Only 30% of Calcium in Global Food Supply is Bioavailable: Study

Just 30% of the calcium present in the global food supply is in a bioavailable form, according to a recent study.

The research was conducted by the U.S. and Canada entity of the International Life Sciences Institute (ILSI) with partial support from ingredient supplier Balchem, and published in the Journal of Nutrition.

For the study, the researchers developed an algorithm using data from the Food and Agriculture Organization (FAO)’s Food Balance Sheets to evaluate the calcium content of foods and the impact of anti-nutrients like phytates and oxalates on calcium bioavailability, which are present in plant-based foods.

The results, Balchem reports, “highlight opportunities for food and supplement brands to optimize their formulations with bioavailable ingredients that limit the effect of anti-nutrients on mineral absorption.

Because phytates and oxalates, present in beans, pulses, and other vegetables, interact with free mineral ions from dietary intake or inorganic mineral salt-based supplements, they form complexes that can’t be absorbed by the body. The new work attempts to take these interactions into a global context to estimate bioavailable calcium across diverse food systems on a country-by-country basis.

There were significant variations in bioavailable calcium content across regions. Asia and Africa, for instance, found that only 23% and 19% of calcium in the food supply was bioavailable, respectively. Meanwhile, 49% of the calcium in EU member countries on average was bioavailable, with a similar figure in the U.S. (47%). Bioavailable calcium levels were relatively lower in Southeast Asia, parts of South America, and the Middle East compared to Europe and the U.S. Reliance on plant-based sources of calcium with limited dairy intake is a major driver of calcium bioavailability by region.

“It’s great to see our algorithm being applied in a global context for the first time. The findings shine a spotlight on the challenge anti-nutrients pose for mineral absorption, compromising the accuracy of intake measurements and limiting the impact of diet and supplementation,” said Stephane Vidry, PhD, executive director of ILSI U.S. and Canada and ILSI Global. “This ultimately highlights the need for future research to incorporate bioavailability data into intake data to better reflect regional dietary patterns and nutrient interactions. Strengthening this evidence will enhance our ability to design strategies that improve access to bioavailable calcium through more tailored food recommendations, fortification, supplementation, and other policy approaches.”

“These findings underscore the need to raise awareness of the impact that these anti-nutrients can have on mineral nutrition,” comments Eric Ciappio, PhD, RD, senior manager of nutrition science at Balchem Human Nutrition & Health. “Ultimately, if calcium cannot be properly absorbed due to the presence of anti-nutrients, many people are missing out on crucial health benefits.”

Chelated minerals can limit the impact of anti-nutrients. Chelation is a process where minerals are bound to organic molecules like amino acids, forming a stable and absorbable complex with a protective structure around the mineral ion, shielding it from anti-nutrient interference. Chelated iron (ferrous bisglycinate), for instance, is recognized by the World Health Organization for its superior absorption compared to conventional iron salts when in the presence of phytates. Chelated minerals also benefit from greater gastrointestinal tolerability and enhanced solubility.

“Through investments in research and our pioneering Albion Minerals portfolio, we are dedicated to be leading the way in chelation science to help people get the most out of mineral nutrition,” said Ciappio. “Looking forward, Balchem is excited to continue supporting ILSI’s work as they adapt the model used in this study to investigate the impact of anti-nutrients on the bioavailability of other minerals such as iron.”