The acronym PREDIMED stands for PREvención con DIeta MEDiterránea (Prevention with Mediterranean Diet).

PREDIMED was a long-term clinical trial undertaken by 16 research groups in seven communities in Spain over 2003-2011, to examine the effects of the Mediterranean diet on the primary prevention of cardiovascular disease (CVD) in nearly 7400 subjects at high risk of CVD. Participants either followed a Mediterranean Diet supplemented with 30g of nuts a day; a Mediterranean Diet supplemented with 50ml of olive oil a day; or a lower fat control diet.

Some 300 journal papers have been published from this trial so far. Here’s a few outcomes the PREDIMED teams have uncovered.

The importance of polyphenols

Those following the Mediterranean diet plus nuts had higher blood antioxidant enzyme activity [1] and polyphenol antioxidants reduced their markers of inflammation [2]. Total polyphenol intake was inversely related to blood pressure and prevalence of hypertension [3, 4]. Those with the highest polyphenol intake (from fruits, vegetables, nuts, coffee and wine) had the lowest blood pressure [3]. Both Mediterranean diets also caused a significant increase in nitric oxide [4, 5] which helps keep blood vessels elastic reducing blood pressure. Those eating a high intake of polyphenols had a 28% reduced risk of type 2 diabetes [6].

Reduced Mortality and CVD

Of 7,216 older men and women at high risk of cardiovascular disease, enrolled into the PREDIMED study for 4.8 years, those eating a handful of nuts (30g) more than three times a week had a 39% reduction in total mortality compared to non nut consumers (P for trend <0.05) [7]. The Mediterranean diet including either nuts or extra-virgin olive oil also reduced cardiovascular events by around 30% (myocardial infarction, stroke, and death from cardiovascular causes) after 4.8 years follow up [8, 9].

No Weight Gain

After nearly 5 years, those eating the nut supplemented diet did not gain weight but reduced their waist circumference by nearly 1cm, compared to those in the low fat control group [10]. This was despite the fact the energy density of the diets increased [11].

Fatty Liver

Preliminary results had found improvements in a fatty liver index. Mediterranean diets with nuts or olive oil may delay or slow down the natural progression of non-alcoholic fatty liver, thus beneficial for its prevention and treatment. Further studies supporting these conclusions need to be undertaken [12].

Diabetic retinopathy

After nearly six years of follow up, it was found both olive oil and nut diet groups reduced diabetic retinopathy – a common eye complication of diabetes [13].

Brain health

After three years of PREDIMED, it was found those eating the Mediterranean diet supplemented with nuts had a 22% lower risk of developing depression compared to the low fat diet group, and in those with type 2 diabetes there was a 41% reduced risk [14].

What is the PREDIMED diet?

Prof Joan Sabate from Loma Linda University US visited Australia in March 2013 and Nuts for Life asked him a series of questions about the health benefits of nuts.

Metabolic effects of the PREDIMED study

In 2012 Prof Jordi Salas Salvado and Dr Emilio Ros, famed researchers from the PREDIMED Mediterranean diet study, visited Australia for the International Dietetics Congress. They were interviewed about the role of nuts in a healthy diet and in the PREDIMED study.