Omega-3 Fatty Acids and Health: an Overview

Definition of omega-3 fatty acids

Omega-3 fatty acids are long-chain polyunsaturated fatty acids (18-22 carbon atoms in chain length) with the first of double bonds beginning with the third carbon atom. They are called “polyunsaturated” because their molecules have two or more of the so-called “double bonds” between carbon atoms. Their designation as “long-chain” fatty acids has to do with the fact that they consist of at least 18 carbon atoms.

The picture below illustrates the molecular structure of alpha-linolenic acid (ALA, omega-3 family) as compared to linoleic acid (LA, omega-6 family). Both of them consist of 18 carbon atoms and are classified as polyunsaturated, but ALA has three double bonds, the first of which is located in the third position from the “end” of the molecule, whereas LA has just two double bonds, starting with the sixth position. These differences may seem very minor, but they are of paramount importance in terms of the physiological action of ALA and LA, making them perform totally different roles in the human body.

The omega-3 family of fatty acids includes alpha-linolenic acid (ALA, 18 carbon atoms, 3 double bonds), eicosapentaenoic acid (EPA, 20 carbon atoms, 5 double bonds), and docosahexaenoic acid (DHA, 22 carbon atoms, 6 double bonds). ALA is the "base" omega-3 fatty acid, from which EPA and DHA are made in the body through a series of enzymatic reactions called "elongation" (the molecule becomes longer by incorporating new carbon atoms) and "desaturation" (new double bonds are created). In nature, ALA is primarily found in certain plant seeds (e.g., flax, hemp, Camelina) and their oils, and in most green leafy vegetables (especially purslane), whereas EPA and DHA mostly occur in the tissues of cold-water fish (such as salmon, sardines, and mackerel), and in some marine plants.

Omega-3s are not just "good fats". They are truly essential for health and vitality

After the advent of the so-called "lipid hypothesis", which linked the consumption of dietary fat with increased risk of heart disease and other health problems, fats were so heavily demonized by the official medical establishment that many people started thinking that the best answer to the "fat problem" is to stay away from it altogether. Big food processing companies were quick to realize the enormous profit potential of this trend, and soon the market became flooded with "low fat" and "fat-free" products, promising to put an end to obesity and heart disease.

However, not all fats were created equal. While the consumption of some types of fat may, indeed, be a risk factor for certain health problems (synthetic trans-fats, so dearly loved by the food-processing industry, rather than natural fats, seem to be the primary culprit here), some other fats, including alpha-liniolenic acid (ALA) from the omega-3 family, are so important for health that they have been termed "essential fatty acids" (EFAs). The essential nature of these fatty acids stems from the fact that our bodies need them to perform vitally important functions, but are unable to manufacture them. Therefore, we must get them from outside sources (such as food or dietary supplements). That's why any attempt to indiscriminately reduce or eliminate all fats from one's diet inevitably leads to an EFA deficit, which may be very detrimental to health.

Essential fatty acids were first discovered back in 1929 by a husband-and-wife research team George and Mildred Burr. While doing animal research, they have noticed that a lack of essential fatty acids caused the animals to develop some serious health problems, including scaling and swelling of the skin, as well as damage to internal organs. If the EFA deficit was left unattended, the animals eventually died.

In 1956, Hugh Sinclair, one of the world's greatest researchers in the field of human nutrition, has suggested that an upsurge in the so-called "diseases of civilization" - namely, coronary heart disease, thrombosis, strokes, diabetes, chronic inflammation, and cancer - was caused by abnormalities in fat metabolism. According to his writings, the main reason for such abnormalities was the fact that modern-day diets are full of processed foods rich in trans-fatty acids, while being extremely poor in essential fatty acids. According to Hugh Sinclair, this EFA deficit was the main reason behind his striking observation: in spite of improvements in medicine and standard of living, the life expectancy of a 50-year-old man had not changed since the middle of the 19th century.

