More
and more compelling evidence are pilling up that the 2 out of 3 Omega 3
fatty acids (namely DHA and EPA ) found in fish or fish helps to preserve
cognitive function and prevent life threatening brain disorders such as
Aizheimer Disease, Depression (suicidal tendencies), Dementia,
Schizophrenia and etc .Below are summaries of the latest scientific
research concerning DHA and EPA.
Fish oil protects against Alzheimer's disease
CHICAGO, ILLINOIS. High levels of the omega-3 fatty acid docosahexaenoic
acid (DHA) are found in the more active areas of the brain including the
cerebral cortex, mitochondria, synaptosomes, and synaptic vesicles. At
least one epidemiologic study has shown that patients with Alzheimer's
disease (AD) have significantly lower levels of omega-3 fatty acids in
their plasma phospholipids than do age- matched controls. Researchers at
the Rush-Presbyterian-St. Luke's Medical Center now report that older
people can reduce their risk of developing AD by increasing their intake
of fish and fish oil (DHA). Their study included 815 men and women over
the age of 65 years who had showed no sign of AD during a thorough
baseline examination. About 2 years after the examination all participants
completed a 154- item food frequency questionnaire and provided
information about their current use of supplements. After another 2 years
all participants were again subjected to a thorough, structured neurologic
clinical evaluation to establish the presence or absence of AD. A total of
131 study participants were found to have developed AD over the 3.9-year
follow-up period.
The researchers found that participants who consumed fish just once a
week had a 60% lower risk of developing AD than did those who rarely or
never ate fish. They also observed that participants whose daily intake of
DHA was about 100 mg/day had an incidence of AD which was 70% lower than
those with an intake of 30 mg/day or less.
Eicosapentaenoic acid (EPA), another component of fish oil, showed no
appreciable effect; however, the maximum intake was only 30 mg/day. A high
total intake of omega-3 fatty acids was also strongly correlated with a
reduced risk for AD. Participants with an intake of 1.6 – 4.1 grams/day
had a 70% lower risk than those with an intake below 1.05 grams/day.
Alpha-linolenic acid (flaxseed oil) intake was not associated with AD risk
except in the case of people with the APOE-epsilon 4 allele where a high
intake was strongly protective. The researchers conclude that an increased
intake of fish or omega-3 fatty acids, especially DHA, can substantially
reduce the risk of developing Alzheimer's disease.
Morris, MC, et al. Consumption of fish and n-3 fatty acids and risk of
incident of Alzheimer's disease. Archives of Neurology, Vol. 60, July
2003, pp. 940-46
Friedland, RP. Fish consumption and the risk of Alzheimer disease.
Archives of Neurology, Vol. 60, July 2003, pp. 940-46
Cognitive function and fat intake
PARIS, FRANCE. Several epidemiological studies have shown that a high
dietary intake of linoleic acid and a low intake of fish oils (eicosapentaenoic
acid [EPA] and docosahexaenoic acid [DHA]) are associated with cognitive
impairment and an increased risk of dementia. French researchers now
report that the fatty acid composition in erythrocytes (red blood cells)
is an indicator of the risk of cognitive function decline (ability to
learn, think and remember).
Their study involved 246 men and women (aged 63 to 74 years) who had
the lipid (fatty acid) composition of their erythrocytes analyzed in 1995.
All participants also underwent tests to determine their cognitive
function at baseline and after a 4-year follow-up period. The researchers
found that study participants with high erythrocyte levels of stearic acid
(a saturated fatty acid) had a 91% higher risk of having experienced a
significant decline in cognitive function over the 4 years than did
participants with average levels. Participants with high levels of
linoleic acid (an unsaturated omega-6 acid) had a 59% increased risk of
decline while those with high levels of EPA and DHA had a 41% lower risk
of experiencing cognitive decline than did those with normal levels.
The researchers suggest that the omega-3 fatty acids EPA and especially
DHA help keep the membranes of brain cells more fluid while saturated and
omega-6 fatty acids tend to "harden" them. They believe this and the
anti-inflammatory effects of EPA and DHA are what help preserve cognitive
function.
Heude, Barbara, et al. Cognitive decline and fatty acid composition of
erythrocyte membranes – The EVA Study. American Journal of Clinical
Nutrition, Vol. 77, April 2003, pp. 803-08
Editor's comment: Stearic acid is found in high quantities in
beef, mutton, and pork while omega-6 fatty acids are abundant in
vegetables oils such as safflower, sunflower, and soybean oil. The
long-chain omega-3 fatty acids (EPA and DHA) are found in fatty fish and
fish oils.
