Examination of ‘edible’ insect toxicities, and differentiating mushroom and insect chitin
Globalists such as World Economic Forum founder Klaus Schwab, Hollywood actors such as Nicole Kidman, Angelina Jolie, and Robert Downey Jr., and other climate alarmist profiteers, are pushing for widespread consumption of insects as a ‘sustainable’ human food, even touting insects as a ‘superfood,’ because of high protein content.
One thing these policy pushers aren’t telling us is that there are significant health risks associated with eating insects. Human instincts, to be repulsed by the idea of eating insects, are not arbitrary or random, but are likely due to the threat to human health.
The Bible also instructs us in Leviticus 11: 20-23, not to eat insects, with the exception of orthopterans, specifically, locusts, crickets, and grasshoppers. Even so, permission to eat these is not instruction to do so, and there certainly isn’t reference to the Israelites making insect offerings, or of Jesus encouraging his disciples to eat them.
Eating these in a survival situation — like that of John The Baptist — is one thing, but to have insects discreetly added to our foods, or touted as the future of the human diet, as is happening in Europe, North America, and abroad, is a threat to our health, and is disgusting. Here I will discuss three types of toxicity from edible insects: allergy, contamination, and mechanical toxicity of parts of insect exoskeletons, arising from their shapes.
Contamination of Insect-based Foods
Bioaccumulation of poisonous heavy metals such as lead, arsenic, cadmium and others, and of pesticides including herbicides, has been documented to occur in insects used for food. This means that as insects grow and develop in a contaminated environment, or if they eat contaminated plant matter, toxic heavy metals or other toxins build up in their bodies over time. Therefore producers must carefully source insect feed, and ensure the rearing environment is free of contaminants.
I’ve designed, built, and managed commercial medical cannabis grow rooms, for which I required strict entry protocols for workers, and used special equipment and other measures, to prevent entry and proliferation of pests and plant diseases. If pests such as insects or mites make their way into such a controlled environment, they may multiply uninhibited by natural factors such as weather fluctuations and predators. For that reason, I installed high-powered air curtains at two separate doorways that had to be passed through consecutively to enter the grow rooms, kept a specialized mat containing a shallow pool of bleach solution to step in at the main entrance, used computer-monitored/controlled air conditioning and dehumidification, utilized sticky traps to monitor for pests, and released beneficial predatory insects, mites, and nematodes in grow rooms and hydroponic systems to prevent pest infestations.
Despite my preventative measures, I discovered an infestation of grain mites on plant leaves in two grow rooms, the likes of which is to date otherwise unreported in cannabis. By careful investigation, I identified the mites and determined that they came from grains used to feed Indian meal moth larvae. The Indian meal moth larvae were in turn used by a supplier to feed Hypoaspis miles predatory mites that I purchased and released in the grow rooms, to prevent infestations of fungus gnats. Fungus gnats were also problematic, as is common in indoor cannabis cultivation. The fungus gnats gained entry to the facility in bags of potting mix used to grow mother plants, prompting the purchase of a heat treatment machine for potting mix.
Indoor insect rearing faces similar challenges to indoor cannabis cultivation, including problems with invasive insects and mites, and insect pathogens. People may assume indoor rearing of insects could easily provide clean, pest-free and disease-free conditions, but this it not the case. Fungi such as Beauveria bassiana parasitize insects, necessitating control of environmental parameters as temperature and humidity, and pests including mites attack insects, even spreading insect viruses such as deformed wing virus, transmitted by Varroa mites. The potential difficulty of controlling such problems makes it likely that insect producers will resort to using miticides, species-specific insecticides, fungicides, etc, which may lack government regulations in various countries, and could contaminate edible insects, and must be considered for food safety implications.
Here’s a hypothetical scenario of how insecticide contamination could occur: Cockroaches could invade insect rearing or processing facilities, leading to insecticide use for controlling or preventing cockroach infestation, and potentiate insecticide contamination of food insects. For example, the insecticide Termidor (active ingredient fipronil), is labeled for use to control cockroaches and many other pests that invade buildings, such as silverfish, spiders, centipedes, millipedes, earwigs, and flies. Termidor is transferred multiple times by insect-to-insect contact. If used to control pests of an edible insect rearing facility, this kind of spread-by-contact action would be one example of how an insecticide, or insecticide degradation products sublethal to insects, could contaminate insects intended for food, and shows the need for further study and development of best management practices and reasonable regulations of rearing and processing facilities, which are lacking.
