A Lower Omega-3 Index Increased the Risk of Having Cognitive Impairment
Why do zombies eat BRAINS? Because they are chock-full of omega-3s!
OK, that’s the extent of the Halloween-theme for this blog, but we are going to talk about something really scary – aging. Being able to age well depends greatly on brain health, and as we have seen in more and more research studies, omega-3 fatty acids may be playing a beneficial role in this arena. A recent study published by Dr. Lukaschek from the University of Giessen in Germany, along with the Omega-3 Index co-creator, Dr. Clemens von Schacky, demonstrates how omega-3 blood levels relate to cognitive function in an elderly population.
The KORA (Cooperative Health Research in the Region of Augsburg… the acronym gets lost in translation from German to English)-Age Research Consortium is a large, population-based study in southern Germany to understand the determinants and consequences of both multi-morbidity (having 2 or more chronic conditions, e.g. heart disease and dementia) and successful aging. The entire cohort consists of ~9,000 participants who were born before 1943. These individuals have had their health and lifestyle choices tracked by researchers since 1984 via periodic surveys, interviews, and physical examinations to look for clues into what makes people live healthier lives for longer.
The Omega-3 Index, which is %EPA+DHA of total fatty acids in red blood cells, was measured in 720 elderly German individuals in the KORA 2 Study from blood drawn in 2012. The Omega-3 Index was measured by Omegametrix, a lab that is the European counterpart to OmegaQuant and run by Dr. von Schacky. For this study, the researchers split the cohort into 3 groups based on their omega-3 levels: low <5.7%, intermediate 5.7-6.8%, and high >6.8%. A possible reason that the researchers did not use the predefined cut-off values of 4% for the low group and 8% for high group could be that the number of individuals in the low and high groups would be much smaller than the intermediate group, making statistical comparisons difficult.
The main outcome that the researchers wanted to compare to omega-3 blood levels was cognitive status. The research group used a survey that can be administered over the phone (which is helpful with 9,000 people in the original study) and measures 4 areas of brain function: orientation, memory, attention/calculation, and language. The survey instrument creates a score that has cutoffs for normal cognitive status, mild cognitive impairment, and probable dementia. For the purposes of their analyses, the researchers combined the mild cognitive impairment and probable dementia individuals into one group (n= 159) to compare to the “normal” group (n=561), again to have better statistical power presumably.
The average Omega-3 Index in older Germans was higher than the US average… but that isn’t so surprising. The mean Omega-3 Index was 6.4%, which is higher than the average US Omega-3 Index score. This makes sense, however, because this is an older population (mean age: 77) and we have seen that the Omega-3 Index increases with age. Compared to those with lower omega-3 levels, individuals with higher omega-3 levels were better educated, older, and less likely to suffer from anxiety, which is similar to patterns observed in other cohorts.
A lower Omega-3 Index increased the risk of having cognitive impairment. Individuals in the low omega-3 group (Omega-3 Index <5.7%) were at a higher risk for some form of cognitive impairment (Odds Ratio: 1.77, 95% Confidence Interval: 1.15-2.73, p-value=0.009), which remained significant after adjusting for age, sex, education levels, metabolic risk factors, and affective disorders, i.e. depression and anxiety. In addition, those in the low omega-3 group had the greatest percentile of individuals with cognitive impairment (29.6%), compared to the intermediate (15.8%) and high (20.8%) omega-3 groups. However, more men had cognitive impairments than women in each omega-3 group, perhaps meaning the metric is more sensitive for women than men.
And now for something a little different… You may be asking, “I’ve heard that omega-3s are good for my brain. Why is that?” The hypothesis is that omega-3 fatty acids (which make up a good portion of the brain) may be particularly beneficial for the hippocampus, the brain region responsible for verbal recall. This area of the brain is susceptible to damage during the aging process, but research as shown that having a higher Omega-3 Index is directly related to greater brain and hippocampal volume (which we have blogged about here). When the brain retains its volume, it generally means the tissue is healthier, which means you have better cognitive function.
In sum, we see that higher Omega-3 Index levels that are at ~7% reduce the risk of functional cognitive decline. This is close to the recommended range for better heart health as well, which is 8% or greater. When you increase your Omega-3 Index from either food or supplements, you are helping your brain and heart age better. But if you don’t get your Omega-3 Index to protective levels, you may not reap the benefits.