by Marion Nestle

Currently browsing posts about: Salt

Aug 14 2014

It’s salt war time again: new research, arguments over public health recommendations, and issues of conflicts of interest

Here are the burning questions about sodium (which is 40% of salt) intake:

(a) Does too much dietary sodium cause high blood pressure?   Answer: an unambiguous yes (although not necessarily in everyone).

(b) Are public health recommendations to reduce salt intake warranted?  I think so, but others disagree.

(c) If so, to what level?  Although virtually all committees reviewing the evidence on salt and hypertension view public health recommendations as warranted, and advise an upper limit of about 2 grams of sodium (5 grams of salt, a bit more than a teaspoon (see table from the Wall Street Journal), these too are under debate.

These recommendations are strongly opposed by The Salt Institute, the trade association for the salt industry, its industry supporters, and some groups of investigators.

Now the New England Journal of Medicine weighs in with three new studies, an editorial, and a cartoon video.  The papers:

Start with the video,  narrated by the editor, Dr. Jeffrey Drazen (click on video link on the right side).  It gives an excellent summary of the three papers.  Despite their methodological differences, all confirm (a).  They disagree on (c) and, therefore, (b).

Are public health recommendations warranted?

But note Dr. Drazen’s suggestion: “throw away the salt shaker.”

He is in favor of reducing salt intake.  But the salt shaker is not where most dietary salt comes from.  At least 75% of salt in American diets comes from restaurant and processed foods.   As Dr. Yoni Freedhoff explains:

If you’d like to reduce the sodium in your diet, rather than keep a running tally of how much you’re actually consuming, why not try instead to determine what percentage of your diet comes from restaurants and boxes? Sure, there’s data to suggest you might simply find other ways to add salt to your diet. But visit restaurants and consume processed foods less frequently, and I’d be willing to wager that you’ll be far more likely to see health benefits than were you to simply fill your grocery cart with low-sodium versions of highly processed foods.

Individuals cannot cut down on salt on their own.  That’s one reason why public health policies are needed—to get restaurants and processed food manufacturers to reduce salt content.

Two of the papers say that the only people who need to cut down on salt are those with hypertension and older people (one of the studies says that means people over age 55).

You can’t expect 70 or 80 million people to reduce salt intake on their own.  Hence: public health recommendations.

Conflict of interest alert

Some of the investigators report receiving grants or fees from companies that make anti-hypertensive drugs but the editorial accompanying the papers is of special concern.   Written by Dr. Suzanne Oparil, it says about one of the studies:

These provocative findings beg for a randomized, controlled outcome trial to compare reduced sodium intake with usual diet. In the absence of such a trial, the results argue against reduction of dietary sodium as an isolated public health recommendation.

These conclusions sent me right to her conflict-of-interest disclosure statement.  Although Dr. Oparil reports receiving grants or fees from companies making anti-hypertensive drugs—-and, even more remarkable, from The Salt Institute—she states that she has no conflicts of interest.

I think she does.

Implications

Her editorial is especially unfortunate because it influences the way reporters write about the studies.

The Associated Press account, for example, begins:

A large international study questions the conventional wisdom that most people should cut back on salt, suggesting that the amount most folks consume is OK for heart health — and too little may be as bad as too much. The findings came under immediate attack by other scientists.

As well they should.  Blood pressure rises with age and huge swaths of the population would be healthier eating less salt.   The AP reporter quoted me saying so:

“People don’t eat salt, they eat food,” she said. “Lots of people have high blood pressure and lots of people are getting older,” making salt a growing concern, she said. “That’s the context in which this is taking place.”

The three studies are complicated to interpret because of differences in methods and discrepancies in outcomes.  They agree that if you already have hypertension or are “elderly,” or eat a lot of salt, you should cut down.

This seems like a good idea for just about anyone.   People don’t eat salt; they eat foods containing salt, and foods high in salt tend to be high in other things best consumed in small amounts.

The studies also talk about the protective effects of potassium, best obtained from vegetables.

Eat a lot of vegetables and not too much junk food, and you don’t have to worry about any of this.

Dec 4 2013

Yes, the environment does influence food choice

I’m in Washington, DC this week on a bit of book tour for Eat, Drink, Vote (see Appearances for schedule).

