A new study has found a link between polyphenol-rich olive leaf extract and decreased risk of cardiovascular disease. Polyphenols are micronutrients that act as antioxidants, and olive plant leaves contain an abundance of them in the form of oleuropein and hydroxytyrosol (HT). Published in the British Journal of Nutrition, the double-blind study randomly divided 18 healthy men and women into two groups: one group was given a single dose of an olive leaf extract (which contained 51 mg oleuropein and 10 mg HT) while the other group was given a single dose of a placebo. After a four-week wash out, the two groups swapped treatments (i.e., those who took the olive leaf extract previously were given a placebo and vice versa). Researchers then measured the participants’ vascular function and tested their blood and urine after dosage and for a 24 hour period. Here is what they found:

• Arterial stiffness and IL-8 production (a marker of inflammation) were significantly reduced after taking the olive leaf extract compared with placebo.
• Breakdown products of olive leaf polyphenols were seen in urine tests done after taking the olive leaf extract, suggesting that higher circulating levels of these polyphenols or their metabolites could have been responsible for the positive effects on blood vessel functioning and inflammatory marker levels.

This study is the first to reproduce these results in humans, and supports previous research which has also linked olive leaf extract to a reduced risk of cardiovascular disease. A larger and longer similar study is expected to be published in 2015.

Source: British Journal of Nutrition