Iris (Definition) The iris is a structure within the eye that helps reduce the amount of light that reaches the retina. The iris is known as the colored part of the eye, and can be blue, brown, or any color or combination of colors in between. The iris is the portion of the eye that responds to light stimulation. ...Read more.
Scientists also speculate that caffeine may provide a mood-boosting effect that helps ease pain. Regardless of the mechanism by which it works, the data does indicate that caffeine does indeed make pain medications more effective and help ease pain.
Coffee and Weight Loss in The Long Term. There is one major caveat here, and that is the fact that people become tolerant to the effects of caffeine (15, 16). In the short term, caffeine can boost the metabolic rate and increase fat burning, but after a while people become tolerant to the effects and it stops working.