Alzheimer’s & Dementia : The Journal of the Alzheimer’s Association.
Our study has enormous advantages by expanding the sample size and adding demographic data over what previous research has done. It also illustrates that studies that begin by focusing on minorities can lead to insights that can benefit other populations. We hope our results will help people make specific nutritional choices and improve their cognitive health. »
Tamar Sofer, Ph.D., director of the Biostatistics Core Program in Sleep Medicine Epidemiology and member of the Division of Sleep and Circadian Disorders at Brigham Hospital.
Today, researchers can discover biomarkers associated with health changes and disease using approaches such as metabolomics profiling, which allows the study of thousands of metabolites in blood samples. A first study conducted in Boston on older adults of Puerto Rican descent revealed a series of metabolites associated with measured cognitive functions. Building on this work, Brigham researchers tested associations between metabolites and cognitive function in 2,222 Hispanic and Latino American adults from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), as well as in 1,365 Europeans and 478 African Americans from the Atherosclerosis Risk In Communities (ARIC) study. They then applied Mendelian randomization (MR) analyzes to determine causal associations between metabolites and cognitive function, as well as between a Mediterranean diet and cognitive function.
The team found that six metabolites were consistently associated with poorer overall cognitive function across all studies. Four of them were sugars or derivatives of sugars. Another metabolite, beta-cryptoxanthin, was associated with higher overall cognitive function in the HCHS/SOL study and is also strongly correlated with fruit consumption.
“It is possible that these metabolites are biomarkers of a more direct relationship between diet and cognitive function,” said lead author Einat Granot-Hershkovitz, PhD, who worked on this study as an intern. postdoctoral fellow in Sofer’s lab at the Brigham.
The diet itself can be an important source of many metabolites, some of which show positive or negative associations with cognitive function. In this study, the Mediterranean diet score was associated with higher levels of beta-cryptoxanthin, which was positively associated with cognitive function. The Mediterranean diet was also negatively associated with levels of other metabolites, which were associated with lower cognitive function. Previous research has also shown that adherence to the Mediterranean diet is associated with cognitive benefits.
Although the study had limitations such as its cross-sectional and observational design which limited conclusions about the potential influence of changing metabolite levels on cognitive function (causal inference), the researchers attempted to use analyzes of RM to account for unmeasured confounders and establish some level of causal inference. Their results showed weak causal effects between specific metabolites and overall cognitive function. The researchers recommend that future studies assess associations between metabolites and cognitive function and seek to determine whether the observed associations indeed indicate that changes in diet – which are manifested by altered metabolite levels – can improve cognitive health.
“Although the causal effect observed in our study may be small, repeated research has shown that the Mediterranean diet is associated with better health outcomes, including cognitive health,” Sofer said. “Our study confirms the importance of a healthy diet for maintaining cognitive function, regardless of race or ethnicity. »
Source :
Hôpital Brigham and Women’s
Journal reference:
Granot-Hershkovitz, E., et al. (2022) Plasma metabolites associated with cognitive function across races/ethnicities affirming the importance of healthy nutrition. Alzheimer’s and dementia. doi.org/10.1002/alz.12786.