The Effects of a 6-Month High Dose Omega-3 and Omega-6 Polyunsaturated Fatty Acids and Antioxidant Vitamins Supplementation on Cognitive Function and Functional Capacity in Older Adults with Mild Cognitive Impairment

Abstract

The aim of the present study was to examine the effects of a high-dose omega-3 and omega-6 fatty acids supplementation, in combination with antioxidant vitamins, on cognitive function and functional capacity of older adults with mild cognitive impairment (MCI), over a 6-month period in a randomized, double-blind, placebo-controlled trial. Forty-six older adults with MCI (age: 78.8 ± 7.3 years) were randomized 1:1 to receive either a 20 mL dose of a formula containing a mixture of omega-3 (810 mg Eicosapentaenoic acid and 4140 mg Docosahexaenoic acid) and omega-6 fatty acids (1800 mg gamma-Linolenic acid and 3150 mg Linoleic acid) (1:1 w/w), with 0.6 mg vitamin A, vitamin E (22 mg) plus pure γ-tocopherol (760 mg), or 20 mL placebo containing olive oil. Participants completed assessments of cognitive function, functional capacity, body composition and various aspects of quality of life at baseline and following three and six months of supplementation. Thirty-six participants completed the study (eighteen from each group). A significant interaction between supplementation and time was found on cognitive function (Addenbrooke’s Cognitive Examination -Revised (ACE-R), Mini-Mental State Examination (MMSE) and Stroop Color and Word Test (STROOP) color test; p < 0.001, p = 0.011 and p = 0.037, respectively), functional capacity (6-min walk test and sit-to-stand-60; p = 0.028 and p = 0.032, respectively), fatigue (p < 0.001), physical health (p = 0.007), and daily sleepiness (p = 0.007)—showing a favorable improvement for the participants receiving the supplement. The results indicate that this nutritional modality could be promising for reducing cognitive and functional decline in the elderly with MCI.

Importance of EPA and DHA Blood Levels in Brain Structure and Function

“…When intervention trials on parameters of cognition published up to 2015 were broken down according to dose of DHA used, it became apparent that trials using more than 600 mg DHA per day had positive results in terms of aspects of memory, executive function, or aspects of learning, while those using lower doses largely had neutral results [ 12 ]. However, more recently, both neutral and positive results were published with doses >600 mg DHA per day [ 119 , 120 , 121 , 122 , 123 , 124 , 125 ]. One trial found the improvement in executive function and verbal fluency to correlate with the increase of EPA in red cells, as well as improvements in pertinent brain structures [ 126 ].…”

Self-Reported Omega-3 Supplement Use Moderates the Association between Age and Exercising Cerebral Blood Flow Velocity in Older Adults

“…For example, the connection between atherosclerosis and dementia has been well-established [43], and a meta-analysis of randomized controlled trials showed that omega-3 fatty acids significantly slowed the progression of atherosclerosis [44], suggesting that omega-3 fatty acids could potentially prevent cognitive decline through improvements in vascular health. One recent trial showed that six months of supplementation with omega-3 and omega-6 fatty acids in combination with antioxidant vitamins reduced both cognitive and functional decline in adults with mild cognitive impairment [5]. Although mechanistic pathways were outside the scope of the secondary analysis, the authors suggested that omega fatty acids may have acted partially through improvements in endothelial function [5].…”

“…One recent trial showed that six months of supplementation with omega-3 and omega-6 fatty acids in combination with antioxidant vitamins reduced both cognitive and functional decline in adults with mild cognitive impairment [5]. Although mechanistic pathways were outside the scope of the secondary analysis, the authors suggested that omega fatty acids may have acted partially through improvements in endothelial function [5]. Indeed, the observed improvement in functional capacity, including an increase in distance walked on the 6-min walk test, coupled with enhanced cognitive function [5] points to a systemic effect of supplementation, which could be explained by whole-body improvement in vascular function that includes higher CBF.…”

“…Although mechanistic pathways were outside the scope of the secondary analysis, the authors suggested that omega fatty acids may have acted partially through improvements in endothelial function [5]. Indeed, the observed improvement in functional capacity, including an increase in distance walked on the 6-min walk test, coupled with enhanced cognitive function [5] points to a systemic effect of supplementation, which could be explained by whole-body improvement in vascular function that includes higher CBF. Future studies that measure changes in CBF would provide evidence for this mechanistic pathway.…”

“…For example, one double-blind, placebo-controlled study found that dietary supplementation with fish oil increased CBF during cognitive tasks in healthy young adults [4]. More recently, a randomized controlled trial in older adults with mild cognitive impairment showed that omega-3 fatty acid supplementation reduced cognitive and functional decline [5]. While this trial did not explore the mechanisms through which omega-3 consumption improved brain function, a previous study found that fish oil supplementation improved the CBF response to hypercapnia and to cognitive stimuli in older adults with borderline hypertension [6], suggesting that omega-3 may act mechanistically by improving blood flow to the brain.…”