by Marion Nestle

Currently browsing posts about: Heart-disease

Jan 2 2024

The Stanford Twin Study: Now on Netflix!

A press release from Stanford University announced: Twin research indicates that a vegan diet improves cardiovascular health.

A Stanford Medicine-led trial of identical twins comparing vegan and omnivore diets found that a vegan diet improves overall cardiovascular health.

In a study with 22 pairs of identical twins, Stanford Medicine researchers and their colleagues have found that a vegan diet improves cardiovascular health in as little as eight weeks.

If this sounds like the basis of a Netflix documentary, it is.  Here’s the trailer.  Here’s where to find the film.

The study: Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical TwinsA Randomized Clinical Trial.

Intervention  Twin pairs were randomized to follow a healthy vegan diet or a healthy omnivorous diet for 8 weeks. Diet-specific meals were provided via a meal delivery service from baseline through week 4, and from weeks 5 to 8 participants prepared their own diet-appropriate meals and snacks.

Findings:  In this randomized clinical trial of 22 healthy, adult, identical twin pairs, those consuming a healthy vegan diet showed significantly improved low-density lipoprotein cholesterol concentration, fasting insulin level, and weight loss compared with twins consuming a healthy omnivorous diet.

Conclusions and Relevance  In this randomized clinical trial, we observed cardiometabolic advantages for the healthy vegan vs the healthy omnivorous diet among healthy, adult identical twins. Clinicians may consider recommending plant-based diets to reduce cardiometabolic risk factors, as well as aligning with environmental benefits.

The study has its share of detractors, American Council on Science and Health (ACSH), for example: Stanford Medicine Releases Confirmation Bias Study; Media Takes The Bait.  Its chief criticisms

  • The improvements were in biomarkers, not health.
  • Both diets were healthy,
  • Obviously, diets without cholesterol will reduce cholesterol.
  • Vitamin B12 levels were ldeficient on the vegan diet.

Comment: The ACSH is an industry-funded front group.  Low B12 is an easy problem to solve, and vegans, who by definition eat no foods of animal origin, have to make sure they complensate for its absence.

The twin idea is clever and adorable—and the reason for the press attention and for the Netflix documentary.  The study shows that vegan diets improve cardiovascular risk biomarkers in healthy people.  Why not?  This is further evidence for the benefits of largely plant-based diets.

Nov 16 2021

The American Heart Association’s new and groundbreaking dietary guidelines

The American Heart Association (AHA) has just issued its latest set of dietary guidelines aimed at preventing the leading cause of death in the United States: 2021 Dietary Guidance to Improve Cardiovascular Health: A Scientific Statement From the American Heart Association.

Because AHA guidelines apply not only to coronary heart disease but also to all other chronic disease conditions—and sustainability issues—influenced by dietary practices, they deserve special attention.

Most of these repeat and reinforce the 2020-2025 Dietary Guidelines for Americans.

The two big differences in the recommendations:

  • Clarifying protein recommendations: these include all sources but emphasize plant sources (#4)
  • Including a new one: minimize ultra-processed foods (#6)

These recommendations are way ahead of the US Dietary Guidelines in recognizing how much ultra-processed foods contribute to poor health, and how important it is to minimize their intake.

Also unlike the US guidelines, these are unambiguous and easily summarized.

 

The statement is worth reading for its emphasis on two other points.

  • This dietary pattern addresses problems caused by other chronic conditions and also has a low environmental impact.
  • Following this dietary pattern requires much more than personal responsibility for food choices.  It requires societal changes as well.

The press release summarizes the problems in society that make following healthy diets so difficult, if not impossible:

  • Widespread dietary misinformation from the Internet;
  • A lack of nutrition education in grade schools and medical schools;
  • Food and nutrition insecurity – According to references cited in the statement, an estimated 37 million Americans had limited or unstable access to safe and nutritious foods in 2020;
  • Structural racism and neighborhood segregation, whereby many communities with a higher proportion of racial and ethnic diversity have few grocery stores but many fast-food outlets; and
  • Targeted marketing of unhealthy foods and beverages to people from diverse racial and ethnic backgrounds through tailored advertising efforts and sponsorship of events and organizations in those communities.

As the statement concludes: “Creating an environment that facilitates, rather than impedes, adherence to heart-healthy dietary patterns among all individuals is a public health imperative.”

