by Marion Nestle

Currently browsing posts about: Cancer

Nov 2 2015

WHO clarifies meat-and-cancer report

The World Health Organization has issued a statement of clarification of the significance of its International Agency for Research on Cancer (IARC) report on the increased risk for colorectal cancer from eating processed and red meat (see my post on this).

The latest IARC review does not ask people to stop eating processed meats but indicates that reducing consumption of these products can reduce the risk of colorectal cancer.

Got that?

The New York Times explains the meaning of this increased risk.  To understand it, you need to know the risk of colorectal cancer among people who never eat processed or red meat.

The main problem with the public health messages put out by the W.H.O. is that the agency did a poor job of explaining what its risk-ranking system really means…it’s based only on the strength of the overall research, not on the actual danger of a specific product…Even the most strident anti-meat crusader knows that eating bacon is not as risky as smoking or asbestos exposure. Smoking raises a person’s lifetime risk of developing lung cancer by a staggering 2,500 percent. Meanwhile, two daily strips of bacon, based on the associations identified by the W.H.O., would translate to about a 6 percent lifetime risk for colon cancer, up from the 5 percent risk for people who don’t enjoy bacon or other processed meats.

My interpretation: Can processed and red meats be included in healthful diets?  Yes, of course.  But for many reasons, people and the planet would be healthier if these foods were consumed in smaller portions, less often.

Oct 27 2015

Some comments on the meat-is-carcinogenic report

Yesterday, the World Health Organization’s International Agency for Research on Cancer (IARC) issued a warning about the carcinogenic potential of processed and red meat.  This, as you might expect, caused a media flurry.  CNN News asked me for a written comment.  They titled it “The other benefit to eating less red meat.”  Here’s what I wrote:

The just-released report from the International Agency for Research on Cancer judging processed meat as clearly carcinogenic and red meat as probably carcinogenic has caused consternation among meat producers and consumers.

Meat producers do not like the “eat less meat” message. Consumers do not want to give up their bacon and hamburgers — delicious and also icons of the American way of life.

But these judgments should come as no surprise to anyone. Eating less processed and red meat has been accepted dietary advice since Ancel and Margaret Keys wrote their diet book for heart disease prevention, “Eat Well and Stay Well,” in 1959. Their advice: “restrict saturated fats, the fats in beef, pork, lamb, sausages …” They aimed this advice at reducing saturated fat to prevent heart disease. Federal committees and agencies have continued issuing such heart-disease advice to the present day.

Cancer entered the picture in the 1970s, when scientists began to link red meat — beef, pork, lamb — to the risk of cancers of the colon and rectum. Even after several decades of research, they had a hard time deciding whether the culprit in meat was fat, saturated fat, protein, carcinogens induced when meat is cooked to high temperatures or some other component.

In the mid-1990s, dietary guidelines committees advised eating lean meats and limiting intake of processed meats, still because of their high fat content. By the late 1990s, cancer experts said that red meat “probably” increases the risk of colorectal cancers, and “possibly” increases the risk of cancers of the pancreas, breast, prostate and kidney. The IARC report, based on more recent evidence, makes even stronger recommendations and favors carcinogens as the causative factors.

To put this in context: For decades, the meat industry’s big public relations problem has been that vegetarians are demonstrably healthier than meat eaters. People who do not eat red meat havemuch less of a chance of developing heart disease and bowel cancers than the average American.

More recently, the 2015 Dietary Guidelines Advisory Committee (DGAC) found diets “higher in red/processed meats…” to be associated with a greater risk of colorectal cancer, and it recommended dietary patterns and low in red and/or processed meats, but higher in vegetables, fruits, legumes, whole grains, lean meats/seafood and low-fat dairy — largely, but not necessarily exclusively, plant-based.

This is good advice for anyone.

Eating less red and processed meats has two benefits: a reduced risk for certain forms of cancer,and a reduced effect on climate change.

The DGAC deemed eating less red meat to be exceptionally beneficial to the environment as well as to human health. The IARC report strengthens the health component of the recommendation. The secretaries of USDA and Health and Human Services, however, have refused to allow environmental concerns to be considered in the 2015 dietary guidelines.

