The French paradox is an apparently paradoxical epidemiological observation that French people have a relatively low incidence of coronary heart disease (CHD), while having a diet relatively rich in saturated fats, [1] in apparent contradiction to the widely held belief that the high consumption of such fats is a risk factor for CHD. The paradox is that if the thesis linking saturated fats to CHD is valid, the French ought to have a higher rate of CHD than comparable countries where the per capita consumption of such fats is lower.
It has also been suggested that the French paradox is an illusion, created in part by differences in the way that French authorities collect health statistics, as compared to other countries, and in part by the long-term effects, in the coronary health of French citizens, of changes in dietary patterns that were adopted years earlier. [2]
In 1991, Serge Renaud, a scientist from Bordeaux University, France—considered today the father of the phrase—presented the results of his scientific study into the term and actual scientific data behind the perception of the phrase. [3] This was followed by a public documentary broadcast on the American CBS News television channel, 60 Minutes .
In 1991, Renaud extended his studies in partnership with then junior researchers, cardiologist Michel de Lorgeril and dietician Patricia Salen. The three enhanced Renaud's study, with their paper concluding that: a diet based on southwestern Mediterranean cuisine (which is high in omega-3 oils, antioxidants and includes "moderate consumption" of red wine) created lower cases of cancer, myocardial infarction and cardiovascular disease; partly through increasing HDL cholesterol whilst reducing LDL cholesterol. [3]
In 1999, Malcolm Law and Nicholas Wald published a study in the British Medical Journal , [2] using data from a 1994 study of alcohol and diet to explain how the French paradox might actually be an illusion, caused by two statistical distortions.
First, Law and Wald attributed about 20% of the difference in the observed rates of CHD between France and the United Kingdom to the under-certification of CHD in France, relative to the UK. [2] [4]
Second, Law and Wald presented a time-lag hypothesis: if there were a delay in serum cholesterol concentrations increasing and a subsequent increase in ischaemic heart disease mortality, then the current rate of mortality from CHD is more likely to be linked to past levels of serum cholesterol and fat consumption than to current serum cholesterol levels and patterns of fat consumption. They wrote, [2]
We propose that the difference is due to the time lag between increases in consumption of animal fat and serum cholesterol concentrations and the resulting increase in mortality from heart disease—similar to the recognised time lag between smoking and lung cancer. Consumption of animal fat and serum cholesterol concentrations increased only recently in France but did so decades ago in Britain.
Evidence supports this explanation: mortality from heart disease across countries, including France, correlates strongly with levels of animal fat consumption and serum cholesterol in the past (30 years ago) but only weakly to recent levels. Based on past levels, mortality data for France are not discrepant
In addition, the French population has become increasingly overweight. A study published by the French Institute of Health and Medical Research (INSERM) revealed an increase in obesity from 8.5% in 1997 to 14.5% in 2009, with women showing a greater tendency toward obesity than men. [5]
The overall impact of the popular perception, in the English-speaking world, that the French paradox is a real phenomenon, has been to give added credibility to health claims associated with specific French dietary practices.
This was seen most dramatically when, in 1991, an early account of the then-novel concept of the French paradox was aired in the United States on 60 Minutes. The broadcast left the impression that France's high levels of red wine consumption accounted for much of the country's lower incidence of cardiac disease. Within a year, the consumption of red wine in the United States had increased by 40% [6] and some wine sellers began promoting their products as "health food." [7]
The cultural impact of the French paradox can be seen in the large number of book titles in the diet-and-health field that purport to give the reader access to the secrets behind the paradox:
Other books sought to boost their credibility by reference to the French paradox. The American edition of The Dukan Diet , written by Pierre Dukan, a Paris-based doctor, is marketed with the subtitle, "The real reason the French stay thin".
The existence of the French paradox has caused some researchers[ who? ] to speculate that the link between dietary consumption of saturated fats and coronary heart disease might not be as strong as had previously been thought. This has resulted in a review of the earlier studies that suggested this link.
