by Marion Nestle

Posts dated: January2010

Jan 29 2010

Not sure about soda taxes? Read this!

The New York City Health Department has produced a handy guide – a tool kit, actually – to soda tax legislation.    It explains the rationale, reviews the evidence supporting the use of such taxes, provides fact sheets, and answers Frequently Asked Questions.  For the academics among us, it provides loads of reference citations.  Take a look and put it to good use!

Update January 30: did a report on reaction to the soda tax bill, “Fresh New York soda tax plans stir up the obesity debate.”  It’s got a great quote from the American Beverage Association:

What’s particularly disconcerting about this proposal is that the tax on a 12-pack of non-alcoholic beverages, like soft drinks, would be more than 9 times higher than the state tax on a 12-pack of alcoholic beverages, like beer.

This, as you might expect, has stirred up some counter-proposals, the most obvious being to increase the tax on alcoholic beverages.  Now that ought to generate some additional revenue!

While we are on the subject of alcohol, a forthcoming paper by Barry Popkin is said to have some interesting trend data:

Among adults aged 19 and over, SSB [sugar-sweetened beverage] consumption had almost doubled from 64 to 142kcal/day and alcohol consumption had increased from 45 to 115 kcal/day [from 1977-2006].

Popkin’s conclusion: “The consumer shift towards increased levels of SSBs and alcohol, limited amounts of reduced fat milk along with a continued consumption of whole milk, and increase juice intake represent issues to address from a public health perspective.”

Jan 28 2010

The latest on acrylamide

The fuss about acrylamide continues.  This, you may recall is a carcinogen formed when foods containing sugars and the amino acid asparagine are cooked at high temperatures.  Acrylamide is formed during the Maillard reaction, which causes baked, fried, and toasted foods to turn attractively brown and taste yummy.

Obviously, acrylamide has been around in foods for a long time.  But now that everyone knows how bad it is, what should be done about it?

A new toxicology study provides estimates for an upper level of intake that can be considered safe: 2.6 micrograms per kilogram of body weight. This would be equivalent to 182 micrograms for a 70 kg human to prevent cancer.  Much higher levels are required to cause neurological problems: 40 micrograms per kg per day, or 2,800 micrograms per day for a 70 kg human.  But since you have no idea how much is in the foods you are eating, these figures don’t help much.

But maybe you don’t need to worry?  Even the lower of the toxic levels is much higher than intake levels estimated by health agencies.  The average exposure of adults to acrylamide in food has been estimated to be below 0.5 micrograms per kilogram of bodyweight, which is five times lower than the upper limit considered safe.

That is somewhat reassuring but how come a European Expert Panel has unanimously decided to put acrylamide on the list of “substances of very high concern?”  This makes it sound as if acrylamide is well worth avoiding at any level of intake.

How to avoid?  A recent study points out that foods low in sugars and high in antioxidants have lower levels of acrylamide.  This translates into standard dietary advice.  Eat lots of fruits and vegetables, and don’t eat too much junk food, and you can cross acrylamide off the list of food issues you need to spend much time worrying about.

Jan 27 2010

Can the food industry self-regulate marketing to kids?

To anyone following the ins and outs of food industry “self-regulation” of marketing to kids, here is a gift – courtesy of Margo Wootan of Center for Science in the Public Interest (CSPI).  Margo forwards a set of background papers and speeches on the topic.  I’ve posted some of these earlier, but it is good to have them in one place.

1. The study of food marketing by Dale Kunkel for Children Now

2. Elaine Kolish’s December speech in response to the Children Now study.  She is the head of the industry kids’ self-regulation unit at the Better Business Bureau.  Her conclusion: self-regulation is working.

3. The Rudd Center’s cereal marketing study summary

4. CSPI’s studies on food industry self-regulation

Enjoy, but also put to good use!

Jan 26 2010

Another Salmonella outbreak: this time Salami (maybe)

As always, I am indebted to Bill Marler for staying on top of the latest food safety scandals.  This one is even more complicated than most.  According to the CDC, 187 people in 39 states have become ill from Salmonella Montevideo (for some reason, I’m unable to get into the CDC site today although the map of the distribution of cases is available and Marler has yesterday’s version posted in full on his site).