Fish oil derivative reduces depression
SHEFFIELD, UNITED KINGDOM. There is considerable evidence that fish oils
help in combating depression and other mental illnesses. What is not quite
clear is whether it is eicosapentaenoic acid (EPA) or docosahexaenoic acid
(DHA) that is the most active component.
The standard medical therapy for depression involves the use of
tricyclic antidepressants or selective serotonin reuptake inhibitors (SSRIs).
These drugs, however, are not terribly effective. Prozac, for example,
produces a 50% improvement in symptoms in only 38% of patients starting
treatment. This is not much better than the placebo effect, which provides
50% improvement in about 25% of patients.
A team of British and Scottish researchers has just completed a study
aimed at determining if the ethyl ester of EPA, ethyl-eicosapentaenoate (EEP),
would be effective in strengthening the beneficial effect of standard
antidepressants. The study involved 60 patients who were already being
treated with SSRIs or tricyclic antidepressants. Fourteen patients
received a placebo while the remaining 46 received either 1, 2 or 4
grams/day of EEP. All participants were evaluated for depression using
several different scales at the beginning of the experiment and after 12
weeks. At the end of the study it was clear that the 1gram/day dosage of
EEP was highly effective in reducing depression and associated conditions
such as sadness, pessimism, inability to work, sleep disturbances, and
diminished sex drive. In most cases, 60- 70% of patients receiving 1
gram/day of EEP showed an improvement of 50% or better. This compares to
only 25% of the patients on the placebo showing a 50% improvement. The
degree of improvement was substantially less in the 2 grams/day and 4
grams/day groups. The researchers speculate that this could be due to the
depletion of the omega-6 fatty acid, arachidonic acid, by an excess of
omega-3 fatty acid (EPA), indicating that the balance between omega-3 and
omega-6 is important when it comes to depression.
The researchers conclude that concurrent treatment with 1 gram/day of
EEP is effective in reducing depression in patients who are still
depressed despite treatment with standard medications. They are now
planning on evaluating EEP on its own as a treatment for depression.
Peet, M. and Horrobin, DF. A dose-ranging study of the effects of
ethyl-eicosapentaenoate in patients with ongoing depression despite
apparently adequate treatment with standard drugs. Archives of General
Psychiatry, Vol. 59, October 2002, pp. 913-19
Fish oils: A cure for depression?
WASHINGTON, DC. On a worldwide basis more working days are lost to
depression than to any other illness. The incidence of depression is
growing with people born within the last 50 years being twice as likely to
suffer from it than were their parents. Dr. Joseph Hibbeln of the National
Institutes of Health believes that the reason for the increase in
depression can be directly attributed to a major shift in dietary
patterns, specifically fat intake. He points out that the vast increase in
the use of soy, corn, palm and cottonseed oils in the last 100 years has
totally changed the traditional ratio of omega-6 to omega-3 fatty acids in
the diet. Soy oil consumption in the US, for example, has increased
thousand-fold in the last 100 years helping to skew the omega-6 to omega-3
ratio from about 1:1 to today's 16:1. This, Dr. Hibbeln believes, spells
trouble. The brain consists pretty well entirely of fat so clearly one's
fat intake could affect one's brain composition, particularly the ion
channels which channel signals in and out of the brain. There is also
evidence that low levels of omega-3 fatty acids are associated with low
levels of the mood hormone serotonin. Dr. Hibbeln's hypothesis is
supported by the fact that the incidence of depression is considerably
lower in countries with a high fish consumption.
Fish, particularly fatty ocean fish, is an excellent source of omega-3
fatty acids and its frequent consumption would help to nudge the ratio
back towards the optimum 1:1. At least three clinical trials have observed
a marked improvement in depressed patients given relatively high doses of
fish oils. This has spurred other scientists to look closer at the
potential benefits of fish oil supplementation. At the moment there are at
least 10 clinical trials underway evaluating fish oils in the treatment of
depression, attention deficit disorder, and schizophrenia.
Small, Meredith F. The happy fat. New Scientist, August 24, 2002, pp.
34-37
Fish consumption reduces suicide risk
KUOPIO, FINLAND. Researchers at the University of Kuopio report that
regular fish consumption reduces the risk of depression and suicide. Their
study involved 1767 Finnish men and women who were evaluated for
depression and suicidal tendencies using the 21-item Beck Depression
Inventory. They were also asked about their fish consumption. The
researchers conclude that people who consume fish twice a week or more
have a 37 per cent lower risk of being depressed and a 43 per cent lower
risk of having thoughts of harming themselves (suicidal tendencies).