I mention the dispute over environmental “sustainability” in the dietary guidelines because largely plant-based diets are appropriate for all kinds of health concerns — obesity, type 2 diabetes, coronary heart disease and now, especially, colorectal cancer — as well as environmental concerns.

By eating less red and processed meats, you promote both your own health and that of the planet.

At issue then is how much red and processed meat is compatible with good health. The IARC commission ducked that question, although it cites evidence that as little as 100 grams (a quarter pound) of red meat a day, and half that much of processed meats, increases cancer risk by 15% to 20%.

Will an occasional hamburger or piece of bacon raise your risk that much? I don’t think so. But the evidence reviewed by IARC strongly suggests that if you do eat meat, eat less when you do, don’t eat meat every day, save processed meats for rare treats and be sure to eat plenty of vegetables.

Fortunately, this advice leaves plenty of room for delicious meals — just with meat taking up much less room on the plate.

Other comments

Jun 18 2014

Time Magazine: “Eat Butter.” Maybe in moderation, please?

I love butter as much as the next person, but when I went to New York’s Food Fest yesterday, the butter makers were all proudly displaying Time Magazine’s provocative June 23 cover.


The cover story is by Bryan Walsh.

It comes with an even more provacative video–one of those “everything you thought you knew about diet is wrong” things.

I’m quoted in his article, but I wish he had quoted more of my comments about context.

He says saturated fat consumption is down, but heart disease is still the number one killer of Americans.

Yes it is, but not nearly as much as it used to be (as I discussed in a previous post):

Americans must be doing something right.

The big problem is type-2 diabetes.  It’s going up in parallel with obesity: Fat calories and sugar calories contribute to obesity.

The dietary bottom line?  Eat your veggies, balance calories, and stay active.

Really, it’s not more complicated than that.

But that kind of advice will never make the cover of Time, alas.

Addition, June 20: David Katz on how easy it is to misinterpret studies of saturated fat (or sugars for that matter) and health.

Jan 22 2014

The latest cancer statistics

Every year, CA–A Cancer Journal for Clinicians publishes an annual review of cancer statistics.

The report has some good news: trends in the overall death rates from cancer show significant declines, for both men and women.

The overall incidence (new case) rates are holding steady or a down a little since 1990,but are still above the rates in 1975.

The incidence patterns differ for cancers at different sites:

Screenshot 2014-01-21 12.05.13

In men, lung cancers are down undoubtedly due to less cigarette smoking.  Prostate and colorectal cancers are down, perhaps due to favorable dietary changes.

In women, lung cancers have leveled off and colorectal cancers are down, but breast cancers don’t seem to budge.

As for the comparison to heart disease, that’s interesting too.  In 2005, cancer surpassed heart disease as the leading cause of death in people younger than age 85.

Plenty of good news here, but plenty more to be done.

Oct 23 2012

Multivitamins prevent cancer (maybe), sell supplements (definitely)

According to a new study in JAMA, multivitamins might reduce the risk of some cancers, although not by much.

But even a tiny benefit, restricted to skin cancers in healthy male doctors—but not prostate cancers, alas—is good news for the supplement industry.  Supplement sellers are eager to make sure you don’t miss this research.

The study results came out on October 18.  Pfizer, the maker of the Centrum Silver pills used in the study, placed this ad in the New York Times on October 19:

But that’s not all.  CVS pharmacy sent me this personal e-mail message:

Pfizer, of course, could not be happier.

Why do I think this is about marketing, not public health?

Jun 15 2012

The food politics of…broccoli !

I have a soft spot in my nutritionist’s heart for broccoli. It’s a lovely vegetable when fresh and lightly cooked, and is loaded with vitamins, minerals, antioxidants, fiber, and all those other good things that nutritionists like me encourage everyone to eat and enjoy.

I expressed some of this fondness for broccoli in a 1997 Commentary in the Proceedings of the National Academy of Sciences with this prescient title: “Broccoli sprouts as inducers of carcinogen-detoxifying enzyme systems: Clinical, dietary, and policy implications.”



In it, I quoted President (#41) Bush’s now famous statement:

I do not like broccoli…And I haven’t liked it since I was a little kid and my mother made me eat it. And I’m President of the United States, and I’m not going to eat any more broccoli!’

Even in the 1990s, broccoli had policy implications.

