• Veterinary Public Health
• Julius Center for Health Sciences and Primary Care

The aim of this study is to conduct a risk assessment of consumption of steroid hormones in cow's milk, by combining relevant toxicological data with data concerning hormone levels in cow's milk and epidemiological data on milk consumption.

Analytic techniques such as HPLC-MS/MS, cell culture, co-culture studies, various molecular biological techniques such as MTT, DNA/RNA isolation, RT-PCR, gel electrophoresis and gene studies by Microarray.

In milk, a major component of the Western diet, growth factors and sex steroids such as estrogens are found in relatively high concentrations. A discussion is ongoing about the risks of the consumption of low concentrations of estrogens found in dairy products in relation with fertility problems and hormone-dependent cancers in the Western world. Analytical studies are done to determine the bioavailability of these estrogens. Afterwards the effects of these compounds are studied in vitro, using a co-culture system consisting of a colon cell line and breast cancer cell line. Estrogens will also be studied in vivo by exposing prepubertal Sprague-Dawley rats, looking at the endpoints gene expression and blood analysis for. Estrogens will be studied separately as well as in biologically relevant mixtures, as can be found in milk, in human plasma or urine.

Biologically relevant target tissues for estrogens in milk are the gastro-intestinal tract and breast tissue. Hence, the effects of estrogens on these particular tissues, mainly focused on genotoxicity and apoptosis, are of interest in this project.

Also an intervention study will be done, in order to assess changes in steroid hormone levels after consuming cow's milk and the human inter- and intra individual variability.