: Phytates inhibit iron and zinc uptake

Summary

This 2010 narrative review by Hurrell and Egli synthesises human evidence establishing phytic acid as the primary dietary inhibitor of iron and zinc absorption. Drawing on stable isotope tracer studies and controlled feeding trials, the authors quantify the magnitude of phytate-mediated inhibition across plant foods and identify populations most vulnerable to micronutrient constraint, particularly those dependent on unrefined cereal and legume staples. The work provides foundational mechanistic and quantitative evidence for understanding bioavailability limitations in plant-based diets.

Regional applicability

The findings are applicable to UK dietary guidance and public health nutrition, particularly for populations consuming high proportions of plant-based protein and staple cereals (e.g. vegans, low-income households). Understanding phytate inhibition is relevant to UK food fortification strategies, plant-based food labelling, and nutrient adequacy assessments for plant-forward diets.

Key measures

Phytate concentration in foods; fractional iron and zinc absorption rates (by stable isotope methods); inhibition ratios and molar ratios of phytate to mineral; bioavailability across dietary contexts and populations

Outcomes reported

The study synthesised human evidence quantifying the magnitude and mechanisms by which phytic acid (phytate) inhibits intestinal absorption of iron and zinc across diverse plant food sources and dietary contexts. The authors examined isotope tracer studies and controlled feeding trials to establish dose–response relationships and population-specific vulnerability factors.

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