12-year study reveals how Mediterranean diet can affect your brain: ScienceAlert

Cognitive decline is less likely in those who follow a Mediterranean diet, according to a French study of 840 people aged 65 and older.

Dementia, like Alzheimer’s disease and other neurodegenerative conditions, often begins with cognitive decline, a slow loss of mental abilities.

Research suggests that eating habits, especially the Mediterranean diet, may help protect against this loss.

Inspired by foods traditionally eaten in regions including Crete, Italy and southern Spain, the Mediterranean diet prioritizes the consumption of fruits, vegetables, unprocessed grains, some fish, cheese and olive oil.

Evidence suggests a number of benefits from this combination of foods, including — potentially — enhanced brain health.

However, there have been conflicting results, possibly due to the use of self-reported dietary questionnaires, which are prone to imprecision.

Studies have linked certain biomarkers to cognitive health, so an international group of researchers has taken this approach, which they suggest is a more accurate way to measure dietary exposure and its relationship to health outcomes.

“We found that adherence to the Mediterranean diet assessed by a panel of nutritional biomarkers is inversely associated with long-term cognitive decline in older adults,” says first author Alba Tor Roca, a nutritionist and public health scientist at UCLA. Barcelona.

Tor Roca and colleagues investigated the relationship between the Mediterranean diet and cognitive decline in older adults through a comprehensive analysis of health and cognitive data collected over 12 years.

A 14-point scale was used to create the Mediterranean Diet Metabolic Score (MDMS). This result is based on two potential dietary metabolic biomarkers for seven important parts of the Mediterranean diet: vegetables, legumes, fruits, cereals, dairy products, fish and fat.

Metabolomics is the study of small molecules called metabolites that are the product of cellular processes. Their levels can change in response to disease, diet and other environmental factors.

Scientists can learn about our health and find potential biomarkers of disease by measuring the levels of metabolites in a sample.

“Within the framework of the study, a nutritional metabolism index was designed – based on biomarkers obtained from the serum of participants – on the food groups that are part of the Mediterranean diet,” says nutrition and food scientist Cristina Andres Lacueva from the university. Barcelona.

“Once this indicator is known, its association with cognitive impairment is evaluated.”

Serum levels of specific substances including saturated and trans fats, polyphenols produced by gut bacteria, and other phytochemicals were measured from participants’ blood samples collected at the beginning of the study.

Over the course of twelve years, participants were given five neuropsychological tests to determine their cognitive ability or impairment.

The researchers found a protective relationship between the Mediterranean diet and cognitive decline in older individuals, based on outcomes and blood biomarkers.

Individuals who adhered more closely to the Mediterranean diet showed significantly slower cognitive decline compared to those with lower levels of adherence.

“These results support the use of these indicators in long-term follow-up evaluations, to monitor the health benefits associated with the Mediterranean diet or other dietary patterns, and thus guide personalized counseling at older ages,” says Tor Rocca.

The study has limitations: for example, blood samples for metabolic analysis were only available at baseline, so the team could not examine previous exposures or changes during follow-up.

Dietary influences on health are always complex, but overall, the findings reinforce the idea that dietary patterns can play a role in maintaining brain health and reducing the risk of cognitive impairment as we age.

“Developing nutritional metabolism scores based on dietary patterns may help improve dietary assessment procedures and will hopefully contribute to a better understanding of the biological mechanisms through which diet affects cognitive health in older adults,” the researchers wrote.

The study was published in Molecular nutrition and nutritional research.