By Caroline Kanaiza and Marjorie Volege
Coffee is a widely consumed beverage in the world. Coffee contains phenolic compounds which are known to exhibit antioxidant activity, a property believed to decrease the susceptibility of LDL cholesterol to oxidation. The phytochemicals in coffee include caffeic, ferulic and p-coumaric acids. Consumption of coffee increases the total blood antioxidant status in humans.
A number of studies have demonstrated a positive correlation between coffee intake and cardiovascular disease (CVD). Nonetheless, the association of coffee consumption with CVD remains to be contradictory.
Oxidized low density lipo-protein (LDL cholesterol ) is linked with atherosclerosis, a cardiovascular disease risk. It causes formation of lesions and plaques in blood vessels. Susceptibility of low density lipo-protein (LDL) to oxidative modification can be influenced by diet. For example, diet rich in fruits and vegetables can reduce the vulnerability of LDL to oxidation and its disease effects.
A group of Italian researchers at the National Institute for Food and Nutrition, Italy, reported that intake of coffee increases resistance of LDL to oxidation.
Their study was conducted on 10 (5 males and 5 females) healthy moderate coffee drinking volunteers aged between 24 and 35 years. They evaluated the effect of coffee consumption on the reduction/oxidation status of LDL as modulated by the possible incorporation of phenolic acid into LDL. The subjects acted as their own controls and were instructed to avoid coffee and other beverages that are rich in phenolic acids for two days before the experiment. After an overnight (10-12 hours) fast, the subjects drank 200ml of freshly prepared American–style coffee. Low density lipo-protein (LDL) reduction/oxidation analysis was done on venous blood sample taken before and 30 and 60 minutes after coffee consumption.
The researchers found that consumption of 200 ml coffee was associated with increased resistance of LDL to oxidation. The phenolic acids, such as caffeic acid, in coffee are incorporated into the LDL and protected the LDL from oxidation.
Consumption of coffee, however, did not have any benefit in terms of reducing the proportion of LDL in the blood.
The researchers suggested that phenolic acids in coffee, because of their antioxidant properties, can represent one of the positive contributors to the beneficial effects of coffee in CVD prevention and management.
The study was published in the American Journal of Clinical Nutrition (2007, Vol 86: 604-609).
Natella, F., Nardini, M., Belelli, F., and Scaccini, C. Coffee drinking induces incorporation of phenolic acids into LDL and increases the resistance of LDL to ex vivo oxidation in humans. Am J Clin Nutr 2007;86:604 –9.