Age-related declines in verbal fluency improve with alpha-linoleic acid, study suggests
Of the multiple cognitive tests conducted, a verbal performance test evaluated executive function of the frontal lobe; a key determinant of the ability to set goals, plans and carry out everyday actions.
Further cognitive tests did not demonstrate any significant differences between the experimental and control groups.
“Daily consumption of flaxseed oil containing 2.2 g alpha-linolenic acid improved cognitive function, specifically verbal fluency, despite the age-related decline, in healthy individuals with no cognitive abnormalities,” the Japanese researchers conclude.
They highlight: “Regarding the impact of the results of this study, the importance of maintaining and even extending one’s verbal fluency capacity is one of the most important functionalities for older adults to age healthily.
“In this context, if ALA intake can support verbal fluency even with increasing age, which is important for communication with others, it could promote social participation among older adults.”
Fats for the brain
The prevalence of dementia has been increasing, mirroring the rapid growth of the population and thus, the aging population. In Japan, the 'super-aged society' has led to reports estimating that by 2025 those suffering with the condition will exceed 7 million.
It has been previously observed that nutrition can play a vital role in brain health, with omega-3 polyunsaturated fatty acids (PUFAs), specifically docosahexaenoic acid (DHA), being noted to have benefits on cognitive health. Thus, the increased consumption of fish and fish oils has been associated with a potential decreased risk of dementia.
Edible oils mostly contain the DHA precursor of the omega-3 fatty acid ALA, which can synthesise DHA within the body. Following this, there has been increased interest into whether ALA can result in similar benefits to cognition.
However, since the evidence remains limited, the researchers conducted the present RCT to investigate the administration of ALA within flaxseed oil on measures of cognition in older adults.
The 12-week intervention study utilised 60 men and women aged 65-80 years from Miyagi, Japan. The subjects were split into experimental or control groups. Experimental groups received 3.7 g/day of flaxseed oil, equivalent to 2.2 g of ALA, whilst the controls received a placebo of corn oil containing only 0.04 g.
Cognitive function was assessed pre- and post- supplementation, assessing the categories of attention and concentration, executive function, perceptual reasoning, working memory, processing speed and memory function. The six categories aimed to represent daily life activities.
It was observed that after 12 weeks of intake, the ALA supplemented group were noted to have significantly improved verbal fluency scores (0.30 ± 0.53), when compared to the control group (0.03 ± 0.49, p < 0.05). The scores were obtained following the frontal assessment battery at bedside; a test determining executive function by asking the participants to answer as many words as possible beginning with a specific letter.
However, it was noted that all other scores for cognition did not prove to be significantly different between the groups.
The RCT presents significant findings to suggest the efficacy of ALA in improving verbal fluency; a key factor in the progression of Alzheimer’s disease.
With regards to the proposed mechanisms exhibited by ALA in the study, the report highlights: “As suggested in a previous review of the effects of DHA, it may have improved the efficiency of cognitive strategies, which decline with increasing age, by altering the structure of neuronal cell membranes in the broad anatomical regions and improving the fluidity and intercellular connectivity of the neuronal cell membrane, which declines with increasing age.”
Yet, the researchers emphasise that longer term studies are required to validate this effect further, as age-related cognitive decline may be less detectable over the duration of this study.
“Supplementation with Flaxseed Oil Rich in Alpha-Linolenic Acid Improves Verbal Fluency in Healthy Older Adults”
by Toshimi Ogawa, Kento Sawane, Kouta Ookoshi and Ryuta Kawashima