Adults consuming extra virgin olive oil as part of a Mediterranean-style meal had significantly lower glycemic markers and improved LDL cholesterol levels when compared with those who ate the same meal with either corn oil or no olive oil, according to research in Diabetes & Nutrition.
Francesco Violi, MD, a professor of medicine at Sapienza University of Rome, and colleagues analyzed data from 25 healthy adults (13 women) who were randomly assigned to a Mediterranean-type meal (pasta, chicken breast, salad, bread and an apple; total 894 calories) either with or without 10 g of extra virgin olive oil. In a second study, the participants were randomly assigned a Mediterranean-type meal with either 10 g of extra virgin olive oil or 10 g of corn oil. Researchers took blood samples before and 2 hours after each meal to measure glucose, insulin, DPP-IV protein and activity, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide and lipid profiles. The two study phases took place between January and March 2013, with a 30-day interval between the phases.
The participants who consumed the meal with extra virgin olive oil in the first phase of the study had a significantly lower blood glucose, DPP-IV protein and activity, LDL cholesterol and oxidized LDL in the 2 hours after the meal, as well as higher insulin, GLP-1 and GIP, when compared with participants who ate a meal without extra virgin olive oil (P < .001 for all except GIP; P = .025 for GIP). For example, participants consuming extra virgin olive oil had an average blood glucose of 79.7 mg/dL at baseline and 105.9 mg/dL 2 hours later; those consuming a meal with no extra virgin olive oil had an average blood glucose of 77.8 mg/dL at baseline and 131.4 mg/dL 2 hours later.
Researchers found similar results in the second phase of the study, with an improved levels of glucose (P = .01), insulin (P < .001), GLP1 (P < .001), DPP-IV concentration (P < .001) and activity (P = .001) and LDL cholesterol (P < .05) for participants consuming a Mediterranean-style meal with extra virgin olive oil compared with those who consumed a meal with corn oil. For example, participants consuming extra virgin olive oil had an average blood glucose of 77 mg/dL at baseline and 98.2 mg/dL 2 hours later; those consuming corn oil had an average blood glucose of 79 mg/dL at baseline and 119.7 mg/dL 2 hours later. Differences in HDL cholesterol and triglyceride levels were not significant but trended toward improvement.
Researchers called the improvement of lipid profile after consuming extra virgin olive oil an unexpected finding.
“The positive impact of [extra virgin olive oil] on postprandial LDL cholesterol is more difficult to interpret,” the researchers wrote. “We have [no] data that may help to explain if such a beneficial effect depends on a specific [extra virgin olive oil] interference with cholesterol absorption in the gastrointestinal tract or on a direct activity of extra virgin olive oil on cholesterol biosynthesis. This issue deserves further investigation.” –Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.