CDC’s Division of Laboratory Sciences coordinates the National Biomonitoring Program (NBP) which offers an assessment of nutritional status and the exposure of the U.S. population to environmental chemicals and toxic substances.
it can be concluded that "Finding a measurable amount of parabens in urine does not imply that they cause an adverse health effect". In other words, unlike insoluble / inert preservatives, you excrete parabens and if you don't consume them regularly your body can get rid of it. That being said, it does increase the risk for some diseases, which is not to say there is conclusive evidence it causes such diseases. Like most substances, there are toxic levels determined by trials*. In the EU, there are maximum daily intake levels considered safe, by which also Nivea must abide, so don't freak out.