High levels of caffeine may reduce body fat and risk of type 2 diabetes

Higher levels of caffeine in the blood appear to reduce the risk of adiposity and type 2 diabetes, the results of a new study suggest.

Explaining that caffeine has thermogenic effects, the researchers note that previous short-term studies have linked caffeine consumption to reduced weight and fat mass. And observational data has shown associations between coffee consumption and lower risks of type 2 diabetes and cardiovascular disease.

In an effort to isolate the effects of caffeine from those of other food and beverage components, Susanna C. Larsson, PhD, of the Karolinska Institute, Stockholm, Sweden, and her colleagues used data from population studies primarily European to examine two specific genetic mutations that have been linked to a slower rate of caffeine metabolism.

Both genetic variants resulted in “genetically predicted higher plasma caffeine concentrations across the lifespan,” the researchers note, “and were associated with lower body mass index and fat mass, as well as lower lower risk of type 2 diabetes”.

It is estimated that about half of the effect of caffeine on type 2 diabetes is mediated by the reduction in body mass index (BMI).

The work was published online March 14 to BMJ Medicine.

“This publication supports existing studies suggesting a link between caffeine consumption and increased fat burning,” notes Stephen Lawrence, MBChB, University of Warwick, UK. “The big leap of faith the authors took is to assume that the weight loss caused by increased caffeine consumption is sufficient to reduce the risk of developing type 2 diabetes,” he told UK Science. Media Centre.

“However, this does not prove cause and effect.”

The researchers agree, noting, “Further clinical study is warranted to investigate the translational potential of these findings to reduce the burden of metabolic disease.”

Katarina Kos, MD, PhD, senior lecturer in diabetes and obesity at the University of Exeter, UK, pointed out that this genetic study “shows links and potential health benefits for people with of certain genes attributed to a [caffeine]…metabolism as an inherited trait and potentially better metabolism.”

“It does not study or recommend drinking more coffee, which was not the purpose of this research,” she told the UK Science Media Centre.

Genome-wide association study demonstrates links

Using Mendelian randomization, Larsson and colleagues examined data from a genome-wide association meta-analysis of 9876 people of European ancestry from six population-based studies.

Higher genetically predicted plasma caffeine concentrations in people with both genetic variants were associated with lower BMI, with a one standard deviation increase in predicted plasma caffeine equivalent to approximately 4.8 kg/m² in BMI (P < .001).

For total body fat, a one standard deviation increase in plasma caffeine was equivalent to a reduction of approximately 9.5 kg (P < .001). However, there was no significant association with fat-free body mass (P = 0.17).

Genetically predicted higher plasma caffeine concentrations were also associated with a lower risk of type 2 diabetes in FinnGen study (odds ratio, 0.77 per increase in standard deviation; P < .001) and the DIAMOND GROUP (0.84, P < .001).

Combined, the odds ratio of type 2 diabetes per standard deviation of increase in plasma caffeine was 0.81 (P < .001).

Larsson and colleagues calculated that approximately 43% of the protective effect of plasma caffeine on type 2 diabetes was mediated by BMI.

They found no strong association between genetically predicted plasma caffeine concentrations and the risk of any of the studied cardiovascular disease outcomes (ischemic heart disease, atrial fibrillation, heart failure and stroke).

The thermogenic response to caffeine has previously been quantified as an increase of approximately 100 kcal in energy expenditure per 100 mg of daily caffeine intake, an amount that may lead to a reduced risk of obesity. Another possible mechanism is increased satiety and suppression of energy intake with higher caffeine levels, the researchers say.

“Long-term clinical studies investigating the effect of caffeine consumption on fat mass and risk of type 2 diabetes are warranted,” they note. “Randomized controlled trials are warranted to assess whether non-caloric caffeinated beverages might play a role in reducing the risk of obesity and type 2 diabetes.”

The study was supported by the Swedish Research Council for Health, Working Life and Wellbeing, the Swedish Heart Lung Foundation and the Swedish Research Council. Larsson, Lawrence and Kos reported no relevant financial relationships.

BMJ Med. Published online March 14, 2023. Abstract

Miriam E. Tucker is a freelance journalist based in the Washington, DC area. She is a regular contributor to Medscape, with other work published in The Washington Post, NPR’s Shots blog, and Diabetes Forecast magazine. She’s on Twitter: @MiriamETucker.

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