The Omega-3 Index: A New Measure of Health & Disease
5% – 8%
An important predictor of health and disease is the amount of omega-3 fatty acids incorporated into cells, tissues and organs. While it would be impossible to routinely take tissue biopsies from the body’s organs just to check the omega-3 fatty acid content, red blood cells are constantly being rebuilt and are readily accessible. Based on this premise, researchers developed the Omega-3 Index as a way to measure omega-3 status.
The Omega-3 Index is defined as the combined EPA and DHA concentration as a percentage of total fatty acids in red blood cells, which correlates well with the amount of EPA and DHA in other tissues.
In fact, studies show that there is a linear correlation between the content of Omega-3 fatty acids in phospholipids of red blood cells and the content of omega-3 fatty acids in the heart.
This means that by measuring the Omega-3 Index in red blood cells, we can also determine the omega-3 fatty acid content in the heart. In large, randomized intervention trials, increasing the intake of omega-3 fatty acids led to an increased Omega-3 Index and reduction of sudden cardiac death, fatal and non-fatal myocardial infarctions, and improved survival and symptoms in congestive heart failure, and other cardiovascular diseases.
Theoretically, the Omega-3 Index represents a person’s overall EPA and DHA status because red blood cells have a phospholipid membrane and incorporate omega-3 fatty acids into their membrane as other tissues do. For example, if there are 64 fatty acids in the red blood cell membranes and three are omega-3 fatty acids, then the Omega-3 Index is 3/64 or 4.6%.
An Omega-3 Index below 4% is associated with an increased risk for cardiovascular diseases, whereas an Omega-3 index above 4% reduces the risk for heart disease.
Similarly, a study investigating patients with stable coronary artery disease found that those with an Omega-3 Index above 4% had a 27% lower risk of death, compared to those with an Omega-3 Index below 4%.
Based on numerous investigations of cardiovascular risk, the ideal range for the Omega-3 Index lies somewhere between 8% and 12%.
At values above 11%, however, studies indicate no further benefit in terms of risk reduction.
Beyond cardiovascular disease, a low Omega-3 Index has also been correlated with an increased risk for the development of depression, cognitive decline, sleep apnea, and osteoporosis.
Overall, the health impact of omega-3 fatty acids is substantial, and can be divided into six segments, including heart disease, central nervous system/behavior, metabolic disorder, immune function, cancer, and others .
In particular, two clinical studies have shown that Ω krill can increase total plasma EPA and DHA more than fish oil intake after both 4-week and 7-week long supplementation periods.
Taken together, these studies suggest that enhanced bio-efficiency of omega-3 fatty acids in the body is desirable. More specifically, increased levels of EPA and DHA in blood have been associated with decreased risk of sudden cardiac death and other harmful cardiac events.
Since decreases in EPA and DHA levels are correlated with sudden cardiac death 18 researchers have recently turned their investigations toward krill oil to see if it can increase omega-3 RBC levels. In an unpublished clinical study, healthy volunteers took either 2 grams of Krill oil for 8 weeks or 2 grams of an omega-3 enriched fish oil. The goal of the study was to compare the delivery of omega-3 fatty acids — PLs versus TGs — to see if the form influences the increase in Omega-3 Index. The results of the study showed that krill oil increased the Omega-3 Index significantly more than fish oil after 8 weeks of supplementation.
In fact, krill oil increased the Omega-3 Index about 70% more than fish oil at the end of study after dose adjustment between the two treatment groups.