A systematic review and meta-analysis by Vanderhout et al discovered a beneficial association between childhood consumption of whole milk and lower odds of overweight or obesity. The authors wrote that clinical intervention trial data and well-designed prospective cohort studies involving large, diverse samples, using standardized exposure and outcome measurements, and with long study duration, would help determine whether the observed association between higher milk fat consumption and lower childhood overweight and obesity is causal.
Key points from the systematic review and meta-analysis:
- Observational research suggests higher cow milk fat intake is associated with lower childhood overweight or obesity
- International guidelines recommending reduced-fat milk for children might not lower the risk of childhood obesity
- Randomized trials are needed to determine whether cow milk fat decreases risk of overweight or obesity
Antecedent systematic reviews and meta-analyses on the association between total dairy consumption and child adiposity (overweight or obesity) showed conflicting findings. Vanderhout et al 2020 noted that the older studies evaluated total dairy consumption but did not specifically consider milk fat. The aim of the study by Vanderhout et al 2020 was to systematically review and meta-analyse the association between whole-fat (3.25%) relative to reduced-fat (0.1 to 2%) cow milk and adiposity in children. In the review, a beneficial association between full fat milk consumption and childhood obesity was observed. Since there was a high heterogeneity between the studies and no intervention studies were identified, the causality of the current findings needs to be further researched.
Over the last 40 years, childhood obesity in North America has been on the rise and approximately 1-in-3 children are now overweight or obese. Meanwhile, consumption of whole-fat cow milk has halved over the same time period.
Health authorities such as the Canadian Paediatric Society and American Academy of Pediatrics recommend that children switch from whole-fat (3.25%) to reduced-fat cow milk (0.1 to 2%) starting 2 years of age. The reasons were to limit fat intake and minimize risk of childhood obesity. In other countries such as Europe, the United Kingdom and Australia, health authorities also make similar recommendations. Generally, guidelines from health authorities are the reference point for health professionals, families, schools and childcare nutrition policy makers. Unsurprisingly, whole-fat milk availability has dropped by 80% in North America since 1970, whereas reduced-fat milk purchases have tripled.
Cow milk is a major dietary source of energy, protein, and fat for children in North America. In Canada, 88% of children aged 1 to 3 years and 76% aged 4 to 8 years drink milk on a daily basis. Thus, it is important to comprehend the association between milk fat and risk of overweight or obesity.