Some researchers[ who? ] have thrown into question the entire claimed connection between natural saturated fat consumption and cardiovascular disease. In 2006, this view received some indirect support from the results of the Nurses' Health Study run by the Women's Health Initiative. After accumulating approximately 8 years of data on the diet and health of 49,000 post-menopausal American women, the researchers found that the balance of saturated versus unsaturated fats did not appear to affect heart disease risk, whereas the consumption of trans fat was associated with significantly increased risk of cardiovascular disease. [8]
Similarly, the authors of a 2009 review of dietary studies concluded that there was insufficient evidence to establish a causal link between consumption of saturated fats and coronary heart disease risk. [9]
It has been suggested that France's high red wine consumption is a primary factor in the trend. This hypothesis was expounded in a 60 Minutes broadcast in 1991. [10] The program catalysed a large increase in North American demand for red wines from around the world. It is believed that one of the components of red wine potentially related to this effect is resveratrol; [11] however, the authors of a 2003 study concluded that the amount of resveratrol absorbed by drinkers of red wine is small enough that it is unlikely to explain the paradox. [12]
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In "Lifestyle in France and the United States" (2010), one study reviewed identifies three major factors likely to be involved in the paradox:
In his 2003 book, The Fat Fallacy: The French Diet Secrets to Permanent Weight Loss, Will Clower suggests the French paradox may be narrowed down to a few key factors, namely:
Clower tends to downplay the common beliefs that wine consumption and smoking are greatly responsible for the French paradox. While a higher percentage of French people smoke, this is not greatly higher than the U.S. (35% in France vs. 25% in U.S.) and is unlikely to account for the weight difference between countries.
One proposed explanation of the French paradox regards possible effects (epigenetic or otherwise) of dietary improvements in the first months and years of life, exerted across multiple generations. Following defeat in the Franco-Prussian War in 1871, the French government introduced an aggressive nutritional program[ which? ] providing high quality foods[ which? ] to pregnant women and young children with the aim of fortifying future generations of soldiers (the program was implemented about three decades prior to an analogous initiative in England in response to the Boer War). It has been suggested that the particular timing of this historical intervention might help explain the relatively low rates of obesity and heart disease found in France. [14]
In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food.
Ancel Benjamin Keys was an American physiologist who studied the influence of diet on health. In particular, he hypothesized that replacing dietary saturated fat with polyunsaturated fat reduced cardiovascular heart disease. Modern dietary recommendations by health organizations, systematic reviews, and national health agencies corroborate this.
A saturated fat is a type of fat in which the fatty acid chains have all single bonds between the carbon atoms. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched chain of carbon (C) atoms. Along the chain, some carbon atoms are linked by single bonds (-C-C-) and others are linked by double bonds (-C=C-). A double bond along the carbon chain can react with a pair of hydrogen atoms to change into a single -C-C- bond, with each H atom now bonded to one of the two C atoms. Glyceride fats without any carbon chain double bonds are called saturated because they are "saturated with" hydrogen atoms, having no double bonds available to react with more hydrogen.
The Mediterranean diet is a concept first invented in 1975 by the American biologist Ancel Keys and chemist Margaret Keys. The diet took inspiration from the supposed eating habits and traditional food typical of Crete, much of the rest of Greece, and southern Italy, and formulated in the early 1960s. It is distinct from Mediterranean cuisine, which covers the actual cuisines of the Mediterranean countries, and from the Atlantic diet of northwestern Spain and Portugal. While inspired by a specific time and place, the "Mediterranean diet" was later refined based on the results of multiple scientific studies.
Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, arrhythmia, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis.
Hypercholesterolemia, also called high cholesterol, is the presence of high levels of cholesterol in the blood. It is a form of hyperlipidemia, hyperlipoproteinemia, and dyslipidemia.
Stanol esters is a heterogeneous group of chemical compounds known to reduce the level of low-density lipoprotein (LDL) cholesterol in blood when ingested, though to a much lesser degree than prescription drugs such as statins. The starting material is phytosterols from plants. These are first hydrogenated to give a plant stanol which is then esterified with a mixture of fatty acids also derived from plants. Plant stanol esters are found naturally occurring in small quantities in fruits, vegetables, nuts, seeds, cereals, legumes, and vegetable oils.
A healthy diet is a diet that maintains or improves overall health. A healthy diet provides the body with essential nutrition: fluid, macronutrients such as protein, micronutrients such as vitamins, and adequate fibre and food energy.
