Did you know that fish helps to prevent heart disease? Heart disease is one of the leading causes of death but people who eat fish regularly have much less heart disease compared to people who never eat fish. And this is one of the reasons that experts recommend that we eat fish at least twice a week. Fish has many benefits - it is rich in protein, needed for growth and repair, as well as being an excellent source of minerals like zinc, selenium and iodine. Fish is rich in B vitamins and oil-rich fish are packed with vitamins A and D as well as essential omega-3 fats.
So how can fish help us with maintaining a healthy diet?
Let's first look at some very interesting background information before going into the obvious benefits.
In the last few years, everybody has heard of the importance of esential Omega-3 oils. They are the most beneficial substance in fish. The oils are termed ‘essential’ because we need them to live a healthy life but cannot synthesise them effectively.
The substantial library of evidence that the fatty acids found in oily fish such as salmon have significant health benefits continues to grow and to expand in the number of benefits identified.
Benefits range from the well-known advantages for cardiovascular health to relief from arthritis and inflammatory diseases and a central role in mental health and brain development, on to evidence that they are important in preventing or moderating cancers. More recently, these fatty acids have been linked with further benefits such as reducing the risk of gallstones.
In addition to the benefits of the essential omega-3 oils, as the UN Food and Agriculture Organization (FAO) reports, “Fish is a food of excellent nutritional value, providing high quality protein and a wide variety of vitamins and minerals, including vitamins A and D, phosphorus, magnesium, selenium and iodine in marine fish.”
In the face of increasing obesity and decreasing health standards, governments and food and health advisory bodies in Europe and the USA are actively encouraging their populations to consume more fish in their diet.
Now it gets a bit technical, but still interesting:
Central to the health benefits being observed are the omega-3 polyunsaturated fatty acids, also referred to as n-3 fatty acids.
Fatty acids are based on a chain of linked carbon atoms and are classified as saturated or unsaturated. The term unsaturated means that the fatty acid has at least one carbon-carbon double bond. Polyunsaturated means there are two or more double bonds. So the (poly)unsaturated fatty acids are the ones to go for - they are the good guys!
Now here is something to note:
About 360 million years ago, when marine life started to crawl out of the oceans and into the extensive swamps, our early ancestors would have eaten a diet based substantially on seafood on the edges of the waters. Says Professor Michael Crawford, Director of the Institute of Brain Chemistry and Human Nutrition, University of North London: “Six hundred million years ago, the evolution of the human brain and nervous system originated in the marine environment (...). This essential fatty acid has been conserved since then for the structure and function of neurological and visual membranes.”
Unfortunately, since then, the diet of most people has radically changed - a large drop of intake of omega-3 fatty acids can be observed. The fall in fish consumption over the past decades and the imbalance between omega-6 and omega-3 acids may account for the apparent rise in occurrence of those diseases where omega-3 consumption has been demonstrated to bring benefits.
Now finally, what benefits do we get out of eating fish?
The following review highlights some typical and important examples of many thousands of research publications linking fish oils with human health benefits.
Reducing heart attacks and strokes
Eskimos, Japanese and Koreans, have lower rates of heart disease because a big part of their diet is based on fish. No blood clots, no narrowing of the arteries by deposition of fatty material. Diabetics especially benefit: People with diabetes are two to six times more likely to develop cardiovascular disease (CVD) than people without diabetes. Fish oil supplementation significantly lowers serum triglyceride levels in diabetic individuals.
The wealth of information available coming out of studies led Professor Walter Willet of Harvard School of Public Health and Harvard Medical School, to comment at the Diet and Optimum Health Conference, in May 2001 , “The evidence that higher intake of omega-3 fatty acids can reduce coronary heart disease mortality due to sudden death is conclusive.”
Easing inflammatory and auto-immune diseases
Omega-3 oils help with rheumatoid arthritis, inflammatory bowel disease, psoriasis (chronic recurring inflammatory disease of the skin) and asthma.
The links between cancer and omega-3 fatty acids are less clear but evidence is being found. Tumours are fewer, smaller and less likely to spread when the diet included fish oils. In Japan, data on medical history, dietary habits (including fish consumption), smoking and exercise of 5,885 men and women were gathered from 1985 to 1999 . A clear link between fish consumption and lung cancer was found. After figures were adjusted, households in which fish was consumed three or more times a week had 77% lower risk of lung cancer. It was 57% less where fish was eaten once or twice a week.
Mental health and development
The old adage that fish is good for the brain has more sense in it than many people realise. There is an increasing amount of evidence that the DHA component of omega-3 fatty acids in oily fish does indeed have a key role in brain function. (See also our "Salmon of Knowledge"...!)
A prospective study in the US followed 815 people aged over 65 from 1993 to 2000. Initially none had Alzheimer’s disease. During the study period 131 developed the disease. When incidence was compared with diet it was seen that those who consumed fish at least once per week had 60% less risk of developing Alzheimer’s disease than those who consumed it less often or not at all.
Typically, a high incidence of depression occurred in those countries with a low consumption of fish. For example, in New Zealand, with fish consumption around 18kg per annum, depression was scored at 5.8%. In Japan, with a fish consumption of 68kg per annum, depression was 0.12%. Taking this another step, in the UK researchers administered EPA (eicosapentaenoic acid) to 70 depressed patients for 12 weeks. The patients, who had all previously tried conventional treatments such as Prozac, reported improvements with sadness, anxiety and sleeping problems. Omega-3 oils also help alleviate the postpartum depression ("baby blues") with women just after giving birth.
Other diseases where omega-3 oils were proven to help:
anorexia nervosa, schizophrenia, aggression, as well as behaviour and learning difficulties in children.
Fish oils in fatty fish are the richest source of a type of fat that is vital to normal brain development in unborn babies and in infants. Without adequate amounts of these fatty acids, normal brain development does not take place.
Without going into great detail at this stage, we want to point out that there are other diseases where the intake of omega-3 oils can greatly improve the situation: gallstones, osteoporosis, weight loss and premature birth for example.
For more detailed information, please read the downloadable document below.