ß-carotene conversion products and their effects on adipose tissue

Recent epidemiological data suggest that ß-carotene may be protective against metabolic diseases in which adipose tissue plays a key role. Adipose tissue constitutes the major ß-carotene storage tissue and its functions have been shown to be modulated in response to ß-carotene breakdown products, especially retinal produced after cleavage by ß-carotene 15,15'-monooxygenase (BCMO1), and retinoic acid arising from oxidation of retinal. However, the possibility exists that ß-carotene in its intact form can also affect adipocyte function. Development of a knock out model and identification of a loss-of-function mutation have pointed out BCMO1 as being probably the sole enzyme responsible for provitamin A conversion into retinal in mammals. The utilisation of BCMO1-/-mice should provide insights on ß-carotene effect on its own in the future. In humans, intervention studies have highlighted the huge interindividual variation of ß-carotene conversion efficiency, possibly due to genetic polymorphisms, which might impact on response to ß-carotene. This brief review discusses the processes involved in ß-carotene conversion and the effect of cleavage products on body fat and adipose tissue function