Caffeine aids weight loss in mice...but at equivalent of 30 cups of coffee a day for humans

27-Jun-2017 - Last updated on 04-Jul-2017 at 14:06 GMT

The mice were given the human equivalent human of around 30 cups of coffee. ©iStock

Caffeine helped obese mice lose weight by suppressing appetites and increasing energy exposure — but one academic has argued an equivalent dose in humans is likely to lead to severe caffeine toxicity and perhaps even a fatal cardiac event.

Writing in the journal Nature Communications, academics revealed that the administration of caffeine suppressed appetite, increased energy expenditure and reduced the body weight of mice fed a high-fat diet.

They found that obese mice had unusual activity in the hypothalamus part of the brain which regulates energy balance. However, caffeine consumption interacted with that part of the brain and led to weight loss.

The researchers believe that a high-fat diet leads to increases in both the circulating levels of adenosine and a specific adenosine receptor (A1R), which results in obesity.

In the study, led by a team from the Huazhong University of Science and Technology in China, it was demonstrated that caffeine assists in blocking the downstream effects of excessive adenosine.

“Caffeine or its derivatives could represent a relevant strategy to counteract obesity and related comorbidities,” they wrote.

Severe toxicity

However, the mice were given the human equivalent human of around 30 cups of coffee, warns a scientist who was not involved in the study.

Dr Ben Desbrow, associate professor in Sports Nutrition at the Menzies Health Institute Queensland at Griffith University, said: “The major limitation with the application of the study (apart from it employing mice) is the dose of caffeine provided, which was 60mg/kg body weight. This is a huge dose, with an equivalent dose in humans likely to lead to severe caffeine toxicity — if not a fatal cardiac event. In the mice, the high dose of caffeine resulted in greater voluntary physical activity and a reduced food intake.”

However, he added there was promise in using caffeine to prompt weight loss: “We've performed a similar study using caffeine to manipulate responses to diet and exercise in humans (albeit with a much lower caffeine dose (6mg/kg body weight)). In this study, we also found that short-term food consumption was reduced and, importantly, that participants found undertaking exercise more enjoyable."

Source: Nature Communications

doi:10.1038/ncomms15904

"Caffeine inhibits hypothalamic A1R to excite oxytocin neuron and ameliorate dietary obesity in mice"

Authors: Guo Zhang, et al.