The results are consistent with those of a large Japanese study involving
265,000 subjects who were followed up for 17 years. This study found a
decreased risk of suicide among people who consumed fish daily. Dr. Andrew
Stoll, MD of the Harvard Medical School points out that Icelanders who
consume a lot of seafood have far lower rates of seasonal affective
disorder (SAD) than do inhabitants of other countries situated at similar
latitudes. Both Dr. Stoll and the Finnish researchers urge large-scale
trials to conclusively determine whether it is appropriate to recommend
increased fish intake or fish oil supplementation to depressed people or
indeed to the population as a whole.
Tanskanen, Antti, et al. Fish consumption, depression, and suicidality
in a general population. Archives of General Psychiatry, Vol. 58, May
2001, pp. 512-13
Dementia associated with low DHA levels
GUELPH, CANADA. Dementia now affects about 47% of the population over 80
years of age in Western countries. The incidence of Alzheimer's disease, a
leading cause of dementia, is growing especially rapidly. There is no cure
for Alzheimer's disease (AD) and it is not at all clear what causes it.
Researchers at the University of Guelph now report that they have found
low levels of long-chain polyunsaturated fatty acids, notably DHA (docosahexaenoic
acid) in people suffering from AD and dementia.
The study involved 84 people (aged 80 years or older) who were given a
thorough clinical evaluation. Nineteen of the people were diagnosed as
having AD, 10 as having non-AD dementia, 36 were characterized as
non-demented but cognitively impaired, and 19 had normal cognitive
functioning. Blood samples were obtained from all participants and
analyzed for fatty acids in the phospholipid phases of the plasma. The
researchers observed significantly lower levels of EPA (by about 42%), DHA
(by 17-33%) and total omega-3 fatty acids (by 23-28%) in the plasma
phospholipids phase of the patients with AD, other dementia and cognitive
impairment (non-demented) than in the normal controls. DHA is highly
concentrated in the cerebral cortex and a deficiency in blood plasma is
likely to translate into a deficiency in the brain.
Other research has confirmed the association between low DHA and EPA
levels and impaired cognitive function. Other studies have found that fish
oil supplementation improves mood, cooperation, appetite, sleep, and
short-term memory in AD patients. The Guelph researchers conclude that an
effort should be made to increase the intake of fish or fish oils in the
population at large and the elderly in particular.
Conquer, Julie A., et al. Fatty acid analysis of blood plasma of
patients with Alzheimer's disease, other types of dementia, and cognitive
impairment. Lipids, Vol. 35, December 2000, pp. 1305-12
EPA cures schizophrenia
LONDON, UK. There is evidence that schizophrenia is associated with an
abnormal metabolism of unsaturated fatty acids in both blood plasma and
red blood cells. This abnormality, in turn, is associated with
extraordinary low levels of long-chain unsaturated fatty acids such as EPA
(eicosapentaenoic acid), DHA (docosahexaenoic acid), and AA (arachidonic
acid) in cell membranes.
Researchers at the Imperial College School of Medicine now report that
fatty acid levels can be restored to normal and schizophrenia symptoms
eliminated or at least vastly diminished by oral supplementation with EPA,
the major component of fish oils. Their experiment involved a 30-year-old
man who had suffered from schizophrenia for over 10 years. He had frequent
(at least daily) hallucinations and also suffered from persecutory
delusions and thought disorder. The patient was put on 2 grams/day of EPA
and was evaluated for schizophrenia symptoms and blood plasma and red
blood cell membrane levels of fatty acids at monthly intervals for 6
months. The results were spectacular. After 6 months the overall score for
schizophrenia symptoms had dropped by a factor of 6 (an 85% reduction in
severity). Episodes of delusions were completely eliminated and there was
an 88% reduction in the number of hallucinatory episodes.
The remarkable clinical improvement in symptoms was associated with
substantial increases in the levels of EPA, DHA and AA in red blood cell
membranes and with significant increases in EPA and DHA levels in blood
plasma. The researchers conclude that EPA supplementation is able to
reverse the abnormal fatty acid profiles found in schizophrenics and that
this reversal is associated with, and is likely to be the cause of, the
clinical improvement.
Richardson, A.J., et al. Red cell and plasma fatty acid changes
accompanying symptom remission in a patient with schizophrenia treated
with eicosapentaenoic acid. European Neuropsychopharmacology, Vol. 10,
2000, pp. 189-93
Fish oil supplementation helps schizophrenia patients
OXFORD, UK. The Cochrane Library, a prestigious medical think-tank
dedicated to the development of evidence-based medicine, has just released
a review of the evidence concerning the use of polyunsaturated fatty acids
(fish oils and evening primrose oil) in the treatment of schizophrenia. A
wide- ranging literature survey revealed 4 studies that met the Library's
stringent quality measures. The most recent study (Shah 2000) included 30
newly diagnosed schizophrenia patients who were not on antipsychotic drugs
at the beginning of the trial. The patients were randomized to receive
either a placebo or a daily dose of eicosapentaenoate (quantity not
specified). At the end of the 12 weeks all the patients in the placebo
group needed to be placed on antipsychotic drugs. Only 9 of the 15
patients in the active treatment group needed these drugs after the 12
weeks.
