Association between creatine kinase activity, oxidative stress and selenoproteins mRNA expression changes after Brazil nut consumption of patients using statins.

Background & Aims: Although the mechanisms by which statins promote muscle disorders remain unclear, supplementation with dietary antioxidants may mitigate statins' side effects. This study aimed to investigate whether the consumption of Brazil nuts modulates serum creatine kinase (CK) activity in patients regularly using statins.
Methods: The study was performed in the Ribeirão Preto Medical School University Hospital. Thirty-two patients in regular use of statins were divided according to CK activity levels (G1: increased or G2: normal) and received one unit of Brazil nut daily for 3 months. Body composition, blood selenium (Se) concentrations, erythrocyte glutathione peroxidase (GPX) activity, oxidative stress parameters, and CK activity were evaluated before and after supplementation.
Results: In both groups, supplementation with one Brazil nut daily for 3 months contributed to achieve decreased levels of CK activity in serum, with positive changes in plasma and erythrocyte Se concentrations (p < 0.0001), and increased levels of GPX activity. Among the parameters related to curbing of oxidative stress, we observed reduced levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in both groups after supplementation. We also found a moderately negative association between CK and GPX activity (r = -41; p < 0.02). Expression of selenoproteins GPX1, SELENOP, and SELENON after Brazil nut supplementation was unchanged.
Conclusion: Brazil nut consumption enhanced the control of CK activity by improving oxidative stress biomarkers in patients using statins but did not modulate mRNA expression of selenoproteins.
Competing Interests: Conflict of Interest The authors declare they have no financial conflict of interest.
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