As mentioned, moderation is the key and most of the various health warnings we hear amount to little more than generalized "best practices" and have little to no validity in specific recommendations for individuals. What one must take into account is that most of these warnings and recommendations are based on a statistical variation in a group of individuals tested or interviewed.
Throwing out numbers arbitrarily ... if 10% of the population will experience a heart attack in their lifetimes and a group taking in double the recommended amount of salt will have 20% experience a heart attack, then we can say to a certainty that too much salt (or red meat, or nicotine, or alcohol, or name your poison) CAN have a negative effect on your health. We can say that it doubles your risk of a heart attack or we can say that it increases your risk by 10%. What we shouldn't say or imply is that, if you ignore the warning, you're going to have a heart attack. That is something that only a physician should ever say and then only after a comprehensive examination of current condition, medical history and genetic disposition. Otherwise, each individual should also know and understand that there is an 80% chance (using our arbitrary numbers) that they will never suffer a heart attack regardless of their behavior.
What is, however, never discussed, measured, studied or tested is the effect of these warnings on the population at large. If we hear often enough that "too much salt will give you a heart attack" so that we come to believe it, then will that belief, that power of suggestion, increase our risk of a heart attack? One could argue that what we believe will kill us is what will kill us. If, in fact, such an argument was shown to be valid with some individuals, then those who issue such opinions bear some responsibility in the unintended collateral damage.