Antioxidants no help vs rheumatoid arthritis, lupus

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Antioxidants no help vs rheumatoid arthritis, lupus

http://www.reuters.com/article/idUSTRE65T4TJ20100630

(Reuters Health) - Antioxidants in food and supplements might not protect

women from rheumatoid arthritis (RA) or lupus after all, a large U.S. study

suggests.

RA is not the same as osteoarthritis, which develops with age or with

wear-and-tear on the joints. RA occurs much less often, but is usually more

severe. RA and lupus are both autoimmune disorders.

The researchers tracked nearly 185,000 women for up to 24 years. Overall,

they found no clear relationship between the women's estimated intake of

antioxidants -- including vitamins A, C and E and beta-carotene -- and their

likelihood of being diagnosed with RA or lupus.

The findings contradict hints from earlier research that women with higher

intake of antioxidants might have lower risks of developing these diseases.

One reason for checking whether antioxidants in the diet would have an

effect is that people with RA and lupus have lower antioxidant levels in

their blood than healthy individuals. And studies in mice have shown that

giving antioxidants helps reduce the type of immune-system-triggered

inflammation that's associated with these diseases.

Not only do antioxidants help control inflammation, but they also protect

body tissue from potentially cell-damaging particles called reactive oxygen

species.

But in the new study reported in the American Journal of Epidemiology,

researchers found no link between the women's reported antioxidant intake

and their risk of developing RA or lupus. The women were participating in

the Nurses' Health Study and Nurses' Health Study II, two large projects

that have tracked lifestyle factors and disease risk among nearly 240,000

U.S. women since 1976 and 1989, respectively.

The study had its limitations -- including the fact that it was

observational. The researchers merely asked the women about their

antioxidant intake and then observed what happened to them over time, so the

outcomes may just be coincidental. A study in which participants are

randomly assigned to take antioxidant supplements or not, then have their RA

and lupus rates followed over time, would provide stronger evidence as to

whether the nutrients affect the risk of developing the diseases.

Nor can the findings exclude the possibility that significant deficiency in

certain antioxidants might play a role in RA or lupus risk, note the

researchers, led by Dr. H. Costenbader of Brigham and Women's Hospital

in Boston.

Lupus -- known formally as systemic lupus erythematosus -- involves painful,

swollen joints, fatigue and skin rash, but it can also damage other parts of

the body, including the heart and blood vessels. RA arises when the immune

system mistakenly attacks joints all over the body, leading to inflammation,

pain and progressive joint damage.

Costenbader's team focused on 184,643 women who were free of RA or lupus at

the outset and had completed detailed questionnaires on their diets and

supplement use starting in 1980 or 1991, depending on the study.

The researchers used those reports to estimate the women's daily intakes of

vitamins A, C and E, as well as alpha- and beta-carotene, lycopene, lutein,

beta-cryptoxanthin and zeaxanthin.

Between 1980 and 2004, 787 women were newly diagnosed with RA, while 192

were diagnosed with lupus.

Women with higher antioxidant intakes did tend to maintain a healthier

lifestyle overall, the study found. They were generally more physically

active and less likely to smoke, for example. When those factors were taken

into account, antioxidant consumption itself showed no strong relationship

to RA or lupus risk.

This finding, of course, does not negate the importance of eating

antioxidant-rich foods for one's overall health. Foods high in the

antioxidants assessed in this study include citrus fruits, leafy greens like

spinach and kale, cruciferous vegetables like broccoli and Brussels sprouts,

and red or orange fruits and vegetables like carrots, watermelon and sweet

potatoes.

SOURCE: link.reuters.com/jax94m

American Journal of Epidemiology, online June 9, 2010.