Nutrient bioavailability – the missing ingredient for sustainable food systems

The nutritional value of different diets is a key issue in academic and policy discussions worldwide on how to simultaneously reduce greenhouse gas emissions and strengthen food security. However, what is often overlooked is the bioavailability, referring to the amount of nutrients actually absorbed by the body. A new publication highlights the importance of considering differences in bioavailability across food groups for reaching both environmental and human health targets.

Bioavailability is influenced by both person-specific factors, such as genetics and health status, and food-level characteristics, including nutrient interactions. For instance, vitamin C enhances iron absorption whereas phytate is known to inhibit the uptake of zinc and other micronutrients.

Variation across food stuffs

A range of tools have been developed to estimate current nutrient supplies and predict how they might change under different scenarios of climate, food production, and demand. The recent perspective in The American Journal of Clinical Nutrition draws attention to how bioavailability varies across 27 essential nutrients and how major studies and dietary guidelines often fail to fully account for these differences.

“Current food models often overlook the fact that the body absorbs nutrients differently from plant-based and animal-based foods”, explains co-author Max Troell, Beijer Institute programme director. “This can lead to misleading conclusions about how nutritious a diet really is, as well as its environmental impact.”

Higher bioavailability for animal-source foods

For a majority of the 27 nutrients, animal-source foods (ASFs), such as meat, dairy, and eggs, offer higher bioavailability for many essential nutrients compared to plant-source foods (PSFs), like grains, vegetables and legumes. Consequently, shifting away from ASFs without carefully considering bioavailability may unintentionally lead to nutrient gaps, according to the researchers behind the perspective, a team led by Khristopher Nicholas, Harvard University. This risk is higher in low- and middle-income countries, where undernutrition is more widespread and reduced access to highly bioavailable nutrients can exacerbate deficiencies.

“Accurately accounting for bioavailability is crucial for balancing global nutrient needs with the environmental footprint of food production”, Max Troell says, adding: “To ensure sustainable, nutritious food systems, future models of dietary change need to incorporate bioavailability differences to a larger extent. Better data and more consistent methods for estimating bioavailability will be crucial.”

Addressing bioavailability requires collaboration across disciplines and nutrition experts play a critical role in ensuring that dietary recommendations are grounded in accurate interpretations of how nutrients function in real-world diets, the team conclude.

Reference: Nicholas, K. M., A. Tone , T. Beal, J. Zamborain-Mason, H. Eneroth, V. Öhrvik , M. Troell, and C. D. Golden. 2026. Nutrient bioavailability is the missing ingredient connecting food systems to nutrition security and environmental sustainability. The American Journal of Clinical Nutrition 123(5).

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