HealthDay News — A Mediterranean diet enriched with extra-virgin olive oil reduced the risk of new-onset diabetes among older adults at high risk for cardiovascular disease, researchers have found.
Compared with a control diet and a Mediterranean diet supplemented with mixed nuts, the olive-oil supplemented Mediterranean diet was associated with a 40% lower likelihood for new-onset diabetes (HR 0.60, 95% CI: 0.43-0.85), Jordi Salas-Salvadó, MD, PhD, from the Instituto de Salud Carlos III in Madrid, and colleagues reported in Annals of Internal Medicine.
For those assigned to a Mediterranean diet supplemented with mixed nuts, the protect benefits were lower (HR 0.82, 95% CI 0.61-1.10).
The Mediterranean diet, which is rich in grains, fruit, fish and vegetables, and light on red meat and poultry, has been tied to a number of health benefits, including reduced risk for stroke, high cholesterol and mortality, as well as protecting small blood vessels in the brain.
Although weight loss is known to reduce the risk for developing diabetes, little is known about how diet changes without calorie restrictions affect diabetes outcomes.
So Salas-Salvadó and colleagues examined the efficacy of Mediterranean diet for primary prevention of diabetes in a cohort of 3,541 patients without diabetes, aged 55 to 80 years and at high cardiovascular risk, for a median follow-up of 4.1 years.
Participants were stratified by region, sex and age and were randomly assigned to receive one of three diets: Mediterranean diet supplemented with extra-virgin olive oil (EVOO), Mediterranean diet supplemented with nuts or a control diet, consisting of low-fat dietary advice. No weight loss or physical activity interventions were included.
Study participants had no cardiovascular disease at baseline, but did have three or more cardiovascular risk factors including current smoking status, hypertension, hypercholesterolemia, low high-density lipoprotein, overweight or obesity and family history of premature cardiovascular disease.
Participants received baseline and quarterly dietary training. Those in the Mediterranean diet groups received supplementary amounts of extra virgin olive oil or nuts, whereas those in the control group received nonfood items such as kitchenware or shopping bags.
During follow-up, 273 participants developed new-onset diabetes, including 80 in the olive-oil group, 92 in the mixed nut group and 101 in the control group. Diet adherence was significantly higher in the Mediterranean diet groups (P<0.01) compared with the control group during the study period.
“A Mediterranean diet enriched with EVOO but without energy restrictions reduced diabetes risk among persons with high cardiovascular risk,” the researchers concluded.
The Fundación Patrimonio Comunal Olivarero and Hojiblanca, the California Walnut Commission, the Borges Mediterranean Group, and Morella Nuts donated the olive oil, walnuts, almonds, and hazelnuts used in the study, respectively.