Omega 3 Fatty Acids
Omega 3 fatty acids are a class of fats most commonly found in fish and seafood. There are several different types the most common being Docosahexaenoic acid (DHA) and Eicosapentaeonic acid (EPA). The current review of the research points to a very likely benefit in cognition from consumption of mainly DHA. Many studies show that deficiency leads to cognitive deficits so in a way omega 3 can firstly be thought of as a vitamin necessary for normal brain function. Indeed numerous studies demonstrate its ability to reverse or prevent cognitive deficits related to aging or stress supporting its action as essential to normal function.
In terms of its effects in healthy individuals the results are mixed. Some show enhancement while others do not. What is clear however is that omega 3 increases molecules and receptors in the brain that are associated with learning and memory. In addition higher omega 3 consumption is associated with more grey matter in the brain.
Where omega 3 seems to have the most promise in healthy people is in combination with other brain enhancing factors. Uridine, lutein and exercise have demonstrated synergistic cognitive enhancements when combined with omega 3 in healthy individuals. Combination with phosphatidylserine show promise for older brains. In conclusion omega 3 fatty acids (in particular DHA) are worth consuming for those wishing to maintain or repair cognitive function. For enhancement above normal functioning they become valuable when used in combination with other strategies.
Most beneficial for - All people wanting to improve cognition (use in combination in healthy brains)
Effective dose - 400mg/day of DHA or about 4g of fish oil
Length until action - 4 weeks (may begin to see benefits after 12 days)
Safety - very safe and well tolerated
Cognition affected - may enhance spacial learning, attention, verbal learning and working memory
Synergists - uridine, lutein, exercise and phosphatidylserine
Supporting Human Studies
Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects (Fontani et al, 2005)
Thirty three healthy human subjects were given either omega 3 supplements or olive oil for 35 days. The dosage was 4g of fish oil or 800mg of EPA and 400mg of DHA. Testing showed omega 3 supplementation increased vigor and reduced anxiety, anger and depression states. Attention and reaction times also showed significant improvements. These tests involved complex cortical processing demonstrating this to be an area likely effected by the omega 3 supplementation.
Serum phospholipid docosahexaenonic acid is associated with cognitive functioning during middle adulthood (Muldoon et al, 2010)
Two hundred and eighty community volunteers aged between 35 and 54 and without any neuropsychiatric disorders or taking fish oil completed this study. They completed a series of cognitive tests and were examined for serum omega 3 fatty acid levels. Higher serum DHA was associated with improved performance of nonverbal reasoning, mental flexibility, working memory and vocabulary. The other omega 3 fatty acids EPA and ALA were not associated with improved cognition.
A randomised control trial in schoolchildren showed improvement in cognitive function after consuming a bread spread, containing fish flour from a marine source (Dalton et al, 2009)
One hundred and eighty three children between 7-9 received either a fish oil enriched diet or a placebo diet. The group consuming the fish oil diet showed significant increases in verbal learning, discrimination and spelling tasks. They showed a more marginal improvement in reading tasks.
Dietary intake of fatty acids and fish in relation to cognitive performance at middle age (Kalmijn et al, 2004)
A cross sectional population based study involving 1613 people from 45 to 70 tested cognition over a five year period. Participants were questioned on dietary habits such as fish consumption. Fish and/or omega 3 consumption was correlated with a significantly lower risk of impaired overall cognitive function.
Fish consumption, n–3 fatty acids, and subsequent 5-y cognitive decline in elderly men: the Zutphen Elderly Study (van Gelder et al, 2007)
Two hundred and ten participants between 79-90 who participated in an earlier study on cognition were analyzed for their long term fish consumption. Those who consumed the most fish had significantly less cognitive decline after 5 years.
n 3 fatty acid proportions in plasma and cognitive performance in older adults (Dullenmeijer et al, 2007)
Eight hundred and seven men and women aged 50-70 underwent regular testing of omega 3 serum levels as well as cognitive function over 3 years. Higher plasma omega 3 levels participants showed less decline in sensorimotor speed and complex speed tests over 3 years. Higher levels were not associated with any changes in memory, information processing or word fluency.
