One of the biggest problems for consumers hoping to choose foods wisely (and for regulators hoping to help consumers in that regard) lies in the difficulty in getting good, clear advice.

Even salt (discussed in yesterday’s posting as well) is more complicated, health-wise, than most people realize. Most people take it as given that salt is bad for you. It’s one of those things that “everyone knows,” and that most people lament. But the science, for better or worse, is not so clear.

See this piece, from the Financial Post: Junk Science Week: Salt scare lacks solid evidence (the piece is by David McCarron, University of California, Davis)

McCarron discusses…

…two critical flaws in the science.

The first relates to the established fact that only a minority of individuals’ blood pressure is sensitive to salt. For the majority, there is no change when salt is reduced and for some their blood pressure will go up. The latter is not a theoretical possibility. The past president of the International Society of Hypertension recently sounded a note of caution in an editorial in the Journal of the American Medical Association. Dr. Michael Alderman, citing data from peer-reviewed articles in the medical literature, documented that it is quite unclear whether reducing sodium intake improves health outcomes, has no effect or causes harm….

The second problem, according to McCarron, lies in the assumption “that public policy pronouncements and intimidation to force a reduction in the salt content of food can in fact result in our eating less salt.”

The significance of this scientific controversy may depend on whether you’re making decisions as an individual, or as a policy-maker. Given that, for any scientific question, evidence can vary between zero and full certainty, individuals and governments have to decide how much certainty is enough to warrant taking action. And the requisite level of certainty is likely to be different for individuals than for governments. For one thing, the principles according to which they ought to make their decisions differ. Governments should make their food-policy decisions on ethical grounds (and the particular ethical principles that ought to apply are up for debate). Individuals, on the other hand, only need to make rational food decisions — decisions that make their lives as good as possible, given available resources. The result is that, this particular bit of scientific uncertainty may not be good reason to give yourself free rein with the salt shaker, but it just may be reason for policy-makers to think twice about heavy-handed regulation.