French paradox

The French paradox refers to the observation that people in France suffer relatively low incidence of coronary heart disease, despite having a diet relatively rich in saturated fats. The phenomenon was first noted by Irish physician Samuel Black in 1819.

When news of this paradox was aired in the United States in 60 Minutes in 1991, the consumption of red wine increased 44% and some wineries began lobbying for the right to label their products as "health food"

However, a growing number of French 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.

Overview
According to FAO data, 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), 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. However, according to data from the British Heart foundation, in 1999, rates of death from coronary heart disease among males aged 35–74 years was 230 per 100,000 people in the US 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 theory was expounded in a 60 Minutes broadcast in 1991. The program catalysed a large increase in North American demand for red wines from around the world. It is believed that one of the ingredients in red wine potentially related to this effect is resveratrol.

Resveratrol and other grape compounds have been shown to fight cancer, heart disease, degenerative nerve disease and other ailments. Red wine typically has health benefits not found in white wine (with some exceptions) because many of these compounds are found in the skins of the grapes and only red wine is fermented with the skins.

The first scientific study of the relationship between alcohol consumption and atherosclerosis was published in the Journal of the American Medical Association in 1904. The first epidemiological study to report that moderate drinkers exhibit greater longevity than abstainers or heavy drinkers was published in 1926 by Raymond Pearl. Hundreds of studies have followed in recent decades.

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. It appears that the most important active ingredient is the alcohol itself.

The major cause of death in the U.S. is heart disease and most research finds that moderate consumption]] of alcohol reduces coronary fatalities by up to 40% to 60%. The mechanisms by which alcohol reduces coronary events are becoming increasingly documented. Research has found that moderate alcohol consumption improves blood lipid profile (increases HDL and reduces LDL), decreases thrombosis (reduces platelet aggregation, reduces fibrinogen and increases fibrinolysis), reduces blood pressure, increases coronary blood flow, and reduces blood insulin levels.

Procyanidins
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. 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." "...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."

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. Conversely, they consume very little animal fat. Dairy fats have been shown to be heathier than other forms of fats, 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 digest food already consumed before more food is added.
 * Lower sugar intake — American low-fat and no-fat foods often contain high sugar. French diets avoid these products preferring full-fat versions without added sugar.
 * Low incidence of snacks between meals.
 * Complete 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 in American grocery stores.

Dr. Clower tends to downplay 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. And while a higher percentage of French people smoke, it's not greatly higher than the US (35% in France vs. 25% in US) and is unlikely to account for the weight difference between cultures.

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. 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.

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 similar western countries. While this doesn’t necessarily account for the paradox it means the discrepancies between other countries are lower than what was at first thought.

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. Law and Waild (1999) used Criqui and Ringel’s (1994) study of alcohol and diet in explaining the French paradox. On analysing past and recent data of serum cholesterol and fat consumption (when earlier data was 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.

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.
 * Cabot, R. C. The relation of alcohol to atherioscleroisis. Journal of the American Medical Association, 1904, 43, 774-775.
 * Ellison, R. C. Does Moderate Alcohol Consumption Prolong Life? NY: American Council on Science and Health, 1993.
 * Hennekens, C. H. Alcohol and Risk of Coronary Events. In: National Institute on Alcohol Abuse and Alcoholism. Alcohol and the Cardiovascular System. Washington, DC: United States Department of Health and Human Services, 1996.
 * 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.
 * Pearl, Raymond. Alcohol and Longevity. NY: Knopf, 1926.
 * 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.