Poster Topical Area: Nutritional Immunology
Location: Hall D
Poster Board Number: 827
Objectives: Obesity is often associated with impaired immune responses, which may lead to increased susceptibility to infection. Bioactive compounds found in various fruits and vegetables (F&V) have been shown to have strong anti-inflammatory and anti-oxidant effects, and some micronutrients in F&V could positively regulate immune functions. However, few intervention studies have examined the effects of F&V on preventing obesity-associated dysregulation of immune and inflammatory responses. The objectives of this study was to determine the impact of a high fat diet (HFD) supplemented with different levels of a mixture of F&V (0-15% w/w) on immune and inflammatory responses. The 15% F&V corresponds to currently recommended daily F&V consumption for humans.
Methods: We formulated a unique F&V mixture containing 24 F&V, and fed mice a high-fat diet (HFD) alone (obesogenic), or together with 0-15% (w/w) F&V (HFD + F&V) for 20 weeks. Serum cytokine ELISAs were performed using electrochemiluminescent multiplex assays. Flow cytometry immunophenotyping was used to determine the percent of CD4+ and CD8+ T cells in spleen. Splenic lymphocyte proliferation was measured using 3H-thymidine incorporation assay.
Results: We found that the mice fed HFD had significantly higher weight gain than those fed the low fat control diet (LFD). However, mice fed HFD+ F&V had significantly less weight gain compared to those fed HFD. Compared to mice fed HFD alone, mice fed HFD + F&V had lower spleen weight and spleen weight index, which was calculated as mg spleen/g body weight. HFD-fed mice also had significantly lower serum concentrations of IL-6 and IL-10 and lower percent of CD4+ and CD8+ T cells in spleen and lower levels of lymphocyte proliferation induced by Con A or anti-CD3/anti-CD28 stimulation compared with the LFD. F&V supplementation partially prevented these changes including maintaining percent of CD8+ T cells and lymphocyte proliferation.
Conclusions: These results suggest that increased consumption of F&V may be beneficial in preventing HFD-associated dysregulation of immune and inflammatory responses. These effects might be mediated by F&V induced changes in weight gain and/or a direct effect of higher level of immune enhancing nutrients in F&V.
This material is based upon work supported by the U.S. Department of Agriculture – Agricultural Research Service (ARS), under Agreement No. 58-1950-4-003.
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