At my Politics & Prose bookstore event last night, I got asked why I think the food environment matters so much in dietary choice.  Isn’t food choice a matter of personal responsibility?

It is, of course, but the food environment greatly influences personal choice.

Two examples:

Large portions: just about anyone presented with a large portion of food with eat more from it, take in more calories (larger portions have more calories!), and underestimate the calories consumed by a much greater proportion than from a smaller amount.

Salt intake: Because 80% or so of salt in the American diet comes from processed and restaurant foods, people eating in restaurants have no control over the amount of salt they take in.

To make it easier for people to take in fewer calories and less salt requires changes in the food environment: serve smaller portions and reduce the salt in restaurant foods.

FDA: Get to work!

Sep 17 2013

The salt debates continue: American Journal of Hypertension

The American Journal of Hypertension has published a series of point-counterpoint articles on the salt debate: are public health campaigns to reduce sodium intake warranted by the data?  Public health agencies argue yes.Others argue to the contrary.

This debate is not easily resolved, mainly because everyone eats a high-salt diet; most salt is already in processed and restaurant foods and eaters have no choice.

So the issue really becomes one of whether it makes any difference to high blood pressure to reduce high salt intakes and, if so, to what level—questions difficult to answer with current methods.

Introduction

The Salt Discourse in 2013
Theodore A. Kotchen

CDC Response

Sodium Reduction Is a Public Health Priority: Reflections on the Institute of Medicine’s Report,Sodium Intake in Populations: Assessment of Evidence
Janelle P. Gunn, Jessica L. Barron, Barbara A. Bowman, Robert K. Merritt, Mary E. Cogswell, Sonia Y. Angell, Ursula E. Bauer, and Thomas R. Frieden

NYC DOHMH Response

Getting the Message Right: Reducing Sodium Intake Saves Lives
Jenifer E. Clapp, Christine J. Curtis, Susan M. Kansagra, and Thomas A. Farley

Editorial

The IOM Report Fails To Detect Evidence to Support Dietary Sodium Guidelines
Michael H. Alderman and Hillel W. Cohen

Researcher Responses

Physiology, Not Policy, Drives Sodium Intake 
David A. McCarron

Extreme Sodium Reductions for the Entire Population: Zealotry or Evidence Based?
Andrew Mente, Martin J. O’Donnell, and Salim Yusuf

Flawed Evidence Should Not Derail Sound Policy: The Case Remains Strong for Population-Wide Sodium Reduction
Lawrence J. Appel and Paul K. Whelton

Sodium: How and How Not to Set a Nutrient Intake Recommendation
Robert P. Heaney

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Jun 13 2013

The endless debates about salt: Don’t worry. Eat (real) food

Since 1980, U.S. dietary guidelines have advised eating less sodium (salt is 40% sodium, 60% chloride).  Although sodium is an essential nutrient, most Americans consume way more than they need or is good for them—around 3,400 milligrams a day.

The 2010 guidelines advised healthy people to consume no more than 2,300 mg per day (~6 grams, or 1.5 teaspoons).  They advised even less, 1,500 mg, for people with or at high risk for high blood pressure.  Since blood pressure increases with age in countries with high salt intake, this applies or will apply to just about everyone.  

In 2011, the Institute of Medicine said it was imperative to find effective strategies to lower salt intake.  This means dealing with processed and restaurant foods, because that’s where most of the salt comes from, as can be seen from this list of major food sources

Because consumers have no choice about the amount of salt in processed and restaurant foods, education cannot be enough to achieve salt reduction.  Scientists in Australia have just proved this point.

As I explained to a reporter,

Why anyone would think that nutrition education alone would change behavior is beyond me. By this time everyone should know that to change behavior requires not only education, but a food environment—social, political, economic—that supports and promotes the behavior change.

Most dietary sodium comes from processed foods, restaurant foods, and other pre-prepared foods.  All the label can do is say ‘don’t eat me’ It can’t help with what people can eat.

The easiest and most effective way to help people reduce sodium intake is to require food producers and food preparers to use less of it. Good luck with that. I’m not optimistic, particularly given the conflicting and confusing science. 