Another study (Peet 1997) compared evening primrose oil supplementation
with placebo in 43 schizophrenics. The patients' mental state was not
improved in either the placebo or the treatment group after 12 weeks. A
third study involving 29 schizophrenics compared supplementation with fish
oil to evening primrose oil and found fish oil superior.
The researchers conclude that fish oils may be useful in the treatment
of schizophrenia and that medical doctors should not discourage their
patients from taking fish oil supplements. They add that fish oils seem to
be well tolerated and free of adverse effects.
Joy, CB, et al. Polyunsaturated fatty acid (fish or evening primrose
oil) for schizophrenia. The Cochrane Library, Issue 4, 2000
Dieting and depression
TUCSON, ARIZONA. Low-fat diets have been widely promoted for lowering
cholesterol levels, for reducing body weight, and for preventing certain
types of cancer. At least one study, however, has found that although a
reduction in cholesterol may reduce mortality from heart disease it may
increase the incidence of fatal accidents, violent deaths, suicides, and
depression. Researchers at the University of Arizona now believe that they
may have found an explanation for this phenomenon. They point out that fat
restriction and cholesterol-lowering drugs may change the concentrations
of polyunsaturated fatty acids (PUFAs) in the tissues including nerve
tissue (neurons). Fat-restricting diets usually lead to a relative
increase in the intake of omega-6 PUFAs and a relative decrease in the
intake of omega-3 fatty acids. This can have serious consequences inasmuch
as the omega-3 fatty acids, eicosapentaenoic acid (EPA) and
docosahexaenoic acid (DHA) found in fish oils, are crucial for the proper
functioning of the nervous system. Several large-scale studies have found
a clear association between low blood levels of EPA and DHA and an
increased risk of depression, violence and suicide; a recent study in
Japan found that DHA supplementation reduced aggression among healthy
Japanese students.
Epidemiologic studies have found a clear correlation between a low
intake of EPA and DHA and the prevalence of depression. In two studies of
population groups in the USA the incidence of depression was found to be
3.7% and 2.9%. Average intake of EPA and DHA in the USA is estimated to be
about 0.1 gram per day. In two Japanese studies, on the other hand, the
incidence of depression was only 0.9% and 0% and the intake of EPA plus
DHA was 1.5 grams per day and 4.2 grams/day respectively. Other studies
have shown that on-off dieting can produce a serious imbalance in the
ratio of fatty acids and may lead to depression
The researchers conclude that an extremely low-fat diet may be
counter-productive and have deleterious psychological ramifications. They
stress that dietary advice regarding cholesterol reduction, weight loss,
and cancer prevention should emphasize the importance of an adequate
intake of omega-3 fatty acids.
Bruinsma, Kristen A. and Taren, Douglas L. Dieting, essential fatty
acid intake, and depression. Nutrition Reviews, Vol. 58, April 2000, pp.
98-108 [116 references]
Low docosahexaenoic acid levels and Alzheimer's disease
BOSTON, MASSACHUSETTS. Docosahexaenoic acid (DHA), a major component of
fish oils, is the most important fatty acid in the brain and retina and
makes up more than 30% of the structural lipid (fat) in neurons. There is
ample evidence that a deficiency of DHA is associated with depression,
attention deficit hyperactivity disorder, and dementia. Clinical studies
have shown that an increased intake of DHA may benefit patients with
dyslexia and Alzheimer's disease.
Researchers at Boston University and Tufts University School of
Medicine now report that they have found a clear association between low
blood levels (in the phosphatidylcholine fraction of serum) of DHA and the
risk of developing Alzheimer's disease. Their study involved 1188 elderly
Americans (mean age of 75 years) who had blood samples drawn and analyzed
for DHA in 1985. Sixteen of the participants had clinically diagnosed
Alzheimer's at the time of blood sampling. The researchers noted that 11
of the 16 (69%) had DHA levels in the lower half of the DNA distribution.
The remaining 1172 participants were followed for 10 years. Again the
researchers noted that participants with DHA levels in the lower half of
the distribution had a 67% greater risk of developing Alzheimer's disease.
The researchers suggest that maintaining adequate levels of DHA through
the consumption of fish or dietary supplements rich in DHA may be
particularly important for the elderly.
