Older adults who are overweight or obese who stick most closely to the Mediterranean diet preserve their cognitive performance and even improve their abilities after three years, according to a study led by researchers at the Hospital del Mar Medical Research Institute, IDIBELL, Hospital de Bellvitge and the CIBEROBN, published in the journal Clinical Nutrition.
The study followed a group of 487 volunteers, almost equally divided between men and women, with an average age of 65 years, for three years. They were all participants in the PREDIMED-PLUS (PREvenciónDIetaMEDiterranea Plus) trial, a multicentre study involving 23 Spanish research centres that analyses the effect of the traditional Mediterranean diet with energy restriction, promotion of physical activity and behavioural intervention in terms of weight loss and the prevention of cardiovascular disease.
At the start of the study, the participants were overweight or obese and had at least three criteria for metabolic syndrome, including high blood pressure, high blood sugar, excess waist fat, low HDL cholesterol, and high triglyceride levels. It is a very common condition, occurring in about 1 in 4 adults worldwide, and carries an increased risk of heart disease, stroke, type 2 diabetes and cognitive impairment.
Using neuropsychological tests, the researchers analysed the volunteers' cognitive status at the start of the study and again after one and three years. Their performance in memory and other cognitive functions, including the ability to make decisions, reason, pay attention, plan, and ignore certain impulses, were assessed.
According to previous studies, over a three-year period, people with metabolic syndrome who did not follow any kind of intervention would have shown a decrease of almost 0.40 points in their overall cognition and 0.10 points in their memory. In contrast, by following the study recommendations, they recorded improvements of more than 0.60 points in global cognition and about 0.90 points in memory. The units for measuring cognition are standardised to enable comparisons between neuropsychological tests that use different scales.
In the patients as a whole, the results indicate a direct relationship between adherence to the Mediterranean diet and cognitive improvement. Compliance with the low-calorie Mediterranean diet is measured using a 17-item questionnaire that explores the consumption of extra virgin olive oil and the number of servings of vegetables and pieces of fruit eaten per day, among other things. Scores above 11 points are considered to represent a high level of adherence to the Mediterranean diet. Therefore, for each point of improvement in terms of sticking to this type of diet, memory improved by 0.13 points.
According to the researchers, this improvement may be due to weight loss and increased physical activity, which is also associated with improved quality of life. In this sense, Dr Rafael de la Torre, one of the principal investigators of the study, points out that this fact "is important, given that cognitive changes may not be perceptible to people, but may be more relevant if combined with improvements in their quality of life".
For his part, Dr. Fernando Fernández-Aranda, project leader from IDIBELL and Hospital de Bellvitge, states that “thanks to this study we have been able to define advantages of the Mediterranean diet beyond weight loss such as verbal memory or attention, who clearly benefit from it”.
Reference article
Natalia Soldevila-Domenech, Laura Forcano, Cristina Vintró-Alcaraz, Aida Cuenca-Royo, Xavier Pintó, Susana Jiménez-Murcia, Jesús F. García-Gavilán, Stephanie K. Nishi, Nancy Babio, Maria Gomis-González, Dolores Corella, Jose V. Sorlí, Rebeca Fernandez-Carrión, Miguel Ángel Martínez-González, Amelia Marti, Jordi Salas-Salvadó, Olga Castañer, Fernando Fernández-Aranda, Rafael de la Torre. Interplay between cognition and weight reduction in individuals following a Mediterranean Diet: Three-year follow-up of the PREDIMED-Plus trial. Clinical Nutrition, Pub Date : 2021-08-05, DOI: 10.1016/j.clnu.2021.07.020