And now the New York Times has come up with a lengthy front-page investigative report on how broccoli came to be used by conservatives as a metaphor for the role of government in health care reform.

The story begins with a question asked by Supreme Court Justice Antonin Scalia.  If the government can require people to buy health insurance, maybe it could force people to buy broccoli: “Everybody has to buy food sooner or later,” he said. “Therefore, you can make people buy broccoli.”

It turns out that broccoli did not spring from the mind of Justice Scalia. The vegetable trail leads backward through conservative media and pundits. Before reaching the Supreme Court, vegetables were cited by a federal judge in Florida with a libertarian streak; in an Internet video financed by libertarian and ultraconservative backers; at a Congressional hearing by a Republican senator; and an op-ed column by David B. Rivkin Jr., a libertarian lawyer whose family emigrated from the former Soviet Union when he was 10.

The Times report is well worth reading, not least as a case study in how conservatives frame issues.  My favorite part is the sidebar on “the broccoli trail.”  Here’s the example from April 2012:

Rush Limbaugh, on his radio program:

“You’re telling me that you want the Supreme Court to decide that the government can tell you that you have to buy health insurance and broccoli?”

In late March, New York Times columnist (and Nobel-prize winning economist) Paul Krugman wrote of “Broccoli and Bad Faith.”

Let’s start with the already famous exchange in which Justice Antonin Scalia compared the purchase of health insurance to the purchase of broccoli, with the implication that if the government can compel you to do the former, it can also compel you to do the latter. That comparison horrified health care experts all across America because health insurance is nothing like broccoli.

Why? When people choose not to buy broccoli, they don’t make broccoli unavailable to those who want it. But when people don’t buy health insurance until they get sick — which is what happens in the absence of a mandate — the resulting worsening of the risk pool makes insurance more expensive, and often unaffordable, for those who remain. As a result, unregulated health insurance basically doesn’t work, and never has.

Maybe the best we can do with all this is to eat our broccoli and hope that it keeps us out of the health care system.

Sep 30 2011

Disappointing UN Declaration on chronic disease prevention

As I mentioned in a previous post, the United Nations General Assembly met this month to consider resolutions about doing something to address rising rates of “non-communicable” diseases (i.e., chronic as opposed to infectious diseases such as obesity-related coronary heart disease, type 2 diabetes, and cancers).

The Declaration adopted by the Assembly disappointed a consortium of 140 non-profit public health advocacy groups who issued a statement noting the conflicts of interest that occur when international agencies “partner” with companies that make products that contribute to an increase in disease risks.”

The consortium suggested actions that they hoped the U.N. would recommend, such as:

  • Realign food policies for food and agricultural subsidies with sound nutrition science
  • Mandate easy-to-understand front-of-pack nutrition labeling
  • Ban the promotion of breast-milk substitutes and high-fat, -sugar and -salt foods to children and young people
  • Prohibit advertising and brand sponsorship for alcohol beverages
  • Increase taxes on alcohol beverages
  • Expand nutritious school meal programs

The group also said that the U.N. should still work on:

  • Developing tools to navigate the trade law barriers to health policy innovation,
  •  Establishing disease-reduction targets and policy implementation schedules
  • Instituting mechanisms to keep commercially self-interested parties at arms-length and public-interest groups constructively involved

Food companies and trade associations are actively involved in lobbying the U.N. not to do any of these things.  This consortium has much work to do.



Jun 15 2009

Cancer statistics, 2009

I’ve just received the latest cancer statistics from CA–A Cancer Journal for Clinicians. The good news is that overall cancer death rates are down from their peak in the 1990s and rates of specific cancers are stable or decreasing.  None seems to be increasing.

Look at what is happening with heart disease (page 15).   Its rates have fallen by half since the mid-1970s for people under age 85.  Even for people over 85, heart disease death rates are falling rapidly.

Obesity is a risk factor for both cancer and heart disease.  So ideas about its effects on health need to take these statistics into consideration.  But before dismissing obesity as a risk factor, note that both heart disease and cancer remain leading causes of death, and both disproportionately affect low-income groups.   Groups with low income and education tend to have many risk factors for these diseases, among them high rates of obesity.

Public health still has plenty of work to do.

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