The role of selenium in nutrition and the manufacturing of selenium-enriched milk

The role of selenium has increased after the discovery of the first seleno-enzyme in the human body. Selenium supports growth, the immune system, the reproductive organs, thyroid and muscle function, has an antioxidant effect, and protects against free radicals. The recommended daily intake of selenium for adults is 55 µg/day, which cannot be covered with food alone in selenium-deficient areas. That is the reason why we chose as our research topic the production of functional food – in this research: milk – in which the selenium level has been elevated naturally.

In our work, we supplemented six Holstein-Friesian cattle feeds with a daily 1, 2, 4, and 6 mg/individual organic selenium, and then we measured the selenium content by ICP-MS. With a selenium enrichment of 1 mg/day, a 60% increase in selenium content was achieved, as the selenium content of milk increased from 32.93 µg/kg to 52.79 µg/kg. With the 2, 4, and 6 mg supplementation, the milk contained 97.2, 182.69, and 231.31 µg/kg selenium respectively. The latter is seven times more than the selenium content of the control sample. We have developed a recommendation for the amount of naturally selenized milk that should be consumed for different age groups. In our opinion, milk with increased selenium content could contribute to improving the selenium status of the population.