Baby boy in sleeping on bed.
(photo credit: ING IMAGE/ASAP)
Researchers in Haifa have just published a study showing that the environment in which infants live in the womb and before the first birthday largely determines height as an adult.
The research, recently published in the Journal of Pediatrics, was led by Prof. Ze’ev Hochberg and Dr. Alina German of the Technion-Israel Institute of Technology’s Rappaport Faculty of Medicine, along with scientists from Haifa’s Bnai Zion Medical Center and Tel Aviv University, in collaboration with regional health offices. The authors called it a pioneering study in the field.
Parents tend to think their baby inherited their genes for height and will eventually grow to be a little taller than them. The team found that while genetics do have a significant effect on a person’s height, so, too, do environmental elements which include the environment in the womb, nutrition and health status in the first year of life, parents and family structure and economic and emotional events. “Following the genetics revolution, today it is customary to attribute our personal traits to the genes,” said Hochberg.
“Indeed, there is no doubt that many of our features are genetic. However, as can be seen in our study, environmental conditions have a very significant role – around 50 percent – in determining growth and height.”
The range difference between people who are tall or short is about 25 centimeters in men and 23 in women.
Half of the variation is set at a decisive growth stage – when the child moves from infantile growth to childhood. The study shows that this half is due only to environmental conditions before birth and during infancy.
The researchers determined this decisive growth stage in 162 sets of twins (including 56 pairs of identical twins, who have identical genes), 106 pairs of fraternal twins (who share only half their genes) and 106 pairs of non-twin siblings (who also share half their genes).
“Studies on twins let us test the balance between genes and the environment,” explained Hochberg. “The difference between identical and fraternal twins shows the impact of genetics. Here we discovered the remarkable power of the environment in shaping a person.
This is called plasticity in human development, which means that environmental conditions such as mother and baby nutrition, social and family interactions, can influence our growth and height.”
From an evolutionary perspective, wrote the researchers, this plasticity helps shape characteristics to suit future living conditions, which are “adaptively predicted” based on current conditions. For example, “children who are born into and grow up in a malnourished environment will be shorter and therefore require less food as they get older, while children born into a well-nourished environment will grow to be tall,” said Hochberg.