by Marion Nestle

Currently browsing posts about: Sugars

Aug 8 2011

It’s time for some Q and A’s

I’ve just turned in the copy-edited manuscript of Why Calories Count: From Science to Politics (pub date March 2012) and now have time to catch up on some questions:

Q. I was recently given to read a book titled “The China Study” which is based on research conducted in 1970’s in China by Dr. Colin Campbell. His main conclusion is that eating dairy and meat causes cancer. His resolution is that a plant-based diet (i.e. vegan) is the (only?) healthy diet for humans. This book has made strong enough of a point to convince several of my friends to “convert” to a vegan diet in order to save their health. Could you share some comments on the validity of the research and conclusions this book presents with regards to detrimental effects of dairy and meat on human health?

A. Campbell makes a forceful argument based on his interpretation of the research and on case studies of people whose diseases resolved when they became vegans. And yes I’ve seen Dr. Campbell’s new movie, Forks over Knives. The first half is a terrific introduction to how the current food environment promotes unhealthy eating.  The second half promotes Dr. Campbell’s ideas about the hazards of meat and dairy foods.

Whether you agree with these ideas or not, the film is well done and worth a look.

Some scientists, however, interpret the research as demonstrating that people are healthier when they eat dairy foods.  For example, the enormous consensus report on diet and cancer risk from the American Institute for Cancer Research and the World Cancer Research Fund concluded in 2007 that eating lots of red meat and processed meat is convincingly associated with an increased risk of colorectal cancer (but no others).

On the other hand, they found dairy foods to be associated with a decrease in the risk of colorectal cancer.  They found limited and less convincing evidence that dairy foods might decrease the risk of bladder cancer but increase the risk of prostate cancer.

How to make sense of this?  These are two food groups in the diets of people who consume many kinds of foods and who do many things that might increase or decrease cancer risk.  Given this complexity, one food or food group seems unlikely to have that much influence on cancer when considered in the context of everything else people eat and do.

Nutrition research, as I am fond of saying, is difficult to do and requires interpretation. Intelligent people can interpret the studies differently depending on their point of view.

The new Dietary Guidelines say to cut down on saturated fats. Those are most plentiful in meat and dairy foods (plant foods have them, but in smaller amounts). Pretty much everyone agrees that plant-based diets promote health/  But whether they have to be 100% plant-based is highly debatable.

The new USDA MyPlate food guide suggests piling plant foods—fruit, vegetables, and grains—on 75% of your plate so the argument is really about what goes on the remaining 25%, what USDA calls the  “Protein” section. You can put beans in that quarter if you don’t want to eat red meat, poultry, or fish.

Q. I’d love to hear your take on the recent walnut flap [accusations that the FDA now considers walnuts to be drugs].  I suspect walnuts got caught with such offenders as Pom, Froot Loops, and Juicy-Juice, but I’d love to find out what the FDA actually said about this. For some odd reason I don’t believe the article is presenting the whole truth.

A. This is a health claims issue. The FDA is not saying walnuts are drugs. It is saying that Diamond Walnut is claiming walnuts as drugs on package labels. How so?

The labels say the omega-3 fatty acids in walnuts may help lower cholesterol; protect against heart disease, stroke and some cancers (e.g. breast cancer); inhibit tumor growth; ease arthritis and other inflammatory diseases; and even fight depression and other mental illnesses. These are disease claims for which the FDA requires scientific substantiation.

The company’s petition did not provide that substantiation so the FDA issued a warning letter. In general, you should be skeptical any time you see a nutritional factor advertised for its ability to prevent or treat such a broad range of problems.

Q. A question about sugar and how it is counted: My books say: 4 g = 1 teaspoon = 15 calories. My Illy Caffe says 10 g of sugar, but 50 calories. Ingredients: coffee, sugar, potassium bicarbonate, potassium citrate. If the drink is 50 calories, shouldn’t it say 12 g or more for the sugar listing?

A. Sugar should be the only ingredient that has calories in this coffee but I’ve seen calorie lists that say 5 calories per gram for sugars. Food companies have some leeway in the way they compute calories. Illy may be using a method that gives 5 rather than 4. But the difference between 40 and 50 is hardly measurable and I wouldn’t worry about amounts this small, annoying as imprecise figures may seem.

