french paradox

The French paradox refers to the fact that people in France suffer relatively low incidence of coronary heart disease, despite their diet being rich in saturated fats. ^[1] The phenomenon was first noted by Irish physician Samuel Black in 1819.

Overview

According to FAO data[1], 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 and most of that as soybean oil[2]. However, according to data from the British Heart foundation [3], 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 [A better reference needed; [4]. The program catalysed a large increase in North American demand for red wines from around the world. It is believed that one of the active ingredients potentially related to this effect in red wine is resveratrol.

Resveratrol and other grape compounds have been positively linked to fighting 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.^{citation needed]} Most researchers now believe that the most important ingredient is the alcohol itself.^{citation needed]} Other researchers believe it is the act of relaxing while drinking that causes longevity.^{citation needed]}

The major cause of death in the U.S. is heart disease and most research finds that moderate consumption of alcohol reduces coronary fatalities in the range of 40% to 60%. The mechanisms by which alcohol reduces coronary events are becoming increasingly documented. Research has found that alcohol 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. In the continuing efforts to resolve this, a study by Professor Roger Corder and team has 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. [5] (R. Corder et al., “Oenology: Red wine procyanidins and vascular health”, Nature vol. 444, p. 566; 30 November 2006)[6] The highest procyanidins are found in wines from the Tannat grape, grown in the Gers area of south-west France. The Madiran appellation requires at least 40 per cent Tannat, but it is not uncommon to find wines that are 100 per cent Tannat.[7]

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 1 gram per litre is found in some traditional style red wines."[8] "...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."

Folic acid

Folic acid, found in spinach, beans, peas and fortified cereals, has been shown to cause rapid reduction in plasma homocystine concentrations. Hyperhomocystinaemia has been attributed to endothelial dysfunction, vascular smooth muscle proliferation and coagulation abnormalities ^[2]. Therefore any reduction should have a positive effect towards cardiac health. This appears to explain some of the paradox

Portion sizes

There is evidence that French portion sizes are lower (Dr. Paul Rozin, UPenn). Lower portion sizes and lower caloric intake could affect heart disease.

Climate and Lifestyle

Geographical factors may also go some way towards explaining the Paradox, and a less stressful lifestyle. France from the Centrale region southwards has a warm ‘Mediterranean’ climate characterised by hot sunny, high pressure systems. The effects of good weather will encourage outdoor leisure pursuits (often physical) to a greater extent than predominantly bad weather. ^[3] cites a study by Scarabin et al. (2003) comparing Toulouse and Belfast that although the total levels of activity are similar French men performed more leisure time physical activity, which could account for decreased incidence of CHD compared to Northern Ireland.

Under-certification

Another possible explanation for the observation of a paradox is the hypothesis of 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 ^[4]. 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 ^[5]. 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.