Are the associations between diet and C-reactive protein independent of obesity?

Objectives To determine the relative magnitude of the effect of dietary factors on circulating C-reactive protein (CRP) levels, controlling for BMI. Methods 1808 men and 2269 women attended the 1994/95 follow-up survey from the Busselton Health Study, Australia. A composite diet score was derived from a short questionnaire. Height and weight were measured. Results After controlling for BMI, CRP levels were associated with red meat intake (males only, p = 0.001), fruit intake (males p < 0.0001, females p = 0.029), potato intake (males p = 0.008, females p = 0.029), using wholemeal bread (males p = 0.014, females p = 0.018), using polyunsaturated fats as a spread and in cooking (females only, p = 0.005), and rarely or never adding salt to food (males p = 0.012, females p = 0.004). The overall diet score was significantly (negatively) related to CRP in males (p < 0.0001) and females (p < 0.0001). The relative decrease in CRP from a moderately healthy diet, compared to an unhealthy diet was 37% in men and 24% in women. This was comparable to a difference in BMI of at least 3 kg/m2 (or a difference in weight of approximately 9 kg for a person of average height). Conclusion A healthy diet and lower weight have independent beneficial effects of similar magnitude on CRP levels.