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Q&A: Eating crickets may improve gut health
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The crunch of an insect might bring about visions of stepping on a water bug or cockroach as you walk down the street. But, what about a crunch that is associated with snacking on insects?
For most, the idea of sitting down to take a bite out of a grasshopper or cricket seems unappetizing. But for Valerie J. Stull, PhD, MPH, a post-doctoral research fellow at University of Wisconsin-Madison, the idea is not as ludicrous as some might think.
Stull and colleagues published a study in Scientific Report that assessed the safety, tolerability and effects that consuming crickets had on 20 healthy men and women aged 18 to 48 years.
Healio Gastroenterology and Liver Disease spoke with Stull about how the study came about, its results, and how eating crickets might develop good gut bacteria. – by Ryan McDonald
Healio: How did this study come about?
Stull: I have a background in public health and nutrition, but I’ve also always been interested in sustainable agriculture and how food impacts the environment. In the last 5 years, I’ve been researching entomophagy, which is the practice of eating insects. Edible insects are fascinating because although humans have consumed insects throughout history, and approximately 2 billion people around the globe regularly consume them today, research on the subject is relatively new.
Source: Adobe Stock.
Like many edible insects, crickets are considered an environmentally friendly protein source. They require significantly less feed, land, and water to survive and thrive than traditional livestock, while also emitting fewer greenhouse gases. Crickets like tight confined spaces, so farming them vertically makes sense. We have good data on the nutritional content of many edible insects, including crickets. Most are very high in protein and other nutrients. But what many people don’t know is that insects also contain fiber, unlike other animal products like beef, chicken, or eggs.
My colleagues and I set out to investigate if edible crickets have any beneficial health impacts beyond their nutritional content. Remember that fiber is not digested by humans directly. Instead, it passes through undigested or is broken down by the microbes in our gut. The microbiota in our gut and their products go on to impact our health in a variety of ways. Dietary fiber can shape microbial growth, and fiber consumption has been shown to contribute to the health of our digestive system. High fiber intake has been associated with a reduced risk of several diseases including breast cancer, diverticular disease and coronary heart disease.
The purpose of the study was threefold. We wanted to confirm that cricket consumption was safe and tolerable. Considering people eat crickets around the world, we expected this to be true, but wanted to verify it clinically. We also wanted to see if eating edible crickets influenced human health directly by changing lipid metabolism or markers of inflammation. Lastly, we were interested in assessing if insect fibers, such as chitin – the primary component of the exoskeleton – could serve as prebiotics. By prebiotics, I mean non-digestible food items that promote the growth of beneficial gut bacteria. Live probiotic bacteria, yogurt for example, eat prebiotics and are known to do good things for the body. Ultimately, we wanted to know if eating crickets was good for gut health.
Healio: How did you and your colleagues conduct the study?
Stull: We set up a double-blind, randomized, crossover clinical trial to evaluate what effects consuming 25 g of whole cricket powder per day had on gut microbiota composition, while also assessing safety and tolerability. A total of 20 healthy adults participated in a six-week dietary intervention. Participants were randomized into two study arms and consumed either cricket-containing or control breakfast foods for 14 days, followed by a washout period and assignment to the opposite treatment. Blood and stool samples were collected at baseline and after each treatment period to assess changes in blood chemistry, liver function, and shifts in microbiota.
Healio: What made you and your colleagues use crickets and not another insect?
Stull: Food-grade crickets are produced commercially in North America, so as far as edible insects go, crickets are readily accessible here. We were able to access a whole cricket powder that could be integrated easily into breakfast foods for our study participants to eat.
Sometimes people in the edible insect world joke that crickets are the ‘gateway bug.’ They are familiar to Americans, but not detested like some other insects. They are kind of cute, but not too cute. When dried or fried, crickets are crunchy and tasty, and they easily take up the flavors of what is around them. Crickets were a good starting point for research on the health impacts of eating edible insects.
Healio: What were the main findings from the study?
Stull: Ultimately, our small clinical trial had a few interesting findings. First, we didn’t see any sign of toxicity or intolerability for study participants after eating crickets, which is good news. Second, we didn’t see changes in lipid metabolism, but we did observe a slight increase in alkaline phosphatase and a decrease in circulating pro-inflammatory cytokine TNF-alpha with cricket consumption. These results are suggestive of an improvement in intestinal homeostasis, meaning that eating crickets may improve gut health and reduce systemic inflammation; however, more research is needed to understand these effects and underlying mechanisms.
We also observed several changes in microbiota after eating cricket powder, including a prebiotic effect. Specifically, after eating crickets, we measured a significant increase in the abundance of one good bacterial species, the probiotic Bifidobacterium animalis. B. animalis has been studied extensively and is known to inhibit pathogens, improve gastrointestinal function, and protect against diarrhea and food borne pathogens.
Healio: What would you say is the significance of the research and its results?
Stull: This study speaks to the potential health benefits of insect consumption. Most importantly, our results demonstrate that we need more research on the topic of edible insect consumption and that considering the microbiome is relevant given the number of people who eat insects now and might want to in the future. Likewise, it suggests that eating crickets may be beneficial for reasons beyond their protein content. We need more clinical research to better understand how humans and their microbiota utilize crickets as food.
Healio: What is the take home message for physicians who treat the gut and patients with gastrointestinal disorders?
Stull: I wouldn’t recommend using crickets as a treatment just yet. We need to learn a lot more about dose and response, as well as mechanism of action. But, I would say that thinking about edible insects as a source of nutrients and fiber is worthwhile. Patients should be careful with edible insects if they have food allergies. Crickets represent a novel food in the American diet and introducing new foods should be done with care.
Healio: What are the next steps for this study?
Stull: This was a small pilot study and only the first clinical trial to look at edible insect consumption in this way. More research on this topic is warranted and necessary given these preliminary findings. We need to repeat the trial for dose response, and with larger sample sizes. We also need to evaluate the impact of cricket consumptions on gut microbiota in diverse populations, as well as assess all potential risks from eating insects.
Stull VJ, et al. Sci Rep. 2018;doi:10.1038/s41598-018-29032-2.
Disclosures: The researchers report no relevant financial disclosures. Entomo Farms did donate a portion of the cricket powder used in the study.