Why Māori and Pacific babies are larger, longer – and leaner

Māori and Pacific newborns are larger and longer, but also leaner, than European and Asian babies – a surprise finding that could refocus early healthcare. Photo / NZ Herald

Māori and Pacific newborns are larger and longer, but also leaner, than European and Asian babies – a surprise finding that could refocus early healthcare.

In a just-published study, researchers at the University of Auckland-based Liggins Institute used special equipment along with tape measurements and sensitive to scales to compare fat and fat-free mass among 440 babies born over three years.

They found Māori and Pacific babies were bigger than their European and Asian counterparts at birth, and heavier than Asian babies – all findings that had been well established.

But the researchers were surprised to find they were also leaner: the extra weight coming from fat-free mass – and not from fat mass.

Fat mass describes the amount of fat as a percentage of body weight – and fat free mass is whatever is left over, such as muscles, organs and bones.

Asian babies were the lightest, shortest and smallest, but had similar amounts of fat mass to babies of other ethnicities, and therefore the highest percentage of fat mass.

Boy babies were heavier, longer and had larger heads than girl babies, but they were also leaner, with a lower percentage of fat mass – a pattern long-recognised in childhood and adulthood.

“We wanted to see if knowing body composition at birth could help identify risk factors for later metabolic disease, such as obesity and type 2 diabetes, and interventions for long-term health,” said study leader Tanith Alexander, a Liggins PhD student and a dietician at Middlemore-based Kidz First.

“The finding that Māori and Pacific babies were heavier but leaner was somewhat surprising, because by the time they reach childhood, they experience the highest rates of overweight and obesity of all ethnicities.

“This suggests that environmental factors in our society are mostly driving this shift in body composition.”

While fat mass percentages differed by ethnicity and sex, the absolute amount of fat mass was similar across all babies in the study.

“The finding that Māori and Pacific babies were heavier but leaner was somewhat surprising,” study leader and University of Auckland PhD student Tanith Alexander says. Photo / Supplied.

“This raises the possibility of a ‘target’ mass of fat for newborn babies to aid transition to life outside the womb,” Alexander said.

“Newborns need a certain amount of fat to maintain their body temperature and for energy stores until breastfeeding fully kicks in.”

Although the findings suggested Asians were born with the so-called “thin-fat” body type, this underlined that small or thin babies did not need fattening up to make them the same size as other babies, as they all had the same fat stores.

“In fact, rapid weight-gain during the first few years of life has been linked to childhood obesity, which in turn raises your risk of developing health problems in adulthood such as obesity, type 2diabetes and cardiovascular disease.”

The researchers say the findings once again highlight the importance of health promotion from the earliest years to set children up for life-long health.

Actions could include supporting mothers to breastfeed, guidance around introduction of solids, community-based promotion of healthy eating and exercise for children and whanau, and regulatory or pricing changes to make healthy food cheaper and more accessible, they say.

The study, published in the journal Early Human Development, was partly funded by Counties Manukau Health and The Nurture Foundation for Reproductive Research.

Source: NZ Herald By: Jamie Morton Science Reporter, NZ Herald.


 



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