Kyle, D.J., et al. Low serum docosahexaenoic acid is a significant risk
factor for Alzheimer's dementia. Lipids, Vol. 34 (suppl), 1999, p. S245
Fish oils and manic-depressive illness
BOSTON, MASSACHUSETTS. Manic-depressive illness (bipolar disorder) is a
common, severe mental illness involving repeated episodes of depression,
mania (rapid mood changes, hyperactivity, and excessive cheerfulness) or
both. It is usually treated with drugs such as lithium carbonate or
valproate. Unfortunately, these drugs are not very effective and
recurrence rates are high. It is generally believed that bipolar disorder
involves an overactivity in the neuronal signal pathways. Omega-3 fatty
acids are known to dampen this overactivity and the hypothesis has been
advanced that they may be useful in the treatment of bipolar disorder.
Medical scientists have now confirmed this in a landmark study just
completed at the Harvard Medical School.
The double-blind, placebo-controlled study involved 30 patients (men
and women 18 to 65 years of age) who had all been diagnosed with bipolar
disorder. Half the patients were given seven fish oil capsules twice a day
while the placebo group were given seven olive oil capsules twice a day.
Each fish oil capsule contained 440 mg of eicosapentaenoic acid and 240 mg
of docosahexaenoic acid. All of the participants except four in the fish
oil group and four in the placebo group also continued to receive a
standard mood-stabilizing drug prescribed previously. The mental state of
the participants was measured using four scales (Clinical Global
Impression Scale, Global Assessment Scale, Young Mania Rating Scale, and
the Hamilton Rating Scale for Depression) at the start of the study and
after two, four, six, eight, twelve and sixteen weeks. Twelve of the 14
participants in the fish oil group completed the four- month study without
major episodes of mania or depression as compared to only six out of 16
participants in the placebo group. Also, while nine of the placebo group
members experienced worsening depression none of the fish oil group
members did. The four patients in the fish oil group who had not been
prescribed mood-stabilizing drugs all completed the study without major
episodes, but only one member in the placebo group not on mood-stabilizing
drugs did. The average decline in depression rating on the Hamilton Scale
was almost 50 per cent in the fish oil group as compared to an increase of
25 per cent in the control group. The Harvard researchers urge further
trials of fish oils in the treatment of depression and manic-depressive
illness.
Stoll, Andrew L., et al. Omega 3 fatty acids in bipolar disorder.
Archives of General Psychiatry, Vol. 56, May 1999, pp. 407-12 and pp.
415-16 (commentary)
Calabrese, Joseph R., et al. Fish oils and bipolar disorder. Archives of
General Psychiatry, Vol. 56, May 1999, pp. 413-14 (commentary)
Omega-3 fatty acids: the missing link?
BERLIN, GERMANY. Dr. Emanuel Severus of the Berlin University points out
that major depression is characterized by a deficiency of omega-3 fatty
acids and that these acids possess powerful antiarrhythmic properties. He
suggests that the missing link in the recently established association
between major depression and sudden cardiac death may be the omega-3 fatty
acid deficiency which characterizes both conditions.
Severus, W. Emanuel, et al. Omega-3 fatty acids: the missing link?
Archives of General Psychiatry, Vol. 56, April 1999, pp. 380-81 (letter to
the editor)
Fish consumption and depression
ROCKVILLE, MARYLAND. Dr. Joseph Hibbeln, a researcher at the National
Institute on Alcohol Abuse and Alcoholism reports in a letter to The
Lancet that he has found a convincing correlation between fish
consumption and the incidence of major depression. Dr. Hibbeln correlated
the annual incidence of major depression per 100 people in nine countries
with the consumption of fish. He found a high incidence of depression in
countries with low fish consumption. New Zealand with an annual fish
consumption of only 40 lbs had an annual incidence rate of depression of
5.8 per cent while Korea with a fish consumption of more than 100 lbs/year
had an annual incidence rate of only 2.3 per cent. Japan with a fish
consumption of almost 150 lbs/year had the lowest incidence of major
depression (0.12 per cent). Dr. Hibbeln cautions that various economic,
social, cultural and other factors could have influenced his results, but
points out that high blood plasma concentrations of docosahexaenoic acid,
an essential fatty acid found in fish, has been linked to increased
serotonin turnover and lower incidences of depression and suicide.
Hibbeln, Joseph R. Fish consumption and major depression. The Lancet,
Vol. 351, April 18, 1998, p. 1213 (correspondence)
Omega-3 fatty acid deficiency linked to depression
SHEFFIELD, UNITED KINGDOM. The composition of cell membranes has a
profound effect on membrane-related proteins such as enzymes and receptors
and there is considerable evidence that cell membrane structure is a
significant factor in depression. This structure in turn is highly
dependent on the presence of certain essential fatty acids, notably
docosahexaenoic acid (DHA).