The effects of omega-3 fatty acids monotherapy in Alzheimer's disease and mild cognitive impairment: A preliminary randomized double-blind placebo-controlled study (Chih-Chiang et al, 2008)
Twenty three participants with mild cognitive impairment and 23 participants with Alzheimer's disease received either 1.8g/day of omega 3 fatty acids or a placebo for 24 weeks. All those taking the omega 3 showed an improvement in the clinician interview based impression compared to the placebo group. Cognition did not improve in Alzheimer's patients however there was significant improvement in cognitive parameters in the mildly cognitive impaired taking the omega 3 compared to the control group. No adverse effects were observed by those taking the omega 3.
Dietary supplementation of arachidonic and docosahexaenoic acids improves cognitive dysfunction (Kotani et al, 2006)
Twenty one patients with mild cognitive impairment, 10 with organic brain lesions and 8 Alzheimer's disease patients were given 240mg per day of a DHA/EPA mix for 90 days or a placebo. Immediate memory was significantly improved in the mildly cognitive impaired group and the organic lesion group. Attention improved in the mild cognitive impaired group and delayed memory improved in the organic lesion group. There were no improvements in the Alzheimer's disease group or those taking a placebo.
Long-chain omega-3 fatty acid intake is associated positively with corticolimbic gray matter volume in healthy adults (Conklin et al, 2007)
Fifty five healthy adults completed interviews about their dietary habits including intake of omega 3 fatty acids. Their brains then underwent MRI to determine the amount of gray matter (brain cells) in certain brain regions (Anterior cingulate cortex, amygdala and hippocampus). People who consumed more omega 3 fatty acids showed larger volumes in gray matter in the subgenual anterior cingulate cortex, right hippocampus and right amygdala. These brain regions are associated with memory and mood.
Supporting Animal Studies
Omega-3 Fatty acids from fish oil lower anxiety, improve cognitive functions and reduce spontaneous locomotor activity in a non-human primate (Vinot et al, 2011)
Adult male lemurs were fed a diet supplemented with omega 3 or a control diet for 5 months. Test revealed that monkeys fed the omega 3 diets performed significantly better on spacial memory tasks and also had lowered levels of anxiety.
Omega-3 fatty acids reverse age-related decreases in nuclear receptors and increase neurogenesis in old rats (Dyall et al, 2010)
Aged rats were fed diets containing omega 3 fatty acids at the concentrations of 270mg/kg/day EPA/DHA mix or 300mg/kg/day DHA only for 12 weeks. Rats brains were evaluated for several markers of memory, cognition and neurogenesis. Both groups receiving the omega 3 supplementation showed increases in brain markers for memory cognition and neurogenesis. These effects were seen to restore these markers to levels normally seen in healthy adult mice.
Effect of the long-term feeding of dietary lipids on the learning ability, fatty acid composition of brain stem phospholipids and synaptic membrane fluidity in adult mice: a comparison of sardine oil diet with palm oil diet (Suzuki et al, 1998)
Mice were fed a 5% palm oil or sardine oil diet for 12 months. Those mice on the sardine oil diet performed better in maze learning tasks and had higher brain DHA levels as well as synaptic membrane fluidity.
Fish Oil Supplementation of Control and (n-3) Fatty Acid-Deficient Male Rats Enhances Reference and Working Memory Performance and Increases Brain Regional Docosahexaenoic Acid Levels (Wan-Ling et al, 2008)
From birth rats were fed a diet with or without fish oil. They then underwent testing at 103-130 days after birth. Those consuming the fish oil had performed better on memory test then those without. Rat with the fish oil deficient diet were then supplemented with fish oil. This improved their scores on spacial learning memory tests. Normal rats that did not undergo a fish oil deficient diet during development were supplemented with fish oil as adults. They showed improvements in both working memory and spacial learning memory.
Chronic administration of docosahexaenoic acid improves reference memory-related learning ability in young rats (Gamoh et al, 1999)
Rats were fed a fish oil deficient diet from birth. After 5 weeks they were divided in to those receiving DHA supplementation at 300mg/kg/day and those without. Memory test were performed after 5 and 10 weeks on this diet. The DHA supplementation over 10 weeks significantly improved reference memory but not working memory.
Age-related changes in synaptic function: analysis of the effect of dietary supplementation with ω-3 fatty acids (McGahon et al, 1999)
Aged rats were fed a diet containing omega 3 fatty acids for 8 weeks. Aged rats were shown to have decreased brain function and decreased neurotransmitter release compared to young rats before the study began. The 8 weeks of omega 3 supplementation reversed deficits in long term potentiation and neurotransmitter release. It also brought levels of omega 3 fatty acids levels in the brain in line with those of younger rats.
