According to a new clinical trial, eating insects is good for your gut. Dr Tiffany Weir of Colorado State University explains how it affects microbes.

What are the benefits of eating insects?

Insects are more nutrient-dense than a lot of the other protein sources we consume: on a per-weight basis, they have more protein and fibre than many meat products. If cultivated in the right way, they can be far more environmentally sustainable [than meat]. Outside of the US and Europe, insect consumption is common: they are regularly eaten by about two billion people.

Why are gut microbes useful to humans?

Each of our bodies contains trillions of microorganisms. The majority of these reside in our gastrointestinal tract and, within any given individual, there are hundreds of species carrying out all kinds of activities. Collectively, all those microorganisms are termed the ‘microbiome’ – it’s not just bacteria, it’s viruses and fungi as well. My colleague Valerie Stull has been studying insect consumption, and my area of interest is the influence of diet on the gut microbiota. We wanted to see if there were any benefits to consuming insects beyond their nutritive value.

How did you study insect consumption?

We had 20 people in the trial, and we asked them to replace their breakfast every day with muffins and chocolate malt milkshakes that either contained or didn’t contain cricket powder. They were eating those meals for two weeks, had a two-week rest period where they went back to their normal diets, and then they switched groups and ate the other meals for two weeks. We collected stool and blood samples to look at the outcomes.

So how did the crickets affect the body?

There were increases in what would be considered certain beneficial bacteria and a reduction in inflammation in the bodies of people who consumed crickets. We saw an increase in Bifidobacterium, one of the first microorganisms that colonises the gut of babies. It helps infants gain more nutrients from their diets, aids with development of the immune system, and protects them from pathogen infections. We maintain those bacteria throughout our life but they tend to decrease as we age, so they’re commonly sold as probiotic supplements or are added to certain types of foods, like yoghurt.

We also saw a reduction in ‘TNF-alpha’, a common inflammatory marker. Small amounts of acute inflammation are necessary for fighting off infections, but high levels – often a side effect of consuming a Western diet – can lead to conditions like diabetes and cardiovascular disease. Reducing inflammation can benefit long-term health outcomes. We were working in a population of young, healthy adults, so we might see greater benefits in a population that’s at risk of chronic diseases of the gut.

What’s next?

We think the benefits are at least partially due to a type of fibre found in insects called ‘chitin’. The only other things in our diet that have chitin are mushrooms and the shells of crustaceans like crabs and prawns, but we typically don’t eat the latter. We think that chitin might be enhancing the growth of the beneficial bacteria. It’s a really small study so it needs to be repeated with more people, but it’s a promising start.

How did you study insect consumption?

We had 20 people in the trial, and we asked them to replace their breakfast every day with muffins and chocolate malt milkshakes that either contained or didn’t contain cricket powder. They were eating those meals for two weeks, had a two-week rest period where they went back to their normal diets, and then they switched groups and ate the other meals for two weeks. We collected stool and blood samples to look at the outcomes.

So how did the crickets affect the body?

There were increases in what would be considered certain beneficial bacteria and a reduction in inflammation in the bodies of people who consumed crickets. We saw an increase in Bifidobacterium, one of the first microorganisms that colonises the gut of babies. It helps infants gain more nutrients from their diets, aids with development of the immune system, and protects them from pathogen infections. We maintain those bacteria throughout our life but they tend to decrease as we age, so they’re commonly sold as probiotic supplements or are added to certain types of foods, like yoghurt.

We also saw a reduction in ‘TNF-alpha’, a common inflammatory marker. Small amounts of acute inflammation are necessary for fighting off infections, but high levels – often a side effect of consuming a Western diet – can lead to conditions like diabetes and cardiovascular disease. Reducing inflammation can benefit long-term health outcomes. We were working in a population of young, healthy adults, so we might see greater benefits in a population that’s at risk of chronic diseases of the gut.

What’s next?

We think the benefits are at least partially due to a type of fibre found in insects called ‘chitin’. The only other things in our diet that have chitin are mushrooms and the shells of crustaceans like crabs and prawns, but we typically don’t eat the latter. We think that chitin might be enhancing the growth of the beneficial bacteria. It’s a really small study so it needs to be repeated with more people, but it’s a promising start.

Jason Goodyer  Commissioning editor, BBC Science Focus (2018). Eating insects is good for your gut. Science Focus, The Home of BBC Science Focus Magazine. Retrieved from: https://www.sciencefocus.com/the-human-body/eating-insects-is-good-for-your-gut/