Which cooking method is most harmful to the kidneys: stir-frying, boiling, steaming, or braising? (Hoa, 35, from Hanoi?

Dr. Nguyen Trong Hung, Director of the Center for Nutrition Counseling, Rehabilitation, and Obesity Control at the National Institute of Nutrition in Hanoi, said braised dishes are often richer and tastier than stir-fried, boiled, or steamed foods. But eating them too often or using too much seasoning can raise the risk of chronic diseases, including kidney problems.

He explained that these dishes are slow-cooked, so they soak up seasonings. Aromatic spices like onions, garlic, ginger, and lemongrass are safe, but too much salt, fish sauce, or soy sauce can cause excess sodium, which harms the kidneys and overall health.

Eating too much salt can raise blood pressure and increase the risk of heart disease, osteoporosis, and kidney disorders, Hung said. Sodium buildup causes the body to retain water, increasing blood flow to the kidneys and forcing them to work harder. For people with underlying conditions, this can exacerbate their illness.

The World Health Organization and the Ministry of Health recommend consuming 4-5 grams of salt per day. Hung noted that people who are used to braised dishes with strong flavors may find boiled or steamed foods bland, and find it difficult to adjust to a healthier diet.

He said braised dishes often contain sugar added without measurement, making intake hard to track. Consuming an excessive amount of sugar, especially refined sugar, can cause obesity, high blood pressure, and liver damage.

People can maintain a healthy diet by limiting salt, sugar, and oil, and increase vegetable intake. Hung advised people with kidney disease, diabetes, obesity, or cardiovascular issues to manage their diet carefully.