The role of omega-3 EFA in disease prevention and treatment

During the 50 years that have elapsed after Hugh Sinclair's discoveries, EFAs, including omega-3 fatty acids, have been extensively researched by scientists. This research has brought some extremely interesting and promising results in terms of the potential of omega-3 fatty acids to prevent and treat many modern diseases. It has been shown that ensuring the presence of an adequate amount of omega-3s in the diet may help to achieve the following health-promoting objectives:

- Anti-clotting (thrombolytic) effect: Omega-3s help to avoid thrombosis (formation of blood clots) by preventing platelets (thrombocytes) from sticking together and forming blood clots. Blood clots, which may result in stroke, heart attack, or pulmonary embolism (PE), are the #1 cause of death in thw Western world, but most of them are preventable by including omega-3 fatty acids and other anti-clotting foods and supplements into one's diet.

- Lowering the risk of heart disease, including CHD (coronary heart disease) and atherosclerosis. Omega-3 fatty acids have been proven in many clinical studies to benefit heart health, particularly through their vasodilatory (widening of blood vessels) and anti-atherogenic (preventing the formation of artery-blocking atherosclerotic plaques) effects. These findings are supported by the American Heart Association guidelines.

- Lowering the level of triglycerides (fats) in the blood. The effectiveness of omega-3s in lowering blood triglycerides (fats) known to be a risk factor for cardiovascular disease has been well established in multiple clinical studies.

- Lowering high blood pressure (alleviating hypertension). Omega-3 fatty acids have been shown to lower mild hypertension when it is due to cardiovascular disease, specifically atherosclerosis (hardening of the artery walls, formation of arterial plaques, and the resulting narrowing of the arteries).

- Reduction in heart irregularities. Omega-3 EFAs have been shown to lower heartbeat rates and prevent arrhythmias (disturbances of the normal rhythm in the heart's beating), thus decreasing the chances of a sudden death from a heart attack.

- Alleviation of circulatory problems. Circulatory problems such as varicose veins and Raynaud's disease benefit from omega-3 supplementation. Omega-3s stimulate blood circulation and increase the breakdown of fibrin, a compound involved in clot and scar formation.

- Helping to alleviate mood disorders, such as depression. Persons with mood disorders may also benefit from omega-3 supplementation. Lack of omega-3 fatty acids has been linked to depression by researchers.

- Reducing aggression. A new study of teenagers has found that the consumption of omega-3 EFAs relates to lower hostility rates in teenagers. Hostility has been shown to play a role in the development and manifestation of heart disease.

- Helping patients with attention deficit/hyperactivity disorder (ADHD), dyslexia and dyspraxia. As is the case with depression and other mood disorders, persons who suffer from ADHD, dyslexia and dyspraxia (absence of ability to perform coordinated skilled movements) benefit from omega-3 supplementation.

- Helping to improve memory and learning skills, and prevent Alzheimer's disease. Studies have proven that omega-3 fatty acids improve brain function and that the intake of omega-3s is linked to a lowered risk of developing Alzheimer's disease. Studies also suggest that omega-3 EFAs may have a protective effect on the nervous system.

- Prevention of allergies in children. Studies have demonstrated that omega-3 fatty acid intake by prospective mothers during pregnancy may protect their babies against the development of allergies. Omega-3s have been found to protect against symptoms of hay fever, sinus infections, asthma, food allergies, as well as allergic skin conditions such as hives and eczema.

- Improving the condition of those who suffer from inflammatory skin disorders such as psoriasis and eczema. In the skin of persons with psoriasis and other inflammatory skin disorders the amount of compounds causing inflammation is many times greater than normal. Omega-3 EFAs inhibit the production of these inflammatory compounds, improving the health of skin, nails and hair.

- Alleviating rheumatoid arthritis (RA) and other inflammatory forms of arthritis, affecting, in particular, persons with psoriasis and gout. Omega-3 fatty acids reduce the amount of compounds causing inflammation, and increase the formation of anti-inflammatory substances such as PGE3.

- Improving the immune status. The intake of omega-3 fatty acids has been proven to be beneficial for the body's immune function. Research has also linked the intake of omega-3s to lowered risk of breast cancer and prostate cancer.

- Alleviating certain symptoms of PMS. Premenstrual symptoms such as pain, cramps and bloating are often alleviated by resorting to omega-3 supplementation. Omega-3 fatty acids are converted into hormone-like substances (type 3 prostaglandins, or PGE3), which help to control contractions of the uterus.