Apr 29 2011

Sugar politics in action: Sugar sues HFCS

Philip Brasher of the Des Moines Register reports: the Western Sugar Cooperative has just filed suit against the Corn Refiners and corn processors to stop them for falsely advertising HFCS as “corn sugar.”

Oh please.  Western Sugar is trying to claim that HFCS is not sugar, when it most definitely is.  To sugar associations, which represent cane and beet producers, sugar means sucrose (the white stuff on the table).

When the Sugar Association threatened to sue me for saying that soft drinks had sugar and nothing else (when they also contained HFCS), I patiently explained the biochemistry.  If you would like to read what they said, I’ve posted the threatening letter and my response at the bottom of this link. Here’s the biochemistry:

  • Sucrose: a double sugar of 50% glucose and 50% fructose linked together
  • HFCS: a syrup of about 45% glucose and 55% fructose, separated

The 5% differences are biologically insignificant and the body can’t tell them apart.

I never heard from the Sugar Association again, but I try to to remember to say sugars, plural.

Whether the FDA should allow the defendants to change the name of HFCS to Corn Sugar is a matter of some debate (see previous posts and comments on them).  The FDA will make its decision in due course.

In the meantime, this lawsuit is about marketing competition among sources of sugars (plural).  It has nothing to do with health.

Sep 20 2010

One more time: corn sugar chemistry

Thanks to alert reader Glen for pointing out that the FDA already has a regulation for Corn Sugar in the Code of Federal Regulations, under food substances Generally Recognized as Safe (GRAS).  CFR Section 184.1857 reads:

(a) corn sugar (C6H12O6, CAS Reg. No. 50-99-7), commonly called D-glucose or dextrose, is the chemical [alpha]-D-glucopyranose. It occurs as the anhydrous or the monohydrate form and is produced by the complete hydrolysis of corn starch with safe and suitable acids or enzymes, followed by refinement and crystallization from the resulting hydrolysate.

(b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), pp. 97-98 under the heading “Dextrose….”

(c) In accordance with 184.1(b)(1), the ingredient is used in food with no limitation other than current good manufacturing practice.

The Corn Refiners have just petitioned the FDA to be allowed to use the name Corn Sugar to apply to both glucose/dextrose and High Fructose Corn Syrup (HFCS).  But the existing definition seems to exclude HFCS.  While HFCS is about half glucose, it is also about half fructose, and its manufacture from corn starch requires one more enzyme.

A reminder about sugar chemistry:

  • Glucose is the sugar in blood, and dextrose is the name given to glucose produced from corn but biochemically they are identical.
  • Fructose is the principal sugar in fruit.  In fruit, it raises no issues because it is accompanied by nutrients and fiber.
  • Sucrose is table sugar.  It is a double sugar, containing one part each of glucose (50%) and fructose (50%), chemically bound together.  Enzymes in the intestine quickly and efficiently split sucrose into glucose and fructose, which are absorbed into the body as single sugars.
  • HFCS is made from corn starch.  It contains roughly equivalent amounts of glucose (45 to 58%) and fructose (42 to 55%).

HFCS raises several issues, health and otherwise:

  • Quantity: the U.S. food supply provides to every American (all ages) about 60 pounds of sucrose and another 60 pounds of HFCS each year.  This is way more than is good for health.  Sugars of any kind provide calories but no nutrients.
  • Fructose: increasing evidence suggests that the metabolism of fructose–which differs from that of glucose–is associated with abnormalities.  This means that it is best to reduce intake of fructose from table sugar as well as HFCS.
  • Farm subsidies: these go to large corn producers and have kept down the cost of HFCS relative to that of sucrose.  The use of corn to make ethanol has raised the relative price of HFCS.
  • Genetic modification: Most corn grown in the United States is genetically modified to resist insects or herbicides.

From a health standpoint, it makes no difference whether the sweetener is sucrose or HFCS.

As for agave sugar as a substitute: it can have much higher concentrations of fructose than either sucrose or HFCS but its labels do not give percentages so you have no way to know how much.

Given all this, what’s your guess about what the FDA will decide?

May 3 2010

Bylines: San Francisco Chronicle (Sugars) and Newsweek (Calories)

Two articles I’ve written are in journals this week: a short one in Newsweek (!) and my monthly Food Matters column in the San Francisco Chronicle.

