If we had even 1 honest meta-analysis for every 10 trials like this, well, we'd know more than we do now. Small trials with inconsistent/poor designs are the bane of medical science.
That said, I drink dark roast so this study must be true.
That said, I drink dark roast so this study must be true.
https://www.nature.com/articles/srep33711
> coffee intake was associated with reduced risk of oral, pharynx, liver, colon, prostate, endometrial cancer and melanoma and increased lung cancer risk.
(Heh. Smokers drink nearly twice as much coffee as non-smokers. Smoking increases caffeine metabolism. I think this explains the lung cancer risk)
But when I looked for a source on that one day it seems like that's a myth. There can be differences based on whether you measure by weight vs volume but that's about it. https://www.kickinghorsecoffee.com/en/blog/caffeine-myths-da...
So now I just say I like light roasts because I like to taste the coffee and not the roast.
In short, a cup of light roast and a cup of dark roast have negligible differences in caffeine content.