The World Health Organization’s Commission on Ending Childhood Obesity, which launched at last year’s World Health Assembly, released an interim report the other week, highlighting important issues and inviting input on various key questions. (Comments are being accepted through June 2015, which can be submitted here.) The commission includes a number of prominent global health experts, and I’ve been eager to see what they come up with.
I’m still going through the report (click here), but after reading a few of the background paragraphs I felt compelled to address a couple of major shortcomings. The fact that this is a WHO commissioned document is even more concerning. Here’s why.
We don’t have evidence to suggest causation
I’ve written about the conflation of correlation and causation before, but the report author’s overstep dramatically in this sense. Paragraph 17 reads,
“Childhood obesity itself is a direct cause (emphasis added) of morbidities including asthma…”
That sounds like a definitive statement to me. I’d expect there to be significant research to back up the claim. The opposite is the case. Yes, a 2014 review of childhood obesity physical and psychological co-morbidiites published in Clinical Therapeutics did recognize that there is a solid literature base supporting a relationship between the two conditions.
However, current research suggests an association. No research to date has demonstrated a definitive causal link. In addition, the review recognizes that there are a number of studies that have found no association between childhood obesity and asthma, particularly among minority populations. The commission’s interim report does not recognize either of these two important limitations.
Further, the only reference provided in the interim report in support of its claim that childhood obesity causes asthma is a study focused only on European children and one that simply estimates the prevalence of various co-morbidities through modeling. This is not a human-subjects study testing the association between the two conditions of interest, obesity and asthma.
What’s the deal with saturated fat?
Another confusing topic addressed in the commission’s interim report is saturated fat (not a shock). In Paragraph 21 of the report, it states,
“Addressing childhood obesity requires attention to both the developmental (life-course) and environmental considerations. Of the latter, important factors include exposure to inappropriate infant and young child feeding, and the influence of the marketing of unhealthy foods (i.e., foods high in saturated fats, trans-fatty acids, free sugars or salt) directly to children.”
Based on this statement, the commission is saying that exposure to saturated fat is an important factor leading to obesity among infants and young children. I won’t address the underlying assumption that saturated fat is bad for your health (see here, for example), but I do want to speak to the contradiction of picking out saturated fat.
Why is this a contradiction? Well, saturated fat is a good thing. And it’s an essential part of a young child’s diet. And it comprises a significant proportion of one particular food source that the World Health Organization recommends children should have exclusively through six months of age and even up until two years old. I’m talking about breast milk!
If you take a look at the nutritional profile of human breast milk, saturated fat is a key part (specifically palmitic acid). So, if a woman and young child are following WHO infant feeding guidelines, breast milk will be an exclusive nutrient source from 0-6 months of age, and a complementary source for up to 24 months. This is to say that by adhering to these guidelines, a young child is already obtaining considerable amounts of saturated fat throughout its first years of life.
Yet, the commission’s report only discusses saturated fat as a nutrient that infants and young children should limit. This is a direct contradiction with WHO’s own guidance. I hope the commission and WHO reconcile this issue in future documents.
I’m sure I’ll uncover more as I read the rest of the report. Stay tuned.