Amen to that.

Comment: From my perspective, this statement thoroughly supersedes the 2020-2025 Dietary Guidelines for Americans, which—because they say nothing about ultra-processed foods , differential protein sources, sustainability, or doing anything to counter societal determinants of poor diets—were out of date the instant they appeared.

Some of the details of the AHA statement will be debated but its overall approach should not be.

The committee that put these guidelines together deserves much praise for basing its advice on today’s research and most pressing societal needs.

Additional AHA Resources:

Apr 12 2021

Industry-funded opinon of the week: eggs and cholesterol

Nutritional Viewpoints on Eggs and Cholesterol. by Michihiro Sugano and Ryosuke Matsuoka.  Foods 202110(3), 494; https://doi.org/10.3390/foods10030494

Opinion:  This review says that although Japanese people eat more eggs than Americans, they may be protected against higher cholesterol levels due to the differences in everything else they eat (more seafood, for example?).

Conclusion: “Although randomized controlled trials with long-term follow-up are required to evaluate the association between consumption of eggs and human health, available information, at least from the nutritional viewpoint, suggests that egg is a healthy and cost-efficient food worldwide.”

Conflicts of interest: “M.S. declares no conflicts of interest, and R.M. is an employee of Kewpie Corporation. There are no other patents, products in development, or marketed products to declare. Kewpie Corporation has no conflicts of interest with this research.”

Comment: Really?  No conflicts of interest?  But Kewpie is Japan’s #1 mayonaise companyKewpie says that it “uses about four billion eggs a year. Recognizing that eggs contain all the necessary ingredients for creating life, we continually study ways of effectively utilizing such ingredients and manufacture fine chemicals for use in a broad range of food, cosmetic, and pharmaceutical applications.”

One of those ways, apparently, is to get its employees to write opinion pieces like this.

With that said, concerns about eggs and cholesterol have diminished in recent years.  The 2020 Dietary Guidelines for Americans says not a word about eggs and cholesterol; it just recommends eggs as a source of protein.  A study in the American Heart Association Journal finds no association between eggs and heart disease mortality.

The American Heart Association notes that eggs are the leading source of dietary cholesterol but their negative effects may be confounded by the fact that they are so often eaten with bacon and sausage.  The AHA egg recommendations:

  • Vegetarians (lacto-ovo) who do not consume meat-based cholesterol-containing foods may include more dairy and eggs in their diets within the context of moderation discussed herein.
  • Patients with dyslipidemia, particularly those with diabetes mellitus or at risk for heart failure, should be cautious in consuming foods rich in cholesterol.
  • For older normocholesterolemic patients, given the nutritional benefits and convenience of eggs, consumption of up to 2 eggs per day is acceptable within the context of a heart-healthy dietary pattern.

And even with that said, the authors should have disclosed Kewpie’s evident conflicted interests.

Jun 10 2019

Industry-funded study of the week: dairy foods, type 2 diabetes, and cardiovascular disease

Knowing that this review was sponsored by the dairy industry, can you predict its conclusions?

Association between dairy intake and the risk of contracting type 2 diabetes and cardiovascular diseases: a systematic review and meta-analysis with subgroup analysis of men versus women. Moshe Mishali, Shiri Prizant-Passal, Tova Avrech, and Yehuda Shoenfeld . Nutrition Reviews 2019;77(6):417–429.

Conclusions: “In conclusion, these results, indicating that dairy product consumption decreases the risk of T2D and CVD, are in line with the recommendations for the public to consume dairy products. The findings about sex differences and the positive effect of milk on women need further establishment. Future studies should focus on isolating the effect of dairy products for men and women throughout their life span

Funding. This work was financed by the Israel Dairy Board.

Declaration of interests. M.M. is a consultant for the Israel Dairy Board. S.P. was paid for her work by the Israel Dairy Board. T.A. is Chief Health Officer at the Israel Dairy Board. Y.S. is a consultant for the Israel Dairy Board.

Comment: This is a study paid for by the Israeli dairy industry.  As such, it can well be considered an advertisement.  Like other such industry-funded studies (as I discuss in Unsavory Truth), it puts a positive spin on equivocal results (“need further establishment”).

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.

INTcover0623LR.jpg

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.