Current recommendations for infant nutrition may need to be reviewed if early findings suggesting a link between lower nutrient intake and better cardiovascular health later in life are confirmed, say UK scientists.
The acceleration of infant growth is thought to increase the later susceptibility to insulin resistance and non-insulin-dependent diabetes in animals, report authors of a study in this week's issue of The Lancet. Slow growth resulting from undernutrition is therefore thought to have a beneficial effect.
To test this proposal in humans, Atul Singhal, Alan Lucas and colleagues from the Institute of Child Health in London, UK, assessed fasting concentrations of a marker for insulin resistance - 32-33 split proinsulin - in 216 adolescents born prematurely in the 1980s who had previously participated in randomised intervention trials of infant nutrition. They compared findings with 61 adolescents who had not been born prematurely who received 'normal' nutrition in the first few weeks after birth.
Fasting proinsulin concentration - and therefore a possible tendency to diabetes - was 20 per cent lower in adolescents who had been given a relatively low nutrient diet early in infancy compared to both preterm infants given a high nutrient diet and healthy children born at full term.
Alan Lucas said: "Whether our results can be generalised to full-term infants requires further research. We recognise that preterm infants are different to those born at term in many respects - most notably that they have medical problems related to prematurity itself. Nevertheless, even if our findings are not generalisable they could still apply to the 6 per cent of the population born preterm."
The authors say they have shown for the first time in human beings the importance of a lower nutrient intake and slower growth early in postnatal life, in promoting health later on.
"Our observations are irrespective of size at birth and in fact suggest that associations between low birthweight for gestation and later cardiovascular risk factors could reflect factors acting early in infancy rather than antenatally," added Lucas and Singhal.
The researchers suggest that these findings could partly explain what up to now has been regarded as "the foetal origins of adult disease".
They also said that because postnatal factors may be more amenable to intervention, the distinction between antenatal and postnatal programming of risk factors for cardiovascular disease, as well as being of scientific importance, probably has important public-health implications.
"Our data lend support to the benefit of relative undernutrition associated with colostrum and breastfeeding very early in infancy in reducing the risk of cardiovascular disease. If confirmed in infants not born prematurely, our findings would suggest that public-health interventions that aim to reduce the risk of coronary heart disease by the promotion of weight gain in infancy, could even be deleterious," said the authors.
They concluded that present recommendations for infant feeding need to be reappraised as new data emerge.