dietary supplement omega 3
n−3 fatty acids (popularly referred to as ω−3 fatty acids or omega-3 fatty acids) are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−3 position; that is, the third bond from the methyl end of the fatty acid.
Important nutritionally essential n−3 fatty acids are: α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The human body cannot synthesize n−3 fatty acids de novo, but it can form 20- and 22-carbon unsaturated n−3 fatty acids from the eighteen-carbon n−3 fatty acid, α-linolenic acid. These conversions occur competitively with n−6 fatty acids, which are essential closely related chemical analogues that are derived from linoleic acid. Both the n−3 α-linolenic acid and n−6 linoleic acid are essential nutrients which must be obtained from food. Synthesis of the longer n−3 fatty acids from linolenic acid within the body is competitively slowed by the n−6 analogues. Thus accumulation of long-chain n−3 fatty acids in tissues is more effective when they are obtained directly from food or when competing amounts of n−6 analogs do not greatly exceed the amounts of n−3.
Chemistry
The term n−3 (also called ω−3 or omega-3) signifies that the first double bond exists as the third carbon-carbon bond from the terminal methyl end (n) of the carbon chain.
n−3 fatty acids which are important in human nutrition are: α-linolenic acid (18:3, n−3; ALA), eicosapentaenoic acid (20:5, n−3; EPA), and docosahexaenoic acid (22:6, n−3; DHA). These three polyunsaturates have either 3, 5 or 6 double bonds in a carbon chain of 18, 20 or 22 carbon atoms, respectively. All double bonds are in the cis-configuration, i.e. the two hydrogen atoms are on the same side of the double bond.
Most naturally-produced fatty acids (created or transformed in animalia or plant cells with an even number of carbon in chains) are in cis-configuration where they are more easily transformable. The trans-configuration results in much more stable chains that are very difficult to further break or transform, forming longer chains that aggregate in tissues and lacking the necessary hydrophilic properties. This trans-configuration can be the result of the transformation in alkaline solutions, or of the action of some bacterias that are shortening the carbonic chains. Natural transforms in vegetal or animal cells more rarely affect the last n−3 group itself. However, n−3 compounds are still more fragile than n−6 because the last double bond is geometrically and electrically more exposed, notably in the natural cis configuration.
List of n−3 fatty acids
This table lists several different names for the most common n−3 fatty acids found in nature.
Biological significances
A 1992 article by biochemist William E.M. Lands provides an overview of the research into n−3 fatty acids, and is the basis of this section.
The 'essential' fatty acids were given their name when researchers found that they were essential to normal growth in young children and animals. (Note that the modern definition of 'essential' is more strict.) A small amount of n−3 in the diet (~1% of total calories) enabled normal growth, and increasing the amount had little to no additional effect on growth.
Likewise, researchers found that n−6 fatty acids (such as γ-linolenic acid and arachidonic acid) play a similar role in normal growth. However, they also found that n−6 was "better" at supporting dermal integrity, renal function, and parturition. These preliminary findings led researchers to concentrate their studies on n−6, and it was only in recent decades that n−3 has become of interest.
In 1963 it was discovered that the n−6 arachidonic acid was converted by the body into pro-inflammatory agents called prostaglandins. By 1979 more of what are now known as eicosanoids were discovered: thromboxanes, prostacyclins and the leukotrienes. The eicosanoids, which have important biological functions, typically have a short active lifetime in the body, starting with synthesis from fatty acids and ending with metabolism by enzymes. However, if the rate of synthesis exceeds the rate of metabolism, the excess eicosanoids may have deleterious effects. Researchers found that n−3 is also converted into eicosanoids, but at a much slower rate. Eicosanoids made from n−3 fats often have opposing functions to those made from n−6 fats (ie, anti-inflammatory rather than inflammatory). If both n−3 and n−6 are present, they will "compete" to be transformed, so the ratio of n−3:n−6 directly affects the type of eicosanoids that are produced.
This competition was recognized as important when it was found that thromboxane is a factor in the clumping of platelets, which leads to thrombosis. The leukotrienes were similarly found to be important in immune/inflammatory-system response, and therefore relevant to arthritis, lupus, and asthma. These discoveries led to greater interest in finding ways to control the synthesis of n−6 eicosanoids. The simplest way would be by consuming more n−3 and fewer n−6 fatty acids.
Health benefits
On September 8, 2004, the U.S. Food and Drug Administration gave "qualified health claim" status to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) n−3 fatty acids, stating that "supportive but not conclusive research shows that consumption of EPA and DHA fatty acids may reduce the risk of coronary heart disease." This updated and modified their health risk advice letter of 2001 (see below).
People with certain circulatory problems, such as varicose veins, benefit from fish oil. Fish oil stimulates blood circulation, increases the breakdown of fibrin, a compound involved in clot and scar formation, and additionally has been shown to reduce blood pressure. There is strong scientific evidence that n−3 fatty acids significantly reduce blood triglyceride levels and regular intake reduces the risk of secondary and primary heart attack.
Some benefits have been reported in conditions such as rheumatoid arthritis and cardiac arrhythmias.
There is a promising preliminary evidence that n-3 fatty acids supplementation might be helpful in cases of depression and anxiety. Studies report highly significant improvement from n-3 fatty acids supplementation alone and in conjunction with medication.