Researchers at the University of Sheffield and the Efamol Research
Institute in Nova Scotia now report that they have found a highly
significant association between severity of depression and the levels of
omega-3 fatty acids in both the diet and the red blood cell membranes.
Their study involved 10 patients with major depression and 14 healthy
control subjects with no history of psychiatric disorder (average age of
participants was 39 years). All participants had blood samples taken and
analyzed for essential fatty acid (EFA) content and also completed a
questionnaire to determine their dietary intake of EFAs over the 7 days
prior to enrollment.
The severity of depression was found to be inversely proportional with
the red blood cell level and dietary intake of omega-3 fatty acids. The
correlation between a low level of alpha-linolenic acid in blood cells and
depression and between low blood cell levels of DHA and depression were
particularly strong. No correlation was found between red blood cell
levels of omega-6 fatty acids and depression. However, there was a slight
positive correlation between dietary intake of omega-6s and severity of
depression when both patients and controls were considered in one group.
The researchers conclude that low levels of omega-3 fatty acids in cell
membranes are associated with depression. They speculate that
supplementation with omega-3 fatty acids may be useful in alleviating
depression.
Edwards, Rhian, et al. Omega-3 polyunsaturated fatty acid levels in the
diet and in red blood cell membranes of depressed patients. Journal of
Affective Disorders, Vol. 48, 1998, pp. 149-55
DHA levels linked to suicide and violence
BETHESDA, MARYLAND. Several studies have found a link between low
cholesterol levels and an increased tendency to violence, suicide, and
depression. Scientists at the National Institute on Alcohol Abuse and
Alcoholism believe that the real culprit in this association is low
concentrations of 5- hydroxyindoleacetic acid (5-HIAA) in the
cerebrospinal fluid and that it is the blood level of polyunsaturated
fatty acids rather than the levels of cholesterol which affect 5-HIAA
levels. 5-HIAA is a metabolite of serotonin.
To test this hypothesis the researchers measured the levels of
cerebrospinal 5-HIAA and the levels of blood plasma polyunsaturated fatty
acids in a group of 176 subjects. Forty-nine of the subjects were healthy
volunteers, 88 were early-onset alcoholics (excessive alcohol use prior to
their 25th birthday), and 39 were late-onset alcoholics. None of the
alcoholics had been drinking for at least 21 days prior to the test. The
researchers found a strong positive correlation between blood levels of
docosahexaenoic acid (DHA) and the level of 5-HIAA in the healthy
volunteers. In other words, the higher the DHA levels the higher the
5-HIAA levels and as a corollary, the lower the tendency to depression,
violence and suicide. In the early-onset alcoholics the situation was
completely reversed. Higher DHA levels corresponded to lower 5-HIAA levels
and thus a possibly increased tendency to violence, suicide and
depression. The researchers found no correlation between 5-HIAA levels and
total cholesterol levels. They conclude that further studies are required
to determine if supplementation with essential fatty acids, notably DHA,
can influence central nervous system serotonin and dopamine metabolism and
modify impulsive behaviour related to these neurotransmitters.
Hibbeln, Joseph R., et al. Essential fatty acids predict metabolites of
serotonin and dopamine in cerebrospinal fluid among healthy control
subjects, and early- and late-onset alcoholics. Biological Psychiatry,
Vol. 44, 1998, pp. 235-42
Your brain needs DHA
NEW YORK, NY. Dr. Barbara Levine, Professor of Nutrition in Medicine at
Cornell University, sounds the alarm concerning a totally inadequate
intake of DHA (docosahexaenoic acid) by most Americans. DHA is the
building block of human brain tissue and is particularly abundant in the
grey matter of the brain and the retina. Low levels of DHA have recently
been associated with depression, memory loss, dementia, and visual
problems. DHA is particularly important for fetuses and infants; the DHA
content of the infant's brain triples during the first three months of
life. Optimal levels of DHA are therefore crucial for pregnant and
lactating mothers. Unfortunately, the average DHA content of breast milk
in the United States is the lowest in the world, most likely because
Americans eat comparatively little fish. Making matters worse is the fact
that the United States is the only country in the world where infant
formulas are not fortified with DHA. This despite a 1995 recommendation by
the World Health Organization that all baby formulas should provide 40 mg
of DHA per kilogram of infant body weight. Dr. Levine believes that
postpartum depression, attention deficit hyperactivity disorder (ADHD),
and low IQs are all linked to the dismally low DHA intake common in the
United States. Dr. Levine also points out that low DHA levels have been
linked to low brain serotonin levels which again are connected to an
increased tendency to depression, suicide, and violence. DHA is
abundant in marine phytoplankton and cold-water fish and nutritionists now
recommend that people consume two to three servings of fish every week to
maintain DHA levels. If this is not possible, Dr. Levine suggests
supplementing with 100 mg/day of DHA.
