Science & Technology, UK (Commonwealth Union) – Caffeine is a natural stimulant found in various plant sources such as coffee beans, tea leaves, and cacao pods. It consumption by people all over the world for its ability to provide a quick energy boost and increase alertness often makes it a popular beverage. However, many scientists have stressed the need to be aware of both the benefits and potential drawbacks of caffeine consumption. Over the years caffeine has received both positive and negative observations in studies, hence the quantity of consumption per individual is likely to be key.
A more recent study has found that elevated blood caffeine levels may lower the body weight in an individual carrying the risk of type 2 diabetes.
The study, which was published in BMJ Medicine, explored the effect of increased blood caffeine levels on body weight and the long-term risks of type 2 diabetes and prominent cardiovascular diseases, like coronary artery disease, stroke, heart failure, as well as irregular heart rhythm.
Researchers applied the statistical method known as Mendelian randomization, which utilizes genetic variants as a tool to explore the causal link between a trait and an outcome.
The findings of their evaluations indicated that increased genetically predicted blood caffeine levels were linked with reduced body weight (BMI). Increased genetically predicted blood caffeine levels were further linked to a lower risk of type 2 diabetes.
Researchers indicated that the results show that it may be worth looking into the possibilities for calorie-free caffeinated drinks to play a role in reducing the risk of obesity as well as type 2 diabetes.
“These findings offer important insight into the potential causal effect of caffeine on adiposity [obesity] and diabetes risk. However, further clinical study is warranted before individuals should use these results to guide their dietary preferences,” explained Dr Dipender Gill, a senior author for the study, from the Imperial College London, School of Public Health.
The research was conducted in partnership between the Imperial College London, the University of Bristol, the London School of Hygiene and Tropical Medicine, as well as the Uppsala University, Sweden.
Prior studies had pointed out that drinking 3-5 cups of coffee per day was linked with a lesser risk of type 2 diabetes and cardiovascular disease, that included an average cup of coffee consisting of approximately 70–150 mg of caffeine.
However, it was observed by researchers in the study, that a majority of the published studies to date has come from observational studies, which is unable to reliably establish causal effects, due to the other possibly influential factors at play. It is also hard to disentangle any particular effects of caffeine from other compounds contained in caffeinated drinks and foods.
Applying Mendelian randomization, the study explored the role of 2 common genetic variants of the CYP1A2 and AHR genes in roughly 10,000 individuals of predominantly European descent who participated in 6 long-term studies. The CYP1A2 and AHR genes were linked to the speed of caffeine metabolism inside the body.
Individuals who have genetic variants related to slower caffeine metabolism consume, on average, lower amounts of coffee, yet have increased levels of caffeine in their blood than individuals who metabolize it faster to reach or retain the levels needed for its stimulant effects.
The study further looked into the extent to which any effect of caffeine on type 2 diabetes risk may principally be driven by concurrent weight loss. The findings demonstrated that weight loss drove almost half of the effect of caffeine for the type 2 diabetes risk. No strong links came up between genetically forecasted blood caffeine levels and the risk of any of the evaluated cardiovascular disease outcomes, as indicated by researchers who also acknowledged that there are restrictions to the study, including the use of just 2 genetic variants, and the inclusion of only people of European ancestry.