According to the study, published in the American Journal of Clinical Nutrition, drinking one cup of cow's milk a day makes children 0.2cm taller than average for their age, while a daily cup of non-cow's milk makes then 0.4cm shorter.
According to the report, each cup of non-cow's milk consumed daily is associated to a loss of.15 inches in height compared to the average for a child's age. For instance, two cups of cow's milk has 0.56 ounce of protein in it, which is exactly the daily amount needed by a 3-year-old child.
The researchers say it's not clear what might be happening at a biological level to produce the effects, but others have hypothesized that milk proteins and insulin-like growth factors that occur naturally in cow's milk give children an edge in their "linear growth".
Height is an important indicator of children's overall health and development, said Dr. Maguire. Maguire however says that marketing of the non-cow milk beverages should be more regulated and claims that these non-cow milks are "of similar nutritional value" as cow's milk should not be made.
What they're trying to find out now is if kids who fall behind by drinking non-dairy milk can catch up later.
Other researchers argue that the study did not take into consideration other aspects of the children's diets, which could be contributing to the growth difference, and that taller does not always mean healthier.
The study found that 92 per cent of children drank cow's milk daily, while 13 per cent drank non-cow's milk. Surveys suggest 12 per cent of children in urban Canada are drinking plant-based and other non-cow's milk beverages, while Canada's per capita consumption of dairy milk plummeted by 22 per cent from 1996 to 2015.
For this study Dr. Maguire and his team included 5,034 healthy Canadian children between ages 2 and 6. Maguire explained that the shorter children were those that consumed lesser amounts and the correlation was significant. IGF-1 is a hormone produced in the liver and body tissues of mammals and is naturally present in cow's milk.
Yet, two cups of almond milk typically contain just four grams of protein, which is only 25 per cent of their daily requirement, he added.
"Cow's milk has been a reliable source of dietary protein and fat for children". This makes it hard for the average consumer to understand the pros and cons of choosing non-cow's milk over cow's milk for their child.
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