| The purpose of this study was to determine the effects of long term walnut consumption on plasma levels of tocopherols and the inflammatory mediators interleukin-1beta (IL-1beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and C-reactive protein (CRP) in healthy participants. Ninety participants were recruited into a 12-month randomized crossover intervention study, which consisted of two phases, the walnut supplemented diet and the habitual diet. Participants were randomly assigned to either of these two phases for six months and then switched to the other phase for the second six months. During the walnut supplemented diet phase, participants incorporated walnuts (28--56 g/d) equal to 12% of their daily energy intake into their habitual diet. Plasma concentrations of alpha-tocopherols were significantly decreased but gamma-tocopherol level was insignificantly increased during walnut supplemented diet. However, the ratio of gamma-tocopherol to cholesterol was significantly higher on the walnut supplemented diet. In addition, data from preliminary analysis on correlation of gender, age and BMI on CRP showed linear effect of BMI to log (CRP) (beta = 0.088 +/- 0.029, p = 0.002), however, no effect of gender and age on CRP levels were found. CRP levels were almost 50% lower in the group of NSAIDs and vitamin E supplement users. Moreover, the walnuts supplemented diet together with vitamin E supplement elevated CRP level by 22.72%. After excluding usage of fish oil, vitamin E supplement and NSAIDs, thirty participants were qualified for the inflammatory mediator analysis. There was no significant change in any of the plasma e-selectin and TNF-alpha level. However, IL-1beta and IL-6 were significantly decreased during the walnuts supplemented diet (p < 0.05). In conclusion, the addition of walnuts for 12% of daily energy intake into the diet did not increase plasma gamma-tocopherol, but decreased alpha-tocopherol level significantly. Moreover, IL-1beta and IL-6 were decreased significantly with this amount of walnuts intake. |
