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Study strengthens olive leaf extract's heart health benefits
Extracts from olive leaf may reduce LDL cholesterol to the same extent as atorvastatin, report researchers from Celal Bayar University in Turkey.
Lab rats were fed a high fat diet, which was found to increase total cholesterol and LDL-cholesterol levels, but doses of olive leaf extract and atorvastatin significantly blunted those increases, according to findings published in Phytotherapy Research.
The benefits of the olive leaf extract were linked to the oleuropein content, which has been previously reported to be an antioxidant, anti-inflammatory, and anti-atherogenic compound.
"Olive foods such as olive oil and olive leaf are major components of [the Mediterranean] diet, and oleuropein is responsible for most of their beneficial effects," wrote the researchers. "Olive leaf also contains siginificant amounts of oleuropein which is traditionally removed from olives because of its biting taste.
"Our findings demonstrated a potential and beneficial effect of olive leaf extract in reducing of the atherogenic index. In this study, atherogenic index, defined as the ratio of non-HDL to HDL was significantly decreased in high cholesterol diet fed rats treated with olive leaf extract."
Study details
The Turkey-based researchers examined the effects of the olive leaf extract (50 or 100 mg/kg/day), atorvastatin (20 mg/kg of body weight daily) or no intervention in lab rats fed a high cholesterol diet for eight weeks.
Results showed that rats eating the high cholesterol diet showed a remarkable increase in the atherogenic index (from about 0.68 to 4.86), but both doses of the olive leaf extract reduced the atherogenic index, with final values of 2.10 and 3.29 for the 50 and 100 mg/kg/day doses, respectively. The atherogenic index of the atorvastatin group was 2.60.
On the other hand, no significant differences were observed between the groups for the activity of the antioxidant enzymes, superoxide dismutase and glutathione peroxidase, and no significant differences were observed between the groups for the degree of lipid peroxidation, as measured by malondialdehyde levels.
In addition, no significant differences between the groups were observed for endothelial health of the animals, which may be due to the short intervention time of their study, explained the researchers.
"The results of this study indicated that olive leaf extract supplementation decreased serum total cholesterol and LDL-cholesterol in high cholesterol diet fed rats while HDL-cholesterol and triglyceride levels remained unchanged," they wrote. "As alternative to statins and other drugs, olive leaf extract supple-mentation may help in improving the lipid profile in hypercholesterolemia."
Source: Phytotherapy Research
Published online ahead of print, doi: 10.1002/ptr.5445
"Olive Leaf Extract Improves the Atherogenic Lipid Profile in Rats Fed a High Cholesterol Diet"
Authors: E. Olmez, et al.