The omega-3 index was developed in the early 2000s in response to the need for an objective measure of omega-3 levels in the human body. An individual’s omega-3 index is defined as the percentage of fatty acids in their red blood cells which are DHA or EPA.
While EPA and DHA can be sampled in a variety of bodily fluids and tissues, it’s been found that omega-3 concentrations in the blood correlate with concentrations in heart muscle, and thus are likely representative of the body’s uptake of EPA and DHA as a whole.
The omega-3 index not only provides a means of measuring omega-3 content in the blood, but also establishes ranges associated with positive and negative health outcomes:
- Optimal: 8% or higher
- Intermediate: 4% to 8%
- Low: Below 4%
People with higher omega-3 indexes have been found in some studies to have reduced incidence of cardiovascular disease and other negative health issues*.
Rather than being arbitrarily defined, the omega-3 index ranges were defined in response to several studies which found that people with omega-3 indexes above 8% had lower incidence of certain negative health issues, such as cardiovascular disease, than those people with low or intermediate indexes. Those with intermediate indexes had outcomes that fell between the ranges of the two groups bracketing them. Those in the low range have been found in some studies to be especially vulnerable to death from coronary heart disease and other serious health consequences.
Dr. Doug Bibus, founder of Lipid Technologies, notes, “Our blood and tissues have approximately 30 common fatty acids. For many Americans, the total omega-3 content in blood is around 4% or 4 out of 100 fatty acids in blood. Many experts agree that this blood level reflects omega-3 deficiency and puts us at risk for adverse health conditions. The omega-3 index test measures omega-3s in your blood, EPA and DHA, and is as simple as a quick finger stick. Raising your omega-3 index from 3-4% to 8% or more results in considerable heart and physical health benefits.”
While there has been a great deal of research on the impact of EPA and DHA on brain health, eye health, and other benefits, the majority of research has focused on potential heart health benefits. Studies have found that optimal omega-3 indexes are associated with:
- 39% reduction in risk of cardiovascular disease
- 17% lower risk of death caused by cancer
- 15% lower risk of death from other causes
Findings like the above are why the American Heart Association now recommends that Americans consume two servings of fish per week—which contains roughly 3 grams of EPA and DHA—and recommends supplementation of DHA and EPA for people with certain kinds of cardiovascular heart disease and high triglyceride levels.
Health conscientious consumers may assume there’s a simple, linear relationship between omega-3 intake and omega-3 index. That isn’t the case.
The omega-3 index is also a critical metric because foods eaten along with omega-3 supplements, variations in metabolism, and behaviors such as smoking can all affect EPA and DHA uptake.
Which omega-3s you eat matters. There are a variety of foods (flaxseed oil, soybean oil, etc.) and supplements promoted to vegan consumers as healthy, plant-based sources of omega-3s. These are generally high in ALA, which is an important omega-3 that research indicates has cardiovascular benefits.
But while it’s been shown that the body can convert ALA into EPA and DHA, the amounts involved are small. Studies have found that increased ALA intake doesn’t increase the omega-3 index. Consumption of EPA and DHA is necessary to move the needle.
It should also be noted that a short-term increase in omega-3 consumption won’t increase your index. It can take 3 to 6 months for a consistent change in diet to translate into a change in omega-3 index.
What you eat with omega-3s also matters. Fatty acid absorption requires the presence of fats. Consequently, the bioavailability of DHA and EPA is minimal when consumed as part of a low-fat diet. If you’re taking an omega-3 supplement on an empty stomach, you may not be getting much benefit.
There are also a variety of non-dietary variables that affect the omega-3 index. An analysis of several studies found that long-term intake of EPA and DHA accounted for no more than 25% of the variability in omega-3 index levels. Heredity was found to account for 24% of index variability, meaning that your body’s ability to metabolize EPA and DHA are in part defined by your genetics. Factors such as increased age and higher socioeconomic status were found to be associated with higher omega-3 indexes, while increased body mass index and smoking were associated with lower omega-3 indexes.
The sum result of all these variables means that the body’s ability to use EPA and DHA can vary a great deal. To quote the analysis, “The inter-individual variability in response to a fixed dose of EPA + DHA has been found to be large, i.e., vary up to a factor of 13.” In other words, omega-3 intake that raises one person’s omega-3 index by 0.1% could raise another person’s index by as much as 1.3%. Incorporating more omega-3s into your diet, whether by eating more fatty fish or taking an omega-3 supplement, will improve your omega-3 index. Having your omega-3 index tested will give you greater insight into how much you need to take to achieve your health goals.
All the key omega-3 fatty acids—EPA, DHA and ALA—are important parts of a healthy diet. Research shows that ALA supports cardiovascular health and regulates blood pressure. But if your goal is to increase your EPA and DHA levels, you need to know how effectively your body is taking in EPA and DHA, so you can adjust accordingly if necessary. The omega-3 index is a crucial tool for better understanding your body’s omega-3 levels and how well your body metabolizes EPA and DHA.
Per Dr. Bibus, “Knowing your omega-3 ‘number’ can help guide you on your dietary or omega-3 supplement strategies to consume EPA and DHA and benefit from their multitude of health benefits. Populational and thousands of peer-reviewed studies confirm the health benefits of omega-3s, but dosing (and subsequent tissue levels) are key to many of these findings. If you are only eating omega-3 rich seafood occasionally or not taking the proper amount of EPA/DHA in a dietary supplement, you may be missing out. Taking a few minutes to submit a dried blood spot for the omega 3 index test is a simple and direct step to take to dial in your dietary omega-3 habits to maximize their benefits.”
For more information, please consult with your general practitioner, a nutritionist, or other qualified health professional. This article is only intended to provide general guidance as to the utility of the omega-3 index as a system for measuring omega-3 levels.