Here’s what I find especially interesting about this one:

  • Cases have been reported at a relatively steady rate since the beginning of July – more than six months ago.
  • In January (did they not do any of this earlier?), the CDC conducted a study to compare foods eaten by 39 sick and 39 healthy people.  Among those who were sick, 51% said they were more likely to have eaten Daniele salami than people who were not sick (15 percent).  In addition, 11 other people said they bought Daniele salami before they became ill.
  • These kinds of studies are really hard to do.  As William Keene, senior Oregon epidemiologist explained (quoted on the Marler blog), people “were questioned left and right and they were asked about salami and very few of them said yes….Investigators re-interviewed people who were thought to be part of the outbreak, such as members of a hunting party from the South who had been to the Great Plains and responded to new questions with answers such as, “Now that you mention it, we did stop at a Wal-Mart in South Dakota and buy some salami.”
  • Daniele issued the recall because a private testing lab identified Salmonella in one of its salami products.  But that Salmonella strain was not Montevideo.  Could multiple strains be involved?
  • Daniele did the recall anyway and mentioned that pepper might be the source of the Salmonella.  Was it?  If so, this is by no means the first time that Salmonella has been associated with pepper, as Marler explains.
  • The public relations firm that has attempted damage control on previous food outbreaks is doing this one too.

Is this salami or pepper, Daniele salami or not?  So far, we still are dealing with guilt by association, but public relations?  How about just producing safe food in the first place?

And in more food safety news, let’s all congratulate President Obama for finally appointing someone to lead food safety efforts in USDA – Dr. Elizabeth Hagen.  Dr. Hagen has been at USDA and knows how that organization works.  Let’s hope she starts making waves today!

Congress: now it’s your turn.  Pass that food safety bill!

Jan 25 2010

A quick Q and A: sugars and fats

I wish I could answer all of the questions that come into Feedback or Comments, but I cannot except occasionally.  It’s a rainy day in New York and today seems to be one of those occasions.

Q: Does the caloric value of a food change when it’s cooked?  In his latest book, “Catching Fire: How Cooking Made us Human,” Harvard Primatologist Richard Wrangham argues that cooking foods changes the available nutrient content and actually raises the available calories.

A:  The rules of physical chemistry tell us that matter cannot be destroyed or created so the number of calories available in a food does not change with temperature.  What can change is our ability to use (digest, absorb) the calories that are there as well as our desire to eat the foods.  Cooking makes the calories in potato starch more available, for example, but has hardly any effect on the calories in meat.  Both, in my opinion at least, taste better cooked.    But cooked or not, the calorie differences will be small and unlikely to account significantly for weight change.

The nutrient situation is also complicated.  Cooking destroys some nutrients (vitamin C is a good example) but makes others more available (beta-carotene).  This is another reason why nutritionists are always advising variety in food intake.  Variety applies to cooked and raw, as well.

Q.  Can you please explain what benefits, if any, there are in using a “natural” sweetener, e.g. agave, over regular sugar?  Are there any differences in terms of glucose/fructose makeup?

A.  Agave is more expensive so you probably won’t use as much of it.  Beyond that, it is higher in fructose than table sugar or honey.  This is because agave contains inulin, a polymer of fructose, which must be hydrolyzed (broken down by heat or enzymes) to fructose to make the sweetener.  It’s a processed sweetener requiring one hydrolysis step, requiring more processing than honey and less than high fructose corn syrup.  It has the same number of calories as any other sugar, about 4 per gram or 16 per teaspoon.

Q.  Also, you’ve written on a prior blog that fructose is “preferentially” metabolized into fat by the body.  Can you explain in more detail what that means?

A.  More and more evidence suggests that high amounts of fructose in the diet are not good for health.  Fructose occurs naturally in fruit and nobody worries about that because fruits don’t contain all that much and the sugar is accompanies by vitamins, minerals, and fiber that are well worth eating.  Honey, table sugar, and high fructose corn syrup (a misnomer) are about 50% each glucose and fructose.  Glucose and fructose are metabolized differently and some investigators believe that excessive amounts of fructose stress metabolism in ways that encourage fat deposition.  Eating a lot of sugars of any kind is not a great idea, which is why there are so many concerns about soft drinks these days.