Levine, Barbara S. Most frequently asked questions about DHA. Nutrition
Today, Vol. 32, November/December 1997, pp. 248-49
Fish consumption slows mental decline
ROTTERDAM, THE NETHERLANDS. Dutch researchers report an intriguing
association between diet and the extent and rate of cognitive impairment
in older men. Their study, part of the Zutphen Elderly Study, involved
almost 1000 men born between 1900 and 1920. The men's intake of various
food components was assessed (by personal interviews) in 1985 and 1990 and
their cognitive function was evaluated in 1990 and 1993 using the
Mini-Mental State Examination scale. The MMSE scale includes questions on
orientation to time and place, registration, attention and calculation,
recall, language, and visual construction.
The researchers found that men with the highest intake of linoleic acid
(mainly from margarine, butter, baking fats, sauces, and cheeses) had a
76% higher degree of cognitive impairment than did men with the lowest
intake. This association held true even after adjusting for age, level of
education, cigarette smoking, alcohol consumption, and calorie intake. The
intake of omega-3 fatty acids, on the other hand, was not associated with
any degree of impairment. Men with a high fish intake were less likely to
be cognitively impaired than men with a low intake and their rate of
decline over the period 1990-93 was half that of men rarely consuming
fish. The intake of beta-carotene, flavonoids, and vitamins C and E was
not associated with a greater or lesser degree of impairment. However,
there was a clear correlation between a high vitamin C intake and a
decline in cognitive function over the period 1990-93. Men with a high
vitamin C intake were twice as likely to have experienced a decline as
were men with a low intake. The researchers speculate that vitamin C may
act as a pro-oxidant in the presence of free iron in the brain.
Kalmijn, S., et al. Polyunsaturated fatty acids, antioxidants, and
cognitive function in very old men. American Journal of Epidemiology, Vol.
145, January 1, 1997, pp. 33-41
Fatty acid profile linked to depression
MELBOURNE, AUSTRALIA. Depression is becoming increasingly prevalent in
Western society. Some researchers believe that part of the reason for this
can be traced to major dietary changes which have taken place over the
past century. During this time there has been a large increase in the
intake of saturated fats and linoleic acid (LA)-rich vegetable oils at the
expense of alpha-linolenic acid (ALA)-rich foods such as fish and wild
game. It is estimated that the ratio between LA-type (n-6) polyunsaturated
fatty acids (PUFAs) and ALA-type (n-3) PUFAs has risen from 1:1 to 10:1 or
higher. Some researchers have postulated that the sharp rises in
depression and other neurological disorders are closely related to the
increased intake of LA-rich vegetable oils.
Now researchers at the Royal Melbourne Institute of Technology report
that the severity of depression is indeed directly associated with the
ratio of LA- to ALA-type PUFAs in red blood cells. Their study involved 20
moderately to severely depressed patients. The severity of depression was
determined using the 21-item Hamilton depression rating scale and a second
scale which omitted anxiety symptoms. All patients had blood samples drawn
and analyzed for arachidonic acid (AA) - the major metabolite of linoleic
acid, and EPA - the major metabolite of alpha-linolenic acid and the main
constituent of fish oils. The researchers found a clear correlation
between a high AA/EPA ratio and increased severity of depression. There
was also a significant association between a low level of EPA in the red
blood cells and increased severity of depression.
The researchers conclude that there is a definite relationship between
high AA/EPA ratios and increased severity of depression, but are not
certain whether the fatty acid imbalance causes depression or whether
depression results in a high AA/EPA ratio. They suggest that further
studies be done to determine the benefits of supplementation aimed at
increasing tissue levels of EPA and thereby decreasing the AA/EPA ratio.
Adams, Peter B., et al. Arachidonic acid to eicosapentaenoic acid ratio
in blood correlates positively with clinical symptoms of depression.