Ah yes.  The conflicting science.  The IOM now says that there’s no evidence one way or the other that reducing sodium below 2,300 mg per day, or even to 1,500 per day, does much good, and that low sodium intakes could be harmful (but this too is controversial).

Yes, they could, but as Mark Bittman blogs,    

It may be true that there are no benefits in an ultra-low-salt diet, but almost no one is eating an ultra-low-salt diet. It’s not quite like worrying about whether we get “enough” sugar, but it’s nearly as ridiculous.

And now, as Food Navigator explains, the IOM committee is complaining that its report has been badly misinterpreted.  All they said was:

As to whether we should cut back to 1,500 mg or to 2,300 mg sodium a day, meanwhile, the jury is out, says the IOM, not because consuming 1500 mg/day is dangerous, but because there is just not enough data on the benefits of consuming such low levels to support a firm conclusion.

IOM committee members were so bothered by misleading press accounts that they wrote an op-ed to JAMA to clarify:

Rather than focusing on disagreements about specific targets that currently affect less than 10% of the US population (ie, sodium intake of <2300 mg/d vs <1500 mg/d),  the IOM, AHA, WHO, and DGA are congruent in suggesting that excess sodium intake should be reduced, and this is likely to have significant public health effects. Accomplishing such a reduction will require efforts to decrease sodium in the food environment….

The bottom line, Bittman says (and I enthusiastically agree), is that

Salt intake — like weight, and body mass index — is a convenient baseline for public policy people to talk about. If you focus on eating less salt — and, indeed, less sugar — you will inevitably eat less processed food, fast food, junk food (it’s all the same thing.) If you eat less processed food (etc.) you eat more real food. If you eat more real food, not only are you healthier, but you probably don’t have to pay attention to how much salt you’re eating. Wowie zowie. 

Mar 23 2012

The arguments about sodium go on and on

Dietary sodium continues to generate much talk but little action.

The CDC issued a recent Vital Signs report on dietary sodium with this graphic:

In translation from the data tables:

  • 90% of Americans consume too much salt.
  • 44% of salt comes from 10 foods: breads and rolls, cold cuts and cured meats, pizza, poultry, soups, sandwiches, cheese, pasta dishes, meat dishes, and snacks.
  • 65% of salt comes from retail processed foods.
  • 25% comes from food served at restaurants.
  • 10% comes from salt added at the table.
  • 10% occurs naturally in foods.
  • $20 billion a year is the cost of salt-related chronic disease.

The bottom line?  Americans would be better off eating less salt.

But from the standpoint of the food industry, reducing dietary sodium is a big problem.  See, for example,  FoodNavigator-USA.com‘s recent articles about sodium in foods and health:

Sodium reduction: The science, the technology… and the business case It’s expensive, risky, and difficult, but manufacturers have made huge progress on sodium reduction in recent years. But how much further can they go, and where is the ROI if consumers are at best indifferent to their efforts, or at worst downright suspicious?.. Read

Bakers on sodium reduction: We can’t afford to make products consumers won’t buy Reducing sodium is expensive and difficult, and many bakers are beginning to wonder whether it is worth investing millions into reformulating products that consumers do not want to buy, according to the Association of Bakers (ABA)… Read

Risks of slashing sodium levels in cheese could outweigh benefits, US researcher A prominent US researcher says that government pressure to cut sodium in cheese could have serious food safety, taste and labeling consequences, and questions the necessity of such a move given minimal evidence of positive health effects and muted consumer demand… Read

Sodium reduction: To boldly go… lower and lower Food manufacturers are under increasing pressure to reduce sodium, but surveys suggest many shoppers are, well, not that bothered. So where does this leave firms plugging sodium reduction solutions? Elaine Watson asks Mariano Gascon, R&D chief at seasonings, flavors and spice specialist Wixon for his take on it… Read

Law professor: Sodium reduction only works if there is a level playing field If consumers are not demanding lower-sodium products, and the government does not mandate reductions, the food industry has “no incentive to be at the forefront of change”, according to one legal expert… Read

National Dairy Council: Low sodium cheese is not taking the market by storm While cheese makers remain committed to salt reduction, demand for low-sodium cheese remains pretty lackluster, according to the National Dairy Council (NDC)… Read

