rainforest camu camu

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 in mice whose diets went otherwise unchanged. The fruit, it appears, reverses weight gain from the inside out.

Camu camu (Myrciaria dubia) is already advertised in a variety of supplements because of its insanely high vitamin C content, which amounts to 20 to 30 that of a kiwi, an already vitamin-packed fruit. Until now, however, there hasn’t been much research on its potential effects on weight management. André Marette, Ph.D, of Université Laval’s Quebec Heart and Lung Institute Research Centre investigated this by first giving two groups of mice a high fat and high sugar chow until they were borderline obese, and then giving one lucky group of them an additional 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 lost weight.

“These mice were going to become diabetic,” Marette tells Inverse. But this was prevented by the camu camu treatment. We believe this is because we changed the gut mircobiome, because these changes could be reproduced when we gave the camu camu affected microbiota to untreated mice.”

camu camu
Camu Camu, which these researchers found can stifle the effects of poor diet in an animal model 

A Change in the Gut Microbiome

Marette believes that Camu Camu can prevent changes to the gut microbiome that borne of high fat diets. For instance 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 lead 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.

microbiome
Mice still ate the same amount of food, but initially lost weight after receiving a transplant of Camu Camu influenced microbiota.

An additional experiment showed that these personnel changes in the gut produced huge effects on mouse body fat. When he performed a fecal microbiota transplant between his mice — he took a solution comprised of poop samples (the natural habitat of gut bugs) from each cohort and inserted them into the gut of newcomer mice — mice who received the Camu Camu-influenced microbiota lost up to five percent of their body mass within one day. Conversely, those who received the microbiome transplantation from the non-treated mice 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.”

brown fat
The Camu Camu (yellow) group had a higher basal metabolic rate due to increased brown fat activity, which the researchers measured by taking the temperature of brown fat concentrations around the rat's necks. 

Marette’s findings showed that Camu Camu extracts had increased the basal metabolic rate of his animals — essentially the amount of energy their bodies burned to keep them alive while they were just sitting around. Different body tissues each have their own individual metabolic rates: for example liver and brain tissue both have high metabolic rates, but usually fat lags behind these leaders. But in these mice it was the fat itself finally doing its share of the burning —specifically a subtype of fats called “brown fat.”

Marette explains that brown fat has a higher metabolic rate (i.e. it burns through energy at a higher rate )than other fat types, like white or yellow fat. Humans have brown fat too, but in very small quantities usually around the neck and back. Marette found that in his rats, Camu Camu 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 aside.