New York’s Calorie Counts: A Good National Model (Newsweek, April 30 online and May 10 in print)

The new health-care law contains an overlooked boost for nutritionists like me: by next year, all national chains with more than 20 locations must offer “clear and conspicuous” calorie information. It’s the most important obesity-related public policy since the USDA’s food pyramid. But reception to the new mandate has been muted so far, largely because the benefits of New York City’s similar 2008 law seem minor: one study found just 15 fewer calories were consumed per meal; another reported it was 30; and a third found that people ate more.

The problem with these studies is that they focus on Starbucks customers and fast-food goers in low-income neighborhoods—patrons who often care about convenience and value above all. They also fail to capture the long-term benefits of calorie counting, namely education and social pressure. Labels will offer case-by-case lessons in exactly what 1,000 calories looks like, and they may even spur restaurants to ease up on sugar and fat. (Denny’s, McDonald’s, and Cosi, among others, have debuted lighter fare in New York City.) Of course, much depends on the definition of “clear and conspicuous.” Still, the country’s nutritional literacy is about to improve—making my job a lot easier.

Sugary school meals hit lobbyists’ sweet spot (San Francisco Chronicle, Sunday, May 2)

Nutrition and public policy expert Marion Nestle answers readers’ questions in this monthly column written exclusively for The Chronicle. E-mail your questions to food@sfchronicle.com, with “Marion Nestle” in the subject line.

Q: I’m stunned by the amount of sugar my daughter is served routinely in school: candied cereals, flavored milk, Pop Tarts, breakfast cookies, fruit juice – 15 teaspoons of sugar, just in breakfast. Why no standards for regulating sugar in school meals, especially when obesity and diabetes are such concerns?

A: Politics, of course. The U.S. Department of Agriculture spends $12 billion a year on school meals. Kids buy foods from snack carts and vending machines. Food companies fight fiercely to protect their shares in that bounty.

If you watched “Jamie Oliver’s Food Revolution,” you witnessed the struggle to get sugary foods out of schools. Fifteen teaspoons – 60 grams and 240 calories – is a lot for breakfast, but kids get even more sugar from snacks, treats from teachers and birthday cupcakes.

Sugars were never a problem when we supported school lunch programs decently. That changed when schools ran out of money, sought vending contracts with soft drink companies and encouraged kids to buy sodas and snacks. Schools evaded restrictions on snack sales during lunch periods. Nobody paid much attention to what kids ate in schools – until kids began getting fatter.

Why no standards? Nobody wants to take on the sugar lobbyists.

In 1977, a Senate committee recommended an upper limit of 10 percent of calories from added sugars. This was so controversial that from 1980 to 2000, the Dietary Guidelines gave no percentages when they said “eat less sugar.” The 1992 food pyramid said “Use sugars only in moderation.” It defined moderation in teaspoons – for example, 12 a day in a diet of 2,200 calories, which comes to less than 10 percent of calories. By then, health officials in at least 30 countries had adopted the 10 percent sugar guideline.

A committee of the Institute of Medicine undermined that consensus. Because science provides only circumstantial evidence for the effects of sugars on obesity and other health problems, the committee suggested a safe maximum of 25 percent of calories. Sugar trade associations happily interpreted this percentage as a recommendation.

In 2003, the World Health Organization issued a research report restating the 10 percent guideline. Using the IOM report as evidence, sugar trade associations enlisted senators from sugar-growing states to lobby U.S. government officials to withdraw funding from WHO. They also lobbied governments of sugar-growing countries to oppose the 10 percent guideline. WHO dropped the 10 percent sugar guideline.

Dietary guidelines are the basis of federal nutrition policy. The 2005 guidelines advised limits on sugars without stating a percentage. In a footnote, the guidelines said that sugars could be part of a day’s “discretionary calories,” defined as 2 to 8 teaspoons a day. This is less than 10 percent of calories, but the guidelines do not say so explicitly.

Neither does the USDA’s 2005 pyramid, which personalizes diet plans based on age, activity level and gender. I, for example, am allowed 195 discretionary calories for added fats and sugars. If I use them all for sugars, I get to eat 12 teaspoons – about 10 percent of my daily calories. This is less than the amount your daughter ate for breakfast or the sugars in a 20-ounce soda. Hence: lobbying.

Will we get an explicit sugar policy when Congress gets around to reauthorizing the Child Nutrition Act? The draft bill says nothing about sugars but does require school foods to adhere to “science-based” nutrition standards based on the dietary guidelines. If so, this means a maximum of 10 percent of calories from added sugars.

