Benefits of Olive Oil Consumption in Type 2 Diabetes Treatment

Summary

Type 2 dia­betes is a global epi­demic with over 300 mil­lion cases, expected to rise to 600 mil­lion by 2030, and research sug­gests that olive oil may have poten­tial ben­e­fits in the treat­ment and man­age­ment of the con­di­tion, includ­ing pro­tect­ing beta-cells against ER stress and improv­ing insulin resis­tance. Studies have shown that a Mediterranean diet enriched with olive oil can improve insulin resis­tance, pro­tect against dia­betic retinopa­thy, and reduce oxida­tive dam­age in indi­vid­u­als with meta­bolic syn­drome, indi­cat­ing olive oil as a promis­ing dietary inter­ven­tion for those with type 2 dia­betes.

Worldwide, type 2 dia­betes is at epi­demic pro­por­tions, with over 300 mil­lion already hav­ing the con­di­tion with an esti­mated rise to 600 mil­lion diag­nosed cases by the year 2030.

Information regard­ing the reduced risk of type 2 dia­betes is fairly com­mon. However, find­ing infor­ma­tion regard­ing treat­ment and man­age­ment for an indi­vid­ual who already has type 2 dia­betes can be some­what more dif­fi­cult.

Therefore, this arti­cle is designed as a mini lit­er­a­ture review of sorts, point­ing to some of the recent research around olive oil and its poten­tial ben­e­fits for use as a dietary inter­ven­tion in type 2 dia­betes treat­ment.

Endoplasmic retic­u­lum stress (ER) is a cen­tral medi­a­tor for pan­cre­atic beta-cell dys­func­tion in type 2 dia­betes. An in vitro study pub­lished in Biochemical and Biophysical Research Communications, 2016, inves­ti­gated if tyrosol, an antiox­i­dant polyphe­no­lic com­pound found in olive oil, could pro­tect against beta-cell dys­func­tion. Researchers found that tyrosol did in fact pro­tect against beta-cell ER stress-induced cell death, sug­gest­ing that it should be explored as a ther­a­peu­tic agent for improv­ing insulin resis­tance and dia­betes.

Insulin resis­tance (IR) is one of the major con­trib­u­tors to dif­fi­cul­ties in main­tain­ing blood glu­cose con­trol. A study pub­lished in Diabetologia, 2015, ran­dom­ized 642 patients to either an olive oil-enriched Mediterranean diet (MedDiet) (35 per­cent fat; 22 per­cent from monoun­sat­u­rated fat) or a low-fat diet (less than 28 per­cent fat) to deter­mine whether dietary inter­ven­tion effects tis­sue-spe­cific IR and beta-cell func­tion. The study found that both diets improved IR, how­ever, liver IR is improved more through a low-fat diet, while mus­cle IR and muscle+liver IR could ben­e­fit more from the olive oil-enriched MedDiet.

At this point there are no clin­i­cal tri­als eval­u­at­ing the role of dietary pat­terns on the inci­dence of microvas­cu­lar com­pli­ca­tions such as retinopa­thy and nephropa­thy in type 2 dia­betes. A post hoc analy­sis of a cohort of type 2 dia­betic par­tic­i­pants, pub­lished in Diabetes Care, 2015, shows that a MedDiet sup­ple­mented with­ex­tra vir­gin olive oil may pro­tect against dia­betic retinopa­thy, a com­pli­ca­tion lead­ing to blind­ness, but not nephropa­thy.

According to a detailed review of 2824 stud­ies, pub­lished in the British Medical Journal, 2015, con­sum­ing a MedDiet is asso­ci­ated with bet­ter gly­caemic con­trol and car­dio­vas­cu­lar risk fac­tors, even com­pared to a lower-fat diet.

Clinical con­di­tions asso­ci­ated with obe­sity, such as type 2 dia­betes, show improve­ments with daily intake of con­ju­gated linoleic acid (CLA) or extra vir­gin olive oil. A study on mice pub­lished in The Journal of Nutritional Biochemistry, 2015, inves­ti­gated whether dietary sup­ple­men­ta­tion of CLA orex­tra vir­gin olive oil could change body metab­o­lism asso­ci­ated with mito­chon­dr­ial ener­get­ics. The study found that while­ex­tra vir­gin olive oil alone did not change any meta­bolic para­me­ter, com­bined with CLA it pro­tects against IR and liver enlarge­ment, while the CLA improves mito­chon­dr­ial action and body metab­o­lism.

According to research pub­lished in Biochimia et Biophysica Acta, 2014, oleic acid, a major bio­log­i­cal com­po­nent in olive oil, is a pri­mary com­po­nent of mem­brane lipids and helps to reg­u­late mem­brane struc­tures by hav­ing the abil­ity to incor­po­rate into phos­pho­lipids, which has var­i­ous advan­tages to cell com­po­si­tion. It is also thought that mem­branes rich in oleic acid have increased flex­i­bil­ity to pro­mote GLUT4 glu­cose trans­port into cells and help reverse sat­u­rated fatty acid-induced IR.

An 8.1‑year fol­low-up of a 4‑year ran­dom­ized trial, pub­lished in Diabetes Care, 2014, eval­u­ated the long-term effects of two dietary inter­ven­tions on 215 over­weight par­tic­i­pants with newly diag­nosed type 2 dia­betes. A low-car­bo­hy­drate MedDiet (LCMD) (less than 50 per­cent car­bo­hy­drate) was com­pared to a typ­i­cal low-fat diet (less than 30 per­cent fat) on the need for anti­hy­per­glycemic med­ica­tion. The LCMD resulted in a sig­nif­i­cantly greater reduc­tion in HBA1c lev­els, a higher rate of dia­betes remis­sion, and a 2‑year dif­fer­ence in the need for dia­betic med­ica­tion com­pared to the low-fat diet.

Dyslipidemia is a con­se­quence of meta­bolic syn­drome and is com­mon in indi­vid­u­als with type 2 dia­betes. An in vitro study on rat liver cells, pub­lished in The Journal of Nutritional Biochemistry, 2014, showed that hydrox­y­ty­rosol, tyrosol, and oleu­ropein, phe­nols present in EVOO, inhibit fatty acid and triglyc­eride syn­the­sis, sup­port­ing other research that shows olive oil exerts pos­i­tive ben­e­fits on cho­les­terol lev­els.

A study pub­lished in Clinical Nutrition, 2013, ran­dom­ized 110 patients with meta­bolic syn­drome to either MedDiet+EVOO; MedDiet+nuts; or low-fat diet to inves­ti­gate the effect of the MedDiet on sys­temic oxida­tive bio­mark­ers. The results showed that com­pared to a low-fat diet, the MedDiet reduced oxida­tive dam­age to lipids and DNA in indi­vid­u­als with meta­bolic syn­drome.

This is not an exhaus­tive list of the research exam­in­ing the ben­e­fits of olive oil in the treat­ment and man­age­ment of type 2 dia­betes, just a brief review of recent evi­dence. However, the research does appear to show that olive oil, it’s phe­nols, polyphe­nols, and prop­er­ties can help improve some of the key mech­a­nisms involved in the devel­op­ment and pro­gres­sion of type 2 dia­betes, being a suit­able rec­om­men­da­tion as part of a healthy dietary inter­ven­tion.