Some research suggests that fish oil intake may reduce the risk of ischemic and thrombotic stroke. However, very large amounts may actually increase the risk of hemorrhagic stroke (see below). Lower amounts are not related to this risk, 3 grams of total EPA/DHA daily are considered safe with no increased risk of bleeding involved and many studies used substantially higher doses without major side effects (for example: 4.4 grams EPA/2.2 grams DHA in 2003 study).
Cancer
Several studies report possible anti-cancer effects of n−3 fatty acids (particularly breast, colon and prostate cancer). Omega-3 fatty acids reduced prostate tumor growth, slowed histopathological progression, and increased survival. Among n-3 fatty acids , neither long-chain nor short-chain forms were consistently associated with breast cancer risk. High levels of docosahexaenoic acid, however, the most abundant n-3 PUFA in erythrocyte membranes, were associated with a reduced risk of breast cancer..
A 2006 report in the Journal of the American Medical Association concluded that their review of literature covering cohorts from many countries with a wide variety of demographic characteristics demonstrating a link between n−3 fatty acids and cancer prevention gave mixed results. This is similar to the findings of a review by the British Medical Journal of studies up to February 2002 that failed to find clear effects of long and shorter chain n−3 fats on total mortality, combined cardiovascular events and cancer.
Other
In 1999, the GISSI-Prevenzione Investigators reported in the Lancet, the results of major clinical study in 11,324 patients with a recent myocardial infarction. Treatment 1 gram per day of n−3 fatty acids reduced the occurrence of death, cardiovascular death and sudden cardiac death by 20%, 30% and 45% respectively. These beneficial effects were seen already from three months onwards.
In April 2006, a team led by Lee Hooper at the University of East Anglia in Norwich, UK, published a review of almost 100 separate studies into n−3 fatty acids, found in abundance in oily fish. It concluded that they do not have a significant protective effect against cardiovascular disease. This meta-analysis was controversial and stands in stark contrast with two different reviews also performed in 2006 by the American Journal of Clinical Nutrition and a second JAMA review that both indicated decreases in total mortality and cardiovascular incidents (i.e. myocardial infarctions) associated with the regular consumption of fish and fish oil supplements. I
dietary supplement omega 3
Health Effects of Omega-3 Fatty Acids: AHRQ Reports Available. Press Release: AHRQ Evidence Reports Confirm that Fish Oil Helps Fight Heart Disease (4/22/04)
Health Effects of Omega-3 Fatty Acids: AHRQ Reports Available
Omega-3 Fatty Acids Working Group Report: Omega-3 Fatty Acids and Cardiovascular Disease. A working group meeting was held on June 2, 2004 to review evidence-based reports on the ...
Omega-3 Fatty Acids
100% Pure Emu Oil Dietary Supplements taken orally provide Omega 3, Omega 6 and Omega 9 Essential Fatty Acids. These essential fatty acids can only be obtained from our diet, the ...
Emu Oil Dietary Supplements with Omega 3, Omega 6 & Omega 9 Essetial ...
Omega-3 fatty acids, fish oil, alpha-linolenic acid ... Dietary sources of omega-3 fatty acids include fish oil and certain plant/nut oils.
MedlinePlus Herbs and Supplements: Omega-3 fatty ...
Welcome to Isodis Natura. Take a look at our supplements that are effective in treating Bipolar Disorder, Nutritional Diet that includes vital omega 3 fatty acid. If you have any ...
Omega 3 fatty acids | Nutritional Dietary Supplement | Bipolar ...
Guide to choosing the best fish oil dietary supplements in relation to omega-3 fatty acids, safety and purity.
Best Fish Oil Dietary Supplements - Best Fish Oil Dietary Supplements
Live Your Healthiest Life! Click here for information on a variety of health topics. Find Answers
Dietary Supplement Information Bureau – Omega 3
Omega-3 Fatty Acids May Prevent Retinopathy-Related Blindness : Published Wednesday, August 1, 2007
Dietary Supplement Information Bureau – Omega-3 Fatty Acids May ...
Pure Concentrated Omega-3. Introduction Quistel 's maximum strength, bio-enhancing Omega-3 dietary supplement contains highly concentrated pure Sand Eel Oil with the enhanced anti ...
Quistel - Omega-3
1: Completed: Diet and Omega-3 Intervention Trial on Atherosclerosis: Condition: Atherosclerosis: Interventions: Dietary Supplement: No dietary counseling and omega-3 capsules ...
Latest News
Will Tebow pass Heisman torch to Bradford? - Boston Globe
Will Tebow pass Heisman torch to Bradford?
Boston Globe
Boston Globe -
Sam Bradford (from left), Colt McCoy, and Tim Tebow would all look at home with the Heisman. (Phelan m. ebenhack/Associated Press) By Mark Blaudschun Call it a game of seconds rather than inches.
Heisman Trophy winner's a toss-up
In a Surprise, the Heisman Winner Remains a Mystery
California approves measure to cut diesel pollution - Los Angeles Times
California approves measure to cut diesel pollution
The Southern Ledger
Los Angeles Times -
Despite opposition from truckers, state Air Resources Board votes to require retrofitting or replacement of older rigs. By Margot Roosevelt Reporting from Sacramento -- California regulators cracked down on diesel air pollution Friday, adopting the ...
Air board adopts strict rules on diesel exhaust
California OKs tough diesel emission rules