It’s been said that “You are what you eat” and many scientific studies bear this out. A healthy diet can often reduce the risk of cardiovascular disease, obesity, diabetes and even neurological disorders. There is a definite connection between the gut and the brain, so food and diet are important to good brain health. Two recent studies, both from the University of Illinois at Urbana Champaign, have focused on the role of polyunsaturated fatty acids as they relate to the structure of the brain and age-related cognitive decline. Two fatty acids, omega-3 and omega-6 were studied and while the results were encouraging, more work will need to be done to test the hypothesis that increasing dietary intake of these substances can be a significant factor in aging and memory.
The researchers looked at two areas of the brain. It’s important to understand that different regions in the brain are responsible for different functions, and, as such, will age at different rates. In the first study, published in the journal Nutritional Neuroscience, a team led by University of Illinois M.D./Ph.D student Marta Zamroziewicz looked at the frontoparietal network. In this part of the brain, what’s called “fluid intelligence” is processed. Fluid intelligence is how the brain solves problems. It’s also one of the first areas to show age related decline. The team also looked at the white matter structure in the fornix of the brain, which is involved in memory. Many patients with Alzhiemer’s disease show deficits in this area in the early stages. Zamroziewicz explained, “A central goal of research in nutritional cognitive neuroscience is to understand how these nutrients affect brain health. Some of these nutrients are thought to be more beneficial than others. Most of the research that looks at these fats in health and healthy aging focuses on the omega-3 fatty acids DHA and EPA, but those come from fish and fish oil, and most people in the Western Hemisphere don't eat enough of those to really see the benefits. Other fatty acids, like alpha-linolenic acid and stearidonic acid, are precursors of EPA and DHA in the body. Those fats can be derived from land-based foods such as nuts, seeds and oils.”
In both studies, participants were adults aged 65 to 75. The team sought to investigate the relationship of the omega-3 and omega-6 nutrients to brain structure and cognition. While fish and fish oil capsules contain omega-3 fatty acids, the recent research found a correlation between fluid intelligence, as revealed in cognitive testing, and blood levels of the fatty acids ALA, stearidonic acid and ecosatrienoic acid. These can be found in nuts, seeds and oils, which means that more dietary options can be utilized to increase intake of these nutrients. Study participants with higher scores in fluid intelligence had larger left frontoparietal cortices and the size of this area of the brain was a reliable predictor of performance on cognitive testing.
In the second study, published in the journal Aging and Disease, the team in Illinois analyzed white matter size and structure in the fornix and compared it to a proper balance of omega-3 and omega-6 acids in the blood. Again there was a correlation between robust size and performance in the fornix and the right ratio of fatty acids in the blood, “These findings have important implications for the Western diet, which tends to be misbalanced with high amounts of omega-6 fatty acids and low amounts of omega-3 fatty acids," Zamroziewicz said. The video below has more information on the two studies and how diet can affect brain health.