Thousands followed in Med diet study
The research was funded by Spain’s Ministry of Health and was published in the New England Journal of Medicine. The researchers conducted a large-scale landmark study called the Spanish PREDIMED (PREvención con DIeta MEDiterranea) trial.
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| Mediterranean diet found to reduce heart disease |
The study enrolled 7,447 people between 55 and 80 years of age, of which 57% were women. In a randomized manner, the participants were given either a Mediterranean diet supplemented with mixed nuts, a Mediterranean diet supplemented with extra-virgin olive oil, or a control diet – which included advice to reduce fats according to American Heart Association guidelines.
The participants were followed for an average of 4.8 years during the trial, and their cardiovascular event histories were measured, along with a stratification (a break out) of risk factors to enable a clear understanding of the role of the diet versus other possible factors.
Those who were on the Mediterranean diet with olive oil had a 30% decreased incidence of cardiovascular events. Those on the Med diet with nuts had a 28% decreased incidence of cardiovascular events.
However, within those events were another surprising result. The Mediterranean diet with the mixed nuts – many of which were walnuts – had nearly half the incidence of strokes.
Remember too, that the control group was given low fat advice by physicians according to the American Heart Association guidelines. This means that the control group’s diet was likely better than a typical Western diet. This of course means that the Mediterranean diet is compared to a typical Western diet would show even more dramatic results.
Other studies have shown that the Mediterranean diet is not only a heart-healthy diet, but significantly reduces the risk of Alzheimer’s disease and dementia.
Med diet with olive oil studied
Scientists from Spain’s University Rovira i Virgili Medical School have determined that a traditional Mediterranean diet with either a high proportion of olive oil or nuts significantly lowers the risk of heart disease and the hardening of the arteries.
The researchers tested 551 people between 55 and 80 years old who already had signs of cardiovascular disease and hardening of the arteries. They were randomly split into three groups. The first group ate a low-fat diet for three months. The second group ate a traditional Mediterranean diet with 15 liters of virgin olive oil over the three-month period, and the third group ate a traditional Mediterranean diet plus 30 grams of walnuts, almonds and hazelnuts per day.
The research found that the two groups that ate traditional Mediterranean diets had significantly reduced levels of cardiovascular disease as indicated by the subjects’ Apo levels and ratios. The women’s risk dropped by nearly 17%, while the men’s cardiovascular risk dropped by 5%.
The apolipoproteins are key markers the risk of cardiovascular disease because they relate directly to the hardening of arteries as a result of LDL oxidation. ApoA-1 is critical to HDL (good) cholesterol levels, while ApoB is a key constituent of LDL (bad) cholesterol.
The study showed that both traditional Mediterranean diet groups had an increase in ApoA-1 levels and decreased levels of ApoB. The Apo ratio – also called the total ApoB/ApoA-1 ratio – was also reduced among the two traditional Mediterranean diet groups.
What is the Mediterranean diet?
The traditional Mediterranean diet emphasizes eating more fruits and vegetables, nuts, seeds, and other plant-based foods. It has been acclaimed as one of the most beneficial diets for weight loss and increased longevity. The Mediterranean diet has been eaten for thousands of years in the Middle East and Mediterranean region. This diet greatly contrasts the Western diet in that it avoids red meats and processed meats. It also contains far more fresh foods and more fiber.
The diet has also been shown to reduce heart disease risk more effectively than pharmaceutical medications.
This was stressed by Dr Miguel Angel Martínez-González, one of the researchers and a professor in the Department of Preventive Medicine at the University of Navarra. Dr. Martínez-González stated that the research has shown that, “a modification in the entire diet pattern managed to achieve, in just one year, results that pharmaceutical drugs did not – even after two years of treatment.”
The Mediterranean diet is rich in grains, fruits and vegetables and low in red meat. This type of diet provides various phytonutrients that provide antioxidant benefits. Oxidative stress has been shown to be at the root of artery disease.
Both nuts and olive oil provide additional nutrients that are heart healthy – notably omega-3 fatty acids found in walnuts and other nuts, as well as monounsaturated fatty acids in olive oil.
