Caffeine May Curb Obesity and Diabetes Risk, Genetic Study Finds
Sweden: A new study published in BMJ Medicine suggests that individuals with naturally higher plasma caffeine concentrations may have a reduced risk of developing type 2 diabetes, largely due to lower body fat levels. The findings, drawn from a two-sample Mendelian randomisation analysis, provide insight into caffeine's potential long-term metabolic effects.
“Lifelong genetically predicted higher plasma caffeine levels are associated with lower body mass index and reduced body fat, which in turn are linked to a decreased risk of developing type 2 diabetes,” the researchers stated. They further noted that nearly half of caffeine’s protective effect against type 2 diabetes is likely mediated by its impact on reducing body weight.
The research aimed to determine whether plasma caffeine levels, influenced by genetic variants, have a causal effect on adiposity, type 2 diabetes, and major cardiovascular diseases. The study utilized data from genome-wide association studies involving predominantly European participants.
Susanna C Larsson, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden, and colleagues focused on two genetic variants—rs2472297 (near the CYP1A2 gene) and rs4410790 (near the AHR gene)—which are known to affect caffeine metabolism and blood concentrations.
The study led to the following findings:
- Individuals genetically predisposed to higher plasma caffeine levels were found to have lower body mass index (BMI) and reduced total body fat.
- For each standard deviation increase in plasma caffeine (around 4.8 kg/m² in BMI), there was a significant decline in both BMI and fat mass.
- There were no significant changes in fat-free mass, including muscle and bone.
- Higher plasma caffeine levels were associated with a 19% reduced risk of developing type 2 diabetes, based on FinnGen and DIAMANTE consortia data.
- Nearly 50% of this reduced diabetes risk was attributed to BMI reduction, suggesting body fat plays a key mediating role.
- There were no strong associations between plasma caffeine levels and risks of cardiovascular diseases such as heart failure, stroke, atrial fibrillation, or ischaemic heart disease.
These findings build on earlier short-term studies showing that caffeine intake may promote modest weight loss. While observational research has linked coffee consumption with a lower risk of type 2 diabetes and cardiovascular disease, this new genetic evidence offers stronger support for a potential causal relationship, especially concerning diabetes prevention.
The researchers emphasized the need for longer-term clinical trials to explore whether caffeine-containing, non-caloric beverages could be beneficial in managing or preventing obesity and type 2 diabetes. They noted that although the findings are promising, further investigation is needed to translate these genetic insights into practical dietary or therapeutic interventions.
"The genetic study provides compelling evidence that elevated plasma caffeine may contribute to lower body fat and reduced type 2 diabetes risk, paving the way for future research on caffeine’s role in metabolic health," they concluded.
Reference:
Larsson, S. C., Woolf, B., & Gill, D. (2023). Appraisal of the causal effect of plasma caffeine on adiposity, type 2 diabetes, and cardiovascular disease: Two sample Mendelian randomisation study. BMJ Medicine, 2(1), 1. https://doi.org/10.1136/bmjmed-2022-000335
