Cracking the code: Advancements in calcium absorption and nutritional understanding

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Inadequate calcium (Ca) intake is a widespread issue globally, affecting individuals of all ages. In America alone, 30% of adult men and a staggering 61% of adult women fall short in their Ca consumption from diet alone.¹ To address this, there’s a key issue at play that’s often overlooked: achieving adequate Ca naturally from our diet depends on the total intake of the nutrient and its bioavailability – the proportion of Ca that is digested, absorbed and available for use in the body. Several factors can alter the absorption of Ca in the body – and, therefore, its bioavailability – including its form, physiology and the calcium load (the amount of Ca ingested at a single time). Additionally, the type of food consumed can also affect absorption as some foods contain mineral inhibitors, such as oxalates and phytates. But current nutrient recommendations do not reflect this.

Recent research conducted by ILSI U.S. and Canada – a global, nonprofit federation dedicated to advancing precompetitive research in the food, nutrition and health realms – and partially funded by Balchem, has shed light on how to improve predictions of Ca bioavailability across different food matrices. This breakthrough is thanks to a predictive algorithm that takes into account oxalate and phytate loads.² Here, we reveal the key takeaways from the analysis and discuss what this means for supplement manufacturers, including why chelated Ca could be the key for brands to develop more optimized Ca solutions.

Decoding ‘true’ Ca absorption

Different vitamins and minerals within foods can either enhance or hinder the body’s absorption of nutrients – including Ca. However, current dietary recommendations often overlook the role of inhibitors when determining nutrient intake and absorption. Take spinach as an example. It’s a good source of Ca, but also contains high levels of oxalate. Oxalate binds to Ca, inhibiting (or blocking) its absorption in the body. Consequently, the health benefits of Ca are not fully realized in the presence of oxalate.

As our partner Stéphane Vidry, PhD, Global Executive Director at ILSI said: “The new algorithm takes these different inhibitors into account, not just Ca load. This important ILSI-led research found that Ca absorption is significantly reduced by oxalate by up to 10% in the presence of just 0.1 grams of oxalate. Phytate is another common Ca inhibitor. If the content of phytate in foods is not considered, the absorption of Ca can be overestimated by up to ≤26%. This highlights the potential inaccuracies of mineral intake on some food labels.”

The universal prediction algorithm will enable more reliable tracking of Ca absorption, to help the food industry provide more precise nutrient values on labels. It signifies a significant leap forward in the nutrition industry, equipping the scientific community with the tools to develop bioavailability-adjusted estimates and ultimately help consumers maximize Ca benefits. The next step is to apply the algorithm to national food balance sheets, allowing for new estimates of nutrient inadequacy to be generated on a country-by-country basis.

What do the findings mean for dietary supplement manufacturers?

Consumers can’t always achieve sufficient Ca intake through diet alone – and sometimes turn to supplements to fill any gaps. This latest research underscores the importance of understanding Ca absorption and the different factors at play, and supplement brands need to be aware of this to optimize their formulations.

Just like inhibitors, mineral form is another crucial influence of Ca absorption and bioavailability. Ca exists in multiple forms, the most common being Ca carbonate, Ca citrate, Ca gluconate and Ca lactate and some are better absorbed than others. Unfortunately, it is too often ignored, leading many supplement products to fall short of their potential. It’s vital for manufacturers to think beyond high nutrient levels or how well-formulated their product is. Ultimately, if the nutrient has not been absorbed it won’t be bioavailable, so the product won’t deliver the desired health benefits and consumers won’t buy it again. There is one way to establish superior mineral absorption though – and that’s by opting for chelated minerals.

How chelated Ca increases the bioavailability of supplements

Chelation is a process where minerals, like Ca or Iron (Fe), are bound to organic molecules, like amino acids. This forms a more stable and readily absorbable complex that improves nutrient absorption.

Choosing chelated minerals, such as mineral bisglycinates, over non-chelated varieties offers multiple advantages to supplement brands:

• The chelated form of key minerals, like Iron, are more resistant to interference from nutrient inhibitors, like oxalate and phytate.³
• Ca Bisglycinate, in particular, has the highest solubility among common Ca salts, making it suitable for beverage applications.⁴

Organic mineral amino acid chelates have been scientifically proven to be more easily absorbed into the human body. Our data reveals that chelated Ca demonstrates 1.5-2 times greater absorption than Ca citrate and Ca carbonate.⁴ By opting for chelated Ca, supplement developers can give the body the best chance to absorb the mineral, providing complete organic mineral nutrition and delivering greater health benefits.

References

1. USDA, Agricultural Research Service, 2023. Usual Nutrient Intake from Food and Beverages, by Gender and Age, What We Eat in America, NHANES 2017-March 2020 Prepandemic. Available at: http://www.ars.usda.gov/nea/bhnrc/fsrg
2. Weaver, C.M.; Wastney, M.; Fletcher, A.; Lividini, K.; An Algorithm to Assess Calcium Bioavailability from Foods. The Journal of Nutrition. 2024, 3, 921-927. DOI: 10.1016/j.tjnut.2023.12.005
3. Bovell-Benjamin, A.C.; Viteri, F.E.; Allen, L.H. Iron absorption from ferrous bisglycinate and ferric trisglycinate in whole maize is regulated by iron status. Am J Clin Nutr. 2000, 71 (6), 1563-9. DOI: 10.1093/ajcn/71.6.1563
4. Heaney, R.P.; Recker, R.R.; Weaver, R.M. Absorbability of calcium sources: the limited role of solubility. Calcif Tissue Intl. 1990, 46, 300-304. DOI: 10.1007/bf02563819

About the author

Eric Ciappio,PhD, RD, is strategic development manager, Nutrition Science at Balchem Corporation. Balchem has been shaping minerals since 1956. The company’s science-backed chelated minerals – including those in the Albion® Minerals portfolio – offer unique advantages in terms of absorption and bioavailability.