Supplements over salmon? Study finds pregnant women choose capsules over food

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Apr 7 2025

Despite the widespread use of fish oil and probiotics during pregnancy, many women remain confused about national guidelines and health benefits, highlighting a gap in dietary counseling across Europe.

Study: Fish oil and probiotic food supplements: consumptions and attitudes of pregnant women in four European countries. Image Credit: VLADIMIR VK / Shutterstock

In a recent study in the European Journal of Nutrition, researchers investigated the consumption of fish oil and probiotic supplements by pregnant women in the United Kingdom, Poland, Italy, and Finland. They also assessed their beliefs about the benefits of supplementation and awareness of official public health guidance.

They found that about 49% of women who submitted product information used fish oil supplements, while 10% reported using probiotics. Polish participants had the highest fish oil use (77%), while Finnish women had the lowest (20%). Polish women also showed the highest awareness of guidelines around fish oil consumption, while Finnish women displayed the most knowledge about probiotics. However, many women were unaware of official guidance, highlighting the need for improved dietary counseling during pregnancy. This was especially true for fish oil, with many Finnish women incorrectly believing it increased the risk of bleeding during delivery, despite safety data showing no such risk at commonly consumed doses.

Background

The European Food Safety Authority defines food supplements as concentrated nutrient sources provided in formats such as liquids or tablets. They are often used during pregnancy to meet increased nutritional needs and prevent issues like anemia. Many countries recommend supplements like folic acid and iron for pregnant women.

Fatty fish are the diet’s primary source of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). They are critical for the development of the fetus, particularly the brain. Since the body’s ability to produce DHA is limited, maternal intake via diet or supplements is crucial.

While countries like Poland recommend fish oil supplements during pregnancy, others like Italy, Finland, and the UK do not, citing insufficient evidence. However, general guidelines suggest taking 200 mg of DHA a day, which can be obtained either through diet or supplements.

Probiotics – live microbes offering numerous health benefits – may reduce childhood eczema and maternal infections during pregnancy, though the evidence is not strong enough to recommend them universally. The World Allergy Organization recommends probiotics for families at allergy risk. In Europe, “probiotics” is legally considered a health claim, limiting marketing language.

About the Study

Given the commercial availability of these supplements and inconsistent national recommendations, researchers aimed to examine supplement use, awareness of guidelines, and beliefs among pregnant women in the UK, Poland, Italy, and Finland.

This cross-sectional study targeted pregnant women aged 18–45. To ensure wide outreach, participants were recruited online through social media platforms. Interested women completed an online survey focused on food supplement use during pregnancy.

The research team collected data on three key areas. First, they assessed the probiotic and fish oil supplements. Second, they gauged the participants’ awareness of national recommendations regarding these supplements. Third, they collected information on the participant characteristics using supplements, including their beliefs about the potential health benefits.

In addition to survey responses, participants who reported supplement use were asked to upload photos of the product labels. This allowed researchers to verify product types and nutrient content, ensuring accuracy in the assessment of actual supplement use.

A total of 1,780 women participated, including 121 from the UK, 584 from Poland, 539 from Italy, and 536 from Finland. Out of these participants, 1,356 provided detailed product information. Supplement use was evaluated by calculating daily intakes, specifically focusing on DHA levels from fish oil products. The median daily DHA intake among supplement users was 220 mg, aligning with expert consensus recommendations.

Ethical approval was obtained following each participating country’s research guidelines, and informed consent was collected from all participants before participation.

The data analysis involved comparing usage patterns, awareness levels, and demographic characteristics across the four countries to identify differences and similarities related to food supplement behaviors during pregnancy.

Findings

Participants were mostly well-educated, with over two-thirds having university-level education, and two-thirds being first-time mothers. Finland and the UK had the highest rates of overweight or obese participants. Overall, 49% of participants who submitted product data reported using fish oil supplements, and 10% used probiotics during pregnancy, with daily use every day across countries.

Poland had the highest fish oil use (77%) and DHA intake, while Finland had the lowest fish oil use but the highest probiotic use (18%). Awareness of national supplement recommendations was limited; only Poland had an official recommendation for fish oil during pregnancy, and few participants across countries correctly identified existing guidelines. Participants in countries without recommendations—including Italy, Finland, and the UK—often mistakenly believed one existed.

Beliefs about supplement health benefits varied significantly: Polish participants were most confident about fish oil’s benefits for the baby’s brain and eyesight, whereas Finnish participants were more aware of probiotics' potential benefits for maternal and infant gut health. However, there were widespread uncertainties and misconceptions. For example, 45% of Finnish women erroneously believed that fish oil consumption increases bleeding risk during delivery.

Fish oil supplement users were more often primiparous. However, their pre-pregnancy BMI and dietary habits (particularly vegetable and whole grain consumption) did not differ significantly from non-users. Probiotic users were also more likely to be first-time mothers and from Finland.

Conclusions

Although DHA intake from supplements generally met recommendations, the absence of dietary intake data limited the ability to assess total DHA consumption, including intake from fish or fortified foods. The participants’ knowledge about health effects and national recommendations varied, with uncertainty, especially about fish oil safety.

The cross-country design and detailed supplement analysis are strengths of this study. However, potential selection bias and reliance on self-reported intake are possible limitations. As most participants had university-level education and were recruited online, findings may not reflect the broader pregnant population. Future research should explore how information sources influence supplement use and further clarify fish oil’s and probiotics’ health impacts during pregnancy.