French paradox

The French paradox is a catchphrase first used in the late 1980s, that summarizes the 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.

Cheese, like this Brie de Meaux, is high in saturated fats, and is a popular food in French cuisine.

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 which were adopted years earlier.[2] Nevertheless the French diet may be considered to be a type of Mediterranean diet which has fairly well established benefits.[3]

Identifying and quantifying the French paradox

The term "French Paradox" was first used in The Letter, the newsletter of the International Organisation of Vine and Wine, in 1986. In 1989, theatre Professor George Riley Kernodle of the University of Arkansas used the term in a chapter in his book Theatre In History, later republished as a separate academic paper.[4]

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.[5] This was followed by a public documentary broadcast on the American CBS News television channel, 60 Minutes.

Renaud's observations regarding the apparent disconnect between French patterns of high saturated fat consumption and their low rates of cardiovascular disease can be quantified using data from the Food and Agriculture Organization of the United Nations.[6] In 2002, the average French person consumed 108 grams per day of fat from animal sources, while the average American consumed only 72 grams. The French eat four times as much butter, 60 percent more cheese and nearly three times as much pork. Although the French consume only slightly more total fat (171 g/d vs 157 g/d), they consume much more saturated fat because Americans consume a much larger proportion of fat in the form of vegetable oil, with most of that being soybean oil.[7] However, according to data from the British Heart Foundation,[8] in 1999, rates of death from coronary heart disease among males aged 35–74 years were 115 per 100,000 people in the U.S. but only 83 per 100,000 in France.

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.[5]

Statistical illusion hypothesis

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.

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,

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)....

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.[9]

Impact

Cultural impact

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%[10] and some wine sellers began promoting their products as "health food."[11]

The cultural impact of the French paradox can be seen in the large number of book titles in the diet-and-health field which purport to give the reader access to the secrets behind the paradox:

  • The Fat Fallacy: The French Diet Secrets to Permanent Weight Loss (William Clower, 2003);
  • The French Don't Diet Plan: 10 Simple Steps to Stay Thin for Life (William Clower, 2006)
  • French Women Don't Get Fat (Mireille Guiliano, 2004, which became a #1 best-seller in 2006)
  • Cholesterol and The French Paradox (Frank Cooper, 2009);
  • The French Women Don't Get Fat Cookbook (Mireille Guiliano, 2010).

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.”

Scientific impact

The existence of the French paradox has caused some researchers to speculate that the link between dietary consumption of saturated fats and coronary heart disease might not be as strong as had previously been imagined. This has resulted in a review of the earlier studies which had suggested this link.

Some researchers 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.[12]

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.[13]

Possible explanations

Explanations based on the high per capita consumption of red wine in France

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.[14] 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;[15] 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.[16]

A glass of red wine

Alcohol in wine
Main article: Alcohol and cardiovascular disease

Research suggests that moderate drinkers are less likely to suffer heart attacks than are abstainers or heavy drinkers (see alcohol and cardiovascular disease for details). Therefore, the alcohol in wine might be a factor in the French paradox.

However, the difference between U.S. annual per capita alcohol consumption (9.2 litres per year)[17] and French consumption (12.2 litres per year) is only 3 litres per year more.[18]

There is a lack of medical consensus about whether moderate consumption of beer, wine, or distilled spirits has a stronger association with longevity. Of ten major studies, three found stronger evidence for wine, three for beer, three for liquor, and one study found no difference between alcoholic beverages.[19]

Resveratrol
Main article: Resveratrol

Wines, particularly red wines, are a source of low levels of resveratrol. However, there is no high-quality evidence that resveratrol improves lifespan or has an effect on any human disease.[20][21]

Polyphenols

Oligomeric procyanidins have been proposed to offer protection to human vascular cells,[22] with other research indicating that red wine polyphenols reduce absorption of malondialdehyde which is implicated in elevating levels of low-density lipoprotein in the onset of arteriosclerosis.[23]

However, once digested and metabolized, the role of polyphenols to assert possible health effects in humans cannot be determined.[24] Although polyphenols are speculated to be part of the health-promoting effects of wine consumption, no evidence exists to date that ingesting polyphenols from red wine or food sources actually provides health benefits.[25]

Explanations based on aspects of the French diet

The French diet is rich in short-chain saturated fatty acids and poor in trans fats

The French diet is based on natural saturated fats such as butter, cheese and cream that the human body finds easy to metabolize, because they are rich in shorter saturated fatty acids ranging from the 4-carbon butyric acid to the 16-carbon palmitic acid. But the American diet includes greater amounts of saturated fats made via hydrogenating vegetable oils which include longer 18- and 20-carbon fatty acids. In addition, these hydrogenated fats include small quantities of trans fats which may have associated health risks.[26][27][28]

Explanations relying on multiple factors

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:

  • Good fats versus bad fats — French people get up to 80% of their fat intake from dairy and vegetable sources, including whole milk, cheeses, and whole milk yogurt.
  • Higher quantities of fish (at least three times a week).
  • Smaller portions, eaten more slowly and divided among courses that let the body begin to digest food already consumed before more food is added.
  • Lower sugar intake — American low-fat and no-fat foods often contain high concentrations of sugar. French diets avoid these products preferring full-fat versions without added sugar.
  • Low incidence of snacks between meals.
  • Avoidance of common American food items, such as soda, deep-fried foods, snack foods, and especially prepared foods which can typically make up a large percentage of the foods found in American grocery stores.

