As the world's population increases and climate change intensifies, there is an increasing need for sustainable protein alternatives. While plant-based "meat" and "dairy" are growing in popularity, they aren't the only green alternatives to traditional meat. Research in mice conducted at the University of Illinois at Urbana-Champaign shows that replacing traditional protein sources with mealworms in a high-fat diet slows weight gain, improves immune response, reduces inflammation, increases energy metabolism, and beneficially changes the ratio of good to bad cholesterol.
New research finds that replacing traditional protein with mealworms in a high-fat diet in mice can lead to numerous health benefits, including reduced weight gain and improved cholesterol. Although Western society is hesitant to eat insects, they are an environmentally sustainable source of protein.
In addition to increasing dietary fiber, nutritionists recommend eating more high-quality protein as part of a weight management plan. "We know from earlier studies in roosters that mealworms are a high-quality, easily digestible source of protein that is also environmentally sustainable," said Kelly Swanson, the study's lead author.
Swanson's team fed mice a high-fat diet (46% of calories from fat) and casein (a protein derived from dairy products), and after 12 weeks, the mice switched to alternative proteins. The other group, a control group, ate lean meats containing casein throughout the experiment. By the time mealworms were introduced, the high-fat diet group had become obese and developed metabolic syndrome, a condition that increases the risk of heart attacks, strokes, diabetes and other health problems.
The mice then began eating two types of dried mealworms in a flour-like powder form to replace either 50% or 100% of the casein in their diets. During and after eight weeks of eating the experimental diet, the team measured body weight, body composition, blood metabolites, and gene expression in liver and fat tissue.
Mealworm protein did not cause obese mice to lose weight, but they gained weight more slowly compared to mice fed a high-fat diet and casein. The benefits go far beyond that.
"It wasn't a case of weight loss; they just slowed their rate of weight gain through the mealworms," Swanson said. "The more important effect was an improvement in their lipid profile. Their LDL, the so-called 'bad cholesterol,' went down, and their HDL, the 'good cholesterol,' went up. From a gene expression standpoint, inflammation was reduced, and some lipid and glucose metabolism genes were altered. Not everything was positive, but from a metabolic standpoint, they were better off."
Some of these benefits may be related to chitin, a fibrous material that makes up the exoskeleton of insects. Swanson said that while chitin's effects haven't been well studied, it appears to act like fiber in stimulating the activity of beneficial microbes in the gut. He is working on another paper examining the impact of mealworms on the mouse microbiome.
Other studies have evaluated the effects of alternative proteins on weight control in obese mice, but most have used genetically altered mice that remain obese regardless. Swanson's team intentionally used "wild-type" mice so that they could gain weight through diet like many humans.
But are humans ready for mealworm protein?
"For many people in Western societies, eating insects is unusual, but some people have relied on insect protein for thousands of years," Swanson said. "With protein shortages becoming a reality, there may be a place for insect meals."
However, mealworm protein has not yet been approved by the U.S. Food and Drug Administration. Those curious about insects can try cricket powder, which can be used in food under the Food, Drugs and Cosmetics Act.
"You can't see the legs or anything like that, it just looks like a flour and it doesn't negatively affect the taste or other properties of the food," Swanson said.