Mealworms (Tenebrio molitor) larvae, full of feces, and supposedly suitable to eat.
One of the most alarming potential problems of food insect production is pre-or-post-processing contamination by Aspergillus, a common fungus that releases the mycotoxin known as aflatoxin. Cooked and dried insects can reabsorb humidity, and could grow Aspergillus, as could pre-processed insects. Aflatoxin is heat stable and cannot be eliminated by cooking insects contaminated by Aspergillus. Mpuchane et al. (1996) identified aflatoxin in edible grasshoppers at a concentration of up to 50 micrograms/kg. The European Union [EU] allows a maximum of 15 micrograms of aflatoxin per kilogram in plant based foods***, but disturbingly, the EU does not have regulations for aflatoxin in animal based foods including insects. Aflatoxin is the one of the most carcinogenic chemicals known to man. This problem must be addressed, but unfortunately, anyone encouraging you to eat insects is not looking out for your health in the first place.
Allergies
Allergies can arise at an early age, or can be developed by repeated exposure to a substance. Therefore, there’s a risk of developing an allergic response to eating insects, even in people who’ve previously tolerated them well. While this could be said of many other foods, it’s particularly common for people to be allergic to shellfish crustaceans such as crabs, shrimp, and lobsters. Like these crustaceans, insects have an exoskeleton composed primarily of chitin. After cellulose, aka ‘fiber’ in dietary vernacular, which is the primary component of plant cell walls, chitin is the second most abundant biological polymer on Earth. Human bodies lack enzymes to breakdown cellulose during digestion; by contrast, humans do make enzymes that break down chitin, albeit chitin is widely considered undigestible, and like cellulose, may act as dietary fiber. Although some studies have indicated chitin activates inflammatory immune responses associated with allergic reactions, contradictory studies have found potential application for chitin in combating allergies.
A specific type of tropomyosin, not chitin, is the primary allergen in crustaceans, and very similar forms are also present in the exoskeletons of insects and mites. Wong et al. (2016) showed evidence that chronic exposure to dust mites primes humans to have a hypersensitive (allergic) response to crustaceans, due to the mutual presence of similar tropomyosins. Conversely, a study on an Icelandic population found that long term exposure to shrimp primed the population for an allergy to dust mites. This suggests that allergic reactions to insects, including hives, asthma, angioedema (swelling of the eyelids, tongue, larynx, etc), rhinitis, and dermatitis, may likewise be largely caused by exoskeleton tropomyosin.
Allergies are very similar to autoimmune diseases. The immune system is responsible for both, although different t-cell white blood cells are involved. Interestingly, Das and colleagues (1993) found that 95% of patients with ulcerative colitis, a type of autoimmune disease, had antibodies in their blood that were reactive to tropomyosin.
There are many different types of tropomyosin, including more than 40 types in mammals and fungi, so an important distinction is that the specific type associated with allergies to mites, shellfish, and insects doesn’t implicate all tropomyosins. By my assessment, exoskeleton-specific tropomyosin helps explain why someone with a shellfish, insect, or dust mite allergy may not be allergic to eating mushrooms, even though chitin is highly present in all of these.
A 2017 paper published in Clinical Toxicology presented evidence of histamine poisoning from insects, in three cases in Thailand, including an outbreak affecting 118 patients, and another incident involving 19 students. The paper focused on direct evidence in another case in which 28 out of a group of 227 students were sickened, and concluded the cause was histamines present in grasshoppers and silkworm pupae they ate at a seminar. The researchers analyzed the leftover foods, and what the 28 sickened and other 199 students ate, and alleged that the histamines were implicated, which like tropomyosins, are heat-stable (resistant to degradation by cooking). The sick students’ symptoms included hives, headache, nausea, vomiting, diarrhea, and breathing problems (bronchospasm and dyspnea).
