Round up bugs to make a square meal

By Liz Meszaros, MDLinx
Published October 2, 2018

Key Takeaways

Eating crickets can support the growth of beneficial gut bacteria, as well as reduce inflammation throughout the rest of the body, according to a recent randomized, double-blind, crossover trial published in Scientific Reports.

“This study is important because insects represent a novel component in Western diets and their health effects in human populations haven't really been studied," said senior author Tiffany L. Weir, PhD, professor, Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO. “With what we now know about the gut microbiota and its relationship to human health, it’s important to establish how a novel food might affect gut microbial populations. We found that cricket consumption may actually offer benefits beyond nutrition.”

Lead author Valerie J. Stull, PhD, MPH, University of Wisconsin-Madison, Madison, WI, further added: “There is a lot of interest right now in edible insects. It’s gaining traction in Europe and in the United States as a sustainable, environmentally friendly protein source compared [with] traditional livestock.”

Crunching on bugs could be advantageous in many ways. First, insects are an excellent source of protein, vitamins, minerals, and healthy fats. They also contain fibers that differ from those found in fruits and vegetables. Fiber, in turn, serves as a microbial food source, and some types of fiber can promote the growth of beneficial bacteria, or probiotics.

For example, mealworms can provide protein, vitamins, and minerals like those found in fish and meat; small grasshoppers provide the same protein content as lean ground beef, with less fat per gram (g); and ants are low in carbohydrates, with 100 g of red ants providing 14 g of protein, almost 48 g of calcium, iron, and other nutrients—all for less than 100 calories.

According to a report from the Food and Agriculture Organization of the United Nations, over 1,900 edible insect species exist worldwide. In fact, over 2 billion people worldwide regularly eat insects. Indeed, 36 African countries, 23 in the Americas, 29 in Asia, and 11 in Europe are entomophagous—or insect eaters.

“Most of the insects consumed around the world are wild-harvested where they are, and when they are, available,” said Dr. Stull, who is a connoisseur of insects worldwide, including caterpillars, cicadas, grasshoppers, and beetle larvae. “People love flying termites in Zambia, which come out only once or twice a year and are really good; they taste like popcorn and are a crunchy, oily snack.”

It is her hope that insects will become a more mainstream food in the United States, along with growth of edible insect producers and the use of insects in food products.

Studying bug eaters

Drs. Weir, Stull, and colleagues conducted this study to determine whether insect fiber had any effects on gastrointestinal (GI) bacteria.

They included 20 healthy adults (mean age: 27 years; mean body mass index: 23.58 kg/m2), recruited in Colorado, who were randomized to two 14-day intervention periods, with a 14-day washout period in between. Subjects ate either a pumpkin spice breakfast muffin and a chocolate malt shake that contained powdered cricket meal (25 g) or a control breakfast. During the washout period, both groups consumed a normal diet, and were then crossed over to the opposite treatment arm.

At baseline and after each intervention period, subjects provided fasting blood samples, a stool sample, and completed a GI questionnaire designed to assess their digestive health.

Researchers assessed serum glucose and enzyme concentrations to assess liver function, and C-reactive protein, which is associated with inflammation. They tested fecal samples for the byproducts of microbial metabolism in the gut, inflammatory chemicals associated with the GI tract, and the content of microbial communities present in the stool.

Fecal acetate and propionate levels were reduced during the cricket diet. Overall microbial composition did not change, nor did gut inflammation. Researchers did, however, observe decreased levels of tumor necrosis factor-alpha (P < 0.05), and increased levels of Bifidobacterium animalis (log fold change: 5.7), which has been linked to improved GI function and other measures of health. In all, five bacterial taxa were significantly increased after cricket consumption, including three operational taxonomic units associated with the phylum Actinobacteria. No adverse events occurred.

“This very small study shows that this is something worth looking at in the future when promoting insects as a sustainable food source,” added Dr. Stull, who is also the co-founder of MIGHTi, the Mission to Improve Global Health Through Insects.

Because this was a small study, Drs. Weir and Stull called for further, larger studies to replicate their results, and perhaps determine what crickets provide that promotes good gut health.

This study was funded by a multistate Hatch project (W3122: Beneficial and Adverse Effects of Natural Chemicals on Human Heath and Food Safety), the Karen Morris-Fine New Investigator Success Fund, the Climate Quest competition, and the Clinical and Translational Science Award program of the NIH National Center for Advancing Translational Sciences. Entomo Farms donated a portion of the cricket powder used in the study.

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