Less sugar works
great for tiny newborns

Tiny premature infants can rev up their "metabolic engines" to produce their own blood glucose using intravenous fats and amino acids provided during the first days of life.

These CNRC research findings suggest that the amount of glucose routinely provided via intravenous feedings can be safely reduced, which could lower the risk of complications for some infants.

"Healthy, full-term infants begin converting their glycogen, fat and protein stores into glucose to feed the brain as soon as the umbilical cord is cut," said Dr. Agneta Sunehag, a CNRC researcher and Baylor assistant professor of pediatrics. "But, very premature infants are born before these stores develop and are too young to suckle. So, they are given intravenous nutrition immediately after birth, including glucose at high infusion rates, to prevent a brain-damaging drop in blood glucose levels and provide important calories."

However, some preemies are unable to handle high glucose infusion rates and develop high blood glucose levels, a condition called hyperglycemia, Sunehag said. When this happens, precious sugar, water and salts are lost through the urine, which can lead to dehydration and electrolyte imbalances. Excess glucose also affects the amount of carbon dioxide produced, which can exacerbate lung problems.

"But, if we knew that premature infants could produce their own glucose from fat and amino acids, we could substitute these fuels for some of the glucose in IV solutions. This would help us avoid hyperglycemia, while providing enough calories to prevent increasing the risk of hypoglycemia, or low blood sugar," she said.

To test the metabolic prowess of her 5-day-old charges, Sunehag slowly cut back glucose infusion rates while providing amino acids and a fat emulsion.

Non-radioactive "tracers" confirmed that the infants were able to use intravenous amino acids and fats to keep their blood glucose levels stable, even when the glucose infusion rate was cut by 75 percent.

Sunehag is now working to determine the optimal mix of amino acids, fats and glucose for intravenous feedings.

"Just 10 years ago, life for the tiniest of premature infants was so precarious that little thought was given to nutrition. Now, medical advances help 90 percent survive. So, we must learn how to help them not only survive, but thrive and grow healthy and strong," she said.