Changing the Mediterranean diet: effects on blood lipids.

A study was carried out on 48 healthy middle-age men and women habitually subsisting on a "Mediterranean type" diet in a rural area of southern Italy. Their freely chosen natural diet was modified for a period of 42 days by partially substituting animal fats for olive oil. Currently available foods were used, and the subjects maintained their habitual lifestyle. Dietary fat content changed from 33 to 37% of total energy and the polyunsaturated to saturated fatty acid ratio changed from 0.48 to 0.22. The base-line serum total cholesterol of men increased during the dietary intervention period from 214 +/- 30 mg/dl (mean and SD) to 245 +/- 33 mg (+15%). Low-density lipoprotein cholesterol increased 19%, while high-density lipoprotein cholesterol remained unmodified. Women, while exhibiting a similar trend in serum total cholesterol (+16%), showed also a 19% increase in their high-density lipoprotein cholesterol (p less than 0.001). Apoprotein B increased in parallel with low-density lipoprotein cholesterol in both sexes. The results of the study confirm the impact of the dietary factor on blood lipids. They also provide additional evidence on the response of high-density lipoprotein cholesterol to diet in free-living populations.