An n-3 fatty acid deficient diet affects mouse spatial learning in the Barnes circular maze (Fedorova et al, 2007)
Mice raised on a omega 3 deficient diet showed no differences in locomotor activity, working memory or anxiety tests. However their reference memory and learning was impaired compared to a control group.
Omega-3 fatty acid ethyl-eicosapentaenoate, but not soybean oil, attenuates memory impairment induced by central IL-1β administration (Song and Horrobin, 2004)
Rats were fed a diet with or without the omega 3 fatty acid EPA. They were then injected with the pro-inflammatory cytokine IL-1beta. IL-1beta has been shown to cause cognitive impairment. Rats fed the EPA diet did not suffer memory and cognition problems as much as the non-EPA group.
Long-term administration of cod liver oil ameliorates cognitive impairment induced by chronic stress in rats (Trofimiuk and Braszko, 2011)
Cod liver oil is a rich source of omega 3 fatty acids. Chronically stressed rats were fed a cod liver oil diet or a control diet. Dosage was equivalent to 300mg/kg DHA and 225mg/kg EPA daily. Cod liver oil supplementation was found to prevent the deleterious effects of chronic stress on memory recall and spacial memory. Codliver oil also contains high levels of vitamin A and D so it is unclear if these also contributed to the result.
Effects of dietary omega-3 polyunsaturated fatty acids on brain gene expression (Kitajka et al, 2004)
Rats were fed diets of omega 3 fatty acids over differing periods of there lives. There brains were then examined for changes in gene expression. Omega 3 was shown to increase a number of molecules associated with brain plasticity and learning.
Contradictory Studies
Omega-3 fatty acids (fish-oil) and depression-related cognition in healthy volunteers (Antypa et al, 2009)
In this double blind placebo controlled trial 54 healthy students received either omega 3 fatty acids daily or a placebo for 4 weeks. A few improvements were observed in risk and control/perfectionism tests but not in other areas of cognition such as attention or memory.
Effect of fish oil on cognitive performance in older subjects (van de Rest et al, 2008)
A double blind placebo controlled trial involving 302 cognitively healthy individuals over 65 years of age. Participants received either 1800mg EPA/DHA, 400mg EPA/DHA or a placebo for 26 weeks. Cognitive testing showed no significant differences between any of the groups despite blood plasma concentrations rising significantly in those taking fish oil.
Intakes of (n-3) fatty acids and fatty fish are not associated with cognitive performance and 6-year cognitive change in men participating in the Veterans Affairs Normative Aging Study (van de Rest et al, 2009)
Over 6 years 1025 elderly men were assessed for fish and/or omega 3 fatty acid intake and cognitive function. The mean age was 68 years. No significant associations were observed between fish/omega 3 intake and cognitive performance.
Cognitive and mood effects of 8 weeks' supplementation with 400 mg or 1000 mg of the omega-3 essential fatty acid docosahexaenoic acid (DHA) in healthy children aged 10-12 years (Kennedy et al, 2009)
This double blind placebo controlled trial gave 90 healthy children between 10-12 either 400mg of DHA, 1000mg of DHA or a placebo daily for 8 weeks. The 400mg group showed a significant improvement in a word recognition test. However all other test showed no differences.
Combinational Studies
Chronic administration of DHA and UMP improves the impaired memory of environmentally impoverished rats (Holguin et al, 2008)
Omega 3 (DHA) at 300mg/kg and uridine monophosphate (UMP) at 0.5% of diets were fed to rats from both enriched (EE) and impoverished environments (IE). All groups of rats were consuming choline in their diets. The administration of the DHA/UMP combination improved IE rats performance in a water maze but not EE rats. Administration of the DHA/UMP was also shown to increase concentrations of brain phospholipids. It was determined that the DHA/UMP could reverse memory deficits caused by an impoverished environment and this was related to hippocampal processing.
Cognitive findings of an exploratory trial of docosahexaenoic acid and lutein supplementation in older women (Johnson et al, 2008)
Forty nine women aged 60-80 without cognitive problems received DHA (800mg/day), lutein (12mg/day), both in combination or a placebo for 4 months. Testing at the completion of the trial showed verbal fluency improved in the DHA, lutein and combination groups but not the placebo. Significant improvements were observed in memory and rate of learning in the combination group but not the other groups. The combination group also showed a less significant improvement in efficiency of learning. Mental processing speed, mood and accuracy tests were not affected by supplementation.