The IOM has just released a “School Meals” report. This says that with careful planning, 10 percent should provide enough sugar discretionary calories to permit sweetened low-fat milk, yogurt and breakfast cereals. The IOM warns that without these sweetened foods, student participation rates and nutrient intakes might decline.

Sorry, but I don’t buy the “kids won’t eat it” argument. I’ve seen plenty of schools where kids eat unsweetened foods. Somehow, they survive. Kids will eat healthier foods when meals are prepared by adults who care what kids eat, as Oliver has demonstrated.

As for legislation, California led the way with the 2007 school food nutrition standards bill, which regulated soda sales and the amount of sugar in snacks. Companies responded by reducing the sugars in their products. Passing the Child Nutrition Act will help, but its big drawback is funding. The draft bill increases school reimbursements by only about 6 cents per meal, not enough to meet costs in many school districts and much less than the $1 increase that many believe necessary.

But with luck, 2010 will bring us national legislation and improved editions of the dietary guidelines and pyramid. Let’s hope these make it easier for schools to help kids cut down on sugars.

Note: Nestle and Malden Nesheim will speak about their new book, “Feed Your Pet Right,” at 3 p.m. May 22 at Omnivore Books in San Francisco and at 3 p.m. May 23 at Point Reyes Books in Point Reyes Station.  Addition: Holistic Hound, Berkeley, Tuesday, May 18, 6:30 p.m.

Marion Nestle is the author of “Food Politics,” “Safe Food” and “What to Eat,” and is a professor in the nutrition, food studies and public health department at New York University. E-mail her at food@sfchronicle.com and read her previous columns at sfgate.com/food.  This article appeared on page K – 8.

Mar 24 2010

HFCS makes rats fat?

I can hardly believe that Princeton sent out a press release yesterday announcing the results of this rat study.  The press release says: “Rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same.”

How they came to these conclusions is beyond me. Here’s the original paper.

It has long been known that feeding sugars to rats makes them eat more and gain weight.  But, as summarized in Table 1 in the paper, the researchers did only two experiments that actually compared the effects of HFCS to sucrose on weight gain, and these gave inconsistent results.  Their other experiments compared HFCS to chow alone.

The study is extremely complicated and confusingly described.  As best as I can tell, here’s what they found:

1.  The first study used 10 male rats in each group and observed them for 8 weeks.  At the end of the study, the rats fed chow alone weighed 462 grams.  The rats fed sucrose plus chow weighed 477±9 grams.   The rats fed HFCS plus chow weighed 502±11 grams.   The authors say the difference between 477 and 502 grams is statistically significant.  But these rats were offered the sugars for 12 hours per day.  The rats fed HFCS for 24 hours per day, which should be expected to be fatter, were not.  They weighed less (470 grams) than the rats fed sucrose for 12 hours per day.  So these results are inconsistent.

2.  The second study did not compare rats eating HFCS to rats eating sucrose.  It just looked at the effects of HFCS in groups of 8 male rats.

3.  The third study used female rats (number not given) and observed them for 7 months.  At the end of the study period, female rats fed HFCS plus chow for 12 hours a day weighed 323±9 grams.  Female rats fed sucrose plus chow under the same conditions weighed 333±10 grams.   This result is not statistically significant.

Although the authors say calorie intake was the same, they do not report calories consumed nor do they discuss how they determined  that calorie intake was the same.  This is an important oversight because measuring the caloric intake of lab rats is notoriously difficult to do (they are messy).

So, I’m skeptical.  I don’t think the study produces convincing evidence of a difference between the effects of HFCS and sucrose on the body weight of rats.  I’m afraid I have to agree with the Corn Refiners on this one.

So does HFCS make rats fat?  Sure if you feed them too many calories altogether.  Sucrose will do that too.

NOTE 3/26: see point-by-point response to this post by Bart Hoebel, one of the authors of the study, in the Comments below.

Addition, November 23: Thanks to Jeff Walker, professor of Biology at the University of Southern Maine, Portland, for doing a detailed critique of the study, most thoughtful and well worth a look.

Mar 9 2010

Sugar politics: not so sweet

I got a comment this morning from Eric who asks whether I had seen the article in yesterday’s New York Times about Florida’s bailout of Big Sugar in the Everglades.  I could hardly miss it.  The story starts on the front page and continues over two full inside pages.

