New Potassium-Poor Veg Could Benefit People With Kidney Disease, Say Researchers

Fancy some arugula with more iodine? Need some Swiss chard with less potassium? All can be catered for with the right cultivation, according to new research.

By growing the vegetables in soilless nutrient solutions, chard, arugula, radishes and peas can all be infused with or sapped of essential elements, say researchers from the University of Bari Aldo Moro, Italy.

The researchers say the bespoke greens could benefit people with conditions like chronic kidney disease, which restricts the levels of potassium a person can consume.

The findings were published in the Journal of the Science of Food and Agriculture.

Personalized potassium

To test how well each vegetable took up potassium and iodine, the researchers planted chard, arugula, radish and pea seeds in plastic trays filled with solutions of each element.

Six solutions were tested in total: iodine at 0, 1.5 and 3 milligrams per liter (mg/L), and potassium at 0, 60 and 120 mg/L.

After growing and harvesting the vegetables, the researchers found that, compared to the un-biofortified crops, the 1.5 and 3 mg/L treatments of iodine resulted in 4.5- and 14-times higher iodine levels, respectively.

Swiss chard had the strongest affinity for potassium (the best crop came in at 14,096 mg/kg), followed by arugula, pea and radish (crops had an average of 2,495 mg/kg).

The researchers were also curious whether the 0 mg/L solutions could deplete the vegetables’ nutritional content. And they did.

Between the arugula, radish and Swiss chard, the crops experienced, on average, a 45% drop in potassium when grown in the 0 mg/L nutrient solution.

According to the researchers, such potassium-poor vegetables could be beneficial for people with kidney disease.

“Since vegetables contain high concentrations of potassium, patients with impaired kidney function are sometimes advised not to eat vegetables, or that they should be soaked in water and boiled to reduce the potassium content through leaching,” said Massimiliano Renna, a professor of agricultural and environmental science at the University of Bari Aldo Moro.

“However, the reduction in potassium using such cooking methods can be considered limited, while other important minerals and vitamins could be significantly lost. In this context, the production of vegetables with low potassium content could be of great interest.”

People living with chronic kidney disease are often advised to watch their potassium levels and consume less than 3 grams per day; regular dietary advice, on the other hand, recommends a daily intake of 3.5 g. 

“Propelled by an ever-growing awareness of the importance of following dietary recommendations, interest in personalized nutrition is on the rise,” Renna added.

“Soilless biofortification of vegetables has opened the door to the potential for adapting vegetable production to specific dietary requirements.”

Reference: D'Imperio M, Bonelli L, Mininni C, Renna M, et al. Soilless cultivation systems to produce tailored microgreens for specific nutritional needs. J Sci Food Agric. 2024. doi: 10.1002/jsfa.13222

This article is a rework of a press release issued by the Society of Chemical Industry. Material has been edited for length and content.