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French paradox

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The French paradox is the observation that the French suffer a relatively low incidence of coronary heart disease, despite having a diet relatively rich in saturated fats.[1] The term French paradox was coined by Dr. Serge Renaud, a scientist from Bordeaux University in France in 1992.[2]

When a description of this paradox was aired in the United States on 60 Minutes in 1991 with the proposal that red wine decreases the incidence of cardiac diseases, the consumption of red wine increased 44% and some wineries began lobbying for the right to label their products "health food".[3]

The authors of a 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,[4] and statistics collected by the WHO from 1990–2000 show that the incidence of heart disease in France may have been underestimated, and may in fact be similar to that of neighboring countries.[3]. In 2008, a study found that high doses of resveratrol (a constituent of red wine) mimicked some of the benefits of caloric restriction (including reduced effects of aging) in mice.[5]

Overview

According to FAO data,[6] the average French person consumed 108 grams per day of fat from animal sources in 2002 while the average American consumed only 72. 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.

Wine

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.[3] 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. [9]

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 (8.6 litres per year)[10] and French consumption (11.4 litres per year) is only 2.8 litres per year.[11] French consumption is lower than Luxembourg (15.6 litres), the Czech Republic (13.0 litres), Hungary (13.6 litres), Germany (12.0 litres), and Croatia (12.3 litres) where no similar paradoxes are observed.

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.[12]

Resveratrol

Main article: Resveratrol

Wines, particularly red wines, are a source of low levels of resveratrol. High doses of reseveratol have been linked to longevity and cancer prevention in other species.[13]

Procyanidins and polyphenols

Although research continues on resveratrol, the concentration in wine seems too low to account for the French paradox. Professor Roger Corder and team have identified a particular group of polyphenols, known as oligomeric procyanidins, which they believe offer the greatest degree of protection to human blood-vessel cells. Tests with 165 wines showed that these are found in greatest concentration in European red wines from certain areas, which correlates with longevity in those regions.[14] The highest procyanidins are found in wines from the Tannat grape, grown in the Gers area of southwest France.

Unlike resveratrol, procyanidins are present in wine in quantities that seem to be high enough to be significant: "Procyanidins are the most abundant flavonoid polyphenols in red wine – up to one gram per litre is found in some traditional style red wines."[15] "… clinical trials of grape seed extract, which have shown that 200–300 mg per day will lower blood pressure. Two small glasses (125 ml glass) of a procyanidin-rich red wine, such as a Madiran wine from southwest France, would provide this amount." However several times this amount of procyanidin can be consumed by eating an apple.[16]

Other research suggests that polyphenols in wine reduce the absorption of malondialdehyde, which is implicated in arteriosclerosis, cancer, diabetes and other diseases.[17][18]

French diet comparisons

In his book, The Fat Fallacy, Dr. 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 (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 pre-prepared foods which can typically make up a large percentage of the foods found in American grocery stores.

Clower tends to play down the common beliefs that wine consumption and smoking are greatly responsible for the French paradox. The French diet tends to cause Americans to lose weight while visiting even if they are not wine drinkers. 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 #1 bestseller French Women Don't Get Fat,[19] 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 US are virtually identical [20]. Guiliano explains the key factors to the French woman's ability to stay slim as:

  • Smaller portion sizes
  • 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[21]

Climate and Lifestyle

Geographical and lifestyle factors may also go some way towards explaining the paradox. France from the Centrale region southwards has a warm Mediterranean climate. The effects of good weather will encourage outdoor leisure pursuits (often physical) to a greater extent than predominantly inclement weather.[1] Ferrieres cites a study by Scarabin et al. (2003) comparing activity and health statistics in men from Toulouse and Belfast that shows although the total levels of physical activity are similar for both cities, French men performed more physical activity in their leisure time, possibly accounting for decreased incidence of CHD compared to Northern Ireland.

In addition to the beneficial cardiovascular effects of such exercise, being outdoors also exposes the body to the sun. Exposure of the skin to sunlight leads to higher levels of vitamin D, which has been shown to reduce the risk of corony artery calcification.[22]

Under-certification

Another possible explanation for the paradox is under-certification of coronary heart disease related deaths by French physicians. However, when the possible bias was accounted for and corrected, CHD mortality rates were still significantly lower than other similar western countries.[1][23]

Time lag hypothesis

The time lag hypothesis states that if there was a delay in serum cholesterol concentrations increasing and a subsequent increase in ischaemic heart disease mortality, then the rate of current disease mortality must relate to past levels of serum cholesterol and fat consumption much more than current levels.[24] Law and Wald (1999) used Criqui and Ringel’s (1994) study of alcohol and diet in explaining the French paradox. On analyzing past and recent data of serum cholesterol and fat consumption (when earlier data were entered and adjustment was made for under-certification of CHD), they found that France fits in with the trend of other countries with similar cholesterol and fat intake. Also, recent data prediction for CHD mortality rates showed that France was similar to other countries.

Hydrogenated and trans fats

In the book, Cholesterol and The French Paradox, there is another explanation given by clinical nutritionist Frank Cooper.[25] He argues that the French paradox is due to the lack of hydrogenated and trans fats in the French diet. The French diet is based on natural ‘saturated fats’ such as cheese and cream that the human body finds easy to metabolise. But the American diet includes larger amounts of artificial ‘saturated fats’ made from a process of hydrogenating vegetable oils. These hydrogenated vegetable oils have an unusual molecular structure that the human body finds difficult to metabolise. In addition, these hydrogenated fats include small quantities of trans fats that have a dangerous molecular structure that the human body sees as foreign, and cause damage to the structure of the cells in the body. Trans fats are well known to cause diabetes [26] , heart disease [27] and macular eye disease [28].

