More Good News about Fish Oil and Heart Disease

James Meschino DC, MS, ROHP

In my previous article I explained the three primary mechanisms through with fish consumption and the use of a fish oil-containing supplement are reported to reduce risk of heart attack and ischemic stroke.  However, there are additionalways that fish and fish oil has been shown to reduce risk of heart and vascular disease. These include the following:

1. Reduce High Triglycerides

High blood triglyceride levels also contribute to risk of heart disease. This seems to be especially true in women, where high triglycerides are strongly linked to heart attack risk. Remember that the leading cause of death in postmenopausal women is heart disease. So using fish oil to help keep triglycerides in the ideal range (under 150 mg/dL) is helpful in cases where triglycerides are too high (1).

How Do Omega-3 Fats Reduce Triglycerides? 
In human studies fish oil supplementation has been shown to help clear triglycerides from the bloodstream (by increasing lipoprotein lipase activity), thereby lowering the amount of triglycerides in the blood. This is the same mechanism through which popular triglyceride-lowering drugs act, such as fibric acid derivatives and high dose niacin, prescribed by physicians for this purpose. We have seen that fish oil supplementation can be very helpful in these cases (2, 3). Human clinical studies have shown that Fish Oil supplementation lowers triglyceride levels, and the higher the initial triglyceride level, the greater the reduction (4).

2. Increase HDL (the good cholesterol)

Studies show that when you lower triglycerides, HDL-cholesterol usually goes up. HDL-cholesterol is the good cholesterol that is thought to remove cholesterol plaque from the artery wall – opening up blood vessels and reversing atherosclerosis to some degree. Studies have shown that fish oil supplements often lower triglycerides,  and also raise the good cholesterol (HDL). Higher HDL levels are strongly associated with reduced risk of heart attack (5).

3. Reduce Blood Vessel Inflammation

Fish oil supplementation has also been shown to reduce inflammation in the blood vessel wall. Inflammation in the blood vessel wall, in the area of atherosclerosis, is strongly linked to heart attack and stroke. Omega-3 fats are used by immune cells and platelets to make anti-inflammatory (prostaglandin) hormones. As well, fish oil supplements are shown to reduce other inflammatory chemicals (tumor necrosis factor-alpha, interleukin-1b), which are also tied to blood vessel inflammation (6).

4. Plaque Stabilization

Fish oil supplementation has been shown to help to stabilize plaque – making it less likely that the plaque will rupture. This helps prevent the major triggering event in many heart attacks. Omega-3 fats get incorporated into the atherosclerotic plaque (esterifying cholesterol), which makes the plaque more fluid and pliable and less rigid and hard. As such, the plaque is less likely to rupture (7).

5. Decrease Arrhythmias

Studies show that fish oil supplements may also help to reduce risk of arrhythmias, which are also known to trigger heart attacks (8).

Summary
In addition to improving blood flow and reducing stickiness of blood platelets consuming fish twice per week and taking a fish oil-containing supplement each day has also been shown to reduce risk of heart attack and vascular disease via other mechanisms, which include:

• Lowering Triglycerides
• Raising HDL levels
• Reducing Blood Vessel Inflammation
• Reducing Risk of Arrhythmia
• Stabilizing Arterial Plaque

References

1. S. Berger, Stroke, 2012: http://stroke.ahajournals.org/content/43/4/958).
2. Harris WS et al. Omega-3 fatty acids and coronary heart disease risk: clinical and mechanistic perspectives. Atherosclerosis 2008; 197:12-24
3. Khan S, et al. Dietary long-chain n-3 PUFA’s increase LPL gene expression in adipose tissue of subjects with an atherogenic lipoprotein phenotype. J Lipid Research 2002; 43:979-985
4. Reference: Balk EM et al. Effects of omega-3 fatty acids on serum markers of cardiovascular disease risk: a systematic review. Atherosclerosis 2006; 189:19-30
5. Chan E.J and Cho L. What can we expect from omega-3 fatty acids.Cleveland Clinic Journal of MedicineApril 2009; 76 (4): 245-251(http://www.ccjm.org/content/76/4/245.long)
6. Reidiger N.D. A systematic review of the roles of n-3 fatty acids in health and disease. J Am Diet Assoc 2009;109:668-679.
7. Chan E.J and Cho L. What can we expect from omega-3 fatty acids.Cleveland Clinic Journal of MedicineApril 2009; 76 (4): 245-251(http://www.ccjm.org/content/76/4/245.long )
8. Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. GruppoItaliano per lo Studio dellaSopravvivenzaNell’InfartoMiocardico. Lancet 1999; 354:447–455.