by Marion Nestle

Currently browsing posts about: Heart-disease

Sep 5 2017

The PURE study warrants some skepticism

I love getting notes like this one from a reader:

Why aren’t you saying anything about the PURE study.  Doesn’t it prove that everything you’ve been saying about eating more fruits and vegetables and about saturated fat is wrong, wrong, wrong.  Admit it.

Not this time.  Whenever I hear the claim that “everything you thought about nutrition is wrong,” I know that skepticism is in order.  Science rarely works that way; it usually progresses incrementally.

What the PURE study is about: The PURE (Prospective Urban Rural Epidemiology) study was designed to examine, among other things, the effects of lifestyle behaviors on the health of about 135,000 people in 18 countries over up to 10 years.  Its results have just been published in Lancet journals.

What the headlines say: “Study challenges conventional wisdom on fats, fruits and vegetables.”

What the studies say:  Three papers report results: 

1,  Fruit, vegetable, and legumes vs. cardiovascular disease and death

Higher fruit, vegetable, and legume consumption was associated with a lower risk of non-cardiovascular, and total mortality. Benefits appear to be maximum for both non-cardiovascular mortality and total mortality at three to four servings per day (equivalent to 375–500 g/day).

2.  Fat and carbohydrate vs. cardiovascular disease and death

High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.  [Note: the data do not distinguish types of carbohydrate.]

3.  Association of nutrients with blood lipids and blood pressure

Our data are at odds with current recommendations to reduce total fat and saturated fats. Reducing saturated fatty acid intake and replacing it with carbohydrate has an adverse effect on blood lipids. Substituting saturated fatty acids with unsaturated fats might improve some risk markers, but might worsen others.

Why the need for skepticism:

I like the way James Hamblin explains the problem in The Atlantic:

The practically important findings were that the healthiest people in the world had diets that are full of fruits, beans, seeds, vegetables, and whole grains, and low in refined carbohydrates and sugar.

As a writer and a reader, though, this is very boring. If I pitched that to my editor, he would laugh at me. What is new here? Why is this interesting? You know what would be novel? You getting fired! Now get out there and find me a story, dammit!

Why did they do this study?  

I looked immediately to see who paid for it.  The list of funders is very long (it must have been extremely expensive).  The list begins:

The PURE Study is an investigator initiated study funded by the Population Health Research Institute, the Canadian Institutes of Health Research (CIHR), Heart and Stroke Foundation of Ontario, support from CIHR’s Strategy for Patient Oriented Research (SPOR) through the Ontario SPOR Support Unit, as well as the Ontario Ministry of Health and Long­Term Care and through unrestricted grants from several pharmaceutical companies, with major contributions from AstraZeneca (Canada), Sanofi­Aventis (France and Canada), Boehringer Ingelheim (Germany and Canada), Servier, and GlaxoSmithkline, and additional contributions from Novartis and King Pharma and from various national or local organisations in participating countries [the funders that follow are mainly government and private research bodies along with a sugar trade association and more drug companies—the list takes up more than half a column].

Drug companies have a big interest in this topic, especially if dietary approaches to heart disease prevention aren’t proven.

What the PURE study really tells us: For this, I am going to quote from David Katz’s lengthy analysis:

On the basis of all of the details in these published papers, the conclusion, and attendant headlines, might have been: “very poor people with barely anything to eat get sick and die more often than affluent people with access to both ample diets, and hospitals.” One certainly understands why the media did NOT choose that! It is, however, true- and entirely consistent with the data.

Also, by way of reminder: the HIGHEST levels of both total fat, and saturated fat intake observed in the PURE data were still LOWER then prevailing levels in the U.S. and much of Europe, providing no basis whatsoever for headlines encouraging people already exceeding these levels to add yet more meat, butter, and cheese to their diets. Absolutely none.

My translation: This study confirms that the single most important risk factor for poor health is poverty.  The study results are consistent with the idea that largely plant-based diets are good for health.  No single study can settle the fat vs. carbohydrate debate because people eat complicated combinations of foods and diets containing those nutrients.  What we really need are well designed studies of dietary patterns—the ones done to date suggest that largely plant-based diets are associated with excellent health and longevity.  

