Dietary components decrease Cd bioavailability in rice

A recent research paper published in Journal of Agricultural and Food Chemistry describes an alternative strategy to reduce Cd exposure.

Heavy metal pollution is one of the oldest environmental problems, which is still a serious health problem, especially in some developing countries. Cadmium is a common toxic heavy metal in the environment. Oral intake is the primary way for people to expose cadmium.

Reducing the exposure of cadmium in diet is an effective and feasible strategy to reduce the risk. One of the ways to reduce the exposure risk is to eat agricultural products with low cadmium content; on the other hand, reducing the bioavailability of Cd in the systemic circulation is another strategy to reduce Cd exposure, and dietary supplements play an important role in modulating or preventing cadmium poisoning.

To investigate some alternative strategies to reduce Cd exposure, under the guidance of associate professor ZHUANG Ping, SUN Shuo, a doctoral student from South China Botanical Garden under Chinese Academy of Sciences conducted in vitro and in vivo bioassays to test Cd bioavailability. The influence of 39 dietary components on Cd bioaccessibility in water or rice were determined using an in vitro gastrointestinal model, following which an in vivo bioassay was used to determine the most effective components on Cd bioavailability in rice.

The results showed that several components significantly reduced the solubility of Cd (10-98%) in intestinal phase. Tannic acid, TiO₂, zinc gluconate, CaCl₂ and proanthocyanidins were the most effective in decreasing Cd bioaccessibility in rice, with reductions of 93–97%, 54–61%, 32–49%, 24–32% and 11–14%, respectively. Upon adding the dietary components, the reduction rates of the Cd-relative bioavailability (Cd-RBA) were 20–58% and 10–31% in the kidney and liver, respectively. The results may have important implications for reducing health risks associated with Cd exposure via consumption of rice.

This is the first report on reducing health risk of Cd exposure from rice by dietary components in China. Since dietary components significantly influenced rice Cd bioavailability, dietary strategies can be used to modulate Cd exposure from rice consumption. For populations susceptible for Cd exposure via rice or other food consumption, dietary components with a high mineral content or antioxidant would be a good strategy to alleviate the adverse impact of rice Cd.

For further reading, please refer to the paper entitled “Use of dietary components to reduce bioaccessibility and bioavailability of cadmium in rice” at https://pubs.acs.org/doi/pdf/10.1021/acs.jafc.0c01582.