A comparison of the bioaccessible calcium supplies of various plant-based products relative to bovine milk

Summary

This laboratory study systematically assessed calcium bioaccessibility in 25 plant-based products using isotopically labelled tracer methods, finding that whilst approximately 50% of products matched or exceeded the gross calcium content of skimmed milk, bioaccessibility varied dramatically (0.1–50%). Three products—kale, finger millet, and fortified white bread—emerged as genuinely good sources of bioavailable calcium, with kale providing five times more bioaccessible calcium per serving than skimmed milk, whilst spinach, plant-based beverages, tofu, dried figs and tahini had very poor bioaccessibility due to high oxalate/phytate content or poor mineral solubility.

Regional applicability

The findings are directly applicable to UK dietary guidance and food composition databases, as kale and fortified white bread are commonly consumed in the United Kingdom. The identification of antinutrient-rich products with low bioaccessibility is relevant to UK populations adopting plant-based diets, though finger millet is less widely available domestically.

Key measures

Gross calcium content (mg/100 g fresh weight), calcium bioaccessibility (%), INFOGEST static digestion model with 43Ca tracer, serving equivalents relative to skimmed milk

Outcomes reported

The study evaluated gross and bioaccessible calcium content in 25 plant-based products from 5 food groups using the INFOGEST static digestion model with isotopically labelled calcium tracers. Products were ranked as good, moderate, or poor sources of bioavailable calcium relative to skimmed milk.

Topic tags