Epidemiology of Olive Oil and Cardiovascular disease

The importance of dietary patterns in the aetiology of cardiovascular disease is now an established acquisition (Keys, 1975). Over the past 30 years, many epidemiological studies have suggested the existence of a causal link between high dietary intake of saturated fat (and, in part, dietary cholesterol) and serum cholesterol levels (Kato et al., 1973; Keys, 1980; McGee et al., 1984; Kushi et al., 1985; Posner et al., 1991), this last largely considered the major risk factor for coronary heart disease (CHD) (Brown and Goldstein, 1996). It was therefore hypothesized that reduction of plasma cholesterol by dietary means might reduce the risk of coronary heart disease ('The diet-heart' hypothesis). However, only trials that have reproduced Mediterranean or Asian-vegetarian dietary patterns, despite being not particularly low in total and saturated fats, have clearly shown significant reduction in CHD mortality and morbidity, and this has occurred mostly independently of serum cholesterol lowering (Burr et al., 1989; Singh et al., 1992; de Lorgeril et al., 1994). These clinical results encourage the adoption of Mediterranean dietary patterns. However, such promotion also needs to be solidly based on epidemiological findings. Moreover, speaking about 'the' Mediterranean diet, or trying to isolate the 'key factor' responsible for its health benefits is likely to be a difficult if not impossible task, given that there is not such a thing as a single 'Mediterranean diet', and dietary components are in any case quite diverse. This is the reason why it would appear more logical to speak of 'Mediterranean lifestyle behaviours' (Simopoulos and Pavlou, 2001; Ness, 2002). At least until the early 1960s, the traditional diet of countries surrounding the Mediterranean Sea featured a high intake of plant foods, whole-grain cereals,