Molecular mechanisms of beta-carotene action in the lung

Beta-carotene is a health improving substance that is often found by nature in vegetables and fruit, and is used as an orange colouring agent in nutrients or as an addition to vitamin preparations. Intake of an unnaturally high dose of beta-carotene involves an increased lung cancer risk in smokers or in people who are exposed to asbestos. This dissertation describes various mechanisms that could be involved there. It is shown that beta-carotene could have a negative effect on DNA damage caused by inflammations. Research with a unique humanized mouse model also shows that male and female mice react oppositely to beta-carotene. In male mice a new beta-carotene-sensitive process was discovered that could play a role in the origin of lung cancer. Most found effects, however, indicated health protection by beta-carotene. Therefore, the explanation for the negative effects can possibly be found in the presence or absence of chronic infections.