jeudi 31 janvier 2019

What we know about fat may be wrong

What we know about fat may be wrong
By: Dr. Guy-André Pelouze
The Star/Asia News Network / 04:19 PM April 25, 2016

Dr. Ancel Keys (Jan 26, 1904–Nov 20, 2004) was an American scientist who studied the influence of diet on health. He is responsible, almost more than any other individual, for the public health misconception around fats that exists today. Through published work that was vaunted across the world, Dr. Keys has had a far-reaching impact on how we think about the role of fats.

When Dr. Keys first published his theories, alleging that saturated fats were uniquely harmful, they were controversial. This controversy remains strong today as the debate on the roles of fat and sugar in relation to cardiovascular disease (CVD) associated with atheroma (the fatty material that forms plaques in arteries) goes on.

This article reflects upon two main subjects: understanding the complexity of chronic diseases as the antithesis of acute infectious diseases; and the principle of falsifiability applied to atheroma theories and the practical consequences this entails.

After World War II, the work of Dr. Keys played a fundamental role in the debate around fats. How?

Because it claimed to demonstrate a link between saturated fats consumption and atheroma: “Many factors are probably involved in the atherosclerotic development and in the clinical appearance of coronary heart disease, but there is no longer any doubt that one central item is the concentration, over time, of cholesterol and related lipids and lipoproteins in the blood serum. No other etiological (sic) influence of comparable importance is as yet identified.” (A. Keys, American Journal of Public Health, Nov 1953, vol 43, 1399-1407.)

Today, in reality, scientists see tobacco, diabetes and hypertension to be much more powerful risk factors. We condemn researchers who, for over 40 years, have not been keen to verify the data and the conclusions it suggested.

Epidemiology in modern history

Epidemiologic observations have drawn the attention of scientists for a long time on the link between dietary change and cardiovascular diseases. Examples of populations with low CVD prevalence or populations where CVD are the first cause of mortality have led epidemiologists to do research on food.

This is what we called the Diet-Heart Hypothesis. But it is so incredibly complex that even till today, we have yet to come up with a definitive answer. Simple hypo- theses (i.e. single-factor cause) and invalid experimental models have produced abundant literature, of which little is actually helpful.

We can, however, wonder about the recent dietary changes brought by the recent industrial transition. In the West, those changes can be qualified with three factors:
Abundance of calories
Abundance of carbohydrates
Abundance of processed foods

Further to these, we should not forget about calorie expenditure. In industrialized countries, we have shifted to a sedentary lifestyle (at work, in public transportation or for personal activities).

Dr. Keys supported his hypothesis with charisma.

How is that possible?

He and his team set out to study the dietary characteristics and lifestyles of different populations worldwide and compare the prevalence of coronary diseases. It was a rather large study at the time and needed significant funding.

This study addressed the issue of the heart attack epidemic that was hitting the United States and other developed countries at the time. He quickly focused on diet-related risk factors, mostly because they were easier to measure, particularly through blood levels.

Among macronutrients, Dr. Keys had already explored fat and the indirect measure of blood lipids via blood cholesterol.

The study would be published in a book in 1980 (Seven Countries. A multivariate analysis of death and coronary heart disease).

In the meantime, Dr. Keys got more famous, was interviewed often, and in January 1961, was on the cover of Time Magazine.

Dr. Keys described a link in the studied cohorts between the percentage of saturated fats in the diet and the death rate by coronary events. The correlation was dependent on the number of countries studied, but it was significant in the cohorts he chose.

As there was a correlation between total blood cholesterol and the same events, and as Dr. Keys highlighted that saturated fats (especially palmitic acid as it is the most common) increased blood cholesterol, a conclusion appeared.

He stated that saturated fats, including palmitic acid, were link-ed to coronary atheroma. Others have then bridged the gap, saying they cause coronary diseases.

Obviously, all of this was not true. Inaccuracies and biases made his observations invalid.