Academic: Government sodium targets are incompatible with rest of dietary guidelines Further evidence that government healthy eating guidelines are more ‘aspirational’ than achievable has been uncovered by researchers testing how easy it is to meet low sodium targets and get the rest of the nutrients we need… Read

IFT urges government to take a cautious approach to sodium reduction The Institute of Food Technologists (IFT) has submitted comments to government agencies suggesting that actions to reduce sodium should not go “too far, too fast”, and has raised concerns about consumer acceptance and the safety of reduced sodium foods… Read

American Heart Association blasts industry sodium reduction skeptics Suggestions by the Salt Association and other industry associations that sodium reductions could hurt rather than improve health are “not supported by science”, the American Heart Association (AHA) has insisted… Read

‘Processed’ foods are often high in sodium – but what’s a processed food? About 75% of the sodium in our diets comes from processed foods. It’s a regularly cited figure – but what exactly is a ‘processed’ food? Consumers might be surprised… Read

But this one just in:

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Jul 25 2011

Campbell Soup fights the salt wars

As I endlessly repeat, even companies that want to make “healthier” products cannot do it—unless the products sell. If they don’t, forget it.

Witness: Campbell Soup. The company has given up on reducing the absurdly high salt content of its soups and is adding back the salt. Why? Its “health-inspired low-sodium push failed to lift sales.”

Campbell’s new CEO announced this at, no surprise, its annual investors’ meeting: “For me it’s about stabilizing it [company sales] first and then planning growth beyond that.”

Campbell shares rose by 1.3%.  Investment analysts were optimistic: “We look for future results to benefit from an increased emphasis on bolstering sales with tasty soup products.” 

From Campbell’s point of view, any guidelines that require it to reduce salt set “virtually unachievable” standards that are “misguided and counterproductive.”

In practice, the “draconian” thresholds for sodium, fat and sugars meant a high proportion of foods currently on the market would not meet the standards, while the proposed nutritional principles “describe products that manufacturers will not produce because children and teens will not eat them.”

From the standpoint of the advertising industry, Campbell’s “U-turn is a cautionary tale.”

Campbell’s problem, according to the industry, is that it “didn’t just dip its toe in the water with some stealthy, under-the-radar sodium reduction, it went for it all guns blazing as part of an overall commitment to ‘nourish people’s lives everywhere, every day.”

Clearly, concern about its customers’ health was a big mistake. And business analysts note that Campbell’s

u-turn – albeit just on one product line – raised questions about just how strong this commitment actually was…What would happen if instead of investing marketing dollars into a ‘please try me again’ campaign, Campbell’s embarked on a ‘we are absolutely determined to make this work’ campaign?

Oops. Bad press. In response, Campbell backtracked again.

In a press release, the company insisted that it is continuing to produce lower-sodium choices including 90 varieties of Campbell’s soups and more than 100 other Campbell products, such as V8 juices, Prego Italian sauces, SpaghettiOs pastas and most Pepperidge Farm breads.

The CEO said:

“Reducing sodium was absolutely the right thing for our company to do”  and Campbell’s Healthy Request, the company’s popular line of heart-healthy soups, has had compound annual sales growth of 21 percent over the past five years.

Campbell also says it “plans to shift the allocation of its R&D resources to ensure the company’s efforts are focused on a variety of ways to bring innovative products to market, not only on sodium reduction.”

We know that many consumers take great interest in the impact of the foods they eat on their long-term health and well-being … But we also recognize that the health and wellness attributes of foods mean different things to different people. For many, weight loss and weight maintenance is of primary importance. Others define their wellness needs in terms of vegetable nutrition, sodium reduction, energy and stamina, or digestive health. Thus, reducing sodium is just one component of our wellness strategy.

And one the company feels must be sacrificed to sales.

Make no mistake: food companies are not social service agencies. When it comes to a commitment to public health, the bottom line is all that counts—and has to be, given the way Wall Street works.

This needs a system change, no?  And one starting with Wall Street, which isn’t a bad idea for other reasons as well.

Jul 15 2011

Interview with Scientific American on the complexities of salt science

I complained to Scientific American about one of its blog posts about salt, which I viewed as rather one-sided.  The result was a conversation with Michael Moyer that ended up in the form of a Q and A.  I did not have a chance to review it before it was posted, so please see addendum at the end). 