I doubt the validity of the researchers’ conclusions in the 2017 paper, because the cause of the reported symptoms is dubious. They believed the symptoms were caused by histamine poisoning, that resulted from poor storage of the insects leading to microbial degradation of histidine present in the grasshoppers and silkworm pupae, thereby converting the histidine to histamine. This is certainly possible, and known to occur in many foods such as tuna fish, but problematically for their conclusion, the human body produces histamines in response to allergenic substances such as tropomyosin, and also, importantly, in response to mechanical injury. And glaringly, the levels of histamine the researchers found in the leftover insects were about 8 mg and 10 mg per 100 g of grasshoppers and silkworm pupae, respectively, and this is only half the concentration of 20 mg histamine per 100 g food the EU allows in fresh fish. The hazardous level of histamine is considered to be 50 mg per 100 g of food, five times higher than was found in the insects. It is possible that a sensitive individual could react to such a low level of histamine as was found, but it’s very unlikely for 28 students to have the same sensitivity.
Also contradicting their conclusion, is that poisoning from histamines that are in food (ie as opposed to histamines produced in the body in response to allergens or injury) usually occurs within a few minutes after eating the tainted food. Contrastingly, the researchers reported the onset of symptoms in the 28 students occurred on average 4 hours after eating the insects. Furthermore, the symptoms of histamine poisoning resemble those of an allergic reaction to IgE antibody-mediated allergens such tropomyosin. The low level of histamine found in the leftover insects, combined with the delayed onset of symptoms, suggests another causative factor at least contributing to — if not almost solely responsible for — the sickness, such as allergens in the insects (possibly tropomyosin) or mechanical abrasion/damage to the digestive lining by insect parts.
This case is notable because the authors tried to place the blame on poor storage, which is a preventable factor, but if the cause was actually inherent in the insects, it rebuts the ‘eating insects is great’ narrative. However, even if their conclusions are wrong, the authors did nevertheless highlight an important storage concern for insects that should be considered. As they pointed out, a 2007 study found a concentration of histamine in silkworm pupae of 87.5 mg per 100 g, nearly double the hazardous level.
Mechanical Toxicity of Spurs, Spines, and Setae (Hairs)
I was prompted to write this article by widespread and well-justified backlash against the push for eating insects, and opponents’ assertions that exoskeleton chitin is toxic to humans. What particularly sparked my interest was that as a horticultural scientist, I knew from my associated study of mycology (fungi) and entomology (insects) that, like insects’ exoskeletons, the cell walls of fungi, including mushrooms, are also predominantly made of chitin. I love eating mushrooms and use several species of powdered mushrooms in my morning coffee for their tremendous health benefits. So, hearing my favorite newscaster/show host, Alex Jones, talk about the toxic effect of eating insect exoskeletons, and implicating chitin, compelled me to research the issue further.
Gastrointestinal upset recently sidelined NBA player Jimmy Butler, who told his teammates that he ate crickets in Mexico City prior to the sickness. Fans and others speculated that the crickets were the cause, although it could not be proven. The reported symptoms were not necessarily indicative of an allergic response however, unlike the aforementioned students with more classical allergy symptoms such as hives and breathing problems. Could there be another cause?
Mechanical toxicity may arise from irritation, abrasion, or other damage caused by the shape of chemical compounds present in foods. For example, plants in the Araceae family contain sharply-angled calcium oxalate crystals, that when ingested, can cause itching, numbing, burning, and sores, in the mouth, throat, and digestive tract, and could even be fatal. Monstera deliciosa (Araceae), an ornamental vine popularly grown on oak trees here in Central Florida, with large, ‘swiss-cheese,’ hole-adorned leaves, has a remarkable edible fruit that most people are unaware of. The fruit tastes like a combination of pineapples and bananas (or mangos), hence the species name deliciosa; but if eaten before fully ripened, the fruit contains calcium oxalate crystals that could cause digestive distress. Another plant in the same family, also containing calcium oxalate crystals, is the traditional Polynesian staple crop taro (Colocasia esculenta), used to make a soupy, mashed potato-like food called poi, eaten in Hawaiian luaus. Taro is toxic if eaten raw; boiling is required to breakdown the calcium oxalate crystals.
Monstera deliciosa foliage and fruit.
