To create food for people with certain health conditions, scientists in Italy grew plants such as radishes, peas, arugula and Swiss chard and precisely controlled certain nutrients. And, they did it without soil.

Researchers working on a commercial microgreen farm in southern Italy wanted to see if they could adjust the iodine and potassium levels in a range of vegetables. Researchers say the farm's vegetables are grown in liquid media, making the project easier to carry out.

Soilless culture is considered an advanced and environmentally friendly agricultural practice to improve the quality of fresh vegetables. Soilless culture systems provide the opportunity to regulate nutrient solutions accurately and efficiently.

After some experiments with different growing medium recipes, the team produced vegetables with 14 times the iodine content of plants not grown in the special formula.

Iodine is a key nutrient for thyroid health. Iodine is typically found in fortified table salt, milk, fish and eggs, but is slowly disappearing from diets as health groups call for reductions in salt intake and as people increasingly move towards vegetarian lifestyles. Researchers believe that by increasing its content in other foods, it could help consumers improve their health.

Next, the scientists grew the same vegetables with 45% less potassium, a dangerous nutrient for people with kidney disease.

"Due to the high concentration of potassium in vegetables, patients with impaired kidney function are sometimes advised not to eat vegetables, or to soak the vegetables in water and boil them to reduce the potassium content by leaching it out," the researchers said. "However, the reduction in potassium content using this cooking method can be said to be limited, while other important minerals and vitamins may be lost in large quantities. In this case, the production of low-potassium vegetables may be of great interest."

Next, researchers from Italy's Institute of Food Production Sciences, the National Research Council and the University of Bari Aldo-Morro plan to turn their attention to changing the nutritional content of edible crops by directly altering the plant's metabolic pathways, rather than simply changing its growing medium.

They said: "To optimize these technologies, it is necessary to conduct in-depth research on the molecular biology of plants, including the metabolic pathways involved in the synthesis of target molecules, and continuously improve growth conditions. The combination of advanced scientific knowledge and innovative technologies can open up new prospects for the production of healthier and more nutritious biofortified vegetables."

Their current research has been published in the Journal of Food and Agricultural Sciences.