Research Data On Omega -3-Fatty Acids

Roles of unsaturated fatty acids (especially omega-3 fatty acids) in the brain at various ages and during ageing

   Dietary omega-3 fatty acids are certainly involved in the prevention of some aspects of cardiovascular disease (including at the level of cerebral vascularization), and in some neuropsychiatric disorders, particularly depression, as well as in dementia, notably Alzheimer's disease. Recent results have shown that dietary alpha-linolenic acid deficiency induces more marked abnormalities in certain cerebral structures than in others, as the frontal cortex and pituitary gland are more severely affected. These selective lesions are accompanied by behavioural disorders more particularly affecting certain tests (habituation, adaptation to new situations). Alpha-linolenic acid deficiency decreases the perception of pleasure, by slightly altering the efficacy of sensory organs and by affecting certain cerebral structures. Age-related impairment of hearing, vision and smell is due to both decreased efficacy of the parts of the brain concerned and disorders of sensory receptors, particularly of the inner ear or retina. For example, a given level of perception of a sweet taste requires a larger quantity of sugar in subjects with alpha-linolenic acid deficiency. The enzymatic activities of sytivities of synthesis of long-chain polyunsaturated fatty acids from linoleic and alpha-linolenic acids are very limited in the brain: this organ therefore depends on an exogenous supply. Consequently, fatty acids that are essential for the brain are arachidonic acid and cervonic acid, derived from the diet, unless they are synthesized by the liver from linoleic acid and alpha-linolenic acid. The age-related reduction of hepatic desaturase activities (which participate in the synthesis of long chains, together with elongases) can impair turnover of cerebral membranes. In many structures, especially in the frontal cortex, a reduction of cervonic and arachidonic acids is observed during ageing, predominantly associated with a reduction of phosphatidylethanolamines (mainly in the form of plasmalogens). Peroxisomal oxidation of polyunsaturated fatty acids decreases in the brain during ageing, participating in decreased turnover of membrane fatty acids, which are also less effectively protected against peroxidation by free radicals. (Bourre JM. J Nutr Health Aging. 2004;8(3):163-74.INSERM Research Director. Unit U26 Neuro-pharmaco-nutrition. Hopital Fernand Widal, 200 rue du Faubourg Saint Denis. 75745 Paris cedex 1)

Prevention of Cardiovascular heart diseases

   Consumption of omega-3 fatty acids from fish or from supplements of fish oil reduces all cause mortality and various CVD outcomes but different types of fish and the method of food preparation may have different effects ,so it is very necessary to administrate Omega-3-fatty acids supplements from external source.(NCBI resources, AHRQ Evidence Reports)

   Clinical evidence suggests that EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid, the two omega-3 fatty acids found in fish oil) help reduce risk factors for heart disease, including high cholesterol and high blood pressure. Fish oil has been shown to lower levels of triglycerides (fats in the blood), and to lower risk of death, heart attack, stroke, and abnormal heart rhythms in people who have already had a heart attack.Omega-3 fatty acids help prevent and treat atherosclerosis (hardening of the arteries) by slowing the development of plaque and blood clots, which can clog arteries.

(Angerer P, von Schacky C. n-3 polyunsaturated fatty acids and the cardiovascular system. Curr Opin Lipidol. 2000;11(1):57-63.)

Intake of polyunsaturated fatty acids(Omeg-3s and 6s-fatty acids)reduces the risk of developing amyotrophic lateral sclerosis

   A high intake of PUFAs is associated with a 50–60% decreased risk of developing ALS, and these nutrients appear to act synergistically.(J Neurol Neurosurg Psychiatry 2007;78:367-371 doi:10.1136/jnnp.2005.083378)

Rheumatoid arthritis

   Most clinical studies examining omega-3 fatty acid supplements for arthritis have focused on rheumatoid arthritis (RA), an autoimmune disease that causes inflammation in the joints. A number of small studies have found that fish oil helps reduce symptoms of RA, including joint pain and morning stiffness. One study suggests that people with RA who take omega-3 fatty acid may be able to lower their dose of non-steroidal anti-inflammatory drugs (NSAIDs). Laboratory studies suggest that diets rich in omega-3 fatty acids (and low in the inflammatory omega-6 fatty acids) may help people with osteoarthritis, although more study is needed.

   An analysis of 17 randomized, controlled clinical trials looked at the pain relieving effects of omega-3 fatty acid supplements in people with RA or joint pain caused by inflammatory bowel disease (IBS) and painful menstruation (dysmenorrhea). The results suggest that omega-3 fatty acids, along with conventional therapies such as NSAIDs, may help relieve joint pain associated with these conditions.(Refference- Berbert AA, Kondo CR, Almendra CL et al. Supplementation of fish oil and olive oil in patients with rheumatoid arthritis.Nutrition. 2005;21:131-6.)

Systemic lupus erythematosus (SLE)

   Several small studies suggest that EPA and fish oil may help reduce symptoms of lupus, an autoimmune condition characterized by fatigue and joint pain. However, two small studies found fish oil had no effect on lupus nephritis (kidney disease caused by lupus, a frequent complication of the disease).

