Non-dairy milk alternatives – like soy, almond and rice milks, for example – may be impacting children’s growth, and it has researchers concerned for their overall health.
According to a study by St. Michael’s Hospital in Toronto, for each cup of non-cow’s milk they drank, children were an average 0.4 centimetres shorter for their age – and for each cup of cow’s milk they drank, children were 0.2 centimetres taller than average.
Put simply, the more non-cow’s milk a child drinks, the shorter their height – and it may point to nutritional deficiencies.
“Let’s be clear – this isn’t stunting their growth,” says Dr. Jonathon Maguire, pediatrician and researcher at St. Michael’s Hospital and lead author of the study. “Stunting is children who are very small who are below their percentile for height, and in Canada nutritional stunting is not very common. But what we are talking about is optimizing children’s growth. Height is actually an indicator of adequate nutrition and that everything is going OK in terms of growth and development, and it’s something children’s doctors monitor closely.”
The study looked at over 5,000 children between the ages 24 and 72 months. Of those who participated in the study, 13 per cent drank alternative milks daily, while 92 per cent drank cow’s milk.
Maguire and his team also observed similar outcomes for children who drank a mix of cow’s milk and alternative milks. As it turns out, the combination of the two did not reverse the link between non-cow’s milk consumption and growth.
By the time children reached the age of three, the height difference for those who drank three cups of alternative milks compared to three cups of cow’s milk per day was as much as 1.5 centimetres.
While the study did not look into why there was a height difference between cow’s milk and non-cow’s milk drinkers, Maguire speculates that it may have to do with the contents found (or not found) in alternative milks.
“There is much more variability in the nutritional content of non-cow’s milk than there is in cow’s milk,” Maguire says. “Cow’s milk is legislated and its nutritional contents are standardized, so it doesn’t really matter what brand you pick, they’re all the same. Whereas non-cow’s milk, there are tons of different beverages out there and they’re not legislated so the nutritional content varies quite a bit in terms of protein amounts, fat amounts and micronutrients – the small things that help us grow and develop.”
For example, two cups of cow’s milk contain 16 grams of protein – which equals to 100 per cent of the daily protein requirements for a three-year-old child.
While Maguire is unable to say if these alternative milks are healthy overall, even for adults, he does say that these height-suppressing effects could potentially follow children into adulthood.
“Many parents are choosing non-cow’s milk for their children because of perceived health benefits and indeed many non-cow’s milks are marketed to be cow’s milk alternatives,” Maguire explains. “But these alternative milks are not at all that similar [to cow’s milk] in terms of nutritional content.”
As for people’s concerns regarding hormones in cow’s milk, Maguire says there is often no need for concern in Canada, where milk products remain quite regulated.
“In Canada, dairy cows aren’t provided [estrogenic] hormones – it’s against legislation to provide dairy cows with hormones,” Maguire says. “So what we call estrogenic hormones that are given to the cattle isn’t an issue in Canada because it’s not permitted. However, just like in breast milk there are hormones in cow’s milk, and whether that has an impact on growth – I don’t know.”
In the end, Maguire just hopes that parents become more aware of the types of products they’re buying for their children, as well as themselves, the next time they’re shopping the grocery store aisles.
“There are many non-cow’s milk products on the market so I think as consumers we have to be a bit savvy in picking ones that have enough nutrients,” he says. “So now that we’re seeing a switch away from cow’s milk, I just think that we need to be careful about reaping all the benefits that we may be getting from cow’s milk from other sources.”
The study was published Wednesday in the American Journal of Clinical Nutrition.
Besides the possible impact on height in childhood, previous studies have pinpointed several other benefits that may be associated with the consumption of cow’s milk throughout life.
According to a 2015 University of Kansas study, researchers found a link between drinking milk and the levels of a “naturally-occurring antioxidant” called glutathione in the brain in older adults who are healthy.
This hormone, researchers say, may help ward off oxidative stress, which is known to be associated with several different diseases and conditions like Alzheimer’s and Parkinson’s.
Regularly consuming full-fat dairy products was also associated with a risk reduction in developing diabetes compared to those who consumed low-fat dairy products.
The study, which was conducted by the Tufts Friedman School of Nutrition Science and Policy, looked at 15 years’ worth of data of adults between the ages of 30 and 75. Researchers found that the higher levels of dairy fat in people’s systems had as much as a 46 per cent lower risk of getting diabetes.