Taro (Colocasia esculenta) foliage
Calcium oxalate is also what kidney stones* are made of, the pain of which highlights the fact that the shape of chemical compounds can be deleterious. Another example of the shape of a chemical compound causing injury is uric acid crystals causing gout, a painful affliction** of the joints. Gout crystals are elongated and sharp, and thereby cause tissue damage and inflammation.
Sharp, gout-causing uric acid crystals in a (synovial fluid?) light microscope sample
Insect exoskeletons feature sharp protuberances made of chitin, including spines, spurs, and rigid ‘hairs’ called setae. As noted by Mézes (2018), the pointy shape of these protuberances may cause them to be mechanically toxic, by damaging the digestive tract. This is not the chitin per se causing toxicity; instead, it’s the shape of the structures formed by chitin leading to toxicity.
Spines are narrowly conical, rigid, fixed projections, found on grasshopper legs, for example. Spurs are similar to spines but are on a socket allowing movement. Setae are hair-like, and contain nerve endings for sensory perception. The hairs on the legs of a fly are an example of setae. All of these structures are very small, and impractical/ impossible to remove via processing, as can be seen in the electron micrograph below, for example, showing the breathing apparatus on the side of a cricket’s body, surrounded by numerous setae.
Another difference between the chitin in insects and the chitin in mushrooms is that adult insects’ exoskeletons are sclerotized. Sclerotization involves the cross-linking of chitin molecules with various proteins and other molecules, creating a harder, more rigid material than chitin alone. A caterpillar’s relatively soft body is mostly made of pure chitin, whereas the chitin in an adult insect’s exoskeleton is sclerotized (albeit caterpillars commonly feature sclerotized projections such as spines, and their mouthparts are sclerotized). This is analogous to cellulose in plants’ cell walls being fairly flexible, unless lignified (wood) or suberized (cork). Crustaceans such as crabs also have sclerotized chitin exoskeletons.
It also seems reasonable to surmise, and even hard to ignore, that chewing an insect exoskeleton would produce sharp fragments that could damage the lining of the esophagus, stomach, and intestines. Similarly, sharp particles could result from grinding insects during food processing.
Summary and Discussion
Possible contamination is a considerable safety hazard associated with eating insects. Producers should prevent contamination by heavy metals and chemicals such as herbicides and insecticides, by carefully scrutinizing the methods and feed used to rear insects.
Further research is needed to determine proper best management practices for rearing and processing insects, and to establish safety regulations. Aflatoxin contamination by ubiquitous Aspergillus fungi is a major threat that governing bodies should immediately set low limits for, and require testing to evaluate, in insect-based food batches.
Chitin is the primary structural component in mushrooms, and in arthropods including insects, mites, and crustacean shellfish. Inconclusive research has implicated chitin in allergic reactions, while also showing its potential for combating allergies. The pointy chitin-based protuberances of insect exoskeletons, and sharp exoskeleton fragments, may explain why insects can sicken people without causing classical allergic responses such as hives or swelling. These sharp structures may also be a clue in clarifying reasons for mixed findings regarding chitin allergies. It is important to recognize the primary role of exoskeleton-associated tropomyosins in allergic reactions to crustaceans and mites, as alike tropomyosins are common to the exoskeletons of insects. These combined facts help explain why mushroom chitin may be well-tolerated by people allergic to, or otherwise sickened by, crustacean shellfish and insects.
God had a reason to command us not to eat crustaceans and most insects. It’s misguided to believe that science is likely to fully elucidate the medical reasons for God’s instructions regarding food, especially considering the plethora of factors involved in human health that complicate dietary scientific analysis, and the sometimes-delayed health effects attributable to various factors. We should also trust our instincts. Even to this entomology enthusiast, the idea of eating insects is disgusting. The best thing to do is to refuse to heed World Economic Forum head Klaus Schwab’s exhortations to “Eat ze bugs.”
*Note: Apatite rock, made of calcium phosphate compounds, is a precursor for calcium oxalate crystals. Drinking sodas containing phosphoric acid may encourage kidney stones and kidney disease by generating calcium phosphate compounds.
**John Milton, author of the masterpiece Paradise Lost, died from complications from gout in 1674.
***Peanuts are commonly infected by Aspergillus, so never eat a rotten peanut (or other nut).
Watch Joe Bender’s appearance on The American Journal Friday:
Revealed: The Harmful Effects Of Eating Ze Bugs