The following ideas can help you evaluate information you encounter about science and health.
Science is a truth-seeking process.
It is, however, a self -correcting discipline. To determine whether bottled water is preferable to tap water, for example, one would have to design a lifelong study of two large groups of people whose lifestyles were similar in all respects except for the type of water they consumed. This is virtually impossible. We therefore have to rely on less-direct evidence in formulating many of our conclusions. It may not be possible to predict all consequences of an action, no matter how much advance research has been done.