Randomized Controlled Trial

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To examine the effects of Omega-3 fatty acid supplementation on some cognitive and physiological parameters in healthy subjects.

• Males and females
• Healthy subjects

• Only subjects in good health, free of drugs and medications and with negative psychiatric and endocrine histories were enrolled in the experiment. Moreover, they must have performed non-competitive athletic activities for four hours weekly (aerobic activity, range three to six hours).

   

• Heavy smoking (more than eight cigarettes per day)
• Drinking (more than two glasses of spirits per day)
• Caffeine consumption (more than two cups of coffee per day).

Recruitment

• Subjects were recruited from members of the local non-competitive athletic associations
• The experiment was carried out on 33 healthy voluntary subjects comprising 13 males and 20 females in the age group 22 to 51 years (mean 33±7 years). 

Design

• The subjects were randomly assigned to either the Omega-3 or P groups and consumed Omega-3 or P in a blind manner.The subjects were all tested and received a daily supplementation of Omega-3 for 35 days. Omega-3 group consumed eight capsules (4g) of fish oil (FO; 2.8g of Omega-3 PUFAs, EPA + DHA in a ratio of 2.1 and 1.60g of EPA, 0.80g of DHA, 0.40g of other types of Omega-3 PUFAs: Alpha linolenic, stearidonic, eicosatetraenoic and docosapentaenoic acid), while the 16 subjects of P group consumed eight capsules (4g) of olive oil (P) per day.
• Similarly, a group of 16 subjects (four males and 12 females, mean age 33±3 years) was tested with the same experimental procedure and received a daily a supplementation of olive oil, considered as placebo (P), for 35 days
• Subjects were tested at the beginning of the experiment and after 35 days
• Blood samples were taken on day one and day 35 to analyze the specific parameters: Arachidonic acid/eicosapentaenoic acid ratio (AA/EPA), cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL) and glycemia
• Tests involving different types of attention were used, i.e., Alert, Go/No-Go, Choice and Sustained Attention
• The subjects filled in a diary card to record their psychological and mood state and other general information
• For each test, the reaction time, the event-related potentials by electroencephalogram (EEG) and the electromyography (EMG) of the forefinger flexor muscle were recorded. The subjects then completed the Profile of Mood States (POMS) questionnaire and performed a series of attentional tests with concomitant recording of physiological activities, i.e., electroencephalogram (EEG), electromyography (EMG) and electrocardiogram (ECG).
• The subjects filled in the Profile of Mood States (POMS) psychometric scale [46] to assess their psychological state. Mood states are temporary and subjects had to report the mood state of the last five days. The POMS consisted of five negative mood scales:
  • Anger (lowest possible value, 40; highest possible value, 99)
  • Anxiety (34 to 85)
  • Fatigue (88 to 37)
  • Confusion (32 to 92)
  • Depression (41 to 91)
  • One positive scale: Vigor (24 to 75).       

Blinding Used

Blinding is used to randomize the subjects.

Statistical Analysis

• Daily supplementation of olive oil as placebo and omega-3 polyunsaturated fatty acids as active supplement for 35 days
• Omega-3 group consumed eight capsules (4g) of fish oil and subjects of placebo group consumed eight capsules (4g) of olive oil (P) per day
• Data from the various tests and biological measures were collected, averaged and then compared by a paired samples T-test for comparison within the same group and a T-test for independent values when comparing between different groups
• Descriptive statistical analyses were used to define the characteristics of the population studied
• The associations between the primary measures of interest and cofactors (age and gender) were addressed by ANOVA statistical model
• Correlations were measured by Pearson’s R-test.

 

Timing of Measurements

Baseline and at the end of 35 days.

Dependent Variables

Profile of Mood States (POMS); attention tests.

Independent Variables

Age and gender.

 

• Initial N: 33 healthy voluntary subjects comprising 13 males and 20 females
• Attrition (final N): 33
• Age: 22 to 51 years (mean 33±7 years) 
• Ethnicity: Italians
• Other relevant demographics: Habits, health, diet, sleep, smoking, use of drugs, alcohol and caffeine, sport activity and work
• Location: Local non-competitive athletic associations, Italy.