Dietary uridine enhances the improvement in learning and memory produced by administering DHA to gerbils (Holguin et al, 2008)
Normal adult gerbils were given choline (0.1% of diet), Uridine (UMP at 0.5% of diet), DHA (300mg/kg) or various combinations of all 3 daily for 4 weeks. The DHA plus choline group showed improvements in various maze tests compared to control groups. Co-administration with UMP further enhanced maze performance.
The effect of phosphatidylserine-containing omega-3 fatty acids on memory abilities in subjects with subjective memory complaints: a pilot study (Richter et al, 2010)
Omega 3 fatty acids containing phosphatidylserine were administered daily elderly people with subjective memory complaints for 6 weeks. Tests showed a 42% improvement in the ability to recall words in the delayed condition.
Phosphatidylserine containing omega-3 fatty acids may improve memory abilities in non-demented elderly with memory complaints: a double-blind placebo-controlled trial (Vakhapova et al, 2010)
One hundred and fifty seven elderly with memory complaints received a phosphatidylserine/omega 3 supplement or a placebo for 15 weeks. At the end of the study verbal immediate recall was significantly improved by the phosphatidylserine/omega 3 supplement. Those that began the study with good cognitive performance who took the supplement also showed significant improvement in delayed recall, learning abilities and time to copy a complex figure. These improvements were not observed in those beginning the study with poor cognitive scores.
Exercise contributes to the effects of DHA dietary supplementation by acting on membrane-related synaptic systems (Chytrova et al, 2010)
Rat were given a 12 day supplementation of DHA or exercise or both. Rats on each regimen showed improved learning and performance on a water maze. Also when rat brains were analyzed they were found to have increased levels of molecules and receptors associated with memory and learning. The combination of both regimens showed and additive effect. These rats had the most learning improvement and highest levels of memory molecules and receptors.
Docosahexaenoic acid dietary supplementation enhances the effects of exercise on synaptic plasticity and cognition (Wu et al, 2008)
Rats received DHA supplementation (1.25% of diet) with or without exercise for 12 days. The DHA diet was found to increase spacial learning abilities. This was further enhanced by exercise. Several brain molecules related to learning and synaptic plasticity were increased by DHA. Levels of these were further increased by exercise.
In terms of its effects in healthy individuals the results are mixed. Some show enhancement while others do not. What is clear however is that omega 3 increases molecules and receptors in the brain that are associated with learning and memory. In addition higher omega 3 consumption is associated with more grey matter in the brain.
Where omega 3 seems to have the most promise in healthy people is in combination with other brain enhancing factors. Uridine, lutein and exercise have demonstrated synergistic cognitive enhancements when combined with omega 3 in healthy individuals. Combination with phosphatidylserine show promise for older brains. In conclusion omega 3 fatty acids (in particular DHA) are worth consuming for those wishing to maintain or repair cognitive function. For enhancement above normal functioning they become valuable when used in combination with other strategies.
Most beneficial for - All people wanting to improve cognition (use in combination in healthy brains)
Effective dose - 400mg/day of DHA or about 4g of fish oil
Length until action - 4 weeks (may begin to see benefits after 12 days)
Safety - very safe and well tolerated
Cognition affected - may enhance spacial learning, attention, verbal learning and working memory
Synergists - uridine, lutein, exercise and phosphatidylserine
Supporting Human Studies
Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects (Fontani et al, 2005)
Thirty three healthy human subjects were given either omega 3 supplements or olive oil for 35 days. The dosage was 4g of fish oil or 800mg of EPA and 400mg of DHA. Testing showed omega 3 supplementation increased vigor and reduced anxiety, anger and depression states. Attention and reaction times also showed significant improvements. These tests involved complex cortical processing demonstrating this to be an area likely effected by the omega 3 supplementation.
Serum phospholipid docosahexaenonic acid is associated with cognitive functioning during middle adulthood (Muldoon et al, 2010)
Two hundred and eighty community volunteers aged between 35 and 54 and without any neuropsychiatric disorders or taking fish oil completed this study. They completed a series of cognitive tests and were examined for serum omega 3 fatty acid levels. Higher serum DHA was associated with improved performance of nonverbal reasoning, mental flexibility, working memory and vocabulary. The other omega 3 fatty acids EPA and ALA were not associated with improved cognition.
