Why Australian children have grown significantly taller since 1990

Aussie youngsters are getting taller, new data shows. But why are today’s kids on average taller than their parents and grandparents, and will future generations keep growing?

Australian youngsters are shooting up with the average five-year-old boy now 3.2cm taller than his 1990 counterpart and the average five-year-old girl taller by 2.5cm.

However the rise of youngsters has its limits – and experts believe Australians are nearing their maximum genetic hight limit.

Between 1990 and 2020 Australian five-year-old boys shot up from an average of 112.7cm to 115.9cm, while girls went from 111.8cm to 114.3cm.

Improved nutrition in the early years of life is a key driver and is why some children today tower over their parents and grandparents who did not achieve their “genetic potential” as youngsters.

Data detailing average heights in more than 200 countries from the Non-Communicable Diseases Risk Factor Collaboration shows Australians among the tallest nations – on average – in the world.

Professor Tim Green, principal nutritionist within the SAHMRI Women and Kids Theme.

It describes itself as “a network of health scientists around the world that provides rigorous and timely data on major risk factors for non-communicable diseases for all of the world’s countries.”

It cited 28 major studies in Australia as the source of material to come to its conclusion on average heights here.

Professor Tim Green, principal nutritionist in the South Australian Health and Medical Research Institute’s Women and Kids Theme, says improved nutrition including in pregnant women is a major factor in children getting taller – the downside is excess energy intake could also be driving obesity.

Prof Green is co-author of the book “The Biology of the First 1000 Days” which explains why the 1000 days from conception to two years is a critical period of growth and development.

Emily Griffiths checks the height of three five-year-olds – Mia Swiecinski, her son Lenny Jones and George Lingley. Picture: Mark Brake

He says failure to gain adequate nutrition in this time can lead to irreversible stunting, while good nutrition can allow a child to reach their “genetic potential”.

However there are limits, with Prof Green saying: “I think in Australia we are pretty close to the maximum height now.

“The Dutch are among the tallest people in the world with average Australian adults not far behind.”

Prof Green noted changed diets, improved economic circumstances and immigration all play a role in a nation’s average heights.

He observed that some nations have people whose growth was stunted as children due to scarcity of adequate nutrition but who are now obese adults due a change to energy-rich diets,

“Immigration also plays a role and you might be thinking of tall migrants from places like The Netherlands and Scandinavia, when it is actually from low income nations such as from South East Asia,” he said.

This is because the migrant parents may be relatively short due to stunting in their own childhood, but their children born in Australia are reaching their genetic potential due to better nutrition – and in some cases are towering over their parents.

“You can see the same thing in parts of Asia where there has been an improvement in nutrition for children, it shows the effect of good nutrition,” he said.

Prof Green noted a World Health Organisation study of five nations with different racial composition, but which only looked at children with access to optimal nutritious foods, found no differences in height.

“So we know it is not a racial difference,” he said. “The nutrition delivered in early childhood is critical to set the foundations for the rest of the child’s life.”

When it comes to picking a global five-year-old boys basketball team, selectors seeking height might want to look to places like French Polynesia, Niue and St Vincents and the Grenadines where average youngsters topped the 120cm mark.

French Polynesia was the only place where the average five-year-old girl challenged the 120cm mark, clocking in at 119.8cm.

At the other end of the chart Yemen, Timor Leste and Bangladesh all recorded boys under an average of 100cm in 1990 but all were just over the mark by 2020, while Yemen, Timor Leste and India had girls under an average 100cm in 1990 but all topped it in 2020.

While the data is all about averages, Adelaide schoolmates Lenny at 124cm, George (114cm) and Mia (110cm) are proof your typical SA five-year-old is far from average.

All are different heights, all – of course – are growing between their 5th and 6th birthdays, and as healthy well nourished children look to be on track to be taller than their forebears.

“Lenny’s tall for his age – his father is quite tall so we’ll see where he ends up,” his mother Emily Griffiths said.

Originally published as Why Australian children have grown significantly taller since 1990