We all know that our diet can have an impact on our health and weight, but could it also affect how we grow in height?
This is what researchers from the Imperial College of London suggest in a paper recently published in The Lancet, based on a study of 65 million children and teens from 193 countries.
The researchers found notable differences in height between children of the same age living in different countries. They examined diet as a potential reason behind the disparity.
Let’s look in more detail at the findings of the study and the causes that could explain the height gap.
Findings of the Study
The researchers behind the paper analyzed data from 2000 studies that tracked the height and weight of school-aged children worldwide between 1985 and 2019. They found the following patterns:
- There was an average height difference of approximately 8 inches in children between the tallest nation and the shortest nation.
- There was a difference in growth for girls and boys between these nations. For example, 19-year-old girls in Guatemala were the same height as average 11-year-old girls in the Netherlands. And 19-year-old boys in Laos were the same height as 13-year-old boys in the Netherlands.
- The tallest children and teenagers in the world were in north-western and central Europe, while the shortest teenagers were in South and South-East Asia, Latin America, and East Africa.
Researchers also examined the Body Mass Index (BMI) levels that measure whether a person has a healthy weight for their height. They found that teenagers in the Pacific Islands, the Middle East, USA, and New Zealand had the largest BMI, while teenagers in South-Asian countries such as India and Bangladesh had the lowest BMIs. The difference between the heaviest and lightest BMIs was approximately 55 pounds!
Main Factors for the Height Gap
So how do the researchers explain such big gaps in height between children growing up in different places?
We know that our height is partly determined by our genes (height heritability). For example, one study in 2004 found that Chinese populations have a height heritability of 65%, while other studies have found a height heritability of 80% for white men in the USA.
But it seems that our diets can also play an important role in how we grow. In fact, studies have shown that while 60-80% of the difference is due to genetics, 20-40% is due to environmental factors, such as nutrition.
In developing countries and poorer areas, nutrition deficits decrease heritability and explain the height differences found in this recent study. In these areas, energy and nutrient-rich foods, including good quality protein, are less readily available to school-aged children. This leads to a tendency for stunted growth, obesity, or undernourishment. Overall, the study reveals a clear correlation between children’s diet and how they grow in their formative years
Since stunted growth impacts a person’s health and wellbeing, it is necessary to invest in better global nutrition policies that focus on the growth patterns of children. Healthy school meals that are currently under threat during the pandemic are a good starting point to guarantee that all children have better access to nutritious foods.
Sources: BBC, Lancet, Scientific American, Science Daily