MANY of you may be aware of the importance of eating fish and how it's food for the brain. The goodness of fish and supplementing the diet with fish oil has prompted many researchers to study the effects of fish consumption, fish oil and omega-3 fatty acids on cardiovascular disease.
Promising results have also prompted many health professionals to actively promote eating fish as a part of dietary intervention.
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are metabolites which are derived from omega-3 fatty acids known as alpha-linolenic acid (ALA). These metabolites play an important role in promoting cardiovascular health.
Till today, the mechanism responsible for the observed effects of omega-3 fatty acids on cardiovascular health are still not known. Those possibly involved are anti-inflammatory properties, anti-thrombogenic, hypotriglyceridemic and reduced susceptibility of the heart to ventricular arrhythmia.
Coronary Heart Disease (CHD)
Many studies support the role of fish consumption in coronary heart disease. A study documented that men who consumed 35g or more of fish daily had a lower risk of death from coronary heart disease and lower risk of non-sudden death from myocardial infarction (MI) compared with those who consumed none.
In another study, fish consumption was associated with a reduced risk from ischemic heart disease and stroke mortality across 36 countries. In a study of Japanese living in Japan and Brazil, researchers reported a dose-response relationship between the frequency of weekly fish intake and reduced CVD risk factors such as obesity and hypertension.
Triglycerides
The hypotriglyceridemic effects of omega-3 fatty acids from fish oil are well established. It has been reported that four grammes of omega-3 fatty acids from fish oil daily decreased serum triglyceride concentrations by 25 to 30 per cent. In this case, a dose-response relationship exists between omega-3 fatty acid intake and triglyceride lowering.
Fish oil can have a therapeutic role in the treatment of hypertriglyceridemia (triglyceride levels >750mg/dL). Effective doses of omega-3 fatty acids range from three to five grammes daily, which can only be obtained consistently by supplementation.
Blood Pressure
Omega-3 fatty acids had been shown to lower blood pressure of hypertensive subjects who consumed more than three grammes to 5.6g of these essential fatty acids daily. DHA seems to be more effective than EPA in lowering blood pressure.
Arrhythmia
Animal experiments have shown that fish oil has potent anti-arrhythmic effects. Fish oil-fed cats were protected from brain damage after stroke induction. Several studies have also supported the anti-arrhythmia properties of fish oil.
Fish for Life
Omega-3 fatty acids have been a part of our diet for millennia. The FDA has ruled that intakes of up to three grammes daily of marine omega-3 fatty acids are recognised as safe for inclusion in the diet as general health maintenance.
Although levels of EPA and DHA intake can be obtained through fish consumption, the right amount of fish intake may be difficult to achieve and sustain over the long term. Those who do not eat fish and those who are allergic to fish may consider supplementation.
The most common fish oil capsules today provide 180mg of EPA and 120mg of DHA per 1,000mg, although strengths of 330mg of EPA and 220mg of DHA per 1,000mg are widely available on the market. Try to look for a fish oil supplement that contains natural "triglyceride" form that is normally found in food, thus making it more bio-available (easily absorbed and used by the body).
Population Recommendation
Dietary recommendations supported by American Heart Association for omega-3 fatty acid intake are as follows:
Patients without documented CHD should eat a variety of (preferably oily) fish, at least twice a week. Include oils and foods rich in alpha-linolenic acid such as flaxseed, walnuts, soybean oils and canola oils. Patients with documented CHD should consume approximately one gramme of EPA and DHA per day. Fish oil supplements could be considered in consultation with the physician.
Patients needing triglyceride lowering require two to four grammes of EPA and DHA per day provided as capsules under a physician's care.
The writer is a pharmacist who is actively involved in the dissemination of information on natural healthcare and holistic therapies.