- Improvement of visual acuity. Research has shown that consumption of omega-3 EFAs is linked to lowered risk of age-related macular degeneration - an eye condition which is the leading cause of severe loss of vision in people over 50.

How omega-3s work: an introduction to prostaglandins

It is obvious that an adequate daily intake of omega-3 fatty acids can play a vital role in the prevention and treatment of a great number of serious and widespread diseases affecting modern societies. The ability of omega-3s to achieve these health-promoting effects is primarily due to their role as the precursors of prostaglandins - localized tissue hormones that seem to be the fundamental regulating molecules in most forms of life. They do not travel in the blood like hormones, but are created in the cells to serve as catalysts for a large number of processes including the movement of calcium and other substances into and out of cells, dilation and contraction, inhibition and promotion of clotting, regulation of secretions, including digestive juices and hormones, and control of fertility, cell division and growth. This unique significance of omega-3s and prostaglandins for major life-supporting processes in the human body led Dr. Mary Enig, a leading lipid researcher and nutritional scientist of our times, and Ms. Sally Fallon, President of Weston A. Price Foundation, to making the following statement:

"Research into prostaglandins holds enormous promise for the treatment of disease with various drugs that selectively inhibit or stimulate the production of specific prostaglandins. Such drugs might be likened to police officers used to direct traffic or called on to help at the scene of an accident. For most of us, however, the best way to ensure adequate prostaglandin production along with proper balance between the various series and their subsets is to follow a diet that provides precursors to eicosanoid production, and keeps the pathways free from blocks and potholes, a diet that provides fuel for our prostaglandin cars and keeps the highways clear." (Tripping Lightly down the Prostaglandin Pathways, Sally Fallon and Mary Enig, PhD, 1996).

In the same article, the authors go on to explain the specific mechanisms behind the formation and major actions of EFA-derived prostaglandins and other eicosanoids (20-carbon hormone-like tissue substances which are similar to prostaglandins):

"Prostaglandins are produced in the cells by the action of enzymes on essential fatty acids. There are two prostaglandin pathways, one that begins with double-unsaturated omega-6 linoleic acid and one that begins with triple-unsaturated omega-3 alpha-linolenic acid. Both pathways essentially involve elongation of the 18-carbon EFA's to the 20-carbon root used in each of the three eicosanoid types, plus further desaturation.

On the omega-6 pathway, the Series 1 prostaglandins are produced from a 20-carbon, triple unsaturated fatty acid called dihomo-y-linolenic acid (DGLA) that is found in liver and other organ meats. The Series 2 prostaglandins are produced from a 20-carbon quadruple unsaturated fatty acid called arachidonic acid (AA) found in butter, animal fats, especially pork, organ meats, eggs and seaweed.On the omega-3 pathway, the Series 3 prostaglandins are produced from a 20-carbon quintuple unsaturated fatty acid called eicosapentaenoic acid (EPA)...". For a detailed diagram describing the omega-3 and omega-6 prostaglandin pathways, please click here.

A fundamental shift in the omega-6/omega-3 ratio created a major prostaglandin imbalance, giving rise to "diseases of modern civilization"

"Early research focused on the interplay between the Series 1 and Series 2 prostaglandins. In the most simple terms, the Series 2 prostaglandins seem to be involved in swelling, inflammation, clotting and dilation, while those of the Series 1 group have the opposite effect. This has led some writers, notably Barry Sears in his popular book The Zone, to call the Series 2 family the "bad" eicosanoids and to warn readers against eating liver and butter, sources of arachidonic acid, the Series 2 precursor. Sears also asserts that perfect balance of the various prostaglandin series can be achieved by following a diet in which protein, carbohydrate and fat are maintained in certain strict proportions. This is a highly simplistic view of the complex interactions on the prostaglandin pathway, one which does not take into account individual requirements for macro and micro nutrients, nor of imbalances that may be caused by nutritional deficiencies, environmental stress or genetic defects. Like all systems in the body, the many eicosanoids work together in an array of loops and feedback mechanisms of infinite complexity...

