A cherry-like fruit that grows deep in the Amazon jungle has the potential to help battle the North American obesity crisis, suggests new research published in Gut. In the study, an extract from camu camu, a round, red, super-tart fruit, reduced obesity and related illnesses in mice whose diets went otherwise unchanged. The fruit, it appears, thwarts weight gain before it can start.
Camu camu (Myrciaria dubia) is already advertised in a variety of supplements because of its insanely high vitamin C content. Until now, however, there hasn’t been much research on its potential effects on weight management. To investigate this, Université Laval Quebec Heart and Lung Institute Research Centre researcher André Marette, Ph.D., first gave one group of mice a high-fat, high-sugar chow until they were borderline obese and then gave a different group the same food alongside a dose of camu camu extract. Over the course of eight weeks, the camu camu group gained 50 percent less weight than the controls, despite their poor dietary habits. In fact, in some additional experiments, they even lost weight.
“These mice were going to become diabetic, but this was prevented by the camu camu treatment,” Marette tells *Inverse. “We believe this is because we changed the gut microbiome, because these changes could be reproduced when we gave the camu camu affected microbiota to untreated mice.”
A Change in the Gut Microbiome
Marette believes that camu camu can prevent changes to the gut microbiome caused by high-fat diets. Some gut bugs, like Lactobacillus, thrive in the microbiomes of obese individuals. But other beneficial bugs, like Akkermansia muciniphila, tend to die off.
“This camu camu treatment was able to prevent these changes from occurring and also led to a blooming of some bacteria such as Akkermansia muciniphila, which is a well-known bug now because it’s associated with metabolic health,” he adds.
An additional experiment showed that changes to the gut biota of each individual produced huge effects on that individual’s body fat. When the team performed a fecal microbiota transplant between the mice — essentially the transfer of poop (the natural habitat of gut bugs) from camu camu mice to the controls — the recipients of the camu camu poop lost up to five percent of their body mass within one day. Those that received the microbiome transplantation from the non-treated mice, meanwhile, gained three percent of their body weight on the first day of colonization.
Fat That Burns Calories
Marette has a hypothesis to explain these changes in weight. “When we saw the massive loss of weight, it’s either because you change appetite or you change excretion. But the two of these were not affected,” he explains. “But when we put the animals in metabolic cages, we confirmed that camu camu treatment was increasing the metabolic rate of these animals, without making them do more exercise.”
Marette’s findings showed that camu camu extracts had increased the animals’ basal metabolic rate, the amount of energy their bodies burn to simply keep them alive. Different body tissues each have their own individual metabolic rates: for example, liver and brain tissue both have high metabolic rates, but fat tissue usually lags behind these fast burners. In these mice, however, it was the fat itself finally doing its share of the burning — specifically, a subtype of fats called “brown fat.”
Brown fat has a higher metabolic rate — that is, it burns through energy at a higher rate — than other fat types, like white or yellow fat, says Marette. Humans have brown fat too, but in very small quantities; it’s usually around the neck and back. In the rats, the camu camu-derived changes in microbiome stoked the naturally burning brown fat fire.
“Genes and proteins that are related to burning of fat in the brown adipose tissue were increased in these animals treated with camu camu,” he explains.
These findings will need to be replicated in human subjects before the camu camu supplement hype gets into full swing. But Marette is already applying for grants to do these experiments and will likely use a similar design that he tested on his animals. If his results hold, he’ll probably have more than enough human volunteers, poop transfusion nonwithstanding.