Even Dr. Keys ended up publishing more balanced conclusions than others: “Our 10 year finding, and concordance with other studies, make it clear that the big three risk factors for coronary heart disease now established are age, blood pressure, and serum cholesterol. The findings about cigarette smoking as a risk factor indicate that here, too, relationships are not as simple as first supposed.” (Seven Countries, page 341).

He later became an advocate of the Mediterranean diet and kept studying it for a while. In 1975, he published How to Eat Well and Stay Well the Mediterranean Way.

Consequences still felt today

Dietary guidelines from experts and governments have been largely based on Dr. Keys’ work.

To lower our intake in cholesterol and saturated fats, populations have massively consumed food products in which fats have been replaced with carbohydrates, and saturated fats with vegetable oils rich in omega-6.

This did not change the prevalence of atheroma-related diseases. New research even shows these changes may be linked to the obesity epidemic and type 2 diabetes.

Palm oil for one, which has a good balance between saturated and unsaturated fats, constitutes a healthy alternative – but it has been unjustly maligned for containing saturated fats.

There have been economic consequences too. This is linked to the food industry’s ability to quickly find a new market opportunity with low-fat food products. It has, as always, been shown to be very innovative in that regard.

Its lobby was powerful and the “low-fat” concept developed globally even though it is not possible as of yet to show it has any positive impact of cardiovascular health.

In the 40 years between Dr. Keys’ work and the shadow cast upon it, many scientific articles have been published to try and explain the anomalies observed in real populations.

None ever questioned what had become a dogma. The different paradoxes, including the famous French Paradox, have only started to shake the foundation of his hypothesis.

Who bears the responsibility?

Surely, Dr. Keys cannot be held responsible for how his data was used.

But his vision clearly influenced medicine for generations and overstated the importance of saturated fats and cholesterol in cardiovascular risk.

A summary of the Seven Countries Study on the University of Minnesota, US (where the study was coordinated), website, had this to say: “The main implications of the Seven Countries Study are that the mass burden and epidemic of atherosclerotic diseases has cultural origins, is preventable, can change rapidly, and is strongly influenced by the fatty composition of the habitual diet.

“The study implies the universal susceptibility of humans to CVD, but that the frequency of susceptible phenotypes is greatly reduced in favorable environments. It suggests there may be other and important protective elements in the diet and lifestyles of Crete and Japan.”

The only concession made to Dr. Keys’ theories is the confirmation of a strong influence of the composition of lipids in the diet, but the words “saturated fats” are no longer used.

The Journal of the American College of Cardiology recently reminded physicians:“Atherosclerosis is a multifactorial disease and requires a multifactorial approach with smoking cessation, dietary modification and weight management, regular physical activity, attention to psychosocial risk factors, and pharmacological therapy of lipid and nonlipid risk factors.

“Comprehensive risk factor control is associated with improved prognosis, and our challenge is to develop care models that will allow us to achieve such control.”

We need to keep in mind that tobacco, type 2 diabetes and hypertension are, in that order, more powerful atheroma risk factors than LDL particles. There is no interest in dietary cholesterol in preventing CVD.

Saturated fats, like monounsaturated fats, and like carbohydrates, increase the amount of LDL particles when in calorie excess and promotes atheroma if other risk factors are present, and if phenotype is susceptible.

This is the reason why we cannot predict among high-LDL patients those who will have a cardiovascular, cerebral or peripheral event, other than watching the three aforementioned powerful risk factors, or having proper atheroma plaques exams.

In summary, Dr. Keys was wrong, and his mistake has been compounded over the decades. It is time now to end the crusade against saturated fats.

(Dr. Guy-André Pelouze is a French cardiothoracic surgeon, and a founder of the French think tank and research group Institut de Recherche Clinique (Institute of Clinical Research). Dr Pelouze is a widely quoted writer and commentator on health and nutrition in France. This article contains extracts from the scientific paper, ‘Ancel Keys: Science is not believing’.)

