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Diet and Inflammatory Mediators

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Individuals after SCI commonly experience chronic inflammation (Allison & Ditor, 2015). This prolonged state of elevated inflammation is associated with immune impairment which can lead to infections and other dysfunctions (Allison et al., 2017). Inflammation is measured by serum levels of certain pro-inflammatory cytokines, such as interleukin and interferon gamma (Hayes et al., 2002). Two methods of reducing inflammation are exercise and diet modification however, SCI individuals often have difficulty participating in exercise (Allison et al., 2018). Several supplements have been identified to have anti-inflammatory properties in uninjured individuals (Galland, 2010). These supplements, such as omega-3 and fatty acids, and anti-inflammation dietary changes have not been studied at length in SCI populations. The following studies have been identified and meet inclusion criteria, examining anti-inflammation diet changes and supplements in SCI.

Table 7 Diet and Inflammatory Mediator Effects
Discussion

Allison et al. (2017) conducted an RCT investigating the effects of an anti-inflammatory diet intervention in SCI individuals. The control group individuals continued their normal diets, where the treatment group eliminated inflammation inducing foods such as foods with high glycemic indices (refined wheat and sugar products), food with common intolerances (milk), and unhealthy food such as hydrogenated oils (Allison et al., 2017). The treatment group participants also consumed anti-inflammatory diet supplements (such as omega-3, chlorella, and antioxidants) up to three times a day depending on the supplement and dosage (Allison et al., 2017). The diet intervention program lasted for 12-weeks. The participants completed detailed 7-day diet records at baseline, and 3-day records at one, two, and three month follow-ups. Outcomes included measuring inflammatory serum markers and nerve conduction (Allison et al., 2017). While the authors found significant reduction in inflammation serum markers in the treatment group, there was no significant interaction effect found between-groups over time for motor nerve conduction (Allison et al., 2017). This study highlights a reduction in known inflammatory serum markers in SCI individuals after an anti-inflammatory dietary intervention, but no significant improvement was seen on motor nerve conduction (Allison et al., 2017). The authors followed-up this study with a secondary analysis investigating the changes in nutrient intake and their relationship with different inflammatory serum markers (Allison et al., 2018). The main findings of this secondary analysis indicate that reducing calories, significantly reducing fats, increasing protein, while no significant change in carbohydrate intake lead to reductions in inflammatory serum biomarkers. When looking at supplements, vitamins A, carotenoids, zinc, and omega-3 were associated with a reduction in serum biomarkers indicating inflammation (Allison et al., 2018). The authors discuss similarities of their diet intervention to the ‘Mediterranean diet’ which has been studied in healthy controls. The Mediterranean diet consists of lowering excess sugar, and red and processed meats, emphasizing ingestion of olive oil, fresh fruits and vegetables, fish and white meats (Estruch et al., 2013). The authors highlight a need for more studies to be conducted with anti-inflammatory diet changes in SCI individuals to better understand the potential benefits.

 

Conclusion

There is level 1b evidence (from one RCT and one secondary RCT analysis; Allison et al., 2017;2018) that a diet intervention focusing on anti-inflammatory diet changes and supplements can reduce inflammatory serum markers, but did not show improvement in motor nerve conduction compared to a control group.

  • A diet intervention focusing on anti-inflammatory foods and supplements can reduce inflammation serum markers, but may not show improvement in motor nerve conduction.