by Marion Nestle

Currently browsing posts about: Fats-and-oils

Feb 5 2019

The Iceman’s Last Meal: high in fat from ibex, red deer, and cereal grains

I’ve long argued that the most intellectually challenging issue in the field of nutrition is finding out what people eat.

Here’s what it takes:  Using DNA technology, investigators examined the stomach contents of the “Iceman,” a man who died 5300 years ago but was frozen in the Alps until his body was discovered some years ago.

The result: “a remarkably high proportion of fat in his diet, supplemented with fresh or dried wild meat, cereals, and traces of toxic bracken.”

A recent radiological re-examination of the Iceman, a 5,300-year-old European natural ice mummy, identified his completely filled stomach (Figure 1A) [2]…Previous isotopic analysis (15N/14N) of the Iceman’s hair suggested first a vegetarian lifestyle [1213] which was later, after careful re-examination of the data, changed to a omnivorous diet [14]. Further analyses of lower intestinal tract samples of the Iceman confirmed that he was omnivorous, with a diet consisting of both wild animal and plant material. Among the plant remains, there were cereals, pollen grains of hop-hornbeam, and fragments of bracken and mosses [14151617181920]… In summary, the Iceman’s last meal was a well-balanced mix of carbohydrates, proteins, and lipids, perfectly adjusted to the energetic requirements of his high-altitude trekking.

Nearly half (46%) of the bulk stomach contents consisted of animal fat, much of it saturated.  This, apparently, had consequences:

computed tomography scans of the Iceman showed major calcifications in arteria and the aorta indicating an already advanced atherosclerotic disease state [33].

Fascinating, no?  Now if we could do this kind of analysis on a population basis, think of the questions we could finally answer!

Jan 24 2019

Palm oil politics: corporate effects on health

The World Health Organization is about to publish a report on how the palm oil industry is promoting obesity and chronic disease as well as environmental degradation as integral parts of its business model.

The draft report gets right to the point.

We highlight the industry’s mutually profitable relationship with the processed food industry and its impact on human and planetary health, including detrimental cultivation practices that are linked to respiratory illnesses, deforestation, loss of biodiversity and pollution. This analysis illustrates many parallels to the contested nature of practices adopted by the alcohol and tobacco industries.

The research behind the report supports the analytical framework for examining industry’s effects on health.

The report documents how the palm oil industry, working with the food industry, acts to maximize profits at the expense of health and the environment, through marketing, supply chain management, lobbying, and corporate “citizenship.”

The report calls for

  • More research on the effects of palm oil on health
  • Actions to mitigate industry influences to protect producers and sellers from needed regulations
  • Use of the Sustainable Development Goals to aid these actions

You don’t get why palm oil raises health and environmental concerns?  Read this.  Now.

 

Dec 4 2018

Where are we on dietary fat?

The endless arguments about dietary fats and dietary fat versus carbohydrate make no sense to me, because we mostly eat these as components of food, and foods as components of diets of massive complexity.

But scientists do like to debate such issues so it comes as a breath of fresh air to read a consensus statement from people who do not necessarily agree about such issues.

Looks good to me.  I’m glad they did this.

 

Nov 12 2018

Another industry-funded study for your amusement

As I discuss in my latest book, Unsavory Truth: How Food Companies Skew the Science of What We Eatfood industry funding of nutrition research produces highly predictable results and, therefore, is not good for science, public health, or trust.

Industry-funded studies are easily recognizable by their titles.  When I see a title like this one, I immediately wonder why anyone would do a study to example this particular question.  And then I look to see who funded it.

Title: Corn Oil Lowers Plasma Cholesterol Compared with Coconut Oil in Adults with Above-Desirable Levels of Cholesterol in a Randomized Crossover TrialJ Nutr 2018 148(10):1556-63.

Conclusion: “When incorporated into the habitual diet, consumption of foods providing ∼54 g of corn oil/d produced a more favorable plasma lipid profile than did coconut oil in adults with elevated cholesterol.”

Sponsor: “Supported by ACH Food Companies, Inc., Oakbrook Terrace, IL,” and all of the authors either received research funding from ACH Food Companies, Inc., or are employees of that company.

Comment: So what is this about?  ACH is the maker of Mazola oil, which must be losing market share to coconut oil.

Which oil is better for you and does it really matter?

I sure would like some independent researchers to weigh in on this.

Jul 12 2018

Food Navigator’s collection of articles on “healthy fats”

Fat remains in the news.  Which ones are health, and which not?  FoodNavigator-USA collects its articles on the topic.  My thoughts:  Beyond that, food fats are mixtures of monounsaturated, polyunsaturated, and saturated fatty acids, of the omega-3, -6, and -9 varieties.  And then there are the hydrogenated trans-fats.  These variations make fats complicated.

One attribute of fats is not complicated: fat has 9 calories/gram compared to 4 for protein and carbohydrate.  A tablespoon of oil, butter, lard, or tallow has about 100 calories.  If you are concerned about energy balance, watch out for fat calories (and the other ones count too).

FoodNavigator’s Special Edition: Healthy fats
Fat – we are told – is back. But what kind of fat, and can you have too much of a good thing? Is the science changing on saturated fats? Is whole milk a better choice, or should we stick to low fat dairy? Is coconut oil as healthy as some marketers make out, and is the pressure off to reduce fat now all eyes are on added sugar?  Get the lowdown on fat in this special edition…

May 14 2018

WHO seeks comments on saturated fat and trans fat

The World Health Organization (WHO) is collecting comments until June 4 on its recent “consultation” (committee report) on saturated fat and trans fat.

The consultation recommends:

  • Saturated fat: no more than 10% of calories
  • Trans fat: no more than 1% of calories

These recommendations are consistent with

I wish that dietary recommendations would refer to foods, not nutrients.

We don’t eat specific fatty acids.  We eat foods containing mixtures of saturated, unsaturated, and polyunsaturated fatty acids; some foods have more than one kind than another.

Trans fats appear in highly processed foods.  Therefore, they are a euphemism for snack and other foods containing them.

As for saturated fats: the Dietary Guidelines give their main sources:

The guidelines use two layers of euphemisms.

  • Saturated fat is a euphemism for meat and dairy foods; these have higher proportions of saturated fatty acids.
  • “Mixed dishes” and “protein foods” are also euphemisms for meat and dairy foods.

But saying so is politically impossible.

Do comment on the WHO guidelines.  It may help clarify the recommendations.

Dec 12 2017

Oops. Fat replacing sugar in US diets.

In the late 1980s, nutrition scientists identified fat and saturated fat as key nutrients that needed to be reduced in US diets.

One result was the Snackwell’s phenomenon in the early 1990s—“no-fat” cookies with just as many calories as the ones with fat.  They flew off the shelves.

Image result for snackwell's no fat cookies

Now the push is to get rid of carbs, especially sugars.  The result?  Fat is back, along with its calories (fat has more than twice the calories per gram as carbohydrates, 9 as opposed to 4).

A tweet from Kevin Bass tells the story:

The USDA tells the same story, but with respect to specific products:

These products may be more satiating, but watch the calories!

Also watch out for the saturated fat:

 

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.