Human Milk: Composition, Clinical Benefits and Future Opportunities. Группа авторов
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in verbal IQ at 6.5 years [30].
These two pieces of experimental evidence give weight to the view that studies that show an association between breastfeeding and superior cognitive outcome are causal.
Cardiovascular Risk Factors
Many epidemiological studies link breastfeeding to CVD risk factors. In our large historic RCT of EHM versus CM exposure in preterm neonates, we found at the 16-year follow-up that the EHM group had favorably reduced the LDL:HDL cholesterol ratio, diastolic blood pressure, insulin resistance, and metabolic tendency to fatness (leptin resistance) [31–33]. Thus, early HM feeding in a strictly randomized trial reduced 4 key risk factors for CVD. The effect size was large; for instance, the impact of early HM feeding on later cholesterol alone would be expected in adults to reduce CVD by 25% and death by 13–14%. These data add weight to the causal nature of a protective role of breastfeeding for future obesity and CVD.
Atopic Disease
The relationship between breastfeeding and later atopy has been observational and uncertain. In our historic RCT comparing EHM with CM exposure, those with a family history of atopy fed an EHM diet had a major reduction in eczema, food and drug reactions, and wheezing at the 18-month follow-up [34]. Thus, strict experimental evidence confirms that HM, at least in those with a family history of atopy, is protective against future development of atopic phenomena.
Conclusion
Clearly, the HM-fed preterm infant is not a perfect model for the breastfed term infant, and some outcomes considered above would not occur in term infants. Nevertheless, it is a very useful model and conceptually, experimental studies in preterm infants add much weight to the view that breast milk is likely to have broad and important causal effects on short- and long-term outcomes in healthy full-term infants.
Further Models
Given the difficulty in providing an evidence-based underpinning for the impact of breastfeeding on clinical outcome, it is important to explore creatively further opportunities for experimental studies. In this paper, I have considered the value of RCTs in preterm infants and noted the inventive Belarus study on breast milk and cognitive development in term infants. One potentially promising area is the use of RCTs to study the impact on outcome of individual components of breast milk, for instance, HM oligosaccharides.
Overview
It has been an objective in this paper to examine some of the general principles that underlie the science of breastfeeding medicine in order to help strengthen this important field, in the interests of improving infant, child, and population health. The critique in the 3 sections of this paper – on human evolution, HM as a gold standard, and the proposed benefits of breastfeeding has significant, practical clinical and public health implications. Breastfeeding and indeed the use of HM in neonatal intensive care is entering a new era of quite unexpected importance for human biology and health.
Disclosure Statement
Alan Lucas has taken part in educational events organized by infant food, breast milk and feeding device companies for which he has received an honorarium and expenses. He has provided medical scientific advice to breast milk companies for which he has received consultancy payment.
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