Sep 26 2016

White House report on heart health: impressive accomplishments

The White House has issued a report on the Obama administration’s accomplishments in addressing heart disease: “Making Health Care Better.”

The good news is that heart disease mortality has been falling steadily since 2009.

But let’s put this in context.  Here’s the long-term trend.  Impressive!

The report gives reasons why—mainly less cigarette smoking and better health care coverage.  Where nutrition fits into this is curious.  The increasing prevalence of obesity has no obvious effect on long-term trends.  Perhaps the decline would faster without it?

In any case, the White House report points to several of its nutrition initiatives:

  • The new Nutrition Facts label with added sugars and updated serving sizes
  • Calorie labels on fast food menus
  • Calorie labels on vending machines
  • Guidance to industry for voluntary sodium reduction
  • Healthier school breakfasts and lunches
  • And everything else that Let’s Move! has done.

There’s more to be done, but these are steps in the right direction.

Sep 9 2014

Canada’s Heart and Stroke Foundation weighs in on added sugars

Dr. Yoni Freedhoff sent me Canada’s Heart and Stroke Foundation’s  new position statement on Sugar, Heart Disease, and Stroke.

Its major recommendation is just like the one from the World Health Organization:

The Heart and Stroke Foundation recommends that an individual’s total intake of free sugars not exceed 10% of total daily calorie (energy) intake,and ideally less than 5%.

The Canadian government, the Foundation says, should:

  • Ensure clear and comprehensive nutrition labelling of the free sugars content in the Nutrition Facts table of all packaged foods, grouping all sugars together when listingingredients on product packaging, and standardized serving sizes on the Nutrition Facts table.
  • Restrict the marketing of all foods and beverages to children.
  • Educate Canadians about the risks associated with free sugars consumption through public awareness and education campaigns.

Shouldn’t we be doing that too?

As Dr. Freedhoff puts it, it’s “Amazing how forceful and sweeping public health organizations can be when they don’t need to worry about upsetting their industry partners.”

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.

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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.

Nov 18 2013

What’s up with the new cholesterol/statin guidelines?

Last week, a Feedback comment from a reader, Judith Rice-Jones, inspired me to try to understand what’s going on with the new heart disease prevention guidelines (I can’t say I’m succeeding very well).

Looking forward to your response to the recent recommendations for more people to take statins. Don’t see anything in the new recommendations about changing lifestyle or diet to reduce risks of stroke or heart attack.

Yes, there are lifestyle recommendations.   But lifestyle changes do not make money for drug companies, and they don’t get press attention.

The American College of Cardiology (ACC) and American Heart Association (AHA) issued four sets of guidelines:

  1. 2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults
  2. 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults
  3. 2013 AHA/ACC Guideline on Lifestyle Management to Reduce Cardiovascular Risk
  4. 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk

These organizations say:

AHA and ACC are pleased to announce a series of new cardiovascular prevention guidelines for the assessment of cardiovascular risk, lifestyle modifications that reduce risk, management of elevated blood cholesterol, and management of increased body weight in adults. These guidelines are based on rigorous, comprehensive, systematic evidence reviews originally sponsored by the NHLBI. The ACC and AHA collaborated with professional organizations to finalize these AHA/ACC cardiovascular prevention guidelines, and stakeholder organizations were invited to review and endorse the final documents.

So these guidelines are a major big deal.  The New York Times said you need to know three things about them:

  • You don’t need to know your cholesterol number (unless it is very high).
  • You do need to know your risk (for this you need to use the risk calculator and, therefore, to know your LDL and HDL levels and blood pressure).
  • If you are at risk, take a statin (most, at least, are generics).

But wait!

As the New York Times also suggested, the new guidelines have taken many by surprise.

This is an understatement.

Problem #1: Authoritative clinicians say more patients should not be taking statins

This announcement is not a result of a sudden epidemic of heart disease, nor is it based on new data showing the benefits of lower cholesterol. Instead, it is a consequence of simply expanding the definition of who should take the drugs — a decision that will benefit the pharmaceutical industry more than anyone else.

