Asthma symptoms during pregnancy may be linked to low omega-3, high omega-6 levels

Key takeaways:

• Within the study’s cohort, omega-3 fatty acid intake was significantly below recommended levels.
• Study authors urged further investigation into the implications of these findings.

SAN DIEGO — Pregnant women from an ethnically diverse cohort with a disproportionately higher asthma burden appeared to have high dietary omega-6 and low omega-3, according to study results.

Najla N. Abdurrahman, MD, fellow in the division of pulmonary, critical care and sleep medicine at the Icahn School of Medicine at Mount Sinai, presented the findings in a poster at the American Thoracic Society International Conference.

“It was important for us to be able to look at this population in particular,” Abdurrahman told Healio. “We know from prior studies that members of economically disadvantaged groups tend to consume a less nutritional diet due to factors such as food deserts and the high cost of healthy foods. This diet tend tends to be lower in omega-3 and higher in omega-6 fatty acids. ”

Abdurrahman started her path in pulmonary medicine through experience in critical care and internal medicine, and she chose this particular study due to her desire to work with mentor Sonali Bose, MD, MPH, associate professor of medicine, pulmonary, critical care and sleep medicine at Mount Sinai. Abdurrahman credits Bose with inspiring her to pursue the study of interactions between diet and inflammation, asthma and airway diseases during pregnancy.

Abdurrahman further emphasized the unique opportunity the study presented in working with marginalized populations.

“Many of our patients in the teaching clinics, which is where we recruited, are uninsured [or] underinsured patients from neighborhoods close to Mount Sinani Hospital, such as Spanish Harmel and parts of the Bronx,” she told Healio.

Study design

The feasibility study included 20 ethnically diverse urban women with asthma (median age, 31 years) enrolled during early pregnancy and followed until delivery.

Among the participants, seven identified as Black, two as white, two as Asian/Pacific Islander, one as mixed race and eight as “other,” with 13 identifying as Hispanic. Further, five reported having a high school education or less, 10 completed some college and five earned at least a bachelor’s degree.

Researchers administered a National Cancer Institute-validated dietary questionnaire to the women during each trimester to estimate their omega-3 and omega-6 fatty acid intake. Blood testing was used to measure fatty acids in serum, and asthma control was assessed using the Asthma Control Test (ACT). Researchers also assessed lung function via daily coached, remote spirometry in each trimester. They then used regression models to find associations between fatty acid status and asthma outcomes.

“We have seen from previous studies that omega-3 may have protective effects on asthma symptoms, and that diets with higher omega-6 can be pro-inflammatory,” Abdurrahman said. “Inflammation and asthma are intertwined in ways that are very complex and not perfectly understood. Looking at the role or the potential effects of these dietary nutrients in asthma in a pregnant cohort was interesting to us because this is a point in the lifespan where diet affects two people and can set the stage for lifelong health of the offspring.”

Study findings

The median daily omega-3 fatty acid intake among participants was 40 mg (interquartile range [IQR], 20-80), or between 8% and 16% of the minimum recommended intake, whereas the median range of total omega-3 fatty acid in the serum was 127 µg/mL (IQR, 75-275). The researchers did not detect any significant associations between omega-3 status and ACT scores, FEV₁ or fractional exhaled nitric oxide.

However, nearly all participants had intake of eicosapentaenoic acid and docosahexaenoic acid — both omega-3 fatty acids — far below the recommended levels of 250 mg to 500 mg per day. Only three participants (15%) were found to have a value within normal range at some point in their pregnancy.

“We found that intake of omega-3 was very low,” Abdurrahman said. “Because study participants were almost universally deficient in omega-3 — one of our primary exposures — we couldn’t say very much about the potential effects of increased omega-3 on asthma control. However, we did detect an association between omega-6 and asthma symptoms. Women with higher plasma concentrations of omega-6 were worse off in terms of their asthma symptoms, after adjusting for potential confounders such as BMI and energy intake.”

ACT results showed that participants had uncontrolled asthma in 50% of trimesters.

Results further showed that for every 1% increase in plasma total omega-6 levels, ACT score decreased by 1.34% (95% CI, –2.29% to –0.39%), and a 50% increase in plasma omega-6 levels was associated with a 35% decrease in ACT scores.

“Our main takeaway from this is that serum omega-6 was inversely associated with control of asthma symptoms and that omega-3 intake was much too low in our study population to detect significant associations,” Abdurrahman said. “But because we know a lot about the importance of omega-3 fatty acids for lung health and also for fetal development from prior research, we think that these findings can inform future public policy and clinical studies.”

Abdurrahman notes that investigators are preparing a future study to replicate these and other findings in a larger cohort.

For more information:

Najla N. Abdurrahman, MD, can be reached at najla.abdurrahman@mountsinai.org .