Titled “Deal to save Everglades may help sugar firm,” the article explains how Florida politicians engineered a taxpayer-supported buyout of United States Sugar for nearly $2 billion in 2008, ostensibly to restore a waterway through the Everglades.  Now, it seems, the restoration projects have stopped for lack of money and U.S. Sugar gets to keep using the land.

U.S. Sugar is or was the largest sugar producer in Florida.  Founded by Charles Stewart Mott in 1931, it owned mills and a railroad as well as land.

Sugar policy, as I explained in a post last September, is special.  Alone among commodities, it is supported by an arcane system of quotas and tariffs designed to ensure that domestic sugar producers get prices for their crops that are higher than values on the world market.  The result?  Taxpayers pay more for sugar than they should.

I suppose I could argue that higher prices for sugar are a good thing.  High prices discourage consumption.   Fortunately or unfortunately (depending on how you look at it), sugar prices are not high enough to do that.

So chalk this one up to politics in action, replete with lobbyists, lawyers, and corporate heads with cozy ties to government officials.   As is all too often the case, the corporation came out ahead.  Whether the Everglades will ever benefit remains to be seen.

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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 19 2010

Cascadian Purely O’s: betrayal or business as usual?

Thanks to my NYU Medical Center colleague, Dr. Melissa Bender for the alert about the blogosphere fuss over Cascadian Farm Purely O’s cereals.  Apparently, Cascadian Farm, now owned by Big Food General Mills:

quietly changed the recipe for its “Purely O’s” cereal — previously an unsweetened favorite among children/toddlers – to include three times the sugar, as well as new fillers/sweeteners such as corn meal and tapioca syrup. They did this with no announcement on the label, taking advantage of those who trusted the brand for its previous simplicity. Loyal customers, particularly parents who had chosen this product because it was one of the few unsweetened options available, are outraged by this secretive yet major reformulation. Many discovered the change when their children spat out the cereal (myself included).

Her note sent me right to the largest of the three Whole Foods stores within walking distance of my Manhattan apartment.  Purely O’s: 3 grams of sugars, 3 grams of fiber, and 160 mg sodium per serving.

Oops: low-sugar, yes, but only medium-fiber and high in sodium.  Even with 0 grams of sugar, it’s not all that great.  Neither, for that matter, is its non-organic analog Cheerios (1 gram sugar, 3 grams fiber, 190 mg sodium).

At 3 grams of sugar per serving, Purely O’s is still lower in sugar than practically every other cereal in Whole Foods.  Whole Foods does not sell Big Food non-organics, so it does not carry Cheerios.  I had to look hard to find the only cereal lower in sugar than the reformulated Purely O’s: Arrowhead Mills Shredded Wheat, Bite Size (2 grams of sugar, 6 grams of fiber, and only 5 mg sodium).  That one, it seems to me, is a much better choice to begin with, pretty much in the same category as oatmeal (1 gram of sugar, 4 of fiber, and 0 mg sodium).  When it comes to cereal, more fiber the better.  Fiber is the point of breakfast cereal.

So I can’t get too upset about the reformulation of Purely O’s.  It’s simply a business decision, entirely to be expected from Big Food.  Cascadian Farms started out with “humble beginnings” as a maker of organic products, none of them cereals.  It was successful enough to be bought first by Small Planet Foods, and later by General Mills, which wanted to get in on the organic market.  Hence: organic Purely O’s.

General Mills is in business to sell cereal, and Purely O’s just didn’t make it past focus groups, as reported in the Boston Globe earlier this year.  General Mills must think there are too few of its deeply loyal customers to matter.  According to a business school case study, it has a history along these lines.  So chalk this one up to corporate imperatives.

Dr. Bender wrote to General Mills and received a reply that said as much:

Our goal is to give consumers quality products at a good value. Prior to introducing any product, extensive consumer testing is done. We conduct market research and product testing continuously to obtain consumer reaction to existing products and to changes being considered. Only when we feel confident that a product change will broaden its appeal will we alter a product’s formulation. We are sorry that you do not agree that the recent change in Cascadian Farm organic Purely O’s cereal was for the better.

If the bloggers are looking for a replacement, try oatmeal or those cute little bite-sized shredded wheat things.