Olive Oil Polyphenols Benefit Insulin Sensitivity in Older Men

by | Nov 22, 2013 | Diabetes, Polyphenols

Written by Greg Arnold, DC, CSCS. Supplementing with olive oil polyphenols for 12 weeks significantly improved insulin sensitivity by 6.6% in overweight middle-aged men at risk of developing metabolic syndrome.

The healthful benefits of olive oil have a lot to do with antioxidants called polyphenols, which help maintain healthy levels of cholesterol (1), maintain bone health (2), and decrease mortality (3).

Now a new study (4) suggests olive oil polyphenols may also benefit insulin sensitivity and reduce the risk of type 2 diabetes, which currently affects 25.8 million Americans and costs our healthcare system $176 billion per year (5).

In the randomized, double-blind study, 46 men with an average age of 46.5 years and an average Body Mass Index (BMI) of 28.062 kg/m2 were given either olive oil polyphenols (51.1 mg oleuropein, 9.7 mg hydroxytyrosol) or placebo per day for 12 weeks. After this period, they stopped their programs for 6 weeks (called a “washout period”) and switched supplement regimens. Before and after the study, subjects provided blood samples and had their blood pressure taken.

After 12 weeks of supplementation, those in the olive oil group saw a 6.6% improvement in insulin sensitivity (5.12 to 5.46 on the Matsuda Index (an index designed to evaluate insulin sensitivity based on the oral glucose tolerance test, with higher readings indicating improved insulin sensitivity (6) compared to a 8.2% decrease in the placebo group (5.12 to 4.73, p = 0.24). The olive oil group also saw a 5.4% improvement in the responsiveness of beta cells, the cells in the pancreas that release insulin (5.17 to 5.45 on the Matsuda Index), compared to a 17.7% decrease in the placebo group (5.17 to 4.26, p = 0.013).

Finally, there were significant increases in 2 proteins related to insulin for those in the olive oil group. Specifically, olive supplementation users had 19.5% higher levels of the protein IGFBP-1 compared to the placebo group (1.59 vs. 1.33 nanograms/millilitre, p = 0.024) and 12.5% higher levels of the protein IGFBP-2 compared to the placebo group (162 vs. 144 ng/mL, p = 0.015). Increases in both proteins help decrease the risk of type 2 diabetes (7).

There were however, no effects on interleukin-8, TNF-a, ultra-sensitive CRP, lipid profile, ambulatory blood pressure, body composition, carotid intima-media thickness, or liver function.

For the researchers, “Supplementation with olive leaf polyphenols for 12 weeks significantly improved insulin sensitivity and pancreatic beta-cell secretory capacity in overweight middle-aged men at risk of developing the  metabolic syndrome.

Source: de Bock, Martin, Jose GB Derraik, Christine M. Brennan, Janene B. Biggs, Philip E. Morgan, Steven C. Hodgkinson, Paul L. Hofman, and Wayne S. Cutfield. “Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial.” PloS one 8, no. 3 (2013): e57622.

© 2013 de Bock et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Click here to read the full text study.

Posted November 12, 2013.

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

References:

  1. de la Torre-Carbot K.  Elevated Circulating LDL Phenol Levels in Men Who Consumed Virgin Rather Than Refined Olive Oil Are Associated with Less Oxidation of Plasma LDL.  Jou Nutr 2010; 140 (3): 501-508.
  2. Santiago-Mora R. Oleuropein enhances osteoblastogenesis and inhibits adipogenesis: the effect on differentiation in stem cells derived from bone marrow. Osteop Int 2010. DOI: 10.1007/s00198-010-1270-xb.
  3. Buckland G. Olive oil intake and mortality within the Spanish population (EPIC-Spain). Am J Clin Nutr 2012;96:142–9.
  4. De Bock M.  Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial.  PLoS One. 2013;8(3):e57622. doi: 10.1371/journal.pone.0057622. Epub 2013 Mar 13.
  5. “2011 National Diabetes Fact Sheet” posted on the CDC website.
  6. “Matsuda Index” posted on the web page of Professor Masa Matsuda.
  7. Livingstone C.  Insulin-Like Growth Factor-Related Proteins and Diabetic Complications.  British Journal of Diabetes and Vascular Disease. 2003;3(5)