The Series 2 prostaglandins do indeed play a role in swelling and inflammation at sites of injury. This is not at all a "bad" effect, but an important protective mechanism - the body's way of immobilizing the affected site to prevent further injury and facilitate healing. Series 2 prostaglandins also seem to play a role in inducing birth, in regulating temperature, in lowering blood pressure, and in the regulation of platelet aggregation and clotting.

Later investigators have focused on the balance between Series 2 and Series 3 prostaglandins. The Series 2 group is involved in intense actions, often in response to some emergency such as injury or stress; the Series 3 group has a modulating effect. Series 2 eicosanoids might be likened to the "fast lane" in that they are often associated "with an explosive, but transient burst of synthesis. . . if the rate of synthesis is too slow, there will be insufficient active eicosanoids to occupy receptors. If the rate is synthesis is too fast, excess active eicosanoids can cause pathophysiology." The Series 3 prostaglandins are formed at a slower rate and work to attenuate excessive Series 2 production. Their response is "less vigorous". The omega-3 pathway might therefore be likened to the "slow lane." Adequate production of the Series 3 prostaglandins seems to protect against heart attack and stroke as well as certain inflammatory diseases like arthritis, lupus and asthma." (Op. Cit.)

The table below illustrates the opposing effects of different-series prostaglandins on human physiology:

It may, indeed, seem from this table that the effects of series 3 prostaglandins derived from omega-3 fatty acids (PGE3) are mostly “positive”, making them “good prostaglandins”, whereas series 2 prostaglandins derived from omega-6s (PGE2) are “bad prostaglandins”. However, as was explained above, this view is too simplistic. The fact is that both groups of prostaglandins perform vitally important functions and supplement each other through complex and multi-faceted interactions. There is only one crucial condition that must be fulfilled if the entire system is to work well and promote health, rather than disease. This condition is BALANCE. For the prostaglandin pathways to run smoothly, the intake of omega-3 and omega-6 fatty acids must be well-balanced, as was the case during 99% of human history – before the global switch to industrial agriculture and processed foods. For many centuries, the ratio between omega-6s and omega-3s was within the 1:1 to 4:1 range believed by most scientists to be acceptable for optimal metabolism of fats and proportionate production of different prostaglandins.

How much omega-3 EFAs do we need and what are the best sources of omega-3s?

Apparently, by adding a certain amount of omega-3 EFAs to the diet it is possible to restore the vitally important prostaglandin balance, avoiding or reversing the negative health consequences of the omega-6 overload. The are two questions that must be answered here: 1) what should be our daily intake of omega-3 fatty acids; and 2) what are the best sources of dietary omega-3s.

Scientists have not yet developed a universal answer with regard to how much omega-3 EFAs are needed daily. Perhaps the most detailed and authoritative recommendations in this regard were made by the participants of the Workshop on the Essentiality of and Recommended Dietary Intakes for Omega-6 and Omega-3 Fatty Acids, held in Bethesda, Maryland, under the auspices of the International Society for the Study of Fatty Acids and Lipids (ISSFAL).

The Workshop participants consisted of investigators of the role of essential fatty acids in nutrition, cardiovascular disease, and mental health. It was truly international in nature bringing together scientists from academia, government, international organizations, and industry from Australia, Canada, Denmark, France, Italy, Japan, Norway, Switzerland, United Kingdom, and the United States.

The Workshop participants came to the following conclusion:

