Fruit juice, apples linked to fetus harm

Photo / Hawke's Bay Today

Pregnant women who eat a lot of sugar-laden food could be compromising their babies' development, new New Zealand research suggests.

In testing carried out on rats, scientists at the University of Auckland's Liggins Institute found a connection between sugars such as fructose and impaired fetal development.

While the data was in its preliminary stages, it could have implications for expectant mothers.

It suggests that pregnant women need to be aware of everything they are eating, and moderate not only their consumption of foods that are fatty but also those that are high in fructose.

The study showed that failing to do so could cause liver problems.
Researchers say the study is a warning to mothers to moderate their intake of processed bread, cake, fizzy drinks and lollies.

"Pregnant women are now eating low-fat milk and low-fat yoghurt. But less attention is paid to fructose content," said senior research fellow Deborah Sloboda.

The study involved feeding rats fructose during pregnancy and lactation.

The researchers discovered that the rats' offspring had higher levels of hormones, which could negatively affect the way the body breaks food down.

Dr Sloboda said the finding was significant because of the implications for human offspring.

"The dose of fructose that we used is moderate, and equivalent to regular consumption in New Zealand - 50g to 80g a day - so for that reason, it has good relevance to the general population."

While 50g of fructose is not excessive for an adult, an unborn child may not be able to cope with its pregnant mother consuming that amount.
Fructose is found in apples and fruit juice, but this form of sugar was processed quite easily in the body.

Of most concern was the highly synthesized fructose that was added to food as sweeteners, such as in corn syrup. It has been blamed as a contributor to the obesity epidemic, because unlike glucose, the body does not detect when it has had enough.

A mother could consume 50g of fructose a day by having four or five cans of fizzy drink.

Dr Sloboda said that although only 10 days old, the rats' livers seemed to convert the fructose into fat. This led to a high concentration of insulin and impairment of liver function.

High levels of insulin are linked to type 2 diabetes and obesity.

The study followed a marked increase in consumption of foods and beverages containing fructose, especially among women of reproductive age.

Dr Sloboda said the effects of high-fat diets on offspring had been widely researched, but very little was known about a high sugar intake.

The study made a discomforting discovery: the rats' bodies gave no external clues to the harm that high fructose consumption was doing.

"There were no grave outward signs of changes," said Dr Sloboda.

"They didn't put on excess weight or excess fat. The only change we did see was in their insulin levels.

"It could be that consuming fructose during pregnancy didn't give the mother any particular indicators ... so women may be unaware that their diet could be compromising the development of their fetus."

The study's other major finding was that at birth, female babies were more vulnerable to impaired development from a sugar-rich diet.

The investigators observed that the females had lighter placentas, which supply nutrients to the fetus.

However, post-natally, the males also showed adverse changes, such as higher levels of hormones.

Twenty years ago in the United States, the use of fructose in food and beverage products rose rapidly. High fructose corn syrup was developed as a cheaper alternative to sugar cane. It is now ubiquitous in American products, and is also found on New Zealand shelves.

Calculating fructose intake can often be difficult, as many products list only their total sugar content.

Dr Sloboda's co-author, Mark Vickers, is now tracking the post-natal development of babies whose mothers have had a sugar-rich diet, to ascertain if there are persistent changes in adults.

The Liggins study was funded by the National Research Centre for Growth and Development, and was published in the high-profile journal Endocrinology this week.

Sugar check

How much fructose are you eating/drinking?
* 1 cup of raisins = 48g of fructose.
* 4 tablespoons of honey = 11g of fructose.
* 1 cup of apple juice = 14g of fructose.
* 1 medium apple = 9g of fructose.
* 1 serving of McDonald's BBQ sauce = 4.3g of fructose.
* 350ml bottle of Powerade = 11g of fructose.