Q.  I would appreciate some comments about the “Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease.

A.  The study concludes:  

A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD [coronary heart disease] or CVD [cardiovascular disease]. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.

This is a review of previous epidemiological studies (not clinical trials).  These fail to find a correlation between consumption of saturated fat and heart disease.  This could be because there is no correlation or there is one but they can’t find it.  My interpretation: even if there is one, it is likely to be small.

I am increasingly convinced that studies of single nutrients – sugar, fructose, saturated fat, or even omega-3s – will give complicated results when removed from their dietary context.  People who eat foods containing a lot of sugars or animal fats eat and behave differently than people who do not, but not so differently that health differences will show up in the kinds of studies scientists are currently able to do.

Keep in mind: nutrition science is exceedingly difficult to do because there are so many factors in foods that affect health and so many behavioral, economic, and social factors that affect what people eat.

All of this is why I find nutrition so interesting but I can understand why others might find it frustrating.

Jan 23 2010

The new salt study

The current issue of the New England Journal of Medicine has an article from investigators at the University of California San Francisco School of Medicine (where I worked from 1976 to 1986) and Columbia using computer models to predict the effect of relatively small reductions in salt intake on health.  Their conclusion:

Modest reductions in dietary salt could substantially reduce cardiovascular events and medical costs and should be a public health target.

The article also is discussed in an accompanying editorial, and was the topic of a long discussion in the New York Times.

I never know what to make of computer models, but one thing is clear: many people consume two or three times the amount of salt recommended.  It’s hard to avoid doing so.  Australian investigators surveyed processed foods and found more than 60% of them to contain salt above recommended levels.  Ours are unlikely to be any different.

While we are on the subject of salt in processed foods:  Juli Mandel Sloves of Campbell Soup correctly points out that my observation that the company’s kids’ soups contain 480 mg sodium per 4 ounce serving is incorrect.  A serving of soup is 8 ounces, not 4.  I see how I made this mistake.  The label states that a serving is half a cup (4 ounces) and that one serving contains 480 mg sodium.   But you are supposed to dilute what’s in the can with another can of water.  That makes it 480 mg sodium per 8 ounces, the same amount of salt but diluted.  The confusing serving sizes are another good reason to rethink and redesign the Nutrition Facts label.

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Jan 22 2010

The Supreme Court and food politics

What is likely to be the effect of yesterday’s Supreme Court decision on food politics?  Nothing good.

The decision to overturn limits on corporate campaign contributions will affect every aspect of society, food included.  I have long argued that campaign contributions are one of two major sources of corruption in government (the other is the way Wall Street requires corporations to report growth every 90 days).

If we want our congressional representatives to make decisions in the public interest, their election campaigns must be publicly funded.  When corporations fund campaigns, representatives make decisions in the corporate interest.   It’s that simple.

Those of us who care about creating a good, clean, fair, and sustainable food system will have to work harder now.  But I can’t think of any more important work to do to protect our democratic institutions.

Addition: here’s my interview with Helena Bottemiller of Food Safety News on the topic.

Jan 21 2010

Childhood obesity explained

I keep saying that you don’t need complicated theories to explain childhood obesity.  Just read the newspapers!  Yesterday’s New York Times carried two stories that fully account for kids’ caloric balance these days.

The first (front page) describes a Kaiser Family Foundation study that counted the number of hours kids spend online each day.  The bottom line: “practically every waking minute.”  Here’s the link to the actual study.

The second is a food section story documenting the astonishing rise in snacking among kids to the point where parents are harassed beyond belief  about having to supply snacks for every activity.  And you should see what goes on in schools.   The bottom line: also practically every waking minute.

No wonder kids are gaining weight.

The question, of course, is what to do about it.   Dealing with the snacks will be easier and that’s a great place to start, no?

Tomorrow: I will comment on the new study on salt, discussed in today’s paper.