NOM

CONCLUSION
Coffee consumption seems generally safe within usual
levels of intake, with summary estimates indicating
largest risk reduction for various health outcomes at
three to four cups a day, and more likely to benefit
health than harm. Robust randomised controlled
trials are needed to understand whether the observed
associations are causal. Importantly, outside of
pregnancy, existing evidence suggests that coffee
could be tested as an intervention without significant
risk of causing harm. Women at increased risk of
fracture should possibly be excluded.

When dose-response analyses have been
conducted and when these have suggested nonlinearity—for
example in all cause mortality,
cardiovascular disease mortality, cardiovascular
disease, and heart failure—summary estimates
indicate that the largest relative risk reduction is
associated with intakes of three to four cups a day.
Importantly, increase in consumption beyond this
intake does not seem to be associated with increased
risk of harm, rather the magnitude of the benefit
is reduced. In type 2 diabetes, despite significant
non-linearity, relative risk reduced sequentially
from one through to six cups a day. Estimates from
higher intakes are likely to include a smaller number
of participants, and this could be reflected in the
imprecision observed for some outcomes at these
levels of consumption.