“Studies have looked at this association in older populations. The new contribution here is that, even at younger ages, if you have a diet that includes some omega-3 fatty acids, you are already protecting your brain for most of the indicators of brain aging that we see at middle age,” said Claudia Satizabal, Ph.D., assistant professor of population health sciences with the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio. Satizabal, who is also the lead author of the study.
This study of 2,183 dementia and stroke-free participants with an average age of 46, looked at the relation of red blood cell omega-3 fatty acid concentrations with MRI and cognitive markers of brain aging, as well as the effects of omega-3 red blood concentrations in those with the AP0E4 genetic variation linked to a higher risk of Alzheimer’s disease. Gas chromatography techniques were used to measure DHA and EPA concentrations from red blood cells, and the omega-3 index was calculated as DHA plus EPA.
The researchers found that having a higher omega-3 index was associated with a larger hippocampal volumes, this brain structure plays a major role in memory and learning. Consuming more omega-3s was associated with better abstract reasoning (the ability to understand complex concepts using logical thinking). Additionally, AP0E4 gene variant carriers with a higher omega-3 index had less small vessel disease, which is important because this gene is associated with cardiovascular disease and vascular dementia.
“Omega-3 fatty acids such as EPA and DHA are key micronutrients that enhance and protect the brain,” said study coauthor Debora Melo van Lent, Ph.D., who is a postdoctoral research fellow at the Biggs Institute. “Our study is one of the first to observe this effect in a younger population. More studies in this age group are needed.”
“We saw the worst outcomes in the people who had the lowest consumption of omega-3s,” Satizabal said. “So, that is something interesting. Although the more omega-3 the more benefits for the brain, you just need to eat some to see benefits.”
Although the researchers were not able to determine how DHA and EPA protect the brain, they theorized that because those fatty acids are needed in the membrane of neurons when they are replaced with other types of fatty acids the neurons become unstable, as well as possibly having something to do with the protective anti-inflammatory properties of DHA and EPA.
“It’s complex. We don’t understand everything yet, but we show that, somehow, if you increase your consumption of omega-3s even by a little bit, you are protecting your brain,” Satizabal said.
“It’s genetics, so you can’t change it,” Melo van Lent said, referring to the vulnerability of the higher-risk AP0E4 carrier group. “So, if there is a modifiable risk factor that can outweigh genetic predisposition, that’s a big gain.”
