A new paper out in the American Journal of Clinical Nutrition shows there’s an association between children drinking non-dairy milk, as opposed to cow’s milk, and lower heights.
It would be tempting to take these results and make a case for ending Canadian dairy supply management, but there are better reasons for ending Canadian supply management.
The press release doesn’t link to the paper.
Children who drink non-cow’s milk — including other animal milk and plant-based milk beverages — are shorter than children who drink cow’s milk, new research suggests.
For each daily cup of non-cow’s milk they drank, children were 0.4 centimetres shorter than average for their age, according to a study published today in the American Journal of Clinical Nutrition. For each daily cup of cow’s milk they drank, children were 0.2 centimetres taller than average. […]
The study did not examine why children who drank non-cow’s milk were shorter on average than those who drank cow’s milk, however the authors hypothesize that children who drink non-cow’s milk may consume less dietary protein and fat than those who drink cow’s milk, resulting in reduced growth.
Here’s the link to the paper if you’re interested.
The press release talks about associations but doesn’t say anything about causality. Nevertheless, the author goes on about the lack of regulation of protein content in non-dairy milk.
And hey, maybe that’s what’s going on. Reduced protein intake could be doing it.
But it looks like the paper doesn’t control for other parts of kids’ diets. If it’s likely that kids on almond milk diets or soy milk diets are more likely to be on vegan diets overall or to have other weird diet issues that could also affect protein intake, it seems kinda odd not to adjust for other parts of the diet.
And while they exclude kids with growth-affecting disease from the study, they do include asthma. Some folks exclude dairy as part of trying to control asthma, and inhaled corticosteroids can suppress growth among kids (though they catch up later).
So it would be a bit premature to run the cross-price elasticities of milk with respect to non-dairy substitutes, multiply by the effect of supply management on milk prices to get the substitution into non-dairy because of supply management, then work out how much shorter supply management is making some Canadian kids.
Featured image: Endre Majoros / Flickr.