited, in tuber form
Cassava, aka manioc, yucca, balinghoy, kmoteng, kahoy, kappa, tapioca root etc., is a tuber plant and a major source of carbohydrates indigenous in Africa and Southeastern Asia. Despite multiple culinary uses of cassava, including alcohol, purees, dumpling, cakes soups and stews, the preparation of cassava requires time and dedication, as lackluster attempts result in debilitating neurological deficits and paralysis, known as Konzo. The cassava roots contain cyanogenic glucosides, linamarin and lotaustralin, which is decomposed by linamarase (naturally occurring enzyme in cassava) into hydrogen cyanide. Bitter cassava contain 50mg/kg of the cyanogenic compounds (even higher during times of famine and poor soils), as compared to the 20mg/kg in sweet cassava roots. The preparation of cassava is a time consuming process involving processing the roots, and then grounding it to a paste, followed by soaking, squeezing, and toasting for hours for the paste to release the toxic HCN into the atmosphere, thus allowing for safe consumption later that day. Treatment for konzo: supportive and nutrition supplementation.