Women
Catching Up On Cardiovascular Heart Disease. Omega-3 Important
for Prevention and Treatment.
By
Morten Bryhn MD, Ph D
1/23/2002
Recent statistics from the
American Heart Association show that deaths from cardiovascular
disease have gone up between 1990 and 1999 after a promising
decline between 1980 and 1990. The increase is directly
related to a frightening increase of cardiovascular deaths
in women while the situation in men continues in the right
direction.
Coronary
artery disease and stroke are still the major causes of
disease, significant reduction of life quality and expectancy,
and death in the Western civilization. Recent figures from
the American Heart Association (1) claimed that 958 775
people died of cardiovascular disease during 1999. Male
deaths was 445 871 and female deaths were 512 904. Mortality
has steadily gone down for men but increases for women.
Coronary heart disease and stroke are caused by the same
condition of the arteries: atherosclerosis. Arteriosclerosis
may be regarded as the long-term consequence of a chronic
inflammatory condition of the arteries. The chronic inflammation
is caused by a series of risk factors like smoking, elevated
blood lipids, hypertension and diabetes. The artery disease
is sustained by activation of immunologic mechanisms. Two
important causal factors are regulating the advent of symptoms:
Heritage and nutrition. Good genes can make our arteries
tolerate an unhealthy life style over more years than those
with family members suffering from coronary conditions at
the age of 50. And proper nutrition can prevent or at least
postpone the advent of cardiovascular disease significantly.
Male gender used to be a significant risk factor but now
the women seem to catch-up. The hormones that used to protect
females from getting arteriosclerosis at the same age as
men seem to loose the battle against smoking and diabetes.
Of
course there is little to be done with heritage but if you
are a young person, male or female with family members having
coronary heart disease or stroke you should include artery
disease prevention in your life strategy and start early.
And those with a more favourable starting point regarding
cardiovascular disease, the advice is not to start too late
with prevention. Studies clearly demonstrate that arteriosclerosis
is present already in the age group of 15-34 years (2).
You may very soon find yourself in the less favourable situation
of disease treatment instead of disease prevention where
the outcome is clearly more doubtful. Disease prevention
is the key to not only a healthier life but also better
life quality, absence of diseases and long life. And there
is so much to be done but you have to invest in a bit of
intellectual property and change certain parts of your lifestyle.
You probably know already that smoking cigarettes is the
most dangerous habit you can entertain. So there is little
to be gained if you do not quit smoking cigarettes. Smokers
fear getting lung cancer but what they really should be
afraid of is coronary heart attacks. In many countries today
smoking is more common in female than male and the young
women seem to be in position no. 1
So,
what scientific evidence are there that really demonstrate
clearly that there is a lot to be gained by adopting to
a more healthy diet? Increased intake of seafood seems to
be very important. Early observations in Greenland Inuits
and the coastal population of Japan found very low incidence
of myocardial disease in these populations having a surprisingly
high intake of fat in their diet. This paradox was explained
by the fact that the source of fat was fish and sea mammals
containing large amounts of polyunsaturated omega-3 fatty
acids.
A
study comparing arteriosclerosis formation of people having
a high intake of omega-3 fatty acids with those entertaining
a standard US diet was published by Newman and co-workers
(3). This was an autopsy study including 130 male Alaska
Natives and 115 non-Natives, mainly American Caucasians
and Hispanics admitted to departments of forensic medicine
due to death of other causes than cardiovascular disease.
Coronary arteries and the aorta from these people along
with adipose tissue were sent to the department of pathology,
Louisiana State University medical School, New Orleans,
where pathologists determined the extent of arteriosclerosis
lesions on the arterial surface. The examiners were not
informed about which group of individuals the specimens
came from. It could clearly be demonstrated that in the
different ages groups arteriosclerosis formation was significantly
more advanced in the non-Natives compared with the natives.
