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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Small Grain and Food Crops Quality Research » Research » Publications at this Location » Publication #409262
Research Project: Developing Accurate and Efficient Laboratory Methods for Testing End-use Qualities of Pulse Crops, Identify Factors Associated with End-use Quality, and Develop Processes to Add Value to Pulses

Location: Small Grain and Food Crops Quality Research

Title: The effect of exogenous cadmium and zinc applications on cadmium, zinc, and essential mineral bioaccessibility in three lines of rice that differ in grain cadmium accumulation

Author
item TAVAREZ, MICHAEL - Lehman College
item Grusak, Michael
item SANKARAN, RENUKA - Lehman College

Submitted to: Foods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2023
Publication Date: 11/4/2023
Citation: Tavarez, M., Grusak, M.A., Sankaran, R.P. 2023. The effect of exogenous cadmium and zinc applications on cadmium, zinc, and essential mineral bioaccessibility in three lines of rice that differ in grain cadmium accumulation. Foods. 12: 4026. https://doi.org/10.3390/foods12214026.
DOI: https://doi.org/10.3390/foods12214026

Interpretive Summary: Rice is an important food source for populations throughout the world. However, when grown in certain soils, the plants and rice grains can accumulate the toxic metal cadmium, which poses health risks for humans. Several strategies to limit cadmium in rice grains have been explored, but even when cadmium concentrations are reduced by a management strategy, total cadmium levels in grains are an unreliable means of estimating human health risk. This is because only a fraction of the minerals in grains are ‘bioaccessible’; that is, the degree to which the minerals are released from a food and are accessible for absorption. The goal of this work was to assess the influence of cadmium and elevated zinc levels supplied to plant roots on the bioaccessibility of cadmium and essential minerals from grains of three rice lines that differed in grain cadmium accumulation. Bioaccessibility of cadmium and different mineral nutrients was studied using ground, whole grain rice. Our results showed that the variety of rice affected the level of cadmium bioaccessibility and the bioaccessibility of other minerals. Higher concentrations of cadmium in grains of some rice varieties didn’t always translate into a higher level of bioaccessibility. This information will help rice breeders identify other lines exhibiting reduced cadmium bioaccessibility, which could help limit dietary exposure to cadmium amongst consumers who eat rice as a staple food.

Technical Abstract: Millions of people around the world rely on rice (Oryza sativa) for a significant portion of daily calories, but rice is a relatively poor source of essential micronutrients like iron and zinc and rice has been shown to accumulate alarmingly high concentrations of toxic heavy metals, such as cadmium. Several strategies to limit cadmium and increase micronutrient density in staple food crops like rice have been explored, but even when cadmium concentrations are reduced by a management strategy, total cadmium levels in rice grain are an unreliable means of estimating human health risk because only a fraction of the minerals in grains are bioaccessible. The goal of this work was to assess the influence of cadmium and zinc supplied to plant roots on the bioaccessibility of cadmium and essential minerals from grains of three rice lines that differed in grain cadmium accumulation. Our results revealed that increased grain cadmium concentration does not always correlate with increased cadmium bioaccessibility. Among the three rice lines tested, zinc bioaccessibility increased in the high cadmium-accumulating line when cadmium was elevated in grains, and in the low cadmium line when both cadmium and zinc were increased in the rice grains. Our results showed that both exogenous cadmium and elevated zinc treatments increased the bioaccessibility of other minerals from grains of the low or high grain cadmium lines of rice. Differences in mineral bioaccessibility were dependent on rice line. Calculations also showed that increased cadmium bioaccessibility correlated with increased risk of dietary exposure to consumers. Furthermore, our results suggest that zinc fertilization increased dietary exposure to cadmium in both high and low lines. This information can inform future experiments to analyze genotypic effects of mineral bioavailability from rice, with the goal of reducing cadmium absorption while simultaneously increasing zinc absorption from rice grains.