Osteoporosis

   Some studies suggest that omega-3 fatty acids may help increase levels of calcium in the body and improve bone strength, although not all results were positive. Some studies also suggest that people who don' t get enough of some essential fatty acids (particularly EPA and gamma-linolenic acid [GLA], an omega-6 fatty acid) are more likely to have bone loss than those with normal levels of these fatty acids. In a study of women over 65 with osteoporosis, those who took EPA and GLA supplements had less bone loss over 3 years than those who took placebo. Many of these women also experienced an increase in bone density.

Prostate cancer

   Population based studies of groups of men suggest that a low-fat diet including omega-3 fatty acids from fish or fish oil help prevent the development of prostate cancer. (Reff- Freeman VL, Meydani M, Yong S, Pyle J, Flanigan RC, Waters WB, Wojcik EM. Prostatic levels of fatty acids and the histopathology of localized prostate cancer. J Urol. 2000; 164(6):2168-2172.)

Colon cancer

   Eating foods rich in omega-3 fatty acids seems to reduce the risk of colorectal cancer. For example, Eskimos, who tend to have a high-fat diet but eat significant amounts of fish rich in omega-3 fatty acids, have a low rate of colorectal cancer. Animal studies and laboratory studies have found that omega-3 fatty acids prevent worsening of colon cancer. Preliminary studies suggest that taking fish oil daily may help slow the progression of colon cancer in people with early stages of the disease. If you have colorectal cancer, ask your doctor before taking any supplements.(Daniel CR, McCullough ML, Patel RC, Jacobs EJ, Flanders WD, Thun MJ, Calle EE. Dietary intake of omega-6 and omega-3 fatty acids and risk of colorectal cancer in a prospective cohort of U.S. men and women. Cancer Epidemiol Biomarkers Prev. 2009 Feb;18(2):516-25.)

Diabetes

   People with diabetes often have high triglyceride and low HDL levels. Omega-3 fatty acids from fish oil can help lower triglycerides and apoproteins (markers of diabetes), and raise HDL, so eating foods or taking fish oil supplements may help people with diabetes. Another type of omega-3 fatty acid, ALA (from flaxseed, for example) may not have the same benefit as fish oil. Some people with diabetes can' t efficiently convert LNA to a form of omega-3 fatty acids that the body can use. Also, some people with type 2 diabetes may have slight increases in fasting blood sugar when taking fish oil, so talk to your doctor to see if fish oil is right for you.(Montori V, Farmer A, Wollan PC, Dinneen SF. Fish oil supplementation in type 2 diabetes: a quantitative systematic review. Diabetes Care. 2000;23:1407-1415.)

Asthma

   Studies examining omega-3 fatty acids for asthma are mixed. In one small, well-designed clinical study of 29 children with asthma, those who took fish oil supplements rich in EPA and DHA for 10 months reduced their symptoms compared to children who took placebo. However, most studies have shown no effect. (Reff- Nagakura T, Matsuda S, Shichijyo K, Sugimoto H, Hata K. Dietary supplementation with fish oil rich in omega-3 polyunsaturated fatty acids in children with bronchial asthma. Eur Resp J. 2000;16(5):861-865.)

Inflammatory bowel disease (IBD)

   Results are mixed as to whether omega-3 fatty acids can help reduce symptoms of Crohn's disease and ulcerative colitis, the two types of IBD. Some studies suggest that omega-3 fatty acids may help when added to medication, such as sulfasalazine (a standard medication for IBD). Others find no effect. More studies are needed. Fish oil supplements can cause side effects that are similar to symptoms of IBD (such as flatulence, belching, bloating, and diarrhea). (Reff- Belluzzi A, Boschi S, Brignola C, Munarini A, Cariani C, Miglio F. Polyunsaturated fatty acids and inflammatory bowel disease. Am J Clin Nutr. 2000;71(suppl):339S-342S.)

Breast cancer

   Although not all experts agree, women who eat foods rich in omega-3 fatty acids over many years may be less likely to develop breast cancer(Reff- Stark KD, Park EJ, Maines VA, et al. Effect of fish-oil concentrate on serum lipids in postmenopausal women receiving and not receiving hormone replacement therapy in a placebo-controlled, double blind trial. Am J Clin Nutr. 2000;72:389-394)

High cholesterol

   People who follow a Mediterranean-style diet tend to have higher HDL or “good” cholesterol levels, which help promote heart health. Inuit Eskimos, who get high amounts of omega-3 fatty acids from eating fatty fish, also tend to have increased HDL cholesterol and decreased triglycerides (fats in the blood). Several studies have shown that fish oil supplements reduce triglyceride levels. Finally, walnuts (which are rich in alpha linolenic acid or LNA, a type of omega-3 fatty acid) have been reported to lower total cholesterol and triglycerides in people with high cholesterol levels. (Reff-Kris-Etherton P, Eckel RH, Howard BV, St. Jeor S, Bazzare TL. AHA Science Advisory: Lyon Diet Heart Study. Benefits of a Mediterranean-style, National Cholesterol Education Program/American Heart Association Step I Dietary Pattern on Cardiovascular Disease. Circulation. 2001;103:1823. Mattar M, Obeid O. Fish oil and the management of hypertriglyceridemia. Nutr Health. 2009;20(1):41-9. Review.)