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lundi 21 janvier 2019

The new zealots of the so called war to save the planet

Published on 

Scientists Call for 'Global Agricultural Revolution' and 'Planetary Health Diet' to Save Lives—and Earth

"The food we eat and how we produce it determines the health of people and the planet, and we are currently getting this seriously wrong."
meal examples for "flexitarian" or "planetary health" diet
In a new report about human health and the environmental, experts call for people across the globe to follow a "flexitarian" or "planetary health" diet. (Photo: The EAT-Lancet Commission)
While scientists continue to call for immediately phasing out fossil fuelsacross the global to avert climate catastrophe, a team of international experts on Thursday unveiled a proposal to address another major driver of the climate crisis: the world's unhealthy and unsustainable food system.
"To be healthy, diets must have an appropriate calorie intake and consist of a variety of plant-based foods, low amounts of animal-based foods, unsaturated rather than saturated fats, and few refined grains, highly processed foods, and added sugars."
—Dr. Walter Willett, Harvard University
"The food we eat and how we produce it determines the health of people and the planet, and we are currently getting this seriously wrong," declared Tim Lang, a co-author of the EAT-Lancet Commission and professor at City, University of London. "We need a significant overhaul, changing the global food system on a scale not seen before in ways appropriate to each country's circumstances."
The commission brought together 37 experts in agriculture, environmental sustainability, human health, and political science from 16 countries. Over three years, they developed the "planetary health diet," which aims to address the global food system's devastating environmental impact as well as mass malnutrition.
Noting that more than 800 million people worldwide "have insufficient food, while many more consume an unhealthy diet that contributes to premature death and disease," co-lead commissioner Dr. Walter Willett of Harvard University said the "world's diets must change dramatically" to reverse the damage that's been done.
"To be healthy," he explained, "diets must have an appropriate calorie intake and consist of a variety of plant-based foods, low amounts of animal-based foods, unsaturated rather than saturated fats, and few refined grains, highly processed foods, and added sugars."
"This is the first attempt to set universal scientific targets for the food system that apply to all people and the planet," according to the final report, Food in the Anthropocene: Healthy Diets From Sustainable Food Systems (pdf).
The "Great Food Transformation" envisioned by the commission acknowledges that the world population is on track to reach an estimated 10 billion by 2050. The researchers considered current food production and consumption trends in terms of not only planet-warming emissions but also cropland and freshwater use, nitrogen and phosphorus cycling, and species extinction.
"Humanity now poses a threat to the stability of the planet," co-lead commissioner Johan Rockström of the Stockholm Resilience Center told the Guardian. "[This requires] nothing less than a new global agricultural revolution."
The report, published in The Lancet, lays out five key strategies for its proposed overhaul of global food norms:
  1. Seek international and national commitment to shift toward healthy diets that feature more plant-based foods—including fruits, vegetables, nuts, seeds, and whole grains—and less animal products.
  2. Reorient agricultural priorities from producing high quantities of food to producing healthy food that nurtures human health and supports environmental sustainability.
  3. Sustainably intensify food production to increase high-quality output with a series of reforms that include becoming a net carbon sink from 2040 forward to align with the goals of the Paris climate agreement.
  4. Strong and coordinated governance of land and oceans, including by implementing a "Half Earth" strategy for biodiversity conservation.
  5. At least halve food losses and waste, in line with the U.N. Sustainable Development Goals(SDGs), on both the production side and the consumption side.
Alongside its report, the commission put out a brief (pdf) identifying top takeaways and specific actions that individuals can take to help transform the global food system. Suggestions include buying more sustainably produced food, embracing plants as a source of protein, and slashing both meat consumption and food waste.
AFP diet graphic
The unveiling of the planetary health diet follows a series of recent studiesthat have shown it is environmentally necessary for humans—particularly in the United States and Europe—to dramatically reduce red meat consumption. The commission estimates that shifting toward such a diet could save at least 11 million adult lives annually.
The commission's report comes as the New England Journal of Medicinepublished a "grim analysis" on Thursday which warns that the World Health Organization's conclusion from just five years ago that rising global temperatures over the next few decades will kill 250,000 people per year is a "conservative estimate."

dimanche 13 janvier 2019

Just for your eyes: ADA is recognizing, in a U-turn this January 2019, that low carb diets show results in T2D: it is one of our mantras in this blog!

