Low zinc levels may suggest potential breast-feeding problems

http://www.eurekalert.org/pub_releases/2015-12/ps-lzl122215.php

Public Release: 22-Dec-2015
Low zinc levels may suggest potential breast-feeding problems
Penn State

Zinc levels in breast milk may be able to serve as an indicator of breast function during lactation, according to Penn State health researchers.

In previous studies, Shannon L. Kelleher and colleagues found that the protein ZnT2 is critical for secreting zinc into breast milk, and women who have mutations in the gene that encodes ZnT2 have substantially lower milk zinc levels, leading to severe zinc deficiency in exclusively breast-fed infants.

They had also found that in mice the deletion of ZnT2 alters milk composition and profoundly impairs the ability of mice to successfully nurse their offspring.

Now the researchers have found that genetic variation resulting in either loss or gain of function may be common in women and in some cases is associated with indicators of poor breast function. They suggest that by identifying women with abnormally low levels of zinc in breast milk, they may be able to more quickly recognize mothers who might have trouble breast-feeding.

In the current study, the researchers found that of 54 breast-feeding women, 36 percent had at least one non-synonymous single nucleotide polymorphism (SNP) -- or mutation -- in the protein ZnT2, and that genetic variation was associated with abnormal levels of zinc in their breast milk. Twelve previously unknown variants of ZnT2 were identified in the participants, and five of these variants were statistically associated with abnormal zinc levels in breast milk.

"We had no idea that genetic variation in ZnT2 would be so common," said Kelleher, associate professor of cellular and molecular physiology and pharmacology, College of Medicine.

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