Lipids, Vol. 31 (suppl), 1996, pp. S157-S61
Fish oils alleviate schizophrenia symptoms
SHEFFIELD, UNITED KINGDOM. Schizophrenia is a serious mental illness
characterized by such symptoms as delusions, hallucinations, emotional
blunting, and social withdrawal. There is growing evidence that
abnormalities in cell membrane fatty acid composition is involved in the
disease. Researchers at the Northern General Hospital have just completed
a study of the composition of red blood cell membranes in 23 drug-treated
schizophrenic patients. They found that the patients had low levels of
arachidonic acid (AA), linoleic acid (LA), eicosapentaenoic acid (EPA),
and docosahexaenoic acid (DHA) when compared to healthy controls. They
also noted that the schizophrenics had higher levels of thiobarbituric
acid reactive substances (TBARS) in their blood plasma indicating that the
depletion of the fatty acids in the red blood cells might be due to an
increase in oxidative breakdown reactions rather than to impaired
incorporation of the fatty acids into the membranes.
A more recent study by the same researchers evaluated the effect of
fish oil supplementation on the severity of schizophrenic symptoms in a
group of 24 patients. They were given 10 grams/day of concentrated fish
oil for a six-week period. The supplementation resulted in a marked
increase in EPA and other omega-3 fatty acids in the red blood cell
membranes and a concomitant decrease in omega-6 fatty acid levels. The
researchers also noted a significant decrease in the severity of symptoms
during the supplementation period. Interestingly enough, none of the
patients were clinically deficient in fatty acid intake prior to
supplementation, but a correlation between higher EPA intake and less
severe symptoms was clearly evident. The researchers conclude that
schizophrenia is somehow related to an abnormal fatty acid metabolism and
urge larger clinical trials to evaluate the potential benefits of omega-3
fatty acid supplementation in the treatment of this disorder.
Laugharne, J.D.E., et al. Fatty acids and schizophrenia. Lipids, Vol.
31 (suppl), 1996, pp. S163-S65
Docosahexaenoic acid fights depression
ROCKVILLE, MARYLAND. Researchers at the National Institute of Alcohol
Abuse and Alcoholism believe that the increasing rates of depression seen
in North America over the last 100 years are due to a significant shift in
the ratio of n-6 (arachidonic acid, linoleic acid) to n-3 (docosahexaenoic
acid, linolenic acid) fatty acids in the diet. The human race evolved on a
diet having a ratio of about 1:1 of these acids; it is now estimated to be
between 10:1 and 25:1. Docosahexaenoic acid (DHA) is a main component of
the synaptic membranes and a lack of it has been linked to depression.
Fish oils are a rich source of DHA and it can also be biosynthesized in
the body from linolenic acid. The researchers speculate that the
depressions which often accompany alcoholism, multiple sclerosis, and
childbirth (postpartum depression) are all due to a lack of DHA and can be
corrected by increasing the dietary intake of DHA or linolenic acid (flax
seed oil). They also point out that depression and coronary heart disease
are strongly associated and that a low intake of n-3 fatty acids has been
linked to both.
Hibbeln, Joseph R. and Salem, Norman. Dietary polyunsaturated fatty
acids and depression: when cholesterol does not satisfy. American Journal
of Clinical Nutrition, Vol. 62, July 1995, pp. 1-9
Fish oils help patient with Alzheimer's disease
MURRAYVILLE, VICTORIA, AUSTRALIA. Dr. Robert Peers, an Australian family
physician, reports on the case of a 77-year-old farmer diagnosed with
Alzheimer's disease (confirmed by a neurologist). The patient, when first
admitted to a nursing home, was restless and destructive and unable to
dress himself. After several months he became calmer, regained weight, and
was again able to dress himself. Dr. Peers ascribes the changes to the
fact that the nursing home served fish every week thus providing the
patient with long-chain omega-3 fatty acids which had been missing in his
previous diet. In the five years prior to being diagnosed with Alzheimer's
disease (AD) the farmer had been in the habit of just frying up meat, rice
and vegetables in an omega-6 vegetable oil. Dr. Peers provides a
compelling scientific explanation of the reasons why a deficiency in
docosahexaenoic acid (DHA), a main component of fish oil, may lead to
Alzheimer's disease. He suggests that patients with AD should be queried
about an excessive intake of omega-6 fatty acids (from vegetable oils and
margarine) and a deficient intake of omega-3 fatty acids. If an imbalance
is observed it should be treated with fish oil supplementation. He points
out that DHA is quickly taken up by the brain and hypothesizes that fish
oil supplementation may not only improve Alzheimer's symptoms, but may
even prevent the disease from progressing further.
Two other Australian physicians, Drs. Simons and Broe, find Dr. Peers'
observation interesting, but caution that considerably more research needs
to be done for fish oil supplementation to be recognized as an effective
treatment for AD.
Peers, Robert J. Alzheimer's disease and omega-3 fatty acids:
hypothesis. Medical Journal of Australia, Vol. 153, November 5, 1990, pp.
563-64 (letter)
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