“After much discussion consensus was reached on the importance of reducing the omega-6 polyunsaturated fatty acids (PUFAs) even as the omega-3 PUFAs are increased in the diet of adults and newborns for optimal brain and cardiovascular health and function. This is necessary to reduce adverse effects of excesses of arachidonic acid (AA) and its eicosanoid products. Such excesses can occur when too much linoleic acid (LA) and AA are present in the diet and an adequate supply of dietary omega-3 fatty acids is not available. The adverse effects of too much arachidonic acid and its eicosanoids can be avoided by two interdependent dietary changes. First, the amount of plant oils rich in LA, the parent compound of the omega-6 class, which is converted to AA, needs to be reduced. Second, simultaneously the omega-3 PUFAs need to be increased in the diet. LA can be converted to arachidonic acid and the enzyme, delta-6 desaturase, necessary to desaturate it, is the same one necessary to desaturate alpha-linolenic acid (ALA), the parent compound of the omega-3 class; each competes with the other for this desaturase. The presence of ALA in the diet can inhibit the conversion of the large amounts of LA in the diets of Western industrialized countries which contain too much dietary plant oils rich in omega-6 PUFAs (e.g. corn, safflower, and soybean oils). The increase of ALA, together with EPA and DHA, and reduction of vegetable oils with high LA content, are necessary to achieve a healthier diet in these countries.” (Artemis P. Simopoulos, MD, The Center for Genetics, Nutrition and Health, Washington, DC, U.S.A.; Alexander Leaf, MD, Massachusetts General Hospital, Charlestown, MA, U.S.A.; Norman Salem, Jr. PhD, National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, U.S.A. Final Statement by the Participants of the Workshop on the Essentiality of and Recommended Dietary Intakes for Omega-6 and Omega-3 Fatty Acids. Bethesda, MD 1999)

With regard to the recommended dosages of omega-6 and omega-3 fatty acids, the Workshop agreed upon the following guidelines:

1) for linoleic acid (LA), an adequate intake (AI)* was set at 4.44 grams per day, with an upper limit of 6.67 grams per day (2% and 3% of daily caloric intake, respectively, based on a 2000-calorie diet);

2) for alpha-linolenic acid (ALA), an adequate intake (AI)* was set at 2.22 grams per day (1% of daily caloric intake), with no upper limit.

Therefore, based on the recommendations of the Workshop, we need at least 2.22 grams of ALA per day. This translates into approximately one teaspoon (5 ml) of flax oil or its more stable and better-tasting counterpart - Camelina (wild flax) oil - daily. However, it is important to realize that it is very difficult not to exceed the upper limit for LA consumption (6.67 grams daily) unless you make a consistent effort to replace processed foods with natural, healthier alternatives present in traditional diets. For example, just one serving of corn, soybean or almost any other "supermarket" vegetable oil supplies 7-8 grams of LA, exceeding the upper daily limit on LA consumption. Moreover, the major problem with processed foods is that highly processed (refined, deodorized, or hydrogenated) omega-6 vegetable oils are one of their “cornerstone” ingredients, sharing this dubious honor with refined sugar and white flour. As a result, by eating processed foods we consume sizable amounts of omega-6 linoleic acid without even paying attention to it. For example, such processed foods as cakes, cookies, crackers, pies, and bread, as well as potato chips, corn chips, popcorn, and other popular snacks (as well as many other “supermarket foods” – there are too many of them to mention here), are usually loaded with omega-6 fats, often in their most dangerous hydrogenated (trans-fat) form. If the consumption of such foods is not curtailed, the daily upper limit for omega-6 fatty acid intake may easily be exceeded many times over.

Moreover, the rate of enzymatic conversion of alpha-linolenic acid into longer-chain precursors of prostaglandins is not uniform, and may be negatively affected by such widespread factors as aging, vitamin and mineral deficiencies, consumption of trans-fatty acids and alcohol, low thyroid function, smoking, and stress. For instance, achieving a maximum rate of ALA-to-EPA conversion requires an adequate daily intake of vitamins C, B6, B3, zinc and magnesium, preferably from natural sources, which are not always available.

With this in mind, in order to ensure an extra degree of protection against disease-causing abnormalities in fat metabolism, it may be advisable to increase omega-3 supplementation to a level higher than 2.22 grams of ALA daily, especially considering that, as opposed to the case with omega-6s, the experts did not impose an upper limit on omega-3 EFA consumption. Therefore, many nutritionists recommend a daily dose of one tablespoon (15 ml) of an ALA-rich oil (such as flax or Camelina oil), supplying about 6 to 8 grams of ALA. This amount of daily omega-3 supplementation will compensate for a probable excess of omega-6s in the diet, as well as for a possibility of an impaired ALA-to-EPA conversion.

For a discussion of the advantages and disadvantages of different available sources of omega-3 fatty acids, please visit this page. If you need more information or have questions, please contact our holistic nutritionists at consult@siberiantigernaturals.com.