Fish Oil and the many benefits

There are good fats and there are bad fats. Artificially produced trans-fatty acids are bad in any amount and saturated fats from animal fats should be kept to a minimum. The best fats or oils rather, since they are liquid at room temperature, are those that contain the essential fatty acids so named because without them we die. Essential fatty acids are polyunsaturated and grouped into two families, the omega-6 EFAs and the omega-3 EFAs.

Seemingly minor differences in their molecular structure make the two EFA families act very differently in the body. While the metabolic products of omega-6 acids promote inflammation, blood clotting and tumour growth, the omega-3 acids act entirely opposite. Although we do need both omega-3s and omega-6s it is becoming increasingly clear that an excess of omega-6 fatty acids can have dire consequences. Many scientists believe that a major reason for the high incidence of heart disease, hypertension, diabetes, obesity, premature ageing and some forms of cancer is the profound imbalance between out intake of omega-6 and omega-3 fatty acids. Our ancestors evolved on a diet with a ration of omega-6 to omega-3 of about 1:1. A massive change in dietary habits over the last few centuries has changed this ratio to something closer to 20:1, and this spells trouble.

The heart
A study on Eskimos highlighted a population with a diet rich in cholesterol yet low incidence of cardiovascular disease. The link was thought to be due to their high consumption of omega-3 fatty acids.1 Such fatty acids enter the food chain through the micro plankton which are ingested by fish. More recently Omega-3 polyunsaturated fatty acids from fish have been associated with reduced incidence of sudden cardiac death.2

The Joints
Fish Oil supplements can reduce the requirement for the use of non-steroidal anti-inflammatory drugs in sufferers of Rheumatoid Arthritis. This is important for RA sufferers as unlike NSAID's, fish oils are not associated with gastrointestinal side effects. EPA has also been seen to reduce the synthesis of two inflammation inducing cytokines. It has been suggested that this in turn may lower the activity of metalloproteinases (enzymes which hydrolyse collagen and are stimulated by the cytokines). A contributing factor to RA is thought to be the over activity of metalloproteinases causing joint erosion. In turn it is thought that the EPA in fish oils may inhibit it.3

Menstrual discomfort
A placebo controlled, cross over study was carried out on 42 adolescents with dysmenorrhoea. The first group was given fish oil daily for 2 months followed by a placebo for 2 months. The second group was given the placebo for the first 2 months followed by the fish oil. The results of the study showed that dietary supplementation with omega 3 polyunsaturated fatty acids was effective in the alleviation of the symptoms of dysmenorrhoea.4

Lung Cancer
It has been found that in some countries, where there was a high incidence of cigarette smoking or animal fat consumption, that there has been a surprisingly low incidence of lung cancer. The researchers found that the higher the fish consumption, the lower the incidence of lung cancer mortality rate in men. It was concluded that if the fish consumption in 36 countries had increased by 1% of total energy intake, it was anticipated that the average lung cancer mortality rate of men in the 45-74 age group would have dropped by 8.4%.5

References:
Kromann,N. Green, A. Acta. Med. Scand. (1980) 208; 401-406
Leaf,A., & Webber, PC., New England Journal of Medicine (1988) Vol 318; No 9; 549-557
Collated Use of Omega-3 low cholesterol poly unsaturated fatty acids in rheumatoid arthritis. (2001) PUFA News Letter Vol 5, No 1.
Harvel, Z., et al., (1996) Am J Obstet Gynecol.1335-1338
Zhang, J et al., Int J Epidemiol, (2000) 29; 615-621