“Human breast milk is not only a perfectly adapted nutritional supply for the infant, but probably the most specific personalised medicine that he/she is likely to receive, given at a time when gene expression being fine-tuned for life” write Cesar Victora and others in The Lancet breastfeeding series group 2016.
A new finding about the carefully tailored richness of human milk has shed light on the importance of myo-inositol, a cyclic sugar alcohol. The levels of myo-inositol are high over the first two weeks of lactation and gradually taper off over a period of a few months. In the early stages, the brain of the newborn is a site of rapid ‘wiring’, as synapses (or connections between nerve cells) are formed in profusion. Proper synapse formation during early development lays the foundation for cognitive development; inadequate synapse formation leads to development difficulties in the brain.
The group of Thomas Biederer at Yale (PNAS) also matched their findings on myo-inositol induced synapse abundance in cultured rat neurons in test tubes. Here too, myo-inositol promoted the formation of synapses between neurons.
Myo-inositol is a cyclic sugar-alcohol, about half as sweet as sugar. It is abundant in the brain, where it mediates the response to several hormones. Our body needs inositol to form cell membranes. Our body makes myo-inositol from glucose, mostly in the kidneys. However, our body’s requirements go up along with the intake of coffee and sugar, and in conditions such as diabetes. The bran of grains and seeds contains a precursor of inositol, phytic acid. Almonds, peas and cantaloupes are also rich sources.
In animal models of diabetes, adding myo-inositol back to the diet of inositol-deprived mice helps prevent cataract formation and other complications associated with diabetes.
Other milk constituents
Other constituents of human milk have unique nutritive values too. Dr Shay Phillips and colleagues of the Mead Johnson Paediatric Nutrition Institute, Mexico, have analysed many factors that impact human milk composition. They point out that an essential nutrient, an Omega-3 fatty acid called dicosahexaenoic acid (or DHA), varies depending on the food the pregnant mother has been eating. The DHA levels vary in the lactating mother’s milk across nations — 2.8% in mainland China, 1% in Japan, around 0.4-0.2% in Europe and the U.S., and only 0.1% or so in several developing countries. DHA is important for the developing brain and retina.
Necrotizing enterocolitis (NEC) is a severe gastrointestinal condition that impacts premature or extremely low birth weight infants. Symptoms include inadequate feeding, abdominal bloating, multiorgan failure, and can be fatal. Risk factors consist of bottle-feeding, prematurity, and low birth weight (1.5 kg or less). The condition arises from a combination of compromised blood flow and intestinal infection. The NEC can be prevented by the utilisation of breast milk and probiotics. Nearly 10% of premature babies develop NEC, with a quarter of affected infants succumbing to the disease. The intestines of premature babies do not produce enough IL-22, which is involved in protecting us from microbial infections.
(The article was written in collaboration with Sushil Chandani, who works in molecular modelling.)
