Researchers from Spain’s University of Navarra have conducted a series of studies that have determined that a Mediterranean diet supplemented with either nuts or extra virgin olive oil results in a reduced risk of mild cognitive impairment (MCI) – and thus Alzheimer’s disease. Another study found that the Med diet with olive oil decreased the risk of MCI even further.
In the major study, 522 elderly adults participated. They had an average age of 75 years. They were split into three groups and followed for six and a half years. One group consumed a standard (Western) low-fat diet, another group consumed a Mediterranean diet supplemented with mixed nuts, and the third group consumed a Mediterranean diet supplemented with virgin olive oil.
The supplemented nuts group consumed 30 grams of mixed nuts per day in addition to their diets, and the supplemented olive oil group consumed one liter of extra virgin olive oil per week.
The subjects were evaluated using the Mini-Mental State Examination and Clock Drawing Test. The Mini-mental exam is a 30-point test used by doctors to check patients for dementia and cognitive impairment. The Clock Drawing Test uses clock drawings to test the patient’s ability to accurately convert, copy and understand – another test for dementia and cognitive impairment.
After the almost seven years, the researchers found that those who ate the Mediterranean Diet with the olive oil had 62% better scores on the Mini-Mental exam than did the control group. This group also had an average of 51% better scores on the Clock Drawing Test. The group consuming the Mediterranean Diet supplemented with nuts had 57% better scores than the conventional diet on the Mini-Mental exam, and 33% better scores on the Clock Drawing Test.
Cognitive impairment is a symptom of Alzheimer’s disease.
Olive Oil Particularly Good for Cognition
Within the same series, the researchers also conducted a study with 285 people. Again, the subjects were divided into three equal and randomized groups.
Before and after the study, the patients were tested for cognition, which included memory testing and language fluency testing using a 14-point questionnaire. Their diets were also carefully validated using food extensive questionnaires.
The researchers found that the Mediterranean diet group that consumed the extra olive oil had a 66% reduced incidence of mild cognitive impairment at the end of the period compared to the control group – the conventional low-fat diet group.
And like the first study, this was after removing many other possible factors, such as smoking, alcohol intake, weight, diabetes and many others.
Mediterranean Diet and heart disease
Other studies have shown the Mediterranean Diet reduces the risk of heart disease and other conditions. The Mediterranean Diet contains higher levels of fruits and vegetables, whole grains, and little or no red meat.
The olive oil result confirms another study done in 2009, where researchers from France’s University of Montpellier followed 6,947 people, and found that consuming more olive oil resulted in a 17% reduction in cognitive decline and a 15% reduction of verbal fluency decline.
Olive oil is one of the healthiest oils because olives contain a number of medicinal phytonutrients. These include oleuropein, an antioxidant and anticancer agent shown to reduce blood pressure and inflammation. We reported on oleuropein’s anti-cancer ability in another article. Other olive phytonutrients include hydroxytyrosol, tyrosol and verbascoside.
Extra-virgin is important for olive oil because this means the olives are freshly pressed without introducing heat into the process. The olives are being mechanically pressed, and there is no heating or addition of extraction chemicals into the process. This results in more polyphenol content within the olive oil.
Contrasting this, most nuts are roasted or boiled. This addition of heat can destroy many of their medicinal qualities. Besides this, while nuts are extremely nutritious, most nuts do not contain the antioxidant capacity of olives. Other research shows this same benefit of the Med diet with nuts.
Martínez-Lapiscina EH, Clavero P, Toledo E, Estruch R, Salas-Salvadó J, San Julián B, Sanchez-Tainta A, Ros E, Valls-Pedret C, Martinez-Gonzalez MÁ. Mediterranean diet improves cognition: the PREDIMED-NAVARRA randomised trial. J Neurol Neurosurg Psychiatry. 2013 Dec;84(12):1318-25. doi: 10.1136/jnnp-2012-304792.
Martínez-Lapiscina EH, Clavero P, Toledo E, San Julián B, Sanchez-Tainta A, Corella D, Lamuela-Raventós RM, Martínez JA, Martínez-Gonzalez MÁ. Virgin olive oil supplementation and long-term cognition: the PREDIMED-NAVARRA randomized, trial. J Nutr Health Aging. 2013;17(6):544-52. doi: 10.1007/s12603-013-0027-6.
Berr C, Portet F, Carriere I, Akbaraly TN, Feart C, Gourlet V, Combe N, Barberger-Gateau P, Ritchie K. Olive oil and cognition: results from the three-city study. Dement Geriatr Cogn Disord. 2009;28(4):357-64. doi: 10.1159/000253483.
Case Adams is a California Naturopath and a Board Certified Alternative Medicine Practitioner with a PhD in Natural Health Sciences, and diplomas in Homeopathy, Aromatherapy, Bach Flower Remedies, Blood Chemistry, Clinical Nutritional Counseling and Colon Hydrotherapy. He has authored 26 books on natural healing strategies.