A randomised control trial in schoolchildren showed improvement in cognitive function after consuming a bread spread, containing fish flour from a marine source (Dalton et al, 2009)
One hundred and eighty three children between 7-9 received either a fish oil enriched diet or a placebo diet. The group consuming the fish oil diet showed significant increases in verbal learning, discrimination and spelling tasks. They showed a more marginal improvement in reading tasks.
Dietary intake of fatty acids and fish in relation to cognitive performance at middle age (Kalmijn et al, 2004)
A cross sectional population based study involving 1613 people from 45 to 70 tested cognition over a five year period. Participants were questioned on dietary habits such as fish consumption. Fish and/or omega 3 consumption was correlated with a significantly lower risk of impaired overall cognitive function.
Fish consumption, n–3 fatty acids, and subsequent 5-y cognitive decline in elderly men: the Zutphen Elderly Study (van Gelder et al, 2007)
Two hundred and ten participants between 79-90 who participated in an earlier study on cognition were analyzed for their long term fish consumption. Those who consumed the most fish had significantly less cognitive decline after 5 years.
n 3 fatty acid proportions in plasma and cognitive performance in older adults (Dullenmeijer et al, 2007)
Eight hundred and seven men and women aged 50-70 underwent regular testing of omega 3 serum levels as well as cognitive function over 3 years. Higher plasma omega 3 levels participants showed less decline in sensorimotor speed and complex speed tests over 3 years. Higher levels were not associated with any changes in memory, information processing or word fluency.
The effects of omega-3 fatty acids monotherapy in Alzheimer's disease and mild cognitive impairment: A preliminary randomized double-blind placebo-controlled study (Chih-Chiang et al, 2008)
Twenty three participants with mild cognitive impairment and 23 participants with Alzheimer's disease received either 1.8g/day of omega 3 fatty acids or a placebo for 24 weeks. All those taking the omega 3 showed an improvement in the clinician interview based impression compared to the placebo group. Cognition did not improve in Alzheimer's patients however there was significant improvement in cognitive parameters in the mildly cognitive impaired taking the omega 3 compared to the control group. No adverse effects were observed by those taking the omega 3.
Dietary supplementation of arachidonic and docosahexaenoic acids improves cognitive dysfunction (Kotani et al, 2006)
Twenty one patients with mild cognitive impairment, 10 with organic brain lesions and 8 Alzheimer's disease patients were given 240mg per day of a DHA/EPA mix for 90 days or a placebo. Immediate memory was significantly improved in the mildly cognitive impaired group and the organic lesion group. Attention improved in the mild cognitive impaired group and delayed memory improved in the organic lesion group. There were no improvements in the Alzheimer's disease group or those taking a placebo.
Long-chain omega-3 fatty acid intake is associated positively with corticolimbic gray matter volume in healthy adults (Conklin et al, 2007)
Fifty five healthy adults completed interviews about their dietary habits including intake of omega 3 fatty acids. Their brains then underwent MRI to determine the amount of gray matter (brain cells) in certain brain regions (Anterior cingulate cortex, amygdala and hippocampus). People who consumed more omega 3 fatty acids showed larger volumes in gray matter in the subgenual anterior cingulate cortex, right hippocampus and right amygdala. These brain regions are associated with memory and mood.
Supporting Animal Studies
Omega-3 Fatty acids from fish oil lower anxiety, improve cognitive functions and reduce spontaneous locomotor activity in a non-human primate (Vinot et al, 2011)
Adult male lemurs were fed a diet supplemented with omega 3 or a control diet for 5 months. Test revealed that monkeys fed the omega 3 diets performed significantly better on spacial memory tasks and also had lowered levels of anxiety.
Omega-3 fatty acids reverse age-related decreases in nuclear receptors and increase neurogenesis in old rats (Dyall et al, 2010)
Aged rats were fed diets containing omega 3 fatty acids at the concentrations of 270mg/kg/day EPA/DHA mix or 300mg/kg/day DHA only for 12 weeks. Rats brains were evaluated for several markers of memory, cognition and neurogenesis. Both groups receiving the omega 3 supplementation showed increases in brain markers for memory cognition and neurogenesis. These effects were seen to restore these markers to levels normally seen in healthy adult mice.
