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Olive oil blunts postprandial glucose response to high glycemic index meals

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February 17, 2016

In patients with type 1 diabetes, augmenting a high glycemic index meal with extra-virgin olive oil diminished the early postmeal glucose response, according to recent study findings.

Angela A. Rivellese, MD, associate professor of internal medicine at Federico II University in Naples, Italy, and colleagues evaluated 13 patients (eight women) with type 1 diabetes on insulin pump therapy who were recruited from the diabetes care unit of the Federico II University teaching hospital. Participants were allocated by coin toss to a 1-week period of consuming either three meals with high glycemic index or three meals with low glycemic index, followed by a crossover to the alternate regimen for an additional week. The meals in each series were comparable in terms of total carbohydrate content, but differed in amount and type of fat, including the following meal types: low fat; high in saturated fat (butter); or high in monounsaturated fat (extra-virgin olive oil). During the two protocols, participants underwent continuous glucose monitoring, wearing sensors 7 days per week. Six-hour postprandial blood glucose was assessed.

The researchers found significant differences in postprandial blood glucose between high and low glycemic index meals. The difference was especially pronounced in the first 3 hours of postprandial response, with the blood glucose 0- to 3-hour incremental area under the curve (AUC) lower after all low glycemic index meals combined vs. all high glycemic index meals combined (112 mmol/L x 180 min vs. 337 mmol/L x 180 min; P = .006).

Within the high glycemic index meal protocol, a steep elevation in blood glucose levels was seen in the early postprandial period with butter or low fat; in contrast, the meal with extra-virgin olive oil demonstrated a blunted response. Blood glucose levels returned to fasting levels in the 3 to 6 hours after the low-fat meal, whereas they remained elevated during the entire postprandial period with the butter meal. There was a high statistical difference in the pattern of postprandial blood glucose responses after the meals (P < .0001). A pronounced difference was observed in the 0- to 3-hour incremental AUC between extra-virgin olive oil (mean, 198 mmol/L x 180 min) and low fat (416 mmol/L x 180 min) or butter (398 mmol/L x 180 min; P < .05). Among the three low glycemic index meals, no significant disparities in postprandial blood glucose were seen.

“Our study demonstrates that the addition of [extra-virgin olive oil] to [a high glycemic index] meal attenuates the early postprandial glucose response observed when this meal is consumed with either low fat or butter. Moreover, [low glycemic index] foods determine a blunted early postprandial response and a late rise of blood glucose levels, independently of type and quantity of fat added,” the researchers wrote. “Therefore, an optimal prandial insulin administration in type 1 diabetes would require considering the quality of both carbohydrate foods and fat.” – by Jennifer Byrne

Disclosure: The researchers report no relevant financial disclosures.

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