Key Findings

• No association was found between the variables studied and age or gender of subjects. AA/EPA was strongly affected by Omega-3 treatment.
• The groups Omega-3 and P did not differ at day one (mean values: 16.39±8.32 vs. 16.17±10.63)
• Comparisons between day one and day 35 in each group, after P and after Omega-3 supplementation, revealed a strong decrease of AA/EPA after Omega-3 [mean values, before Omega-3 (14.26±8.87) and after Omega-3 (4.29±2.60) T=6.89; P<0.0001], while no significant differences were observed after P
• Other blood parameters did not show significant variations
• Supplementation with Omega-3 PUFAs was associated with a clear variation of the profile of mood state
• The POMS analysis showed an increase of vigor and a decrease of the other mood states (anger, anxiety, fatigue, depression, confusion)
• Vigor and the other mood states did not differ from the period preceding the olive oil supplementation
• The reaction time (RT) decreased only after Omega-3 supplementation. This reduction occurred in Go/No-Go and Sustained Attention test, but no significant effects were observed in the Alert and Choice tests.
• The effect was particularly evident in the Sustained Attention test and the reduction of RT appeared to have been distributed over the entire test period with a concomitant reduction of variability after Omega-3 supplementation
• There was also a significant reduction in the number of errors from a mean of four to two errors/test after Omega-3 (P<0.04)
• The decrease of RT after Omega-3 supplementation could have been owing to a reduction of the latency of EMG activation of the forefinger flexor muscle engaged in pressing the computer key (time from onset of the stimulus to beginning of EMG activation N= EMG latency), or to an increase in the speed of contraction of the same muscle (time from the beginning of EMG activation to RT).
• The latter measurement did not show any significant variation the EMG latency was reduced in Go/No-Go, Choice and Sustained Attention tests after Omega-3 supplementation
• The event-related potentials showed no significant variations during Alert, Choice and Sustained Attention tests, while a change in the wave amplitude occurred in the Go/No-Go test after Omega-3 supplementation
• There was an increase in amplitude for the negative wave preceding the stimulus (CNV) and for P3, the positive peak after the stimulus
• The negative peak of the pre-stimulus wave passed through -30μV to -60μV after Omega-3 (P<0.0003)
• The P3 positive peak recorded before and after Omega-3 supplementation showed an increase in the amplitude in both the Go trial [peak amplitude mean values: before Omega-3 (43.77±42.80μV) and after Omega-3 (84.27±75.23μV); T=2.46; P<0.02] and No-Go trial [peak amplitude mean values: before Omega-3 (37.40±35.23μV) and after Omega-3 (75.65±69.28μV); T=2.40; P<0.02]
• In particular, after Omega-3 the percentage of the beta-2 band decreased significantly in all the tests and in the relaxation period. Its reduction was accompanied by a concomitant increase of the theta and alpha bands.
• The analysis of possible relationships between the variation of frequency percentage and other physiological parameters revealed a positive correlation between the theta band percentage in the Sustained Attention test and the vigor state recorded in POMS
• The results of the POMS questionnaire showed an enhanced vigor state and a concomitant decrease of the negative mood states after Omega-3 supplementation.

• The results of this experiment revealed an influence of Omega-3 on the activity of the central nervous system
• This was shown by the improvement of reactivity, attention and cognitive performances in addition to the improvement of mood state and the modifications of some neuro-electrical parameters
• These results have been obtained from a small study group and need further confirmation in a wider group of subjects and in particular for the possible influences of age and gender
• The absence of association between the variable studied and age or gender, observed in the present experiment, may be owing to the limited number of subjects
• It may be assumed that the importance of these results is strengthened by the fact that they occur in subjects in good health and performing physical activity in whom Omega-3 fatty acids improve an already good condition of well-being.

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• A very small study and study duration is only 35 days
• It is not a double blind trial
• The pilot study results are showing positive impact of omega 3 fatty acids and an improvement of reactivity, attention and cognitive performances in addition to the improvement of mood state and the modifications of some neuro-electrical parameters in healthy subjects
• Further studies are required in a large population including EPA, DHA and the ratio of EPA/DHA and AA/EPA on mood state and other neuro-electrical parameters.