Salt and Heart Disease

Our bodies are very complicated.

Consider a new study about the link between salt consumption and heart disease. We know that eating salt raises blood pressure, and high blood pressure is a causal factor in heart disease. It stands to reason, then, that cutting salt in our diets ought to reduce heart disease.

But it doesn't. Or, at least, the latest, biggest, and most sophisticated meta-analysis of studies failed to find any link. Why would that be?

The study's own lead author says this might be a problem with the data, that is, all these studies rely on what people tell us about how much salt they eat, and they may be lying. Or, they may keep off the salt for a while but then slowly go back to eating as much as they did before:

They're intensively followed up for a couple years, and 8 or 10 years later these people's behavior has probably reverted to what it was.

But whatever the reason, we are left with the odd fact that even though we know ingesting salt raises blood pressure and high blood pressure leads to heart disease, we have no real evidence that reducing salt intake is healthy.