Comment: Readers following the war in Gaza, and news from several other countries suffering mass starvation, may have heard about the dangers of reintroducing food too fast for those who are malnourished. What should be lifesaving can instead have fatal consequences.
Researchers have discovered that the same physiological risks from ‘refeeding syndrome’ can apply to babies born prematurely. They have developed nationwide clinical guidelines to help reduce this risk by ensuring babies receive adequate nutrition, including sufficient phosphate, and by closely monitoring blood phosphate and other electrolyte concentrations during the critical first weeks after birth.
Although refeeding syndrome is a modern medical term, the phenomenon has been recognised for centuries, with descriptions dating back to Hippocrates. Only in recent decades have researchers unravelled the underlying physiology and recognised it as a distinct syndrome. Its history is fascinating but disturbing.
In September AD70, Roman forces, led by the future emperor Titus Flavius Vespasianus, breached the final defences of the Jewish capital, Jerusalem, and razed the city. The siege lasted four months, three weeks and five days and produced mass starvation.
The Roman invaders killed or enslaved thousands of inhabitants, and thousands more were forced to flee. But for those who survived famine and ‘freedom’, there was a final, unexpected nail in their coffins. According to the Roman-Jewish historian Flavius Josephus, some of the starved people who were finally given food died within a few days. He attributed their deaths to greed or gluttony – people who ate at a more restrained pace survived, he said.
Josephus’ account of the end of the Siege of Jerusalem is one of the earliest descriptions of ‘refeeding syndrome’ – a syndrome that causes severe illness or death of someone who has been starved or is severely malnourished, a few days after they start eating again.
We now know it’s caused by a dramatic metabolic shift in the starved people’s bodies; the influx of food causes an insulin surge. This drives essential minerals, particularly phosphorus, magnesium and potassium, out of the bloodstream and into cells. In a body already coping with depleted stores of these critical micronutrients, this sudden shift leads to an acute deficiency which can cause heart failure, breathing problems or seizures.
It has occurred throughout history. During the Irish potato famine in the 1840s; the events following the mutiny on the shipwrecked British warship HMS Wager in 1741; the siege of Tottori Castle in 1581; and the liberation of concentration camps in Europe and Asia after World War II – all dramatic world events when feeding starving people has often resulted in illness or death.
Refeeding syndrome has also been associated with treatment for alcoholics, and patients with severe anorexia nervosa and cancer.
The term itself was coined in 1981 by American clinician-researchers Van Weinsier and Carlos Krumdieck, referring to the death of two malnourished patients who were fed “overzealously”.
It took 30 years before researchers, including at the University of Auckland’s Liggins Institute, began to suspect that very preterm babies might also be affected by refeeding syndrome.
Preterm birth is a syndrome rather than a disease and being born early is usually the result of a process that may have started even in early pregnancy; problems with how the placenta transfers nutrients to the baby is a common cause. Thus, many babies born prematurely have been subjected to chronic malnutrition, or ‘starvation’, in the womb.
These babies are significantly smaller than babies of a similar gestational age who remain in the womb and are born at the usual time. The smallest preterm babies weigh as little as 350-1000g; some are small enough to fit in the palm of your hand. It would seem logical that the best thing to do for a tiny, malnourished newborn would be to make sure they get as much good nutrition as possible – until you put refeeding syndrome into the mix.
In 2014, as part of the wider Protein Intravenous Nutrition on Development preterm nutrition trial, Liggins Institute researchers tried to find out whether babies could have refeeding syndrome. The results were shocking: of the 338 extremely low birthweight babies (under 1000g) in the trial, 20 percent had refeeding syndrome.
This is the world’s biggest multicentre study of refeeding syndrome in babies with extremely low birth weight to date. Babies with refeeding syndrome, or with very low plasma phosphate concentrations, were more likely to die than those who did not have refeeding syndrome, or who had normal phosphate concentrations.
A follow-up study, also by researchers at the Liggins Institute and published last year, found that increasing the amount of phosphate these tiny babies received through the intravenous nutrition solutions they need before they can breastfeed was associated with a significantly lower incidence of refeeding syndrome.
This research shows refeeding syndrome in preterm babies is not simply caused by ‘feeding too much too soon’. It’s a more complex problem linked to how their tiny bodies adapt to nutrition after birth. The condition can look quite different in extremely preterm babies (those born before 28 weeks’ gestation) compared with older children or adults, and rates differ widely between hospitals.
This suggests that the way babies are fed and monitored in the first days after birth can make a real difference.
Preterm babies still need enough protein and energy to grow and for brain development. The key is giving the right balance of nutrients, including enough phosphate, and close monitoring, especially in the first week after birth.
These findings have helped shape the new national Pēpi Whānau Wawe Nutrition Guideline for preterm babies, developed over the past three years to support more consistent and safer nutrition care for preterm babies across Aotearoa.
The draft guideline has recently gone out for national stakeholder consultation and is expected to be introduced across neonatal units in New Zealand by the end of the year.
On Thursday July 2 6pm-7pm Professor Frank Bloomfield and Dr Barbara Cormack will be presenting at a Liggins Institute public lecture about their research in early nutrition, where seemingly small decisions can shape brain development. Reserve a spot for Tiny babies, big questions: the high-stakes science of early nutrition