Phytosterols are phytosteroids, similar to cholesterol, that serve as structural components of biological membranes of plants. They encompass plant sterols and stanols. More than 250 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols.
Mary Gertrude Enig was a nutritionist and researcher known for her unconventional positions on the role saturated fats play in diet and health. She disputed the medical consensus that diets high in saturated fats contribute to development of heart disease, while she advocated for a low-carbohydrate high-fat diet, rich in animal fats and coconut oil.
Nathan Pritikin was an American inventor, engineer, nutritionist and longevity researcher. He promoted the Pritikin diet, a high-carbohydrate low-fat plant-based diet combined with regular aerobic exercise to prevent cardiovascular disease. The Pritikin diet emphasizes the consumption of legumes, whole grains, fresh fruit and vegetables and non-fat dairy products with small amounts of lean meat, fowl and fish.
The Western pattern diet is a modern dietary pattern that is generally characterized by high intakes of pre-packaged foods, refined grains, red meat, processed meat, high-sugar drinks, candy and sweets, fried foods, industrially produced animal products, butter and other high-fat dairy products, eggs, potatoes, corn, and low intakes of fruits, vegetables, whole grains, pasture-raised animal products, fish, nuts, and seeds.
The chronic endothelial injury hypothesis is one of two major mechanisms postulated to explain the underlying cause of atherosclerosis and coronary heart disease (CHD), the other being the lipid hypothesis. Although an ongoing debate involving connection between dietary lipids and CHD sometimes portrays the two hypotheses as being opposed, they are in no way mutually exclusive. Moreover, since the discovery of the role of LDL cholesterol (LDL-C) in the pathogenesis of atherosclerosis, the two hypotheses have become tightly linked by a number of molecular and cellular processes.
David Mark Hegsted was an American nutritionist who studied the connections between food consumption and heart disease. His work included studies that showed that consumption of saturated fats led to increases in cholesterol, leading to the development of dietary guidelines intended to help Americans achieve better health through improved food choices.
A health claim found on a food labels and in food marketing is a claim by a food manufacturer that their product will reduce the risk of developing a disease or condition.
The Seven Countries Study is an epidemiological longitudinal study directed by Ancel Keys at what is today the University of Minnesota Laboratory of Physiological Hygiene & Exercise Science (LPHES). Begun in 1956 with a yearly grant of US$200,000 from the U.S. Public Health Service, the study was first published in 1978 and then followed up on its subjects every five years thereafter.
The Portfolio Diet is a therapeutic plant-based diet created by British researcher David J. Jenkins in 2003 to lower blood cholesterol. The diet emphasizes using a portfolio of foods or food components that have been found to associate with cholesterol lowering to enhance this effect. Soluble fiber, soy protein, plant sterols, and nuts are the four essential components of Portfolio diet. The diet is low in saturated fat, high in fibre. Researchers have suggested that the Portfolio diet may be a useful addition to statin therapy to help people achieve their lipid targets.
The Israeli paradox is an apparently paradoxical epidemiological observation that Israeli Jews have a relatively high incidence of coronary heart disease (CHD), despite having a diet relatively low in saturated fats, in apparent contradiction to the widely held belief that the high consumption of such fats is a risk factor for CHD. The paradox is that if the thesis linking saturated fats to CHD is valid, the Israelis ought to have a lower rate of CHD than comparable countries where the per capita consumption of such fats is higher.
Trans fat, also called trans-unsaturated fatty acids, or trans fatty acids, is a type of unsaturated fat that occurs in foods. Small amounts of trans fats occur naturally, but large amounts are found in some processed foods. Since consumption of trans fats is unhealthy, artificial trans fats are highly regulated or banned in many nations. However, they are still widely consumed in developing nations, resulting in hundreds of thousands of deaths each year. The World Health Organization (WHO) had set a goal to make the world free from industrially produced trans fat by the end of 2023. The goal was not met, and the WHO announced another goal "for accelerated action till 2025 to complete this effort" along with associated support on 1 February 2024.
The North Karelia Project was worldwide the first public health project for the prevention of cardiovascular disease mortality. It was first conducted from 1972 to 1977 in North Karelia and due to the success from 1977 to 1997 in all of Finland. It addressed the three risk factors identified by the British Doctors Study, the Framingham Heart Study, and the Seven Countries Study.
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