Mother's milk helps improve baby's DNA: Study

Researchers at the University of Illinois have found that infants' first food affects their gene expression, giving a possible mechanism for how breast milk impacts health.
Gene expression is the process by which instructions in a gene are used to synthesise a functional gene product, mostly proteins. When genes are expressed, it is as if they are "turned on".

Lead researcher Sharon Donovan of the University of Illinois said that it has already been known that breast milk contains immune-protective components that make a breast-fed infant's risk lower for all kinds of illnesses.

"But what we haven't known is how breast milk protects the infant and particularly how it regulates the development of the intestine," she said, adding that understanding those differences could help formula makers develop a product that is more like the real thing.
"Genes are really sensitive to nutrition. And we now have genes that may explain many of the clinical observations of how breast-fed and formula-fed infants differ," she told LiveScience.

Using a novel noninvasive technique for their study, the researchers compared 10 three-month-old formula-fed babies with 12 breast-fed infants of the same age.
Capitalising on the natural sloughing off of intestinal cells during digestion, they looked for signs of gene expression, in the form of messenger RNA, in the babies' poop.
Breast milk and formula have different effects on at least 146 genes, the researchers found.

According to Donovan, most of the genes enhanced by breast milk promote quick development of the intestine and immune system.

Some of the genes positively affected by breast milk protect against "leaky gut", a disorder in which foreign particles enter the bloodstream through the intestinal wall, she said.

Leaky gut increases the risk of allergies and various inflammatory diseases such as asthma, colitis and Crohn's disease -- seen mostly among formula-fed babies, previous research has suggested.

According to Donovan, breast milk and formula likely affect gene expression in one of two ways. They could change the factors responsible for decoding DNA into its active forms, or they could have an epigenetic effect, where the DNA spiral is refolded, making certain genes more or less available for use.

The latter (epigenetics) is usually, but not always, permanent and, if this is the mechanism used, it might explain why breast milk can have life-long health benefits, she said.

According to the researchers, the breast milk evolved to feed human infants and it contains a number of bioactive elements such as hormones, growth factors and plentiful fibers.

Breast milk-fed babies have stronger immune systems, fewer allergies and may be more resistant to chronic diseases, such as asthma, digestive disorders and obesity.

"Cow's milk (the primary ingredient in formula) evolved to feed calves," Donovan continued. Its composition is much different than human milk, and its bioactive elements are often destroyed during processing, she added.

The research was published in the American Journal of Physiology, Gastrointestinal and Liver Physiology.