Extra-virgin is the oil of choice to protect against LDL oxidation
Many Mediterranean populations that consume large amounts of
olive oil as part of their diets enjoy a decreased incidence of
coronary heart disease. The presence of monounsaturated fatty
acids and antioxidants in the diet is directly related to the
ability of low-density lipoprotein (LDL) cholesterol to resist
oxidation. Oxidative damage of LDL cholesterol has been linked
to development of atherosclerosis and other cardiovascular diseases.
The present study was conducted to investigate whether differences
in olive oil processing methods yield any measurable health benefits.
Extra-virgin olive oil (VO) is characterized by very low acidity
and retains the fatty acids and antioxidants present in the olives.
Refined olive oil (RO), by contrast, has the same fatty acid composition,
but because of additional processing lacks the antioxidants present
in VO. In this randomized, crossover study, one group of patients
with peripheral vascular disease received VO to use in cooking
for three months, followed by a three-month washout period, then
received RO for the final three months. The other group consumed
the oils in the opposite order. Intake of alpha-tocopherol, considered
to be a first line of defense against LDL oxidation,
was higher for patients consuming VO. LDL oxidation rate was lower
for patients consuming VO than RO, and during periods when patients
consumed VO, a decreased uptake of oxidized LDL by macrophages
was also noted. Significant differences in the susceptibility
of LDL to oxidation during VO consumption periods led researchers
to conclude that the antioxidant composition of VO appears to
be more protective against LDL oxidation than RO.
Ramirez-Tortosa M, Urbano G, López-Jurado M, et al.
Extra-virgin olive oil increases the resistance of LDL to oxidation
more than refined olive oil in free-living men with peripheral
vascular disease. J Nutr 1999; 129: 2177-2183.