Researchers from Canada, Germany, Spain and the United States sought to update a 2016 global map that highlighted significant variation in O3I levels, with most countries having less-than-desirable levels.
The review published in Progress in Lipid Research assessed blood samples taken between 2000 and 2023.
The results of the new research underscore the need for continued research on global omega-3 levels and encourage collaboration between researchers and industry stakeholders, which could lead to innovations in omega-3 formulations and better alignment with consumer preferences.
According to data from GOED provided for NutraIngredients, the global volume of omega-3 ingredients reached 124,480 metric tons in 2023, a 1.4% increase from 2022. The market value rose to over $2 billion, a 22.5% increase from close to $1.7 billion the previous year.
Study details
The authors used O3I, which measures EPA and DHA in red blood cells (RBCs), as a risk factor for coronary heart disease mortality. An O3I over 8% is considered optimal, 4% to 8% intermediate and under 4% is associated with high risk.
The researchers conducted a literature search using the GOED Clinical Study Database and PubMed. The search focused on original research, specifically observational studies (OS) and randomized controlled trials (RCTs).
The researchers extracted demographic data and EPA/DHA levels from eligible studies, which required the study be published in English and involved participants over the age of 16.
The authors also only included research where EPA and DHA levels were reported in certain blood fractions: whole blood (WB), red blood cells (RBC), plasma total lipids (PTL), plasma phospholipids (PPL) or plasma phosphatidylcholine (PPC). Blood samples had to be collected in the year 2000 or later.
The final analysis included 328 studies. Countries were categorized into four levels based on O3I values: desirable (>8%), moderate (6%-8%), low (4%-6%) and very low (≤4%). Special regions with distinct diets (e.g., indigenous populations) were treated separately and colored independently on the map.
Almost half of the participants in the study came from North America (49%), mostly from the United States, followed by Europe with 43%. As a result, 92% of the data for the n3 map came from only about 15% of the world's countries.
Regions like Asia, Africa and Central and South America contributed less than 10% of the studies. Central and South America, Africa, Eastern Europe, and West and Southeast Asia were significantly underrepresented.
In South America, only Brazil provided data, and in Africa, data came from just Tunisia, Egypt, Nigeria and South Africa. Russia lacked enough data to be categorized. Only Japan, China, France, the United Kingdom, Canada and the United States had O3I data based on more than 5,000 individuals.
In 15 countries, data came from 1,000 to 5,000 individuals, while 30 countries had fewer than 1,000, including 14 with fewer than 200. Representative population surveys were available only for Canada and the United States.
In terms of blood sample types used, EPA and DHA were most commonly measured in red blood cells (57% of studies), followed by plasma total lipids (27%) and plasma phospholipids (13%).
O3I levels varied widely across countries. A desirable O3I (above 8%) was found in Japan, South Korea, Iceland and Norway, while a very low O3I (4% or lower) appeared in Iran, Egypt, India and Brazil. Most countries, including those in North America and Europe, had low to moderate O3I levels.
Differences between the 2024 and 2016 maps
The 2024 map features 342,864 subjects from 48 countries, compared to 112,151 subjects from 54 countries in 2016.
Key changes in O3I include: United States, Canada, Italy, Turkey, United Kingdom, Ireland and Greece improved from red to orange; France, Spain and New Zealand moved from orange to yellow; and Finland and Iceland progressed from yellow to green.
The inclusion of new datasets was the primary reason for changes in O3I, particularly in the United States, Canada and the United Kingdom, according to the researchers.
Large-scale studies that were not included in 2016 significantly impacted the current O3I values. For example, data from the UK Biobank shifted the United Kingdom’s O3I from red to orange.
Nigeria, however, saw a decline, moving from green to orange due to new data. It is uncertain if the changes were due to actual population shifts in omega-3 intake, increased supplement use or changes in the studied populations, the authors wrote.
To raise O3I from 4% to 8%, an additional daily intake of about 1.4 g of EPA and DHA is needed. This can be achieved through increased consumption of oily fish or omega-3 supplements.
Journal: Progress in Lipid Research
“Omega-3 world map: 2024 update.”
doi: 10.1016/j.plipres.2024.101286
Authors: Schuchardt, J, P. et al.