Omega-3 Fatty Acids, Fish Oil, Alpha-Linolenic Acid : Part 2

by MedlinePlus

(Page 2 of 6)

Rheumatoid arthritis (fish oil)

Multiple randomized controlled trials report improvements in morning stiffness and joint tenderness with the regular intake of fish oil supplements for up to three months. Benefits have been reported as additive with anti-inflammatory medications such as NSAIDs (like ibuprofen or aspirin). However, because of weaknesses in study designs and reporting, better research is necessary before a strong favorable recommendation can be made. Effects beyond three months of treatment have not been well evaluated.Ingestion of fish oil omega-3 fatty acids relieved several clinical parameters used in the present study. However, patients showed a more precocious and accentuated improvement when fish oil supplements were used in combination with olive oil.

Protection from cyclosporine toxicity in organ transplant patients

There are multiple studies of heart transplant and kidney transplant patients taking cyclosporine (Neoral®), who were administered fish oil supplements. The majority of trials report improvements in kidney function (glomerular filtration rate, serum creatinine), and less hypertension (high blood pressure) compared to patients not taking fish oil. Although several recent studies report no benefits on kidney function, the weight of scientific evidence favors the beneficial effects of fish oil. No changes have been found in rates of rejection or graft survival.

Secondary cardiovascular disease prevention (α-linolenic acid [ALA])

Several randomized controlled trials have examined the effects of alpha-linolenic acid in people with a history of heart attack. Although some studies suggest benefits, others do not. Weaknesses in some of this research make results difficult to interpret, such as the use of other foods that may also be beneficial. Additional research is necessary before a conclusion can be drawn in this area.

Primary cardiovascular disease prevention (α-linolenic acid [ALA])

Several large studies of populations ("epidemiologic" studies) report a significantly reduced risk of fatal or non-fatal heart attack in men and women who regularly consume foods high in α-linolenic acid. Other epidemiologic research reports no such benefits. Although the existing research is compelling, weaknesses in this research make results difficult to interpret, such as the use of other foods that may also be beneficial, or effects of risk factors for heart disease such as smoking. Additional research is necessary before a conclusion can be drawn in this area.The American Heart Association, in its 2003 recommendations, suggests that in addition to eating fish at least two times per week, all adults should consume plant-derived sources of omega-3 fatty acids, such as tofu/soybeans, walnuts, flaxseed oil, and canola oil.

Stroke prevention

Several large studies of populations ("epidemiologic" studies) have examined the effects of omega-3 fatty acid intake on stroke risk. Some studies suggests benefits, while others do not. Effects are likely on ischemic or thrombotic stroke risk, and very large intakes of omega-3 fatty acids ("Eskimo" amounts) may actually increase the risk of hemorrhagic (bleeding) stroke. At this time, it is unclear if there are benefits in people with or without a history of stroke, or if effects of fish oil are comparable to other treatment strategies.Multiple mechanisms have been proposed for the beneficial effects of omega-3 fatty acids. These include reduced triglyceride levels, reduced inflammation, slightly lowered blood pressure, reduced blood clotting, and diminished buildup of atherosclerotic plaques in blood vessels. Experiments suggest that omega-3 fatty acids may reduce platelet derived growth factor (PDGF), decrease platelet aggregation, inhibit the expression of vascular adhesion molecules, and stimulate relaxation of endothelial cells in the walls of blood vessels.

Atherosclerosis

Some research reports that regular intake of fish or fish oil supplements reduces the risk of developing atherosclerotic plaques in the arteries of the heart, while other research reports no effects. Additional evidence is necessary before a firm conclusion can be drawn in this area.

Prevention of restenosis after coronary angioplasty (PTCA)

Several randomized controlled trials have evaluated whether omega-3 fatty acid intake reduces blockage of arteries in the heart following balloon angioplasty (percutaneous transluminal coronary angioplasty/PTCA). Some research has reported small significant benefits, while other investigations have not found benefits. The evidence in this area remains inconclusive.

Prevention of graft failure after heart bypass surgery

There is limited study of the use of fish oils in patients after undergoing coronary artery bypass grafting (CABG). Initial research suggests possible small benefits in reducing blood clot formation in vein grafts. Additional evidence is necessary before a firm conclusion can be drawn in this area.

Angina pectoris

Preliminary studies report reductions in angina associated with fish oil intake. Better research is necessary before a firm conclusion can be drawn.

Cardiac arrhythmias (abnormal heart rhythms)

There is promising evidence that omega-3 fatty acids may decrease the risk of cardiac arrhythmias. This is one proposed mechanism behind the reduced number of heart attacks in people who regularly ingest fish oil or EPA + DHA. Additional research is needed in this area specifically before a firm conclusion can be reached.

Cancer prevention

Several population (epidemiologic) studies report that dietary omega-3 fatty acids or fish oil may reduce the risk of developing breast, colon, or prostate cancer. Randomized controlled trials are necessary before a clear conclusion can be drawn.

Colon cancer

Omega-3 fatty acids are commonly taken by cancer patients. Although preliminary studies report that growth of colon cancer cells may be reduced by taking fish oil, effects on survival or remission have not been measured adequately.

Infant eye / brain development

It has been suggested that fatty acids, particularly DHA, may be important for normal neurologic development. Fatty acids are added to some infant formulas. Several studies have examined the effects of DHA on development of vision in preterm infants. Short-term benefits have been reported compared to formulas without DHA, although these benefits may not be meaningful in the long-term. Well-designed research is necessary before a clear conclusion can be reached.

Ulcerative colitis

It has been suggested that effects of omega-3 fatty acids on inflammation may be beneficial in patients with ulcerative colitis when added to standard therapy, and several studies have been conducted in this area. Although results have been promising, the majority of trials are small and not well designed. Therefore, better research is necessary before a clear conclusion can be drawn.

Crohn's disease

It has been suggested that effects of omega-3 fatty acids on inflammation may be beneficial in patients with Crohn's disease when added to standard therapy, and several studies have been conducted in this area. Results are conflicting, and no clear conclusion can be drawn at this time.

IgA nephropathy

There are conflicting results from several trials in this area.

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