New study finds UK mums-to-be miss out on key nutrients

With nutrient shortfalls widespread among expectant mothers in the UK, new research reveals why focused dietary advice, effective supplementation, and better policy could make all the difference for families across generations.

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In a recent briefing paper in the journal Nutrition Bulletin, researchers elucidate patterns of maternal nutrition during prenatal and perinatal periods among UK women. They aim to provide scientifically sound nutritional advice for prospective and new mothers, clinical professionals, and policymakers.

Findings reveal that most of the UK’s women fall short on essential nutrients, with these deficiencies pronounced in teenagers, women from lower-income households, ethnic minorities, smokers, those with multiple pregnancies, and those experiencing food insecurity. It identifies inconsistencies in nutritional advice received by women, even when following respected national guidelines.

The review acknowledges the surge in popularity of plant-rich diets but emphasizes that proactive management through fortified foods and targeted supplements (such as B12 and algal DHA) is essential to avoid key nutritional deficiencies. It calls for clear, consistent, and culturally appropriate guidance from healthcare professionals to optimise maternal and public health.

Background

Pregnancy isn’t just about expecting a baby; it represents a critical time and a powerful opportunity to shape lifelong health. Decades of evidence have highlighted the strong link between the diet during pregnancy and long-term health outcomes for both the mother and her child. During prenatal and perinatal periods, women should focus on nutrient density over quantity, as they do NOT need to “eat for two”, prioritising diets rich in essential nutrients.

Research has established the crucial roles of protein, specific fatty acids, complex carbohydrates, and essential vitamins in supporting foetal growth, lactation, and minimizing gestation complications. Weight management (both pre-pregnancy BMI and gestational gain) is also increasingly recognized for its pregnancy impacts. Unfortunately, women often receive inconsistent advice, and reviews seeking to inform public health policy through nutrition guidance can be generic.

The work of Williamson’s 2006 review partially addressed this gap by investigating relationships between dietary intakes and pregnancy outcomes. This work updates Williamson’s findings with new data and examines potential discrepancies between UK dietary guidance and science-based nutrient priorities.

About the study

The British Nutrition Foundation (BNF) briefing builds upon Williamson’s study by leveraging UK national surveys, clinical guidelines, and systematic reviews to advise expectant mothers, healthcare professionals, and policymakers on key nutrient priorities during pregnancy. It identifies patterns and trends in the UK and evaluates how well national recommendations align with scientific evidence, aiming to support future policy reform.

The review focuses on four key areas: 1. Nutrient intakes, 2. Supplementation, 3. Food safety, and 4. Weight management. Study data were obtained from extensive UK survey datasets, the National Institute for Health and Care Excellence (NICE) clinical guidelines, and systematic reviews (Maternal & Child Nutrition, Nutrition Bulletin, and scientific journals).

The review conducted extensive nutrition monitoring by comparing survey data to UK recommendations, analysed demographic factors to identify high-priority groups, and evaluated how guidelines from NICE and the World Health Organization (WHO) align with current clinical evidence. It also examined the implications of different dietary patterns, assessed the impact of pre-pregnancy weight and gestational weight gain on health outcomes, and reviewed food safety by identifying dietary trends and high-risk foods.

Study findings

UK survey data reveal that most pregnant women fail to meet the UK-recommended intakes of folate and iron (dietary and supplemental), with only 19.7% taking pre-conception folic acid supplements (400 µg/day). Vitamin D (10 µg/day advised during October to March) and iodine (UK RNI: 140 µg/day; EFSA recommends 200 µg/day during pregnancy) recommendations also reveal widespread shortfalls, underscoring a significant nutritional public health challenge.

Confusion arises not from UK guidelines but from inconsistent advice delivery and global variations. While NICE clearly recommends 10 µg/day vitamin D, other international bodies suggest different ranges. This inconsistency in global positions likely contributes to confusion among some professionals.

Suboptimal weight management is widespread, with over 20% of UK pregnant women entering pregnancy with obesity. Both insufficient and excessive gestational weight gain are problematic, with IOM guidelines providing BMI-specific targets. Excessive GWG is linked to gestational diabetes, hypertension, preeclampsia, preterm birth, and long-term obesity for mother and baby. These risks are even higher among vulnerable groups, including teens, low-income women, ethnic minorities, and those with multiple pregnancies.

On a more positive note, the review identified a positive trend of increased adherence to plant-based foods in the UK. While plant-based foods are known to support healthy pregnancies and are nutritionally adequate when well-planned, they may fall short in critical nutrients, such as vitamin B12, calcium, iodine, iron, and long-chain omega-3 fatty acids. Healthcare providers must proactively manage these potential deficiencies through dietary strategies (fortified foods), targeted supplementation (e.g., B12, algal DHA), and monitoring.

Conclusions

The present briefing paper by the BNF conveys a clear message – a balanced diet supplemented with specific nutrients (folic acid pre-conception, vitamin D, and DHA from 20 weeks) is essential for optimal outcomes. It emphasizes that nutrition advice must be specific, consistent, culturally appropriate, and supportive. It asks healthcare providers to ensure personalized interventions for pregnant women, especially those in high-vulnerability populations.

Weight management based on pre-pregnancy BMI, food safety education (including avoidance of liver, high-risk cheeses, and meats, and limiting caffeine intake to more than 200mg per day), and tailored advice for plant-based diets are all equally important. Bridging the gap between public health recommendations and lived dietary habits through accessible resources could dramatically improve maternal and infant outcomes across generations.