Analysis
of the fat tissue revealed that while the Alaska natives
had high concentrations of marine omega-3 fatty acids the
non-natives had low concentrations of these fatty acids
and high values of omega-6 fatty acids and saturated fatty
acids. The fatty acid pattern in non-natives is typical
for the Western diet of today. Obeying the advice of dieticians
we have managed to reduce the intake of saturated fat to
a certain extent but we have increased the intake of unsaturated
omega-6 fatty acids from vegetable and seed oils. And people
do not eat fish anymore, which is the reason why the intake
of omega-3 fatty acids is steadily going down. Truly the
diet containing marine omega-3 fatty acids seemed to offer
protection against arteriosclerosis in the Newman study.
They were able to demonstrate that arteriosclerosis was
postponed in the individuals with a high intake of omega-3
fatty acids: Natives in the age group of 35-44 years had
arteriosclerosis to the same extent as 25-34 years old non-natives
and natives in the age group 35-44 years had arteriosclerosis
as 35-44 years old non-natives
Since
male gender has been associated with increased risk for
getting cardiovascular disease men only have usually been
invited to participating in studies. An exception is the
Nurses' Health Study which was started in 1976 including
data from a total of 98 759 women. 79 839 women met the
criteria's of no history of cardiovascular disease, cancer
and major risk factors. The participants were followed for
14 years. Iso and co-workers (4) reported the risk of stroke
in relation to fish intake in this study. Stroke is another
important consequence of arteriosclerosis responsible for
167 366 people killed in the US during 1999. In Nurses'
Health Study 574 incidents of stroke were documented in
the women participating. Compared with those who ate fish
less than once per month, the seafood lowers had a lower
risk of stroke.
This
study and other large epidemiological studies have shown
convincing evidence for a protective effect of the omega-3
fatty acids found in fish. Based on these studies the American
Heart Association issued recommendations last year on including
fishmeals in the regular diet of the healthy population
in order to bring the death tolls on coronary heart disease
and stroke down. Even patients with cardiovascular disease
do profit from increasing the intake of omega-3 fatty acids
by eating fish or by taking omega-3 supplements. The study
GISSI Prevenzione from Italy recruiting 11 324 patients
recently discharged from the hospital with myocardial infarction
investigated the effects of Pronova Biocares omega-3 based
pharmaceutical on mortality (5). The group given the omega-3
drug experienced reduced cardiovascular death by 30% and
sudden death by 45%. Interestingly most of the patients
were already on a risk reduction regimen comprising aspirin,
beta-blockers and cholesterol lowering statins. It is well
known that all these pharmaceuticals offer reduction of
death in this subset of patients by 20-40%. A stunning 30%
reduction on top of this regimen indicates again that the
effects of omega-3 fatty acids, as secondary prevention
after myocardial infarction is very potent.
Treatment
of cardiovascular disease is getting increasingly sophisticated
and new pharmacological and surgical treatments are introduced
every year. However, the scientific world is synonymous
in the conclusion that only preventive measures will bring
mortality and morbidity in cardiovascular disease down.
Besides avoiding risk factors change of inferior dietary
habits is the most promising measure. Increasing intake
of fish or taking omega-3 supplements seems to be one of
the most promising advices that could be given to the general
population and the patients with atherosclerotic disease.
REFERENCES:
1) AHA. 2002 Heart and Stroke Statistical Update
2)
Strong JP, Malcom GT, McMahan CA, et al. Prevalence and
extent of arteriosclerosis in adolescent and young adults.
JAMA 1999;281:727-735
3)
Newman WP, Middaugh JP, Propst MT, et al. Arteriosclerosis
in Alaska natives and non-natives.
Lancet 1993;341:1056-1057
4)
Iso H, Rexrode KM, Stampfer MJ, et al. Intake of fish and
omega-3 fatty acids and risk of stroke in women.
JAMA 2001;285:304-312
5)
Valagussa F and the GISSI investigators. Dietary supplementation
with n-3 polyunsaturated fatty acids and vitamin E after
myocardial infarction: results of the GISSI-prevenzione
trial.
Lancet 1999;354:447-455
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