Whole diet

In the 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.[29]

Validity questioned

Nevertheless, the medical causes of the French paradox are still not entirely clear and research continues. Meanwhile, some researchers have questioned altogether the validity of this paradox, although it is clear that dietary habits, particularly those that involve saturated fat, act as significant determinants of coronary heart disease. This view has recently received broad support through 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 does indeed affect heart disease risk, though the consumption of trans fat grossly exceeds the risk posed by saturated fat intake.[30]

See also

References

  1. ^ a b c Ferrieres, J. (2004). The French Paradox; Lessons for other countries [Electronic version]. Heart, 90, 107–111.
  2. ^ Serge Renaud: from French paradox to Cretan miracle. The Lancet, Volume 355 , Issue 9197 , Pages 48 - 48 B . Simini
  3. ^ a b c "Drink Like the French, Die Like the French"
  4. ^ [1]
  5. ^ Barger J. L. et al. A Low Dose of Dietary Resveratrol Partially Mimics Caloric Restriction and Retards Aging Parameters in Mice
  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)
  9. ^ http://www.sciencedaily.com/releases/2008/11/081126122203.htm
  10. ^ WHO Core Health Indicators: United States of America
  11. ^ WHO Core Health Indicators: France
  12. ^ Edell, D. Eat, Drink and be Merry: America’s Doctor Tells You Why the Health Experts are Wrong. NY: HarperCollins, 1999, pp. 191–192
  13. ^ "Scientists Identify a Potentially Universal Mechanism of Aging"
  14. ^ Procyanidins May Be the Factor Behind Red Wine's Cardioprotective Effect, from Nature vol. 444, p. 566; 30 November 2006
  15. ^ Real Link Between Drinking Red Wine and Increased Longevity – Food and Health
  16. ^ Hammerstone J. F. et al. Journal of Nutrition. 2000;130:2086S–2092S
  17. ^ Red wine exercises its benefits before it enters the bloodstream
  18. ^ The Stomach as a “Bioreactor”: When Red Meat Meets Red Wine
  19. ^ http://query.nytimes.com/gst/fullpage.html?res=9405E3D71530F93AA35757C0A9609C8B63
  20. ^ http://www.mireilleguiliano.com/qanda.htm
  21. ^ http://www.mireilleguiliano.com/q&a.htm
  22. ^ de Boer IH, Kestenbaum B, Shoben AB, Michos ED, Sarnak MJ, Siscovick DS (2009 May 14.). "25-Hydroxyvitamin D Levels Inversely Associate with Risk for Developing Coronary Artery Calcification". J Am Soc Nephrol. PMID 11493580. {{cite journal}}: Check date values in: |date= (help)CS1 maint: multiple names: authors list (link)
  23. ^ The French Paradox - The obsessing preoccupation about death certificates
  24. ^ (Law & Wald, 1999)
  25. ^ Cooper, Frank A. Cholesterol and The French Paradox. Queensland Australia: Zeus Publications, 2006, pp 152–162.
  26. ^ Hu, FB (2001 Jul;). "Diet and risk of Type II diabetes: the role of types of fat and carbohydrate". Diabetologia. 2001 Jul;44(7):805-17. Diabetologia. PMID 11508264. Retrieved 2010-01-26. {{cite web}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: extra punctuation (link)
  27. ^ Clarke, Robert (2006 July 29). "Trans fatty acids and coronary heart disease". BMJ. 2006 July 29; 333(7561): 214. BMJ Publishing Group Ltd. doi:10.1136/bmj.333.7561.214. Retrieved 2010-01-26. {{cite web}}: Check |doi= value (help); Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  28. ^ "The Eye Digest - Macular degeneration info". University of Illinois Eye & Ear Infirmary, Chicago, IL. 05/19/2009. Retrieved 2010-01-26. {{cite web}}: Check date values in: |date= (help); Unknown parameter |Page Reviewed= ignored (help)
  29. ^ Pollan, Michael In Defense of Food. Penguin Press, 2008.
  30. ^ Couzin, Jennifer Women's Health: Study Yields Murky Signals on Low-Fat Diets and Disease Science 10 February 2006: Vol. 311. no. 5762, p. 755 DOI: 10.1126/science.311.5762.755

Other sources

  • Abdulla, A. & Badaway, B. (2001). Moderate alcohol consumption as a cardiovascular risk factor: the role of homocycteine and the need to re-explain the ‘French Paradox’ [Electronic version]. Alcohol & Alcoholism, 36, 185–188.
  • Law, M. & Wald, N. (1999).Why heart disease mortality is low in France: the time lag explanation.[Electronic version]. British Medical Journal, 318, 1471–1480.
  • Perdue, W. Lewis, et al. the French Paradox and Beyond. Sonoma, CA: Renaissance, 1993.
  • Rozin, P., Kabnick, K., Pete, E., Fischler, C., & Shields, C. (2003). The ecology of eating: Part of the French paradox results from lower food intake in French than Americans, because of smaller portion sizes. Psychological Science, 14, 450–454.

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