Effect of the long-term feeding of dietary lipids on the learning ability, fatty acid composition of brain stem phospholipids and synaptic membrane fluidity in adult mice: a comparison of sardine oil diet with palm oil diet (Suzuki et al, 1998)
Mice were fed a 5% palm oil or sardine oil diet for 12 months. Those mice on the sardine oil diet performed better in maze learning tasks and had higher brain DHA levels as well as synaptic membrane fluidity.
Fish Oil Supplementation of Control and (n-3) Fatty Acid-Deficient Male Rats Enhances Reference and Working Memory Performance and Increases Brain Regional Docosahexaenoic Acid Levels (Wan-Ling et al, 2008)
From birth rats were fed a diet with or without fish oil. They then underwent testing at 103-130 days after birth. Those consuming the fish oil had performed better on memory test then those without. Rat with the fish oil deficient diet were then supplemented with fish oil. This improved their scores on spacial learning memory tests. Normal rats that did not undergo a fish oil deficient diet during development were supplemented with fish oil as adults. They showed improvements in both working memory and spacial learning memory.
Chronic administration of docosahexaenoic acid improves reference memory-related learning ability in young rats (Gamoh et al, 1999)
Rats were fed a fish oil deficient diet from birth. After 5 weeks they were divided in to those receiving DHA supplementation at 300mg/kg/day and those without. Memory test were performed after 5 and 10 weeks on this diet. The DHA supplementation over 10 weeks significantly improved reference memory but not working memory.
Age-related changes in synaptic function: analysis of the effect of dietary supplementation with ω-3 fatty acids (McGahon et al, 1999)
Aged rats were fed a diet containing omega 3 fatty acids for 8 weeks. Aged rats were shown to have decreased brain function and decreased neurotransmitter release compared to young rats before the study began. The 8 weeks of omega 3 supplementation reversed deficits in long term potentiation and neurotransmitter release. It also brought levels of omega 3 fatty acids levels in the brain in line with those of younger rats.
An n-3 fatty acid deficient diet affects mouse spatial learning in the Barnes circular maze (Fedorova et al, 2007)
Mice raised on a omega 3 deficient diet showed no differences in locomotor activity, working memory or anxiety tests. However their reference memory and learning was impaired compared to a control group.
Omega-3 fatty acid ethyl-eicosapentaenoate, but not soybean oil, attenuates memory impairment induced by central IL-1β administration (Song and Horrobin, 2004)
Rats were fed a diet with or without the omega 3 fatty acid EPA. They were then injected with the pro-inflammatory cytokine IL-1beta. IL-1beta has been shown to cause cognitive impairment. Rats fed the EPA diet did not suffer memory and cognition problems as much as the non-EPA group.
Long-term administration of cod liver oil ameliorates cognitive impairment induced by chronic stress in rats (Trofimiuk and Braszko, 2011)
Cod liver oil is a rich source of omega 3 fatty acids. Chronically stressed rats were fed a cod liver oil diet or a control diet. Dosage was equivalent to 300mg/kg DHA and 225mg/kg EPA daily. Cod liver oil supplementation was found to prevent the deleterious effects of chronic stress on memory recall and spacial memory. Codliver oil also contains high levels of vitamin A and D so it is unclear if these also contributed to the result.
Effects of dietary omega-3 polyunsaturated fatty acids on brain gene expression (Kitajka et al, 2004)
Rats were fed diets of omega 3 fatty acids over differing periods of there lives. There brains were then examined for changes in gene expression. Omega 3 was shown to increase a number of molecules associated with brain plasticity and learning.
Contradictory Studies
Omega-3 fatty acids (fish-oil) and depression-related cognition in healthy volunteers (Antypa et al, 2009)
In this double blind placebo controlled trial 54 healthy students received either omega 3 fatty acids daily or a placebo for 4 weeks. A few improvements were observed in risk and control/perfectionism tests but not in other areas of cognition such as attention or memory.
Effect of fish oil on cognitive performance in older subjects (van de Rest et al, 2008)
A double blind placebo controlled trial involving 302 cognitively healthy individuals over 65 years of age. Participants received either 1800mg EPA/DHA, 400mg EPA/DHA or a placebo for 26 weeks. Cognitive testing showed no significant differences between any of the groups despite blood plasma concentrations rising significantly in those taking fish oil.
