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Distribution of selenium in human milk.
The American Journal of Clinical Nutrition
|March 1, 1987
Summary
Most selenium in human milk is protein-bound, with distribution influenced by total selenium content. Researchers identified nine selenoproteins, including glutathione peroxidase, in milk samples.
Area of Science:
- Biochemistry
- Human Nutrition
- Trace Elements
Background:
- Human milk is a vital source of nutrients for infants.
- Understanding selenium's role and distribution in human milk is crucial for infant health.
- Selenium is an essential trace element with important antioxidant functions.
Purpose of the Study:
- To characterize the distribution of selenium in human milk.
- To investigate factors affecting selenium distribution, such as protein binding and lactation stage.
- To identify specific selenoproteins present in human milk.
Main Methods:
- Analysis of selenium distribution in human milk samples.
- Dialysis to assess protein-bound versus free selenium.
- Molecular sieve chromatography (Sephadex) for selenoprotein separation.
- Enzyme activity assays for glutathione peroxidase.
Main Results:
- Most selenium in human milk is protein-bound.
- Percentage of dialyzable selenium correlated with total milk selenium content.
- At least nine distinct selenoproteins were detected.
- Glutathione peroxidase accounted for 15-30% of milk selenium.
- Half of milk peroxidase activity was selenium-dependent.
Conclusions:
- Selenium in human milk is primarily protein-associated.
- Selenium distribution is influenced by milk's overall selenium concentration.
- Glutathione peroxidase is a significant selenium-containing protein in human milk.