Another Perspective on the Sodium Wars... Too Little Sodium Bad for Insulin Resistance?

Another perspective on the sodium wars

A couple of weeks ago, a colleague from our sister site asked me to comment on New York City's new campaign to reduce sodium in packaged and restaurant food. I told her I thought the across-the-board movement was probably overkill. The majority of people don't have high blood pressure--and most of those who do are not salt sensitive. In effect, we'd be "treating" a lot of people who don't need it in order to get at those who do. On the other hand, I said, there's no harm in reducing sodium and it would save lives.

Hold that thought. A new commentary in the Journal of the American Medical Association questions some of the received truths about the benefits and risks of these population-wide efforts to restrict sodium intake.

Experts writing in the New England Journal of Medicine recently estimated that reducing salt intake nationwide would prevent tens of thousands of strokes, heart attacks and deaths. But the JAMA authors counter that the evidence for this is indirect at best. Reducing salt intake will reduce average blood pressure readings. But it is merely an assumption that this will in turn reduce heart attacks, strokes and deaths.

Where's the Evidence?

There have been no randomized clinical trials showing that reducing sodium reduces illness or death in otherwise healthy people. Observational studies on the relationship between sodium intake and health have been mixed. Some have found a relationship between high sodium intake and cardiovascular events; others found no relationship.

Reducing Sodium Isn't Always Harmless

Furthermore, the JAMA commentators point out, it's not true that restricting sodium does no harm. (This was news to me.) Reducing sodium enough to lower blood pressure has also been shown to reduce insulin sensitivity, for example.

Are We Jumping to Conclusions (Again)?

As the JAMA authors point out, the move to restrict sodium intake is well-intentioned. But jumping to conclusions sometimes makes things worse, not better.

In 1980, for example, the government advised everyone to reduce their fat intake. But as our fat intake declined, an epidemic of obesity and diabetes bloomed. In 2000, the government withdrew this recommendation. Another piece of well-intentioned but ultimately bad advice: substituting margarine (trans fats) for butter (saturated fats).

What do you think? Is a governmental crusade to reduce sodium intake across the board premature?