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 phenomenon was first noted by Irish physician Samuel Black in 1819. 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]
However, some health researchers question the validity of this paradox. 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 it was 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 a mice study.[4] However, the effects of resveratrol are insufficient to explain the French paradox.
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[edit] Overview
According to FAO data,[5][not in citation given] 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.[6][not in citation given] However, according to data from the British Heart foundation,[7] in 1999, rates of death from coronary heart disease among males aged 35–74 years was 115 per 100,000 people in the US but only 83 per 100,000 in France.
[edit] 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[8] that one of the ingredients in red wine potentially related to this effect is resveratrol.
[edit] Alcohol in wine
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 US annual per capita alcohol consumption (8.6 litres per year)[9] and French consumption (11.4 litres per year) is only 2.5 litres per year.[10] 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.[11]
[edit] Resveratrol
Wines, particularly red wines, are a source of resveratrol which has been linked to longevity and cancer prevention in other species.[12]
[edit] 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.[13] 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."[14] "… 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.[15]
Other research suggests that polyphenols in wine reduce the absorption of malondialdehyde, which is implicated in arteriosclerosis, cancer, diabetes and other diseases.[16][17]
[edit] 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,[citation needed] including whole milk, cheeses, and whole milk yogurt. Conversely, they consume very little animal-flesh fat. Dairy fats have been shown to be healthier than other forms of fats,[citation needed] and they make a person feel full earlier thus encouraging smaller portion sizes.
- 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 for 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. Even without wine consumption, the French diet tends to cause Americans to lose weight while visiting even if they are not wine drinkers.[citation needed] And while a higher percentage of French people smoke, this is not greatly higher than the US (35% in France vs. 25% in US)[citation needed] and is unlikely to account for the weight difference between cultures.
[edit] 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.
[edit] 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]
[edit] 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.[18] 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.
[edit] Hydrogenated and trans fats
In the book, Cholesterol and The French Paradox, there is another explanation given by clinical nutritionist Frank Cooper.[19] He argues that the French paradox is due to the lack of hydrogenated and trans fats in the French diet.[dubious ] 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, heart disease and macular eye disease.[citation needed]
[edit] 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, not 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.[20]
[edit] Validity questioned
Nevertheless, the medical causes of the French paradox are still not entirely clear and research continues while some researchers have questioned altogether the validity of this paradox by dismissing dietary saturated fat as a cause of coronary heart disease, a view that has recently received support when the results of the 20 year-long Nurses' Health Study run by the Harvard School of Public Health suggested, after accumulating over a decade of data on the diet and health of almost 300,000 Americans, that total fat consumed has no relation to heart disease risk, provided it is not trans fat.[21]
[edit] See also
[edit] References
- ^ a b c Ferrieres, J. (2004). The French Paradox; Lessons for other countries [Electronic version]. Heart, 90, 107–111.
- ^ Serge Renaud: from French paradox to Cretan miracle. The Lancet, Volume 355 , Issue 9197 , Pages 48 - 48 B . Simini
- ^ a b c "Drink Like the French, Die Like the French"
- ^ Barger J. L. et al A Low Dose of Dietary Resveratrol Partially Mimics Caloric Restriction and Retards Aging Parameters in Mice
- ^ FAOSTAT
- ^ FAOSTAT
- ^ 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)
- ^ http://www.sciencedaily.com/releases/2008/11/081126122203.htm
- ^ WHO Core Health Indicators: United States of America
- ^ WHO Core Health Indicators: France
- ^ Edell, D. Eat, Drink and be Merry: America’s Doctor Tells You Why the Health Experts are Wrong. NY: HarperCollins, 1999, pp. 191–192
- ^ "Scientists Identify a Potentially Universal Mechanism of Aging"
- ^ Procyanidins May Be the Factor Behind Red Wine's Cardioprotective Effect, from Nature vol. 444, p. 566; 30 November 2006
- ^ Real Link Between Drinking Red Wine and Increased Longevity – Food and Health
- ^ Hammerstone J. F. et al. Journal of Nutrition. 2000;130:2086S–2092S
- ^ Red wine exercises its benefits before it enters the bloodstream
- ^ The Stomach as a “Bioreactor”: When Red Meat Meets Red Wine
- ^ (Law & Wald, 1999)
- ^ Cooper, Frank A. Cholesterol and The French Paradox. Queensland Australia: Zeus Publications, 2006, pp 152–162.
- ^ Pollan, Michael In Defense of Food. Penguin Press, 2008.
- ^ 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
[edit] 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.