Extra virgin olive oil is oil from olives that have been pressed mechanically at lower heats. This yields fewer radicals and more heat-sensitive polyphenols.
This fact was confirmed in another element of the PREDIMED study, published recently, wherein the researchers found that the polyphenols in olive oil produce increased health benefits in the diets of the more than 7,000 participants. The researchers stated that, “The consumption of olives and olive oil was a differentiating factor in the phenolic profile of this Spanish population compared with other countries.”
Improving metabolism
A study from Italy shows that the Mediterranean diet significantly improves metabolism, glycemia, insulin levels, C-reactive protein levels and body mass index.
All of these factors present the issues related to metabolic syndrome. Metabolic syndrome is symptomized by cardiovascular disease, being overweight and a tendency for type 2 diabetes.
The study followed 80 volunteers who were between 51 and 59 years old. They were randomly split into two groups, and one group ate the Mediterranean diet and the other ate a western diet. Before and after six months, the subjects underwent extensive testing.
After 25 weeks on the diet, the Mediterranean diet subjects had an average of 12.4% lower body mass index, 8.3% less weight, 9.2% lower fasting glycemia and 32% lower fasting insulin. The Med diet group also had 34% lower levels of C-reactive protein.
C-reactive protein (CRP) is a marker for inflammation. High CRP levels indicate systemic inflammation, often accompanying the hardening of the arteries, also called atherosclerosis, coronary artery disease and a higher risk of heart disease and stroke in general.
What this means
Lower fasting glycemia levels means lower levels of blood sugar, related to a lower risk of diabetes.
Lower fasting insulin levels are also a marker that is associated with a reduced risk of diabetes.
The Mediterranean diet has a greater number of fruits, vegetables, nuts, healthier oils and dairy. Red meats are kept minimally in the Med diet. Fish are a greater part of the Med diet than meats.
The diets of the Med diet group proved consistent with these in this study. The Med diet group showed 39% higher levels of fruit, 30% higher levels of vegetables, 18% higher cheese and 38% higher levels of fiber.
Other studies have shown that the Mediterranean diet results in lower levels of heart disease, lower levels of dementia and Alzheimer’s disease and a reduced risk of cancer.
This plant-based diet provides a range of benefits, including longer lifespan and reduced risk of dementia. The Med diet also helps prevent diabetes according to other research. It also helps prevent cognitive decline.
REFERENCES:
Estruch R, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. NE Jour. Med. 2013. Jan 25. DOI: 10.1056/NEJMoa1200303
Tresserra-Rimbau A, Medina-Remón A, Pérez-Jiménez J, Martínez-González MA, Covas MI, Corella D, Salas-Salvadó J, Gómez-Gracia E, Lapetra J, Arós F, Fiol M, Ros E, Serra-Majem L, Pintó X, Muñoz MA, Saez GT, Ruiz-Gutiérrez V, Warnberg J, Estruch R, Lamuela-Raventós RM. Dietary intake and major food sources of polyphenols in a Spanish population at high cardiovascular risk: The PREDIMED study. Nutr Metab Cardiovasc Dis. 2013 Jan 16. doi:pii: S0939-4753(12)00245-1. 10.1016/j.numecd.2012.10.008.
Solá R, Fitó M, Estruch R, Salas-Salvadó J, Corella D, de La Torre R, Muñoz MA, López-Sabater Mdel C, Martínez-González MA, Arós F, Ruiz-Gutierrez V, Fiol M, Casals E, Wärnberg J, Buil-Cosiales P, Ros E, Konstantinidou V, Lapetra J, Serra-Majem L, Covas MI. Effect of a traditional Mediterranean diet on apolipoproteins B, A-I, and their ratio: a randomized, controlled trial. Atherosclerosis. 2011 Sep;218(1):174-80.
Panunzio MF, Caporizzi R, Antoniciello A, Cela EP, Ferguson LR, D’Ambrosio P. Randomized, controlled nutrition education trial promotes a Mediterranean diet and improves anthropometric, dietary, and metabolic parameters in adults. Ann Ig. 2011 Jan-Feb;23(1):13-25.