Figure 5.

Summary of the spectrum of data and our endpoint conclusions for healthy adults, weighted for level of confidence in the body of evidence considering risk of bias, magnitude, consistency, and other factors. Shading indicates that data reported effects at the corresponding intake level (<400, 400, or >400 mg caffeine/day), and darker shading indicates increased confidence in the body of evidence (from very low to high). X indicates the SR weight-of-evidence conclusion for the level of intake not associated with significant health effects. Although effects were observed at exposures below 400 mg (e.g., blood pressure, bone mineral density and osteoporosis), these results did not affect the overall conclusion of the SR, due to considerable variability in individuals’ sensitivity to caffeine and potential confounding, and the effects were limited to physiological effects following acute exposure, and subgroups of clinical endpoints, such as those with low calcium intake. Such effects were generally of low magnitude, and/or were of overall low or negligible consequence to downstream effects. Several studies also showed a lack of effects on clinical endpoints at exposures above 400 mg.