The randomized crossover study included 35 participants who were assigned to follow either a high-fiber diet or a fiber-supplemented diet. Both diets included 30 grams of fiber per day. Eighteen of the subjects were lean and with normal blood pressure and 17 were obese with elevated blood pressure.
Overall, average CRP levels decreased by 13.7 percent in the high-fiber diet group and by 18.1 percent for the fiber-supplemented diet group. Unexpectedly, when the lean and the obese participants were considered separately, differences in the CRP response were observed. In lean individuals, CRP levels decreased by 30 percent when consuming the high-fiber diet and 40 percent when consuming the fiber-supplemented diet. In the obese participants, no significant change in CRP levels was observed for either diet.
Although more research is needed to explain the different effects seen in the lean versus obese individuals, the present study supports the assertion that high-fiber intakes are beneficial in reducing the risks of heart disease and diabetes.