The Omega-3 Index measures the level of long-chain omega-3 fatty acids; EPA+DHA, in red blood cell membranes expressed as a percentage of total fatty acids. An Omega-3 Index in the range of 8-12% is one indicator of better overall health; and may help to maintain heart, brain, eye and joint health as a part of an overall healthy lifestyle.
Writing in the American Journal of Clinical Nutrition, an international team; led by scientists from Penn State University and OmegaQuant Analytics, reported that for 95% of people to raise their Omega-3 Index from approximately 4% to 8%; a dose of 2 g/d EPA + DHA needed, and that omega-3 supplements in the triglyceride form increased omega-3 index levels; more than supplements with omega-3s in the ethyl ester form.
“A dose of about 2000 mg/d of EPA + DHA is much higher; than current recommended intakes to reduce CVD [cardiovascular disease] risk,” wrote the researchers. “However, the 2015–2020 Dietary Guidelines for Americans recommend 8 oz of sh per week; which said to be equivalent to about 250 mg/d EPA + DHA; and the American Heart Association recommends 1–2 servings of “oily” fish per week (assumed to approximate 500 mg/d EPA+DHA) to reduce CVD risk.
However, the Omega-3 Index test was invented by Dr William Harris, PhD, of the Sanford School of Medicine at the University of South Dakota, along with a collaborator. Dr Harris is also the president of OmegaQuant; the company he founded to manufacture and market the test kits. The minimally invasive test, which has been on the market for several years; easily measures omega-3 levels in the blood.
But the new study aim to model how the Omega-3 Index is acted by EPA + DHA supplementation. However, using data on 1,422 people from 14 published omega-3 intervention trials, the researchers developed a model equation that could predict the impact of Omega-3 Index; taking into account baseline levels, dosages, and the chemical form consumed.
However, the model equation could used in two ways: the predict the Omega-3 Index based on baseline index scores; and the dose used, or to calculate the dose needed to achieve a target Omega-3 Index. For example: “One can calculate the approximate EPA + DHA doses (TG forms) to achieve a mean O3I of 8% in 13 weeks: 2200 mg/d for a baseline O3I of 2%, 1500 mg for a 4% baseline; and 750 mg for a 6% baseline.
EPA + DHA supplementation
“Using this example, they predict that the minimum dose of EPA + DHA necessary; to be 95% certain that the mean baseline O3I of 4% will increase to 8% (in 13 weeks) is ∼1750 g/d of TG or 2500 g/d of EE. The daily dose needed over a lifetime to achieve an O3I; of 8% is likely much lower.” The scientists noted that data for krill oil were available.
Omega-3s in krill oil are in a different chemical form the phospholipid form; and giving omega-3s in this form the model was observed with the other forms of the ingredient. “[T]he equation developed here can aid in predicting population O3I changes; but because of the large interindividual variability in the O3I response to EPA + DHA supplementation; it will likely be less useful in the clinical setting where direct testing of the O3I would be the preferred approach to assessing EPA + DHA status,” they concluded.