Although there is a natural decline in cognitive performance associated to aging, particularly in memory, some studies described factors that can help minimize this effect despite the passing years. Food is one of these factors. Epidemiological studies suggest that fruits, vegetables, fish, wine and nutrients such as polyunsaturated fatty acids, vitamin B and antioxidants can protect against cognitive decline related to aging and Alzheimer's disease. Furthermore, dietary patterns as the Mediterranean diet have also been linked with a lower incidence of mild cognitive impairment and neurodegenerative diseases.
The study published in the Journal of Alzheimer’s Disease focuses on assessing whether the consumption of antioxidant foods typical of the Mediterranean diet is associated with better cognitive performance. The work was conducted with a subsample of 447 participants of the PREDIMED study, a multicenter clinical trial of nutritional intervention with Mediterranean diet in 7,447 individuals without prior vascular disease but at high cardiovascular risk aged 55 to 80 years. This study is funded with public funds from the Instituto de Salud Carlos III through the "CIBER Pathophysiology of Obesity and Nutrition (CIBERobn)", led by Dr. Ramon Estruch, from the Internal Medicine Service of Hospital Clínic, and "RETIC PREDIMED (RD 06/0045)", led by Dr. Miguel Angel Martinez-Gonzalez, from the Department of Public Health at the University of Navarra. All volunteers were given a food habits questionnaire as well as a neuropsychological test to determine cognitive performance, particularly in the area of memory. In addition, investigators measured the excretion of polyphenols in urine as a marker of the intake of these antioxidant compounds present in many Mediterranean foods.
Consumption of olive oil, as well as drinking coffee, was associated with better scores on tests of verbal memory. The intake of nuts was associated with better working memory and moderate wine consumption was associated with better global cognitive function. A common feature of all these foods is that they are rich in polyphenols, which are highly bioactive molecules with beneficial effects on the modulation of free radicals caused by oxidation. Also, people who had higher levels of polyphenols in urine, an indicator of increased consumption of foods containing it, scored better on memory tests.
It has been reported that oxidative stress and subsequent inflammation are the main cause of the pathologies associated with aging-related disorders. The present results suggest that foods rich in polyphenols characteristic of the Mediterranean diet could counteract the cognitive decline associated with age due to its high antioxidant power. The longitudinal follow-up of these participants will provide stronger evidence of the potential of the Mediterranean diet and its components in maintaining a good cognitive functioning in spite of aging, and reducing the incidence of Alzheimer's disease.