Omega-3 fatty acids, EPA and DHA, are crucial ingredients in any heart-disease prevention or reversal program. Studies such as the 11,000-participant GISSI Prevenzione trial demonstrated substantial decrease in heart attack and death with omega-3 fatty acid supplementation (28% reduction in heart attack; 45% reduction in sudden cardiac death). 

Average Americans ingest 150 mg of omega-3s per day and have only 2.5-3.0% of all fatty acids in the blood occupied by omega-3s . Studies, such as the ERA JUMP study, comparing men from PIttsburgh, Pennsylvania to men in Japan, suggest that low omega-3 blood levels are associated with more severe plaque in the carotid and coronary arteries. 

The proportion of omega-3 fatty acids in red blood cells (RBCs) is called the omega-3 index. An omega-3 index of 7% or greater has been associated with reduced risk for sudden death from heart disease. Recent evidence suggests that a level of 9% may also reduce risk for heart attack.
 

"The risk of sudden death associated with an omega-3 intake of 3.3% is 10 times the risk of sudden cardiac death associated with an omega-3 index of around 7%. . . The risk indicated by the omega-3 index may very well vary more than 15 fold, which makes the omega-3 index a highly discriminative risk factor." 

William Harris, PhD


Among the nutritional mistakes made during the 1980s and 1990s was the idea that polyunsaturated fats rich in the omega-6 fraction of fats were healthy. We now know that they are not. Most Americans overconsume omega-6s and lack omega-3s, with a ratio of omega-6:omega-3 of 20:1, sometimes higher. The ideal omega 6:omega-3 ratio is a matter of debate, though some authorities argue that 2:1 or even 1:1 is ideal. 

The omega-6:omega-3 ratio can also now be measured along with your omega-3 index to provide even greater insight into the health of your diet and fat intake.   

The omega-3 fatty acids from animal sources, especially fish, should not be confused with another omega-3 fatty acid, linolenic acid, the form sourced from flaxseed oil. While linolenic acid is a healthy form of oil, perhaps the healthiest form of oil after EPA and DHA from animals and fish, it does not confer the same health benefits of EPA and DHA, including no effect on triglyceride reduction nor the impressive heart attack and mortality-reducing effects.  

Both the percentage of omega-3 fatty acids in red blood cells and the omega-6:omega-3 ratio can now be determined with a fingerstick using a convenient at-home technology.



Omega-3 Index, Omega-6:Omega-3 Ratio 

Q:  I heard that eating fish and taking fish oil capsules could reduce my risk for heart attack. I therefore try to eat fish at least once per week. I also take one or two capsules of a high-quality fish oil every day. 

Shouldn't that be enough to be sure I have an ideal quantity of omega-3 in my blood? 


A:  It may not be.  

For most Americans, omega-3 fatty acid supplementation is a recent development. But the populations of the world best at obtaining omega-3 fatty acids, the Inuits ("Eskimoes") and the Japanese, have been consuming omega-3 fatty acids for years over a lifetime. 

Increasing the proportion of omega-3 fatty acids in your blood and tissues requires years. It is also dependent on the dose of omega-3s, the concentration of omega-3s in the preparations used, and your efficiency of absorption. Metabolic factors, such as sensitivity to insulin and genetic differences, can also influence the quantity of omega-3s in the blood.  
  
It is therefore not possible to accurately estimate the proportion of omega-3 fatty acids in your blood just by observing your omega-3 fatty acid intake. The most confident means of knowing your omega-3 fatty acid level is to measure it. The measurement of the proportion of omega-3 fatty acids as a percentage of total fatty acids in red blood cells is called the omega-3 index. 

Because of the errors made during the low-saturated fat era, many people worsened the problem by overconsuming foods rich in omega-6 fats, such as corn oil, vegetable oil, and soybean oil. This tips the scales further towards a blood level of fats dominated by omega-6s, while depleted in omega-3s. This perspective can be measured as the omega-6: omega:3 ratio. 

Knowing both values, the omega-3 Index (the percentage of fatty acids in red blood cells that are omega-3) and the omega-6: omega-3 ratio, provide insight into the adequacy of your diet and omega-3 intake to gain maximal cardiovascular protection. 

 

Overview

Omega-3 fatty acids easily qualify as the fraction of fats that are associated with the greatest health benefits. 

The beneficial effects of omega-3 supplementaion are far-reaching: 28% reduction in heart attack, 45% reduction in sudden cardiac death. Omega-3s reduce triglycerides better than any other known agent. Omega-3s can also reduce psychiatric illness (depression, bipolar illness), reduce various measures of inflammation, enhance immune responses, and improve learning in children.   

The blood level of omega-3s have been observed to be powerfully associated with risk for heart attack. But the association is especially strong for sudden cardiac death:




Harris W 2008

There is over a 10-fold difference in relative risk for sudden cardiovascular death comparing lowest to highest (quartiles) omega-3 indexes.


Additional Information Sources

TRACK YOUR PLAQUE SPECIAL REPORTS 

Omega-3 fatty acids and fish oil

Who's afraid of fish oil?

Triglyceride buster


Other resources

Omega-3 and heart health

The omega-3 index: The new measure of heart health