They are taller only than Indonesians (158 cm), Filipinos (161.9 cm), and Bolivians (160 cm), the independent U.S. organization that provides data and information about global population growth said.

Cambodians are one place above the Vietnamese with an average height of 162.5 cm.

Rounding off the bottom 10 were Nepal (163 cm), Ecuador (163.5 cm), Sri Lanka (163.6 cm), Nigeria (163.8 cm) and Peru (164 cm).          

Europeans are the world's tallest people, occuppying the top 10 list. People in the Netherlands are 183.8 cm tall, followed by Montenegro (183.2 cm), Denmark (182.6 cm) and Norway (182.4 cm).

The average Vietnamese man is 162.1 cm tall and the average woman 152.2 cm, far shorter than their Asian peers like Chinese, Singaporeans, Japanese, and South Koreans.

The averages are 170.7 cm and 157.4 for South Korean, 169 cm and 158 cm for Chinese and 172 cm and 158 cm for Japanese.

According to a UNICEF report, Vietnam also has the highest rate of stunting in Southeast Asia with a rate of 23.8 percent among children under five. This is attributed to a number of reasons, including lack of nutrition in early childhood.

"Genetics determine the bone elongation but environmental factors, especially nutrition, help children reach their full height potential no matter the geographical and cultural differences," Robert Murray, professor of human nutrition, College of Education and Human Ecology, at Ohio State University, said.

UNICEF also said more than 230,000 children under five in Vietnam suffer from severe acute malnutrition every year, which is a major cause of stunting and death.

The government launched a program in 2013 aimed at improving the nutrition and physical health of its citizens, which could increase the average height of the population.

The $285 million project targets that by 2030 the average heights of women and men will increase to 157.5 cm and 168.5 cm.