The Salt Wars Rage On: A Chat with Nutrition Professor Marion Nestle

A researcher explains why there may never be a good study on whether excess dietary salt causes hypertension and heart disease

By Michael Moyer | Thursday, July 14, 2011

 Is salt bad for us? In just the past few months researchers have published seemingly contradictory studies showing that excess sodium in the diet leads to heart disease, reduces your blood pressure, or has no effect at all. We called Scientific American advisory board member Marion Nestle, a professor of Nutrition, Food Studies, and Public Health at New York University and the author of Food Politics, to help parse the latest thinking regarding salt and heart health.leads to heart disease, reduces your blood pressure, or has no effect at all. We called Scientific American advisory board member Marion Nestle, a professor of Nutrition, Food Studies, and Public Health at New York University and the author of Food Politics, to help parse the latest thinking regarding salt and heart health.

[An edited transcript of the interview follows.]

I understand this area is controversial.

Hugely.

Could you take us through some of the controversy?

If you talk to any kidney specialist or anybody working on hypertension they will tell you that the first thing they do is try to lower the amount of salt their patients are eating because it helps with blood pressure control. But if you do a clinical trial where you try to put large amounts of people on a low-salt diet, you just don’t see much difference between the people who say they eat a lot of salt and the people who say they don’t eat a lot of salt. In clinical trials the relationship doesn’t show up.

Why not?

Two reasons: One that it’s impossible to put a population of people on a low-salt diet. Roughly 80 percent of the salt in the American food supply is in foods before people eat them—either in processed food or in restaurant food. Because so much salt is added to the food supply and because so many people eat out, it’s impossible to find a population of people who are eating a low-salt diet. They basically don’t exist.

In the one comparative epidemiological study they did some years ago—the Intersalt study—they managed to find two populations of people in remote areas of the jungle someplace who weren’t eating a lot of processed foods and who weren’t eating in restaurants. They were on a low-salt diet, and they never developed hypertension.

So in that trial did they put one group on a high-salt diet and put one on a low-salt diet?

No, no, no. It wasn’t a comparative trial. They just looked at the amount of salt that populations were eating and the amount of hypertension that they had. Only in these two populations were there very low rates of hypertension. With everybody else the salt intake was so high that they couldn’t see any difference between high and higher.

So except for people living in the jungle somewhere, there aren’t any populations on Earth that are eating a low amount of salt?

Not anymore. Maybe we used to be, but not anymore. We have a global food supply, so it’s impossible to do a really careful study.

What’s the other issue?

Not everybody responds to a low-salt diet. There’s a proportion of people in the population who are sensitive to salt—if you lower their intake of salt, then their blood pressure goes down. There’s another (probably larger) percentage of the population who doesn’t respond. They are people who can eat as much salt as they want and still their blood pressure is low.

So you have this curious anomaly where whenever you do a clinical trial you get these complicated, difficult-to-interpret results that don’t show much of an effect. But everybody who works with patients who have hypertension think they do better [on a low-salt diet]. And every committee, body, and group that has ever in my lifetime considered whether salt has anything to do with hypertension says, “yes,” and has recommended salt reduction as a public health measure. That’s the curious situation that we are in.

There’s one other wrinkle and has to do with people’s taste for salt. Campbell’s soup, for example, just announced yesterday that can’t sell low-sodium soups and so they’re adding salt back. And part of the reason they can’t sell it is that if you’re on a high-salt diet, food that isn’t salty tastes terrible to you. And if you’re on a low-salt diet it takes three to six weeks to get accustomed to being on a low-salt diet and then everything you eat tastes salty. And so the more salt in the food supply the more salt people need to bring the flavor you associate with salt. That complicates things, too.

So from a public health standpoint, if you want to deal with the percentage of the population that seems to be extremely responsive to a low-salt diet what you want to do is get the sodium level in the food supply as low as you can. And that makes the people who sell salty food go nuts. And it makes the people who like salty foods go nuts. They think the food tastes bland. And so there are different stakeholders in this system who have very different views and that accounts for the level of passion, I think, in a situation where the science is murky.

Couldn’t you just make the case that people should eat fewer processed foods?

