“At present, 2 billion people around the world are suffering from 'hidden hunger,' and the number in China is 300 million,” said Wan Jianmin, an academic with the Chinese Academy of Engineering, during a lecture on Sept. 1. Although the quantity of grains is basically satisfactory for the needs of Chinese people, a shortage of micronutrients has caused malnutrition among a high number of citizens, especially those living in remote and mountainous regions, Wan explained.

A 2015 report on nutrition and chronic disease in China showed that Chinese people's intake of minerals and vitamins including iron, calcium, vitamin A and vitamin D did not reach the recommended levels.

"In addition to carbohydrates, lipids and proteins, the human body needs 16 kinds of minerals and 13 kinds of vitamins," Wan said. What's more, chronically insufficient intake of micronutrients can lead to birth defects and increase the mortality rate of children and pregnant women.

Wan said that when he did poverty alleviation work in Guizhou and Hunan provinces in May 2016, the health condition and nutrition of children in those regions had barely improved compared to a decade ago.

As for a solution to the problem, Wan suggested that the emphasis in grain production should be shifted from quantity to quality, drawing more attention to nutrition.