Does providing lactating women with their individual breast milk DHA level promote an increase in DHA intake?
Authors: Jackson Kristina Harris , Juber Brian , Johnson Kristopher , Baack Michelle , Harris William S 
Published: November 2023

BACKGROUND

Essential long‐chain polyunsaturated fatty acids including docosahexaenoic acid (DHA) and arachidonic acid (AA) are especially important for normal infant growth and neurodevelopment. Breast milk DHA levels are highly variable and are dramatically affected by maternal intake, whereas AA levels are more stable. Recent recommendations for fish and DHA intake during pregnancy and lactation may be confusing for lactating women and their healthcare providers limiting anticipated improvements in milk DHA levels and provision for breastfeeding infants.

OBJECTIVE

The purpose of this study was to determine 1) current milk DHA content in Midwestern US women, 2) factors that influence milk DHA levels, and 3) the effect of feedback regarding milk DHA levels on dietary intake of DHA as it relates to milk DHA content.

METHODS

Lactating women were invited to participate by answering a survey about DHA intake and providing a milk sample (1 drop on an antioxidant‐treated card) for analysis by gas chromatography at baseline and again in 4 weeks. Individual levels were reported to participants. Women with baseline milk DHA higher than the worldwide average (WWA, 0.32%) were advised to make no changes, whereas women with lower levels were advised to increase DHA intake.

RESULTS

Milk from 81 women was available at baseline. DHA content was highly variable (0.05–0.73%) with a median 0.18%. Baseline milk DHA levels were inversely associated with weeks of lactation (R= −0.23, P=0.04) and parity (R= −0.25, P=0.03), but not with pre‐pregnancy BMI, age, or length of gestation. Women who reported taking DHA supplements at baseline (n=41) had higher levels than those who did not (n=40; 0.23% vs. 0.15%, P<0.0001), but fish intake was unrelated to milk DHA levels. Median milk DHA content increased significantly from baseline to 4 week follow‐up. (n=64; 0.18% to 0.23%, P<0.01). Those who reported changing their diet (n=43) had significantly greater change in their milk DHA compared to those who did not (40% vs. −9%, P<0.01). There was no interaction between group (above‐ or below‐WWA milk DHA level) and their reported change in DHA intake.

CONCLUSIONS

Median milk DHA levels in Midwestern US women were lower than previously reported levels for non‐supplementing US women from 10 years ago (~0.20%), hence dietary guidelines to avoid fish during pregnancy/lactation may be reducing DHA intakes as reflected by milk DHA levels. DHA supplementation (but not higher fish intake) was associated with higher milk DHA levels. Offering women information on their own milk's DHA level and providing them with international recommendations for DHA intake motivated dietary changes as quickly reflected in their milk DHA content.

Support or Funding Information

This study was internally funded by OmegaQuant Analytics, LLC. Dr. Baack receives funding support from the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health (K08HD078504) and an NIH Center of Biomedical Research Excellence (COBRE) grant (P20 GM103620‐01A1).