Well what about restaurants? I’m a food professional. I eat out professionally.

Well chefs need to make their food taste good—otherwise people won’t go to their restaurant.

No, they need to make the food taste good by their standard. And chefs, because they’re dealing with a great deal of salt in their food, tend to raise the sodium level. It just goes up and up and up and up. As they get more used to a certain level of salt taste it no longer tastes salty to them and they have to raise it. So the pressure is to raise the salt in the food supply. And reducing it is very difficult.

So you advocate regulation to limit the amount of salt in restaurants?

Yeah, I do. Certainly for processed food. I think everybody would be healthier if they ate less salt. You can always add salt if you don’t think it’s salty enough, whereas I can’t take it away if it’s presented to me. And that’s the dilemma. And the ferocity of the arguments gets into the whole question of personal responsibility and “nanny state” and all of these other enormous debates that really don’t get at the public health question. And the public health question is hard to resolve because the science is really difficult to do.

Couldn’t you imagine a study where you look at sodium levels in urine, which is a direct measure of salt intake, and correlate that with hypertension?

Yeah they’ve done that, and they don’t see any difference in hypertension rates. The reason is that the baseline [level of salt intake] is so high that it doesn’t make any difference. To suggest that people get down to 1,500 mg a day—the recommended level—would be really really hard, and that level may be too high. And it’s unclear that that’s the right level because you can’t do a really decent dose response, and because people vary so much.

Will there ever be a good study?

I don’t know!

Is it possible that this represents the limits of science? It’s black hole event horizons and salt intake?

It may be. It very well may be. Or the science that we have is completely adequate and we already have the answer. I was once at a sodium meeting at which there were a bunch of statisticians. And I left with the statisticians and they said that “anyone who thinks that salt has anything to do with hypertension is delusional.” And that was on the basis on the clinical trials that show so little. And yet every single committee that has dealt with this question says, “We really need to lower the sodium in the food supply.” Now either every single committee that has ever dealt with this issue is delusional, which I find hard to believe—I mean they can’t all be making this up—there must be a clinical or rational basis for the unanimity of these decisions.

But that’s the thing—these committees should be able to point to the evidence that supports their recommendations. But they seem to rely so much on anecdote and individual experience.

Or on some clinical trials that everybody argues about. Everybody argues about every clinical trial no matter what the conclusion. So I find the whole thing completely fascinating. I don’t think anybody can underestimate the difficulty of doing nutritional research. Because people aren’t eating just sodium. They’re eating sodium in food. And it may be that high-sodium diets are a marker for some other things in the food supply or it may be that the physiological differences are so profound that you just don’t get clean results. That human variation is so great. I don’t know the answer to that. I just know it works for me. That’s anecdotal. With an “n” of one.

Addendum

If I had been given the opportunity to review this before it was posted, I would have edited it carefully.  Yes, this is the way I talk but I don’t think what I said reads clearly in print.  In reading over this piece, I think it may give the wrong impression of my views on how expert committees decide on salt recommendations.  The piece may give the impression that committees make dietary recommendations basied on anecdotal evidence, not science.  That’s not true.  They base their recommendations on their interpretation of the experimental and clinical evidence, including that from clinical trials.

For example, the Advisory Committee for the 2010 Dietary Guidelines concluded that “a strong body of evidence has documented that in adults, as sodium intake decreases, so does blood pressure.”  Was this committee delusional in viewing the evidence as strong?  I don’t think so.

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Apr 26 2011

Should food labels say salt or sodium?

According to today’s Food Chemical News (which, unfortunately, requires a subscription to read), the FDA is arguing to make the international standard for food labels say sodium, not salt.

The U.S. delegation to the Codex Committee on Food Labeling will push for requiring the term “sodium” rather than “salt” on nutrition labels.

The European Union and its allies prefer “salt,” arguing that it is better understood by consumers.  But:

The United States is strongly opposed to removing “sodium” from the list of nutrients requiring disclosure. “We hope to achieve compromise and not remove sodium from the list,” said Schneeman. Asked about resolution of the dispute, she replied, “We still have our feelers out [to potential supporters]. Sodium is the nutrient, not salt.”

Maybe, but salt is what people eat.

I think “salt” makes more sense.  You?


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