High blood omega-3 levels are associated with lower risk of dementia and Alzheimer's disease

Having high levels of omega-3 in the blood is associated with a lower risk of dementia and Alzheimer's disease, according to a study co-led by the Hospital del Mar Research Institute and published in the journal Nutrients. This is the study with the largest number of participants in this field to date, analyzing data from 260,000 people from the UK Biobank database. Researchers from the Fatty Acid Resarch Institute of the United States and the CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN) have participated in the study.

The authors of the study have been able to access the blood metabolite profile of individuals included in the UK database. In addition to examining the associations by different types of omega-3, being able to work with such a large number of participants has made it possible to include younger population groups than those traditionally studied. Thus, they have divided the participants into volunteers aged 40 to 50 years, 50 to 60 years and over 60 years. They have also been able to relate this information to the onset of Alzheimer's disease or other dementias as distinct entities. As Dr. Aleix Sala-Vila, a researcher in the Cardiovascular Risk and Nutrition Research Group at the Hospital del Mar Research Institute, explains, "it has helped us to study whether having high levels of omega-3 at age 50 can help prevent the onset of dementia many years later”.

The study has taken into account the age, sex, level of schooling of the participants and the genetic characteristics associated with an increased risk of Alzheimer's disease. The conclusions indicate that "high levels of omega-3 are associated with lower risk for all age groups, for men and women and for both diseases, but the strongest associations are found in men, in people over 60 years of age, and for dementias other than Alzheimer's disease," explains the lead author of the study. At the same time, the associations are also particularly beneficial for omega-3s other than DHA (docosahexaenoic acid). This omega-3 is provided by oily fish, and, therefore, the study "reinforces the idea that there are some foods, which do not have to be fish, such as walnuts, that could be beneficial for brain health," says Dr. Sala-Vila.

To help design new studies

The results obtained do not establish a direct causality between blood fatty acid levels and the risk of Alzheimer's disease and other dementias. To do so, studies with volunteers supplementing their diet with omega-3 will have to be developed. But they do serve to "help define future studies in more detail," according to Dr. Aleix Sala-Vila. These new studies will have to take into account which population is most likely to benefit from this type of intervention, since the response to supplementation is not the same for everyone. It will also help to better define what type of omega-3 to test, what is the most appropriate dose, or the duration that will be necessary to be able to see a clinically relevant effect.

Image: Dr. Aleix Sala-Vila

Reference article: Sala-Vila A, Tintle N, Westra J, Harris WS. Plasma Omega-3 Fatty Acids and Risk for Incident Dementia in the UK Biobank Study: A Closer Look. Nutrients. 2023 Nov 23;15(23):4896. doi: 10.3390/nu15234896. PMID: 38068754; PMCID: PMC10708484.