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.

Mireille Guiliano, author of the 2006 bestseller French Women Don't Get Fat,[29] agrees that the weight differences are not due to French smoking habits. She points out that the smoking rates for women in France and the U.S. are virtually identical.[30] Guiliano explains the key factors to the French woman's ability to stay slim as:

  • Smaller portion sizes: - she advocates the 50% rule, i.e. asking for half of whatever food one is offered, "la moitié, s'il vous plaît" in French
  • Savoring food to increase the feeling of satisfaction, choosing a small amount of high quality food rather than larger amounts of low quality food
  • Eating 3 meals a day and not snacking
  • Taking in plenty of liquid such as water, herbal tea and soup
  • Sitting down and eating mindfully (no multitasking and eating while standing up, watching TV, or reading)
  • Emphasizing freshness, variety, balance, and, above all, pleasure[30]

Whole diet

In his 2008 book In Defense of Food, Michael Pollan suggests the explanation is not any single nutrient, but the combination of nutrients found in unprocessed food; not any one nutrient, nor the amount of carbohydrates or fats or proteins, but the whole length and breadth of nutrients found in "natural" foods as opposed to "processed" foods.[31]

Higher fruit and vegetable intake

It has been suggested that a higher intake of fruit and vegetables in the diet may lower the risk of cardiovascular diseases.[32]

Early life nutrition

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 providing high quality foods 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.[33]