Intakes of (n-3) fatty acids and fatty fish are not associated with cognitive performance and 6-year cognitive change in men participating in the Veterans Affairs Normative Aging Study (van de Rest et al, 2009)
Over 6 years 1025 elderly men were assessed for fish and/or omega 3 fatty acid intake and cognitive function. The mean age was 68 years. No significant associations were observed between fish/omega 3 intake and cognitive performance.
Cognitive and mood effects of 8 weeks' supplementation with 400 mg or 1000 mg of the omega-3 essential fatty acid docosahexaenoic acid (DHA) in healthy children aged 10-12 years (Kennedy et al, 2009)
This double blind placebo controlled trial gave 90 healthy children between 10-12 either 400mg of DHA, 1000mg of DHA or a placebo daily for 8 weeks. The 400mg group showed a significant improvement in a word recognition test. However all other test showed no differences.
Combinational Studies
Chronic administration of DHA and UMP improves the impaired memory of environmentally impoverished rats (Holguin et al, 2008)
Omega 3 (DHA) at 300mg/kg and uridine monophosphate (UMP) at 0.5% of diets were fed to rats from both enriched (EE) and impoverished environments (IE). All groups of rats were consuming choline in their diets. The administration of the DHA/UMP combination improved IE rats performance in a water maze but not EE rats. Administration of the DHA/UMP was also shown to increase concentrations of brain phospholipids. It was determined that the DHA/UMP could reverse memory deficits caused by an impoverished environment and this was related to hippocampal processing.
Cognitive findings of an exploratory trial of docosahexaenoic acid and lutein supplementation in older women (Johnson et al, 2008)
Forty nine women aged 60-80 without cognitive problems received DHA (800mg/day), lutein (12mg/day), both in combination or a placebo for 4 months. Testing at the completion of the trial showed verbal fluency improved in the DHA, lutein and combination groups but not the placebo. Significant improvements were observed in memory and rate of learning in the combination group but not the other groups. The combination group also showed a less significant improvement in efficiency of learning. Mental processing speed, mood and accuracy tests were not affected by supplementation.
Dietary uridine enhances the improvement in learning and memory produced by administering DHA to gerbils (Holguin et al, 2008)
Normal adult gerbils were given choline (0.1% of diet), Uridine (UMP at 0.5% of diet), DHA (300mg/kg) or various combinations of all 3 daily for 4 weeks. The DHA plus choline group showed improvements in various maze tests compared to control groups. Co-administration with UMP further enhanced maze performance.
The effect of phosphatidylserine-containing omega-3 fatty acids on memory abilities in subjects with subjective memory complaints: a pilot study (Richter et al, 2010)
Omega 3 fatty acids containing phosphatidylserine were administered daily elderly people with subjective memory complaints for 6 weeks. Tests showed a 42% improvement in the ability to recall words in the delayed condition.
Phosphatidylserine containing omega-3 fatty acids may improve memory abilities in non-demented elderly with memory complaints: a double-blind placebo-controlled trial (Vakhapova et al, 2010)
One hundred and fifty seven elderly with memory complaints received a phosphatidylserine/omega 3 supplement or a placebo for 15 weeks. At the end of the study verbal immediate recall was significantly improved by the phosphatidylserine/omega 3 supplement. Those that began the study with good cognitive performance who took the supplement also showed significant improvement in delayed recall, learning abilities and time to copy a complex figure. These improvements were not observed in those beginning the study with poor cognitive scores.
Exercise contributes to the effects of DHA dietary supplementation by acting on membrane-related synaptic systems (Chytrova et al, 2010)
Rat were given a 12 day supplementation of DHA or exercise or both. Rats on each regimen showed improved learning and performance on a water maze. Also when rat brains were analyzed they were found to have increased levels of molecules and receptors associated with memory and learning. The combination of both regimens showed and additive effect. These rats had the most learning improvement and highest levels of memory molecules and receptors.
Docosahexaenoic acid dietary supplementation enhances the effects of exercise on synaptic plasticity and cognition (Wu et al, 2008)
Rats received DHA supplementation (1.25% of diet) with or without exercise for 12 days. The DHA diet was found to increase spacial learning abilities. This was further enhanced by exercise. Several brain molecules related to learning and synaptic plasticity were increased by DHA. Levels of these were further increased by exercise.