Writing in the journal Nutrients, researchers were able to identify reference intervals and cut-offs for fatty acids in red blood cells (RBC) from 203 pregnant women in Norway, in agreement with those reported in other countries.
Additionally, a direct association between omega-3 Long Chain Polyunsaturated Fatty Acids (LCPUFAs) in maternal RBC and the intake of seafood and omega-3 supplements was found.
“The findings were as expected,” explains says study researcher Pedro Araujo. “This is still the largest study that has documented such a connection between seafood intake and dietary supplements, and omega-3 levels in pregnant women.”
Norway advises a daily intake of 200 milligrams (mg) docosahexaenoic acid (DHA) for pregnant women with aquatic foods and omega-3 supplements the main eicosapentaenoic acid (EPA) and DHA sources.
However, there are discrepancies concerning the DHA supplementation effects during pregnancy and in the early phase of infant cognitive development.
Identifying fatty acid levels in RBC is considered a good indicator of the last 30–60 days of intake.
EPA and DHA, along with another fatty acids such as short-chain fatty acids in milk, are indirect biomarkers of specific foods as these foods are the primary dietary source of the respective fatty acids.
Reference intervals provide insight on certain biomarkers in population-based cohort studies and offer understanding of the initial status and provide the basis for comparison over time.
Most laboratories and scientific reference tables offer information derived from healthy nonpregnant women but lack reference intervals for pregnant women.
During pregnancy, there are changes in many biological markers, and therefore, reliable reference values derived from a healthy pregnant population are of importance for correct clinical decisions.
Without adequate reference intervals, there is an increased risk of missing important changes, due to pathological conditions and to erroneously interpretation of normal changes as pathological events.
Here, the women took part into the Small in Norway (LiN), a nationwide study with over 1000 families led by the University of Oslo.
Alongside blood tests, the women completed electronic food frequency questionnaire (e-FFQ) intended to map their dietary habits. Gas chromatography was used to determine RBC fatty acid levels.
Participants (29.1%) reported eating seafood as dinner according to the Norwegian recommendations, with 76.9% also using omega-3 supplements.
“This shows that there is a group that is aware that these fatty acids are important, but that they choose to take a supplement instead of eating fish,” says Araujo.
The team reported the concentration levels of fatty acids in RBC were in agreement with those reported in similar populations from different countries.
The reference interval 2.5/97.5 percentiles for EPA, DPA, DHA were 0.23/2.12, 0.56/2.80, 3.76/10.12 in relative concentration units (%), and 5.99/51.25, 11.08/61.97, 64.25/218.08 in absolute concentration units (µg/g), respectively.
Japan & reference values
“In other countries, such as Japan, the reference values are often based on a group from only one city or part of the country,” says Araujo.
“And if this city is close to the sea, and the population eats a lot of fish, this will not be representative of the rest of the country.”
In conclusion, the research team wrote that given the importance of seafood and omega-3 supplements during pregnancy, further studies were warranted to investigate the impact on various indexes (e.g., omega-3 index, ω6/ω3) associated with fatty acid status by using relative and absolute units.
They add that the proposed reference intervals in RBC may be a useful tool when studying associations between fatty acids and health outcomes.
Published online: doi.org/10.3390/nu12102950
“Fatty Acid Reference Intervals in Red Blood Cells among Pregnant Women in Norway–Cross Sectional Data from the ‘Little in Norway’ Cohort.”
Authors: Pedro Araujo et al.