PREDIMED is a Spanish study (recruited almost 7,500 high-risk participants) that was designed to assess two variations of the Mediterranean diet, based either in extra virgin olive oil or nuts.
These two types of Mediterranean diet were compared to a low-fat diet, which is the standard recommendation for people at high risk for cardiovascular disease. The main targets of the study were to find out how many of the participants would suffer from serious cardiovascular conditions (stroke, myocardial infraction, hypertension etc) or develop diabetes (metabolic syndrome) during the study.
Essentially, the study wanted to find out whether Mediterranean diet can actually prevent any of these conditions. Participants were advised to not reduce their calories in any way or increase physical activity. The only requirements were the consumption of extra-virgin olive oil or mixed nuts (both supplied on a weekly basis) or reducing dietary fats respectively.
Based on previously published data, the study was designed to last for 6 years. From a statistical point of view, that amount of time would be sufficient to show whether Mediterranean diet had indeed any preventive value. The results quickly showed that participants eating a Mediterranean diet enjoyed superior health benefits, which the participants in the low-fat group were increasingly missing out.
The PREDIMED study produced an impressive amount of data regarding the therapeutic and preventive value of the Mediterranean diet. Since 2013, hundreds of studies have been presenting parts of the results. Below, I am outlining two golden nuggets from this important study that highlight the importance of this specific diet for our long-term health.
Participants who complemented their diet with extra-virgin olive oil or nuts, enjoyed a reduction in risk of combined heart attack, stroke and death from cardiovascular disease by 30 percent and 28 percent respectively. In the graph below (taken from Estruch et al., 2013), we can clearly see that as years pass, the difference in risk between the people who followed a Mediterranean diet and the low-fat group is gradually increasing.
In other words, the more the study would continue, the low-fat group would be increasingly more vulnerable to cardiovascular disease and risk of death. These results reached statistical significance for men but not for women.
A different analysis of the some of the PREDIMED data shows that individuals in high-risk for cardiovascular disease (CVD) can reduce significantly their oxidative stress markers, such as oxidized LDL, very fast. This is important because it is now recognized that chronic oxidative damage of tissues is key in the development and progression of CVD and in fact most chronic debilitating diseases. The graph below (taken from Estruch et al., 2006) shows just how much oxidized LDL levels are reduced within three months of following a Mediterranean diet.
A different analysis showed that both types of the Mediterranean diet outperformed low-fat diet, by reducing the risk for developing the diabetes and/or metabolic syndrome by a whopping 52% (Salas-Salvado et al., 2011)!
Because of all the health benefits associated with the two types of Mediterranean diet, it became obvious that the participants of the low-fat group were increasingly essentially harming their health during the study.
Since all scientific research is required to protect the health and safety of all participants, the PREDIMED study was terminated on average at 4.8 years, instead of six, having adequately established the preventive value of Mediterranean diet for cardiovascular and metabolic diseases.
But the health benefits of the Mediterranean diet do not stop in cardiovascular and metabolic health of high risk adults at all. Expectant moms and their babies could actually reap some great benefits too. There is evidence from another important scientific study (following 3,500 women more than 9 years) showing that women who eat frequently Mediterranean-style meals before pregnancy have significantly reduced risk for serious pregnancy complications, such as preeclampsia (a condition characterized by hypertension and protein in the urine). Preeclampsia is intimately linked to maternal obesity and it increases the risk for developing cardiovascular disease later in life.
Just like CVD and diabetes, preventing preeclampsia is a significant public health issue. More than 6.5 million women worldwide develop preeclampsia every year. In the US alone, 18% of maternal deaths and 15% of premature births are due to this condition. We don’t know what causes preeclampsia but we know that the only way it passes is by delivering the baby as soon as possible. There are very few ways to manage it successfully and until recently, no way to prevent it.
Now we know that the more women eat a Mediterranean diet, the more health benefits and protection from gestational hypertension they enjoy. A different line of evidence shows that, another component of the Mediterranean diet, the consumption of fruit and vegetables during pregnancy, also helps to prevent gestational hypertension and therefore preeclampsia.
The right diet before and during pregnancy could help many babies to be delivered full term, rather than prematurely. Premature babies are extremely vulnerable to several health problems, both short- and long-term, so any way to prevent such complications is much needed and welcome.
Perhaps for the first time we have a safe, inexpensive and non-invasive intervention that could improve the perinatal and long-term health of mothers and their babies.
Estruch R, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. The New England Journal of Medicine, 2013.
Salas-Salvado J, et al. Reduction in the Incidence of Type 2 Diabetes With the Mediterranean Diet: Results of the PREDIMED-Reus nutrition intervention randomized trial. Diabetes Care, 2011.Estruch R, et al. Effects of a Mediterranean-Style Diet on Cardiovascular Risk Factors. Annals of Internal medicine, 2006.
Schoenaker DA et al. 2015. Prepregnancy dietary patterns and risk of developing hypertensive disorders of pregnancy: results from the Australian Longitudinal Study on Women's Health. Am J Clin Nutr. 102(1):94-101.
Danielle AJM Schoenaker et al. 2014. The association between dietary factors and gestational hypertension and pre-eclampsia: a systematic review and meta-analysis of observational studies. BMC Med. 2014; 12: 157.
Eleni Roumeliotou is a clinical nutritionist, geneticist and founder of Primal Baby, a health sanctuary for all things pregnancy: before, during and after. Eleni passionately helps women, who are trying to conceive or are already expecting a baby, to optimize their diet and lifestyle in order to conceive naturally and have the healthiest baby possible. Her passion is to empower women to take control of their fertility and their baby´s health, safeguarding the wellbeing of the next generation, one baby at a time. Read all of Eleni's MOTHER EARTH NEWS posts here.
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