by Marion Nestle
Feb 3 2010

The research on salt

Since Mayor Bloomberg started going after salt, my inbox is overflowing with commentary on all sides of the salt debates.

First a review of the research: has published a series of pieces on the importance of salt reduction to health and the implications of doing so for the food industry:

  • January 15: a summary of a Japanese study linking high salt diets to cancer.
  • January 26: a review of studies on several conditions affected by salt intake.
  • January 27: a discussion of the economic effects of reducing salt intake.
  • January 28: an overview of how the salt issues are viewed in Europe.
  • January 29: a discussion of the purported benefits of sea salt.
  • Also on January 29: a report on Kellogg’s salt-reduction initiative in Europe.
  • February 1: a review of the arguments over the science.
  • February 2: an account of how Ireland is dealing with the salt issue.

Jane Brody of the New York Times weighed in on the benefits of salt reduction.

Salt in restaurant meals: On January 31, an intrepid New York Times reporter had the bright idea of sending some restaurant meals off to a lab to test for sodium.  Ouch.  Large clam chowder 3100 mg, two slices of pizza 2240 mg, steak with creamed spinach 2660 mg, Katz’s corned beef with pickles 4490 mg.  Stroke anyone?  No wonder it’s so hard to avoid sodium.

The “leave salt alone” crowd: JAMA has just run an editorial from Michael Alderman arguing that salt reduction does no good, might do harm, and should be tested in clinical trials before moving forward.  And Greg Miller of the National Dairy Council sent me this piece from Dr. Judith Stern of U.C. Davis, a member of the advisory board of the Salt Institute, saying much the same thing.

These are old arguments. What I find remarkable about them is that despite such individual opinions, every committee that has ever reviewed the research over the years has consistently come to the same conclusion: salt reduction is a good idea.  Are the committees delusional?  I don’t see how.  As for clinical trials, how could anyone do one?  There is already so much salt in the American diet that it will be hard to find a population of people able (even if willing) to reduce salt intake to a level where differences in health will be measurable.  The research disputes are difficult to sort out I don’t see how they can be easily resolved.

Under these circumstances, you could take your pick of whose research interpretation to believe – if you actually had a choice.  But you don’t.  If you eat processed food or in restaurants, you are eating a lot more salt than you need.

I’d like the default to  be a lower salt environment.  Drs. Alderman and Stern can always add more salt to their food.  I have no way of removing it from mine.

Stay tuned.  We will be hearing a lot more about this one.

  • QUOTE —
    “If you eat processed food or in restaurants, you are eating a lot more salt than you need.”

    Uh-oh. I’m in big trouble.

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  • Have there ever been studies on the effects of different types of salt on the diet? For example, using untreated sea salt vs. highly processed grocery store cooking salt? Does that make a difference in the health outcomes?

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  • What? No word from the salt shaker manufacturers Advisory Board?
    I use salt mainly to shake over my shoulder 3x.
    I like to taste my food.
    Thanks for all the excellent coverage on this.

  • I agree that a “low salt environment” would be wonderful. Those who desire more salt can always add it back in, but you can’t take it out. You only need to add a little bit of salt while cooking to enhance the flavors. You don’t need tablespoon after tablespoon. Working in a restaurant, I’ve seen the enormous handfuls of salt they add into food. Since everything at restaurants is overly salted, our taste buds become desensitized to salt, and then it causes a whole cycle of over-salting everything

  • I agree that a low salt environment would be a big improvement. I eat a mainly whole foods diet, and make nearly all my food from scratch. Avoiding restaurant and processed food allows me to really taste my food. Most people can’t taste all the salt they are consuming. On the rare occasion I eat something processed, the saltiness nearly gags me.

  • I can’t help but feel that if we didn’t eat out as often as we do, this wouldn’t be such a huge issue. I still consider eating out a special occasion kind of thing, and the extra dose of salt on those occasions won’t hurt me when I’m eating a regular diet most of the time.

    I’m also pretty curious about the sodium differential between lower-end fast food and higher-end restaurant food.

    All of these nutrition debates and troubles can, I think, really be mitigated by teaching people and encouraging people to cook their own darn meals again, from real food and not from a box.

  • marisa

    Imagine how little salt our ancestors used. Salt was worth its weight in gold, so a little salt for them probably went a long way, and they probably thought a pinch in food tasted glorious. Now we can’t even taste it when there’s 4000mg in a dish!

  • Anthro

    Three cheers to meatlessmama and laura k! I’m with the two of you. This needs to start in school, though, as it’s not happening much in the home.

    We are lucky to have Marion sorting through all the reports and give us a reasoned opinion. Thank you Ms. Nestle!

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  • Emily

    Julie, I, too, am curious if sodium source makes a difference. Soy sauce is high in sodium, but don’t we keep reading that the rates of most cancers are very low in east Asia? (And then there’s kimchee and umeboshi and li hing mui and….) One can’t help but wonder.

  • ET Addison

    This is where it gets sticky. Where iffy and incomplete and ambiguous science meets public policy.

    You do NOT declare fact by concensus. Just because a ‘committee’ agreed to recommend something is scientifically and factually meaningless. Just because 12 people believe something doesn’t make it so. Marion’s trust of committees is touching.

    We could just as easily say ‘the sun can’t be 93 million miles from the earth. That seems way too high. That doesn’t seem right, I mean, people get sunburn and all. I just can’t see how it can be that far away.”

    We say it should be 45 million miles. That seems about right.

    I’m sure somebody could make a measurement that would show that is correct.

    There is way too much moralizing and tsk-tsking and value-judging and guessing in nutrition.

    ‘We think sodium consumption is too high’ is group-think, not science.

  • I’m not sure where Dr. Alderman has been looking but I’m pretty sure the DASH Diet feeding studies, with and without lowered sodium, plus the Trials of Hypertension Prevention in the 1970s, qualify as “clinical trials”. Dr. Alderman is a longtime advisor to (and I think board member of) the Salt Institute, and despite his eminent academic status, that makes him a questionable spokesman on the real public health picture for salt and hypertension.

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