About Omega 3

About fat
Fat has a bad reputation. It is a word associated with obesity, heart disease and many other disease states. However, not all fats are bad fats.

The different types of dietary fat fall into three main groups: saturated; mono-unsaturated; and polyunsaturated.

Saturated fats are the animal-derived 'hard' fats such as butter, lard and fat in meat (and used in many processed foods). Chemically-speaking, saturated fats are a chain of carbon atoms jointed by single links, which means that the maximum amount of hydrogen is present. These are the fats to reduce in the diet.

Of the unsaturated fats (so-called because extra hydrogen atoms can be inserted chemically) monounsaturated fatty acids (MUFA) are made up of a chain of carbon atoms containing one double bond. They characteristically have a lower melting point than saturated fats and so are generally liquids (oils) rather than solids (fats). Olive oil is the best-known example of an oil which contains predominantly monounsaturated fatty acids.

A polyunsaturated fatty acid (PUFA) has more than one double bond in the chain. Two to six double bonds can be found in common edible oils. Vegetable oils such as sunflower oil, and the oils from fish contain high levels of polyunsaturates.

Polyunsaturated fatty acids are further divided into two sub-groups called omega-6 and omega-3 (sometimes referred to as w-6 or w-3 or n-6 and n-3).

Both of these groups are essential for good health and normal growth. Since they cannot be manufactured by the human body, they must be supplied in the diet. For this reason, they are often referred to as 'essential fatty acids' (EFAs).

The differences between omega 6 and omega 3 lie in their chemical structure and their roles in the body.

About Omega 3
Omega-3 (you may sometimes see it written as n-3 or w-3) is the name given to a family of polyunsaturated fatty acids. The parent omega-3 - alpha-linolenic acid (ALA) - is described as 'essential' as, like vitamins, it must be obtained from diet. It is polyunsaturated and has 18 carbon atoms and 3 double bonds (18:3).

However, from the point of view of human nutrition, the long-chain omega-3 fatty acids eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6) - EPA and DHA - are considered much more valuable as these are the forms the body requires. In theory, humans are able to synthesise EPA and DHA from dietary ALA, but in practice this process is inefficient.

Scientists have therefore concluded that EPA and DHA should be obtained from diet. Oil-rich fish and supplements such as fish oil and cod liver oil, are the richest and most readily available sources. Other sources such as krill and fortified everyday foods like bread and fruit juices are in production in a minor way in various parts of the world.

Omega-3 fatty acids play an important role as structural membrane lipids, particularly in nerve tissue and the retina and are precursors to eicosanoids - highly reactive substances such as prostaglandins and leukotrienes that act locally to influence a wide range of functions in cells and tissues.

Basically, the omega-3s have anti-inflammatory benefits and help prevent heart disease, whereas omega-6s lower blood cholesterol and support the skin.

Like all fats, EFAs provide energy. Their calorific value is similar to other fats and oils but, unlike saturated fats, they have important health roles. In fact, as their name suggests, they are essential and must be consumed regularly as the body has limited storage for them.

Both of the important EFA families - omega-6 and omega-3 - are components of nerve cells and cellular membranes. They are converted by the body into eicosanoids, leukotrienes and prostaglandins - all of which are needed on a second-by-second basis by most tissue activities in the body.
EFAs are involved in normal physiology, including:

• regulating pressure in the eye, joints, and blood vessels, and mediating immune response
• regulating bodily secretions and their viscosity
• dilating or constricting blood vessels
• regulating collateral circulation
• directing endocrine hormones to their target cells
• regulating smooth muscles and autonomic reflexes
• being primary constituents of cell membranes
• regulating the rate of cell division
• maintaining the fluidity and rigidity of cellular membranes
• regulating the inflow and outflow of substances to and from cells
• transporting oxygen from red blood cells to the tissues
• maintaining proper kidney function and fluid balance
• keeping saturated fats mobile in the blood stream
• preventing blood cells from clumping together (blood clots that can be a cause of heart attack and stroke)
• mediating the release of inflammatory substances from cells that may trigger allergic conditions
• regulating nerve transmission and communication
• If the diet is deficient in either omega-6 or omega-3 long-term degenerative illnesses will result.

Both omega-6 and omega-3 fatty acids are essential but the body requires them in a ratio that is not normally achieved by the typical diet of today's industrialised nations.

Experts think that man evolved on a diet which would have had roughly 1-2 times more omega-6 than omega-3, though there is a school of thought which argues for a 1:1 ratio. Currently, average UK intakes are in a ratio of around 8:1 in favour of the omega-6s, while in the US it is around 10:1, and in Australia nearer 12:1. Many individuals within those populations will have an even greater omega-6 to omega-3 imbalance.

Because of their wide-ranging roles, virtually every area of the human body is susceptible to problems if the balance of the two polyunsaturates becomes out of kilter. How extreme the imbalance needs to be before problems are felt is not yet known for sure and in practice it will probably vary from one person to the next.

Main nutritional benefits

Benefits of eating fish and shellfish

• Less chance of developing heart disease. (Many studies have pointed to very strong links between omega-3s and heart health - protection against death by heart attack particularly. There is also some evidence to show that the omega-3s can protect against thrombotic stroke by promoting healthy blood flow. Omega-3s are also helpful in maintaining blood circulation to the extremities as they improve tolerance to cold exposure and delay spasm of the blood vessels.)
• Ensures the proper development of brain, nervous tissue and eyes of the fetus during pregnancy (When babies are developing during the last third of pregnancy, the brain and nervous system begins accumulating DHA, one of the long chain omega-3s found in oily fish. DHA is a critical component for building brain tissue, for nerve growth and for the retina in the eye. Before birth, babies get the DHA they need from their mother, after birth they obtain it from breast milk.)
• May live longer, even if you already have heart disease (Last year a study from England reported that men who had survived a hearth attack and who had then began eating rich fish, lived longer than similar hearth patients who did not eat fish regularly.)
• Lowers blood pressure (In a research people who had their arteries surgically „unclogged” had less re-clogging of their blood vessels afterward when they consumed oils found in fish.)
• Lowers risk of heart attack if you already have heart disease
• May improve kidney function in severe diabetes
• May improve certain inflammatory conditions such as arthritis, psoriasis, kidney disease (These are inflammatory diseases and increasing the amount of the long chain omega-3 polyunsaturates in the diet is known to aid in bringing about a more anti-inflammatory state. The disease is not cured by the omega-3 polyunsaturates, but it does become much easier to live with, and can be more readily controlled. Another aspect of the situation is that the omega-3 polyunsaturates can help to counteract some of the adverse effects of conventional drugs.)
• May destroy cancer cells (Scientists in Oslo, Norway believe fatty fish could have the power to destroy cancer cells. Researchers from the Institute for Nutrition Research at the University of Oslo claim that fatty acids from fish oils and fatty fish can destroy the "power station" - the mitochondria - in certain types of cancer cells, essentially making the cells commit suicide.)
• May make you happier! (People who have low concentrations of 5HIAA serotonin are especially prone to suicidal and impulsive behaviour. Researchers found that low concentrations of DHA in the plasma correlated to low concentrations of 5HIAA in cerebrospinal fluid. This finding is important because 5HIAA predicts serotonin levels, and serotonin is key to the biochemistry of depression, suicide and violence. Studies with depressed patients have shown lower than average blood levels of the omega-3s and a study with severely depressed patients showed dramatic improvements when they were treated with fish oil.)