Blood EPA and DHA status among people living in the United States from 2000 to 2023

Long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs), specifically eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3), are well-known for their various health benefits, including cardiovascular and cognitive health. In this study we explored the EPA+DHA blood status across different states within the United States. A widely used marker to assess the EPA+DHA status is the omega-3 index - defined as the % of EPA+DHA in red blood cells (RBC) in relation to total fatty acids. A systematic literature search was conducted for US-studies from 2000 until October 2023 reporting EPA+DHA blood values. Further inclusion criteria were: information in which US state the study was carried out, no pregnant women, at least 16 years of age. A total of 46 studies met all inclusion criteria. EPA+DHA levels from studies utilizing blood metrics other than RBC were converted to an estimated RBC EPA+DHA (eRBC EPA+DHA) status marker using established conversion equations. The mean eRBC EPA+DHA across the US was 5.28% and, is in line with previous investigations. Most US states showed an average eRBC EPA+DHA in the range 4.50% to 5.50%. Furthermore, we found that coastal states tend to have higher eRBC EPA+DHA (5.26%) than inland states (4.86%). This is consistent with the slightly higher fish consumption in coastal states compared to inland states. The data from the studies included in the evaluation show that the blood status of EPA+DHA is suboptimal. The supply of EPA and DHA should be improved, especially in inland states. Further research is needed to better monitor EPA+DHA status in the US. Since the EPA+DHA blood status is a modifiable risk factor for many diseases, public health officials should take steps to emphasize the significance of n-3 PUFAs in preserving the health of the US population.