This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
My husband and I discovered our daughter’s peanut allergy while we were 35,000 feet in the air over Denver. Even though we knew she was allergic to eggs, our allergist had told us there was no reason to avoid any other foods, and so the week before I’d given her a bit of peanut butter and chalked up the slight rash she developed to eczema. As we began our descent into Denver, I gave her a bite of a protein bar
. About ten minutes later she started screaming. Her face turned bright pink.
Was it anaphylaxis or the pressure in her ears from landing? She was only about a year old at the time, so it’s not like we could ask her. My husband gave her the epinephrine shot and within seconds she had stopped crying and was perfectly calm. It was like magic but the kind of magic that requires you to go immediately to an emergency room for observation. Still, the epinephrine worked. Thankfully, our daughter was fine.
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Peanut allergies are one of the more frightening food allergies to have, because the body’s response can be both deadly and entirely unpredictable. A history of mild reactions doesn’t mean you won’t one day accidentally eat a peanut and go into anaphylactic shock. Also, it’s not just as simple as passing on the PB&J and pad Thai. The list of what my daughter can’t eat is a long one. We can’t buy most supermarket-brand cereals, granola bars or cookies because of the cross-contamination risk. The sourdough bread at my Trader Joes carries a “may contain pecans” warning and I’ve seen similar nut warnings on mayonnaise, ice cream, pumpkin seeds, hummus and sesame oil. The other week I had to very quickly but politely ask a nice older lady who had just been eating from a bowl of roasted almonds to please not touch my daughter.
There seems to be something new written about food allergies every day, and I try to read it all. Of course I’ve been especially excited to read stories about biotech wunderkind CRISPR and the idea that it could create a life-saving allergy-free peanut. A piece at Fast Company about the “CRISPR revolution” informs me that CRISPR will revolutionize our food system, and that includes removing allergens from peanuts. According to Business Insider, scientists could create “an allergy-free version of the popular snack food.” A piece at Inverse with a sub-heading that promises “Allergy-free peanuts will soon be a reality…” makes the new peanut sound like a foregone conclusion: “Take a peanut plant, identify the genes that encode the major allergens, send CRISPR in to cut them out, then breed a new crop devoid of allergens. Then take over the market”
It sounds so simple—remove a few genes and kids like my daughter will be able to safely eat peanut butter—but it turns out that creating an allergy-free peanut is anything but a foregone conclusion. There are significant science and market-based challenges to creating a hypoallergenic peanut and CRISPR, though incredibly powerful, won’t be revolutionizing the peanut market with an “allergy-free” product anytime soon.
“I would never say ‘allergy-free’,” says Peggy Ozias-Akins, a plant geneticist at the University of Georgia who works with CRISPR and other biotech tools to reduce peanut allergenicity. I also spoke with Ozias-Akins and Richard Goodman, an expert in allergenicity and genetically modified crops at the University of Nebraska, about the enormous challenges involved in modifying the peanut to remove allergenic genes. Both scientists agree that an allergy-free peanut just isn’t possible. The peanut is an incredibly complex crop made up of many allergenic proteins, and each of those proteins contains multiple genes. You’d need to remove all of the allergenic genes in order to call a peanut “allergy-free” and that’s a significant challenge, even with a tool as powerful as CRISPR. According to Ozias-Akins, “to knock out five genes simultaneously might be a stretch.” Goodman agrees: “The companies working on this cannot and do not claim to remove all allergens from the peanut.”
Even if scientists could remove every last allergenic gene with CRISPR, it’s unlikely anyone would want to eat what’s left. Some of those allergenic genes are significant sources of protein and can’t be removed without drastically changing the plant itself. “Removing all of those proteins might mean making the peanut plant less nutritious,” says Goodman. Ozias-Akins adds, "you might be dramatically changing the nutritional value, flavor and processing properties.”
To make the task even more complicated, there’s a chance scientists haven’t identified every last allergenic peanut gene. The science on what causes an allergic reaction plays a role here too. According to Goodman, “until the plants are made and tested, it’s not clear what the final products would be like in expression of other proteins and impact related to elicitation of new allergies or new sensitization.”
So what can scientists working with CRISPR hope to accomplish here? It’s certainly possible to remove some of the allergenic genes (Aranex, for example, says they’re working on removing just three genes) but that still doesn’t mean you’ve got a commercially viable product. Both Ozias-Akins and Goodman warn there would need to be industry-wide agreement about what “hypoallergenic” means in order to give a product that label. “It’s very complicated because there isn’t a clear definition for peanuts,” explains Goodman. In contrast, he says, “The FDA has defined hypoallergenic formula as not causing a reaction in nine out of ten milk allergic infants.” But peanuts are different, says Goodman. “Milk occasionally causes a fatal reaction but in the U.S., peanuts are one of the most common causes of fatal or near fatal allergic reactions.”
With peanut allergies, the risk is just too high and unpredictable. Food allergy experts aren’t ready to embrace a hypoallergenic peanut either. James R. Baker, Jr., MD and CEO and Chief Medical Officer of Food Allergy Research and Education, an advocacy group for people with food allergies, cautions, “we still have much to learn about the biology of an allergic response to a food protein. At this point, there are too many unanswered questions in the field of food allergy and in the specific research on hypoallergenic peanuts to be able to foresee all of the challenges and implications that such a product would bring. ”
I wouldn’t want to feed my daughter a “hypoallergenic” peanut butter, nor would I expect any other peanut allergic person to do the same, but maybe a reduced-allergen peanut could at least decrease the risk from cross-contamination. Food allergies cause more than 300,000 ambulatory-care visits per year for kids under 18. Imagine the kid who wipes his peanut buttered mouth with his hands and touches a peanut allergic kid. If you fed him a low allergen peanut butter rather than regular peanut butter, you’d at least reduce the risk of a serious reaction.
But segregating a low allergen peanut crop from regular crops will be incredibly difficult, and growers and manufacturers may not want the cost or hassle. Ozias-Akins says there’s always a chance insects might cross-pollinate a low allergen crop with wild peanut plants. Goodman is even more skeptical, as he imagines mix-ups with seeds or harvested peanuts in shipment, wholesale marketing and food processing: “The risks for the allergic consumer and food companies is just too high. How can you differentiate the “hypoallergenic peanut” from natural peanuts? What if there’s a mistake that causes severe or fatal anaphylaxis?”
Patrick Archer, President of the American Peanut Council, describes the many steps required to bring a hypoallergenic peanut to the marketplace. “At every stage of the distribution, hypoallergenic peanuts would have to be separated from non-hypoallergenic peanuts,” something he calls “a risky process at best.” Farmers would have to separate the crops, but also ensure the low allergen fields weren’t used the year before to grow regular peanuts. Separate equipment would need to be used for harvesting, drying, shelling and processing. Companies would need to transport and warehouse the low-allergen peanuts separately too. Even if the industry could achieve this high level of segregation, Goodman says that high costs won’t be attractive to many in the peanut industry. High cost and high risk aren’t exactly great selling points, which may explain why the peanut industry doesn’t seem so interested in the CRISPR revolution.
CRISPR is certainly a promising advance in biotechnology, but even a powerful tool like CRISPR may not be enough to tackle the complexities of the peanut genome, severe food allergies and a commodity crop industry. CRISPR may revolutionize some of what we eat, but it doesn’t seem like it will transform the landscape for parents of kids with peanut allergies anytime soon.