Nurses who consumed more than one tablespoon or eight grams of total olive oil had a lower risk of developing type 2 diabetes compared to those whose diet did not include any olive oil at all.

Scientific evi­dence sug­gests that the kind of dietary fat con­sumed affects risk of devel­op­ing type 2 dia­betes. Specifically, diets high in sat­u­rated fats increase the risk of type 2 dia­betes, while replac­ing sat­u­rated fats with unsat­u­rated fats is asso­ci­ated with a lower risk. Results of the PREDIMED study found that a Mediterranean diet sup­ple­mented with extra vir­gin olive oil was more effec­tive in reduc­ing dia­betes risk than a diet low in total fat intake.

While stud­ies con­ducted in the Mediterranean region show an asso­ci­a­tion between olive oil intake and low­ered risk of type 2 dia­betes, no such study has been con­ducted in the US, where olive oil con­sump­tion is much lower than in Mediterranean coun­tries, accord­ing to a recent arti­cle pub­lished in the August 2015 issue of the American Journal of Clinical Nutrition.

For the study, researchers from Harvard Medical School and Brigham and Women’s Hospital in the US and two Spanish uni­ver­si­ties — Rovira I Virgili University and University of Navarra — tested the hypoth­e­sis that higher olive oil con­sump­tion leads to a lower risk of devel­op­ing dia­betes in the US.

Investigators fol­lowed 59,930 nurses, aged 37 to 65 years from the NHS group and 85,157 nurses, aged 26 to 45 years from the NHS II group, two large cohort Nurses Health Studies (NHS) that spanned a period of 22 years. Food fre­quency ques­tion­naires, com­pleted by the nurses every four years, assessed dietary food intake of more than 130 foods includ­ing olive oil con­sump­tion in two cat­e­gories — olive oil as a salad dress­ing and that added to food or bread.

At the end of the study, the authors iden­ti­fied 5,738 cases of dia­betes in the NHS group and 3914 cases in NHS II group.

Results show that nurses who con­sumed more than one table­spoon or eight grams of total olive oil had a lower risk of devel­op­ing type 2 dia­betes com­pared to those whose diet did not include any olive oil at all. Additionally, for every eight-gram increase in olive oil con­sump­tion, their risk of devel­op­ing type 2 dia­betes decreased by six per­cent. In this study, the high­est daily olive oil intake was 13.25 grams in the NHS group and 20 grams in the NHS II group.

Further analy­sis showed that sub­jects who con­sumed health­ier diets along with higher amounts of olive oil reduced their risk of devel­op­ing type 2 dia­betes com­pared to their peers who con­sumed high amounts of olive oil but a less healthy diet.

Interestingly, women who con­sumed olive oil were more likely to have Mediterranean or Southern European roots. They ate more fish, whole grains, fruits, veg­eta­bles, and nut; exer­cised more and had a lower BMI com­pared to women who never con­sumed olive oil.

Furthermore, women of Mediterranean/​Southern European lin­eage who con­sumed high amounts of olive oil had a 23 per­cent lower risk of devel­op­ing type 2 dia­betes com­pared to sub­jects who con­sumed high intake of olive oil but did not have Mediterranean/​Southern European ances­try. This could be because sub­jects from Mediterranean fam­i­lies prob­a­bly con­sumed olive oil as part of their tra­di­tional diet for a longer time than those from non-Mediterranean fam­i­lies.

Another inter­est­ing find­ing of the study was that olive oil added to bread or food showed a stronger asso­ci­a­tion in low­er­ing risk of type 2 dia­betes com­pared to olive oil salad dress­ing. A pos­si­ble expla­na­tion — olive oil added to food or bread is more likely to be extra vir­gin olive oil while that present in salad dress­ings is less often based on extra vir­gin olive oil.

In an addi­tional aspect of the study, the authors found that hypo­thet­i­cally replac­ing one table­spoon of mar­garine with one table­spoon of olive oil low­ered risk of type 2 dia­betes by five per­cent, while risk reduced by eight per­cent when replac­ing but­ter and by 15 per­cent when replac­ing may­on­naise. These results, although hypo­thet­i­cal, indi­cate that use of olive oil over other sources of fat may lower risk of devel­op­ing type 2 dia­betes.

While this study pro­vides evi­dence that higher intakes of olive oil lower risk of type 2 dia­betes in US women, addi­tional stud­ies are needed to estab­lish the role of olive oil in low­er­ing risk of dia­betes. Diabetes is preva­lent in 29 mil­lion or 9.3 per­cent of the US pop­u­la­tion and can lead to seri­ous health prob­lems such as heart dis­ease, stroke, blind­ness and kid­ney fail­ure accord­ing to the 2014 National Diabetes Statistics Report. It is also a seri­ous health prob­lem world­wide: dia­betes inci­dence in adults was 8.3 per­cent in 2013 and is expected to rise to about 10 per­cent by 2035.

According to the authors, “Our results of a 10 per­cent lower risk of devel­op­ing dia­betes with higher olive oil intake lend addi­tional sup­port to olive oil’s poten­tial role in dia­betes pre­ven­tion, even in pop­u­la­tions out­side the Mediterranean.”



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