Estimation of Total Usual Dietary Intakes of Pregnant Women in the United States.
Level 4 - case-series / case-control
Cross-sectional survey of NHANES data (CEBM 2011 Level 4).
PubMed 31225890 · doi:10.1001/jamanetworkopen.2019.5967
What was done
A cross-sectional analysis evaluated total usual dietary intake (from foods and dietary supplements) among a nationally representative sample of 1003 pregnant US women aged 20 to 40 years from the 2001–2014 National Health and Nutrition Examination Survey (NHANES). Usual intakes were estimated from two 24-hour dietary recalls adjusted for within-person variation using the National Cancer Institute method and evaluated against Dietary Reference Intake thresholds (Estimated Average Requirement [EAR], Adequate Intake [AI], and Tolerable Upper Intake Level [UL]).
What was found
Overall, 69.8% (SE 2.3%) of pregnant women used dietary supplements. Intake was below the EAR for magnesium (47.5% [SE 2.8%]), vitamin D (46.4% [SE 2.7%]), vitamin E (43.3% [SE 2.7%]), iron (36.2% [SE 2.8%]), folate (16.4% [SE 1.6%]), vitamin A (15.5% [SE 2.1%]), calcium (12.9% [SE 2.4%]), vitamin C (11.5% [SE 1.9%]), vitamin B6 (11.5% [SE 1.5%]), and zinc (10.9% [SE 1.9%]). Adequate Intake was met or exceeded by 41.7% (SE 2.9%) for potassium, 47.9% (SE 4.3%) for vitamin K, and 7.9% (SE 3.2%) for choline. Conversely, 95.0% (SE 2.2%) exceeded the UL for sodium, 33.4% (SE 2.8%) for folic acid, 27.9% (SE 2.8%) for iron, 7.1% (SE 1.6%) for zinc, and 3.0% (SE 0.8%) for calcium. Supplement use reduced the prevalence of inadequate iron intake (from 95.3% to 80.3% from food alone) but drove excess folic acid and iron intakes.
Why it matters
This study demonstrates widespread concurrent micronutrient shortfalls (notably magnesium, vitamin D, and vitamin E) and excessive intakes (particularly sodium, folic acid, and iron from supplements) in US pregnant women, highlighting the need to refine maternal nutritional and supplementation guidance.
Limits
The study relies on self-reported 24-hour dietary recalls subject to recall error and underreporting. The cross-sectional design precludes assessment of maternal or fetal clinical outcomes, and biological markers of nutrient status were not evaluated.
Cited by
- supports Approximately 90% of pregnant women do not get enough choline during pregnancy.
- supports Approximately 90% of pregnant mothers do not consume enough choline.