Omega 3s improve cognitive ability and intelligence in the elderly

Omega-3 fatty acids are essential for the maintenance of brain health and so-called fluid intelligence, i.e., the brain's ability to cope with new situations regardless of prior knowledge. In particular, high concentrations of ALA (alpha linolenic acid), SDA (stearidonic acid), and ETE (eicosatrienoic acid), are linked to better fluid intelligence and increased volume of the brain region involved in this function, confirming how cognitive decline in old age also depends on nutritional status.

This was demonstrated by researchers at the University of Illinois Urbana-Champaign, in a study published in the journal Nutritional Neuroscience in recent months.

Omega-3s protect cognitive abilities

A large body of scientific evidence shows that polyunsaturated fatty acids have protective effects on the brain during aging. In particular, omega-3s are known to be present in high amounts in the membranes of neurons where they contribute to structural integrity, regulate their fluidity, and the production of neurotransmitters and neuropeptides, the substances responsible for transporting information between cells in the nervous system. High omega-3 consumption has been linked to improved memory performance, and associated with decreased risk of dementia in the elderly.

Recent studies have also shown that the decline in fluid intelligence, one of the most debilitating aspects of cognitive aging, is linked to omega-3 fatty acid levels in the blood. Fluid intelligence is the brain's ability to deal with new situations. It is different from crystallized intelligence, which is the set of previously acquired knowledge and experience. A decline in fluid intelligence is indicative of a reduced ability to achieve new skills, and is due to the deterioration of a system of neurons that is the support for new learning. Fluid intelligence is in fact linked to a particular area of the brain called the frontoparietal cortex (FPC). 

The link between cognitive ability and the level of the omegas EPA and DHA is now known, while there are few studies that have evaluated whether the concentrations of their precursors and other omega-3s, such as ALA (alpha-linolenic acid), SDA (staeridonic acid), and ETE (eicosatrienoic acid), are implicated in this protective effect. Similarly, the concentration of EPA, DHA has been associated with better performance on cognitive tests in older adults; but that of other omega-3s has been little examined. Scientific evidence has unveiled that plasma ALA amounts are related to dementia risk. The decline in fluid intelligence is a key feature of cognitive changes preceding dementia, so ALA and its derivatives, including just SDA and ETE, could represent signal molecules of the state of fluid intelligence. Just as EPA and DHA, SDA and ETE can also be synthesized by the human body from alpha linoleic acid.

ALA, ETE and SDA omega-3s protect fluid intelligence

In this new study, researchers investigated the link between the maintenance of cognitive abilities and omega-3s that can act on particular aspects of brain health, such as the ability to acquire new knowledge and information. Analyses revealed that levels of alpha-linolenic acid, stearidonic acid and eicosatrienoic acid were linked to fluid intelligence and total volume of CVT, suggesting how fatty acids are able to preserve this cognitive capacity by keeping the structure of the cerebral cortex intact in healthy elderly people. These results suggest that some little-studied omega-3s have important effects on mental health, regardless of their role in the pathway leading to EPA and DHA formation. ALA, in fact, has always been considered uninfluential by researchers because of its poor ability to form EPA and DHA; its conversion rate is low and may be further reduced by an excessive level of saturated fat in the diet, a common feature of Western dietary patterns. A 1998 Swiss study on the subject concluded that with a diet rich in saturated fat, the conversion of ALA to its derivatives is about 6 percent for EPA and 3.8 percent for DHA, and that with a diet also rich in omega-6, conversion is reduced by as much as 40-50 percent.

Some details of the study

In the research, U.S. scientists selected 122 cognitively healthy adults aged 65 to 75 years, 100 of whom were involved in the study. Each had their blood levels of various omega-3s measured. Fluid intelligence and other abilities were estimated through specific cognitive tests. The volume of the cerebral cortex was assessed by MRI. Through appropriate statistical analysis, all the data collected were correlated, taking into account the age, sex, education and Body Mass Index of each subject. The results revealed that individuals who had higher blood concentrations of ALA, SDA and ETE had better scores on cognitive tests and showed greater CVT volume, suggesting a link between these three parameters.

Results paving the way for new research

According to the scientists who conducted the research, their findings identify certain omega-3s linked to cognitive abilities, and a new relationship between them, brain structure and fluid intelligence. Future investigations will need to understand whether the molecules are neuroprotective as such, or whether their elevated levels are a sign of increased conversion toward EPA the DHA. The fatty acid SDA, in fact is able to convert to EPA more efficiently than ALA. In any case, the results of the study confirm that age-related cognitive decline depends not only on brain degeneration, but also on the state of nutrition; ALA, SDA and ETE are fatty acids found in various foods of animal (fish) and plant (oilseeds, nuts) origin.

Source: Zamroziewicz MK , Paul EJ , Zwilling CE , Barbey AK . "Determinants of fluid intelligence in healthy aging: omega-3 polyunsaturated fatty acid status and frontoparietal cortex structure" 2017 May 11:1-10. Nutritional Neuroscience.