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See also

References

Citations
  1. Ferrieres, J. (2004). "The French Paradox; Lessons for other countries". Heart. 90 (1): 107–111. doi:10.1136/heart.90.1.107. PMC 1768013. PMID 14676260.
  2. Law, M.; Wald, N. (1999). "Why heart disease mortality is low in France: the time lag explanation". British Medical Journal. 318 (7196): 1471–1480. doi:10.1136/bmj.318.7196.1471. PMC 1115846. PMID 10346778.
  3. https://www.independent.co.uk/life-style/health-and-families/the-french-paradox-turned-out-to-be-an-illusion-but-it-led-to-some-interesting-research-a7839086.html The Independent: The 'French paradox' turned out to be an illusion, but it led to some interesting research
  4. George Riley Kernodle (1 December 1989). Theatre In History. University of Arkansas Press. ISBN 978-1557280121.
  5. B. Simini (2000). "Serge Renaud: from French paradox to Cretan miracle". The Lancet. 355 (9197): 48. doi:10.1016/S0140-6736(05)71990-5. PMID 10615898.
  6. FAOSTAT
  7. FAOSTAT
  8. Tab 3.5 RSD web08: Age-standardised rate of finished consultant episodes for operations for CHD by sex and local authority, all ages and under 75 years, 2001/06, England (Table) Archived 4 February 2009 at the Wayback Machine
  9. Matthew Saltmarsh (7 March 2010). "Nestlé Bringing American-Style Diet Plans to Europe". The New York Times.
  10. Phillips, Rod (2014). Alcohol: A History. University of North Carolina Press Books. p. 517. ISBN 978-1-4696-1760-2.
  12. Couzin, Jennifer (2006). "Women's Health: Study Yields Murky Signals on Low-Fat Diets and Disease". Science. 311 (5762): 755. doi:10.1126/science.311.5762.755. PMID 16469884.
  13. Andrew Mente; Lawrence de Koning; Harry S. Shannon; Sonia S. Anand (2009). "A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease". Arch Intern Med. 169 (7): 659–669. doi:10.1001/archinternmed.2009.38. PMID 19364995.
  14. The French Paradox, CBS News, 23 January 2009
  15. Potentially Universal Mechanism Of Aging Identified, ScienceDaily, 27 November 2008
  16. Goldberg, David M.; Yan, Joseph; Soleas, George J. (2003). "Absorption of three wine-related polyphenols in three different matrices by healthy subjects". Clinical Biochemistry. 36 (1): 79–87. doi:10.1016/S0009-9120(02)00397-1. PMID 12554065.
  17. WHO report on alcohol consumption in the United States of America
  18. WHO report on alcohol consumption in France
  19. Edell, D. (1999). Eat, Drink and be Merry: America's Doctor Tells You Why the Health Experts are Wrong. HarperCollins. pp. 191–192. ISBN 978-0-06-019155-9.
  20. Sahebkar A, Serban C, Ursoniu S, Wong ND, Muntner P, Graham IM, Mikhailidis DP, Rizzo M, Rysz J, Sperling LS, Lip GY, Banach M (2015). "Lack of efficacy of resveratrol on C-reactive protein and selected cardiovascular risk factors--Results from a systematic review and meta-analysis of randomized controlled trials". Int. J. Cardiol. 189: 47–55. doi:10.1016/j.ijcard.2015.04.008. PMID 25885871.
  21. Warner, HR (2015). "NIA's Intervention Testing Program at 10 years of age". Age (Dordrecht, Netherlands). 37 (2): 22. doi:10.1007/s11357-015-9761-5. PMC 4344944. PMID 25726185.
  22. Corder, R.; Mullen, W.; Khan, N. Q.; Marks, S. C.; Wood, E. G.; Carrier, M. J.; Crozier, A. (2006). "Oenology: Red wine procyanidins and vascular health". Nature. 444 (7119): 566. Bibcode:2006Natur.444..566C. doi:10.1038/444566a. PMID 17136085.
  23. Kanner, J.; Gorelik, S; Roman, S; Kohen, R (2012). "Protection by polyphenols of postprandial human plasma and low-density lipoprotein modification: The stomach as a bioreactor". Journal of Agricultural and Food Chemistry. 60 (36): 8790–6. doi:10.1021/jf300193g. PMID 22530973.
  24. "Flavonoids". Linus Pauling Institute, Micronutrient Information Center, Oregon State University. 2015. Retrieved 8 June 2015.
  25. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) (2010). "Scientific Opinion on the substantiation of health claims related to various food(s)/food constituent(s) and protection of cells from premature aging, antioxidant activity, antioxidant content and antioxidant properties, and protection of DNA, proteins and lipids from oxidative damage pursuant to Article 13(1) of Regulation (EC) No 1924/20061". EFSA Journal. 8 (2): 1489. doi:10.2903/j.efsa.2010.1489.
  26. Hu, FB; van Dam RM; Liu S.Hu FB; van Dam RM; Liu S (2001). "Diet and risk of Type II diabetes: the role of types of fat and carbohydrate". Diabetologia. 44 (7): 805–17. doi:10.1007/s001250100547. PMID 11508264.
  27. Clarke, Robert; Lewington, Sarah (2006). "Trans fatty acids and coronary heart disease". BMJ. 333 (7561): 214. doi:10.1136/bmj.333.7561.214. PMC 1523500. PMID 16873835.
  28. "The Eye Digest – Macular degeneration info". University of Illinois Eye & Ear Infirmary, Chicago, IL. 19 May 2009. p. Reviewed = 05/19/2009. Archived from the original on 10 January 2010. Retrieved 2010-01-26.
  29. Paperback best sellers, The New York Times, 9 April 2006
  30. Archive.org
  31. Pollan, Michael In Defense of Food. Penguin Press, 2008.
  32. Hartley, L; Igbinedion, E; Holmes, J; Flowers, N; Thorogood, M; Clarke, A; Stranges, S; Hooper, L; Rees, K (2013). "Increased consumption of fruit and vegetables for the primary prevention of cardiovascular diseases". The Cochrane Database of Systematic Reviews (6): CD009874. doi:10.1002/14651858.CD009874.pub2. PMC 4176664. PMID 23736950.
  33. Newnham, JP; Pennell, CE; Lye, SJ; Rampono, J; Challis, JR (June 2009). "Early life origins of obesity". Obstetrics and Gynecology Clinics of North America. 36 (2): 227–44, xii. doi:10.1016/j.ogc.2009.03.004. PMID 19501311.

Sources

Further reading
  • Michel de Lorgeril; Patricia Salen (2011). Thierry Souccar (ed.). "Prévenir l'infarctus (Preventing heart attack)". Cite journal requires |journal= (help)
  • Michel de Lorgeril (2008). Thierry Souccar (ed.). Cholestérol, mensonges et propagande (Cholestérol, lies and propaganda). ISBN 9782365490481.
  • Michel de Lorgeril (2007). Thierry Souccar (ed.). "Dites à votre médecin que le cholestérol est innocent (Tell your doctor that cholesterol is innocent)". Cite journal requires |journal= (help)
  • Serge Renaud (2004). Odile Jacob (ed.). "Le régime crétois (The Mediterranean Regime)". Cite journal requires |journal= (help)
  • Serge Renaud (1998). Odile Jacob (ed.). "Le régime santé (The Health Plan)". Cite journal requires |journal= (help)
  • George Riley Kernodle (1 December 1989). Theatre In History. University of Arkansas Press. ISBN 978-1557280121.
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