For people with type 2 diabetes or prediabetes, low-carbohydrate eating plans show potential to improve glycemia and lipid outcomes for up to 1 year (6264,8689). Part of the challenge in interpreting low-carbohydrate research has been due to the wide range of definitions for a low-carbohydrate eating plan (85,86). As research studies on low-carbohydrate eating plans generally indicate challenges with long-term sustainability, it is important to reassess and individualize meal plan guidance regularly for those interested in this approach. Providers should maintain consistent medical oversight and recognize that certain groups are not appropriate for low-carbohydrate eating plans, including women who are pregnant or lactating, children, and people who have renal disease or disordered eating behavior, and these plans should be used with caution for those taking SGLT2 inhibitors due to potential risk of ketoacidosis (65,66). There is inadequate research about dietary patterns for type 1 diabetes to support one eating plan over another at this time.

Juste pour vos yeux: l'ADA reconnaît, en janvier 2019, que les régimes à faible teneur en glucides donnent des résultats positifs pour le DT2: c'est l'un de nos mantras dans ce blog!

Pour les personnes atteintes de diabète de type 2 ou de prédiabète, les régimes alimentaires contenant peu de glucides peuvent améliorer les résultats liés à la glycémie et aux lipides pendant un an maximum (62–64,86–89). Une partie du défi que pose l’interprétation de la recherche sur les aliments à faible teneur en glucides est due au large éventail de définitions d’un régime alimentaire pauvre en glucides (85,86). Les études de recherche sur les régimes alimentaires contenant peu de glucides indiquant généralement des problèmes de viabilité à long terme, il est important de réévaluer et d’individualiser régulièrement les orientations des plans de repas pour les personnes intéressées par cette approche. Les prestataires doivent maintenir une surveillance médicale constante et reconnaître que certains groupes ne sont pas adaptés aux régimes alimentaires faibles en glucides, notamment les femmes enceintes ou allaitantes, les enfants et les personnes souffrant d'insuffisance rénale ou de troubles du comportement alimentaire. Ils doivent être utilisés avec prudence. pour ceux qui prennent des inhibiteurs de SGLT2 en raison du risque potentiel d’acidocétose (65,66). Les recherches sur les habitudes alimentaires du diabète de type 1 sont insuffisantes pour soutenir un régime alimentaire au lieu d'un autre à l'heure actuelle.

Nutritional supplements are often more expensive than caviar or foie gras...

Nutritional supplements may contain ingredients that are toxic and may cause harmful reactions with medications or other supplements. Supplements are weakly regulated and undergo little or no government testing for safety or effectiveness. A balanced, varied diet of whole foods provides all the vitamins and nutrients needed for good health.

Les suppléments nutritionnels peuvent contenir des ingrédients toxiques et provoquer des réactions néfastes lors de l’utilisation de médicaments ou d’autres suppléments. Les suppléments sont faiblement réglementés et ne sont soumis à aucun test de sécurité ou d'efficacité de la part du gouvernement. Un régime équilibré et varié composé d'aliments complets fournit toutes les vitamines et les nutriments nécessaires à une bonne santé.

samedi 5 janvier 2019

War on meat

mercredi 2 janvier 2019

Quel est le facteur principal de la santé des populations de chasseurs-cueilleurs ?

Il est très curieux et complètement à l’envers des conclusions de l’article de considérer que c’est l’environnement qu’il soit au singulier ou au pluriel qui fait la santé des peuples Hadza et des autres chasseurs-cueilleurs.
« One common element of traditional lifestyles that clearly seems to be protective against non‐communicable disease is a high level of daily physical activity. Hunter‐gatherers and subsistence farmers accumulate several times as much physical activity each day as people in developed countries »

C’est bien l’hygiène de vie.
Et c’est accessible à tous.