How big children grow later depends on many factors. One of them is nutrition. In a long-term study, researchers have investigated the role that protein intake in childhood and adolescence plays in the later height of girls and boys. Accordingly, too much protein in girls can lead to a larger stature. An average plus of seven grams of protein per day more than recommended is associated with an increase in adult height of one centimeter. In boys, on the other hand, there was no association between protein consumption and height.
Many boys wish to be as tall as possible when they grow up. For girls, on the other hand, a particularly tall body size is often considered less desirable. The most important factor influencing the later height of a child is the height of the parents. They pass on the disposition for a particularly large or small height to their offspring via numerous different genes. Hormone levels also play a role. This is where drug therapies come in, which are intended to treat excessively large or small body size in children. But diet is also important.
More proteins = more growth?
Yifan Hua and Thomas Remer from the University of Bonn have now evaluated a long-term study on the nutrition of children and adolescents with regard to the question of what influence protein intake has on the later adult height of girls and boys. “For the first time, the study shows the anabolic potency of the essential nutrient protein with detailed nutritional data over a period from 3 to 17 years of age,” says Remer. In this context, the growth-promoting effect is referred to as anabolic potency.
To do this, the researchers evaluated diet logs, 24-hour urine collections and height measurements from 189 healthy girls and boys. As part of the DONALD study (DOrtmund Nutritional and Anthropometric Longitudinally Designed Study), the subjects were recruited for the study as infants and regularly took part in examinations into adulthood. The study has been running since 1985 and includes a total of more than 1000 children, adolescents and young adults. Hua and Remer recorded the protein intake on the one hand via the nutrition logs and on the other hand by measuring protein breakdown products in the urine. In their calculations, they also considered other factors such as parental size, total energy intake, and socioeconomic conditions.
Protein excess affects female height
The result: While there was no effect on height in boys who consumed a particularly large amount of protein, there was a clear correlation in girls. For them, the protein content of the food then had an effect if it exceeded the daily recommendations. The German Society for Nutrition recommends 0.8 to 0.9 grams of protein per kilogram of body weight for girls, for example 48 grams of protein for a 60-kg adolescent. According to the study, even an additional intake of seven grams of protein per day is associated with an adult height of one centimeter in girls. Some of the children and adolescents from the study consumed significantly more proteins, sometimes twice as much as recommended.
“If no increase in height is desired, girls can even reduce their later adult height by a few centimeters during growth by adapting their protein intake to the recommendations, i.e. by forgoing increased protein intake,” says Remer. In boys, on the other hand, the researchers could not find any connection between protein intake and growth. “Apparently, the significantly stronger effects of the sex hormones – including testosterone – on the growth hormone axis in them leave less room for an additional anabolic nutritional effect through protein,” explains Hua.
Source: Yifan Hua (University of Bonn) et al., Journal of Clinical Endocrinology and Metabolism, doi: 10.1210/clinem/dgac205;