Having fat decreases the ability of a good diet to decrease inflammation (CRP)

Researchers at the University of Porto in Portugal found a protective effect for fruit, vegetables, vitamin C, and fiber against elevations in C-reactive protein (CRP), a marker of inflammation which is used as a predictor of cardiovascular disease risk.

The study included 385 men and 675 women residing in Portugal . Questionnaires completed by the subjects concerning dietary intake over the previous year were analyzed for the intake of fruit, vegetables, carotenoids, vitamin C, vitamin E and fiber. Participants' serum CRP levels were categorized as low at less than 1.0 mg/L; moderate, at 1.0 to 3.0 mg/L; and high at over 3.0 mg/L.

In men whose weight was normal there was a 30 % lower probability of being categorized in a higher CRP category with every 100 g increase in fruit and vegetable intake. Vitamin C, carotenoids, fiber, and fruit and vegetables separately showed protective benefit. No significant associations were found for women who tended to be higher in CRP in general.

In their discussion, the authors remark that women's body fat, which tends to be proportionally greater than men's, is a source of proinflammatory cytokines which could be responsible for the greater amount of inflammation documented in this group. The same explanation was suggested for the lack of a positive effect associated with the nutrients analyzed in this study in overweight men, in whom increased inflammation is likely to overcome potential benefits. The study is published in the November 2009 issue of the European Journal of Clinical Nutrition .