Prior studies have suggested that the antioxidant potential of dietary carotenoids may protect against the oxidative damage that can result in inflammation.
A team from the University of Manchester and the University of Cambridge in the UK analysed data from the European Prospective Investigation of Cancer Incidence (EPIC)-Norfolk study, a study of more than 25000 subjects who completed a baseline seven-day diet diary.
They were followed up to identify new cases of inflammatory polyarthritis, which was defined as synovitis that affected at least two or more joint groups.
The average daily intake of beta-cryptoxanthin was 40 per cent lower in those who developed the condition than the 176 controls without, while zeaxanthin intake was 20 per cent lower, write the researchers in this month's issue of the American Journal of Clinical Nutrition (vol 82, no 2, pp451-455).
People in the top one-third of beta-cryptoxanthin intake were almost half as likely to develop the condition as those in the lowest third, and this association was still significant after adjustments were made for total energy and protein intakes and for cigarette smoking.
"These data are consistent with previous evidence showing that a modest increase in beta-cryptoxanthin intake, equivalent to one glass of freshly squeezed orange juice per day, is associated with a reduced risk of developing inflammatory disorders such as rheumatoid arthritis," conclude the researchers.
Rheumatoid arthritis affects one in 100 people in the UK.
In 2003, researchers using data from the Iowa Women's Health study found that women who consumed less than 40 micrograms of beta-cryptoxanthin were at a slightly higher risk of developing rheumatoid arthritis than women who consumed more than that amount.