This opinion piece points out that members of the group writing the recommendations have financial ties to drug makers, as do both the AHA and ACC.

The guidelines might make sense, they say, if statins

actually offered meaningful protection from our No. 1 killer, heart disease; if they helped people live longer or better; and if they had minimal adverse side effects. However, none of these are the case…as shown in a recent BMJ article co-written by one of us.

Perhaps more dangerous, statins provide false reassurances that may discourage patients from taking the steps that actually reduce cardiovascular disease…80 percent of cardiovascular disease is caused by smoking, lack of exercise, an unhealthy diet, and other lifestyle factors. Statins give the illusion of protection to many people, who would be much better served, for example, by simply walking an extra 10 minutes per day.

Problem #2: The risk calculator greatly overestimates risk

The lead article in today’s Times summarizes studies to be published in The Lancet tomorrow concluding that the risk calculator makes the risks seem greater than they really are.

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New Picture (1)

It will lead many doctors to prescribe statin drugs to people who do not need to take them (from the standpoint of drug companies, that’s the point).

The calculator overpredicted risk by 75 to 150 percent, depending on the population. A man whose risk was 4 percent, for example, might show up as having an 8 percent risk. With a 4 percent risk, he would not warrant treatment — the guidelines that say treatment is advised for those with at least a 7.5 percent risk and that treatment can be considered for those whose risk is 5 percent.

What to do?

  • Best to discuss this one with your doctor.
  • For sure, eat your veggies and be active.
  • If you still smoke cigarettes, stop.
  • Stay tuned for further developments.

Just for fun

Let’s let Brian McFadden (Sunday’s New York Times Week in Review) have the last word for today.

Apr 15 2013

CT scans of ancient mummies show indications of atherosclerosis

I had no idea scientists were taking CT scans of mummies, and was riveted by a paper in the April 6-12 issue of The Lancet.  The investigators acquired or took CT scans of 137 mummies collected from various museums, the Brooklyn Museum among them (this photo is from the British Museum).

The mummies originated from four different parts of the world.

  • Ancient Egypt
  • Ancient Peru
  • Southwest America (ancient Pueblo Indians)
  • The Aleutian Islands

Their deaths occurred over nearly a 6000-year span, from perhaps 3800 BCE to 1900 CE.

The CT scans revealed calcifications in the arteries of 34% of the mummies.  The older the mummies were at the time of death, the more calcifications they displayed (average age at death was about 43).

The authors’ conclusion:

Atherosclerosis was common in four preindustrial populations including preagricultural hunter-gatherers. Although commonly assumed to be a modern disease, the presence of atherosclerosis in premodern human beings raises the possibility of a more basic predisposition to the disease.

The most fun is the table itemizing details about each of the 137 mummies.  For example, #57 was a male mummy from Egypt, age 40-45, from the Middle Kingdom Dynasty 12, around 1981-1802 BCE, with definite calcifications of the iliac, femoral, popliteal, and tibial arteries.  

The authors say that the presence of calcifications in the arteries of four preindustrial populations across a wide span of human history argues that “the disease is an inherent component of human ageing and not characteristic of any specific diet or lifestyle.”

Maybe, but we don’t know whether the calcifications caused the death of these individuals.  The paper assumes that calcifications seen on the CT scans indicate atherosclerosis.  Even if they do, it’s not clear whether or under what circumstances they might lead to coronary heart disease or stroke. 

The accompanying editorial doubts that dietary cholesterol and cigarette smoking were responsible for atherosclerosis in antiquity.  Instead, “infection is likely to provide the unifying explanation” (via inflammation).

More research needed!  But this is an entertaining example of the use of modern medical technology to explore interesting questions in human anthropology, physiology, and health.

Reference:  Thompson RC, et al.  Atherosclerosis across 4000 years of human history: the Horus study of four ancient populations.  The Lancet 2013;381:1211-1222, and editorial on pages 1165-1166.

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.


 

 

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