Inconsistent Supplementation Recommendations for Women During Pregnancy Raises Questions

Folic acid is the most common food supplement recommended to women during preconception and pregnancy, according to authors of a study recently published in Nutrition Research. However, recommendations for other common supplements for pregnancy—iron, vitamin D, and iodine—were more varied; these recommendations appear to be dependent on the country’s location and income level.

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“Geographic location of the country may influence the need for food supplements, as, for example, countries situated in a higher latitude have restricted sunlight exposure especially during the wintertime and therefore a greater requirement for dietary Vitamin D,” wrote the study authors.

Vitamins and minerals are important for the healthy growth of a fetus—the fetus gets most of this nutrition from the mother’s diet, but sometimes food supplements are needed when diet does not provide all necessary nutrients. There have been numerous studies which evaluate vitamins and minerals that support a woman’s heath during preconception or pregnancy, but there are many unknowns about specific nutrient requirements.

Moreover, not every country has the same vitamin and supplement recommendations, but “the differences in food supplement recommendations may lead to consumer confusion and even lower consumption of the supplements,” wrote the authors.

To identify what supplements and at what doses are recommended for women during preconception and pregnancy, investigators conducted a study across 43 geographically diverse countries. They also evaluated whether these recommendations, specifically for folic acid, iron, vitamin D, and iodine, vary based on geographical location, health service system, or income.

In 2017, the team performed an electronic internet search of keywords related to pregnancy,supplement, and recommendations to identify these recommendations and the organizations and policies driving the recommendations. The team then reevaluated the data in 2022.

Folic acid was the only supplement recommended for women in preconception or pregnancy in every country; the most common recommended dose was 400 µg/day for women in preconception or pregnancy.

Recommendations for vitamin D, iron, and iodine were influenced by geographical location and income level. For instance, study results indicate that countries with a higher latitude and incomewere more likely to have guidelines recommending vitamin D supplementation—this accounted for approximately 25% of countries in the study.

Iron supplementation (dose range, 16–195 mg/day) was recommended in 50% of countries, although it was less likely to be recommended in a high-income country compared to an upper-middle or lower-middle income countries. Authors hypothesize that iron supplementation isrecommended in these countries because deficiency is more prevalent. Only about 25% of countries had guidelines or policies that recommended iodine (150–200 µg/day)supplementation.

Findings were limited by language barriers and a low response rate among experts who were asked to validate findings. Further research is needed to evaluate countries that have little to no data about supplement recommendations.

Moreover, authors suggest that these data could be used to harmonize supplement recommendations for this patient population, but doing so might fail to acknowledge that different countries have different population-based needs, which extend to supplementation.

“If the recommendations are harmonized, various factors need to be considered, including the targeted population, geographic location of the country, and dietary habits and culture,” the study authors wrote. “Hence, it may be inappropriate to harmonize all the food supplement recommendations across countries.”

REFERENCE

Saros, L, Hart K, Koivuniemi E, Egan B, Raats M, Laitinen K. Micronutrient supplement recommendations in pregnancy vary across a geographically diverse range of countries: a narrative review. Nutrit Resear. 2024;(123). doi:0.1016/j.nutres.2023.12.012