Inflammatory polyarthritis (IP) often progresses to rheumatoid arthritis (RA), a debilitating condition affecting a relatively large segment of the population. Preventative steps to combat this condition are likely dietary in nature, such as a high intake of vitamin C or fruits. This can be explained by the theory that the pathogenesis of RA and many inflammatory disorders is linked to oxidative damage. Therefore, higher intakes of antioxidants like vitamin C should decrease the risk of developing such conditions. A study published in the American Journal of Clinical Nutrition (2005;82(2):451-455) shows that higher dietary intakes of B-cryptoxanthin is associated with decreased risk of developing inflammatory polyarthritis. B-cryptoxanthin is a carotenoid that has also shown a protective effect against developing RA in the large Iowa Women's Health Study. Researchers wanted to examine this association in the development of IP.
A case-controlled study was undertaken as part of the Norfolk arm of the European Prospective Investigation of Cancer Incidence study (EPIC-Norfolk), an ongoing study involving more than 25000 subjects. These subjects were under ongoing surveillance for detection of new cases of IP, and for this study 88 subjects with newly diagnosed IP were identified and matched with controls. Participants completed a detailed diet diary for 7 days to assess the dietary intakes of various carotenoids. The results showed that the median B-cryptoxanthin intake was almost 40% lower and zeaxanthin 20% lower in subjects with IP than in controls. However, there were no significant differences in the intakes of B-carotene, lutein, and lycopene (other carotenoids). Vitamin C intake was corrected for, demonstrating that the association is independent of this potent antioxidant.
B-cryptoxanthin is found in significant quantities in oranges, bell peppers, and some tropical fruit. There are also carotenoid supplements containing B-cryptoxanthin and zeaxanthin, and some multi-vitamin/mineral supplements also contain these compounds.
Posted by Kristopher Foster on February 20, 2006 06:27 PM
