title: Selenium and Zinc Status in Chronic Myofascial Pain: Serum and Erythrocyte Concentrations and Food Intake.
abstract: BACKGROUND
  Nutritional disorders have been reported to be important causal factors that can intensify or cause a painful response in individuals with chronic musculoskeletal pain.
  
  
  OBJECTIVE
  To assess the habitual intake of and the serum and erythrocyte levels of selenium and zinc in patients with chronic myofascial pain.
  
  
  METHODS
  A case-control study of 31 patients with chronic myofascial pain (group I) and 31 subjects without pain (group II). Dietary record in five days for assessing food intake were used. The serum and erythrocyte concentrations of selenium and zinc were analyzed using an atomic absorption spectrophotometry. Pain intensity was assessed using a visual analog scale.
  
  
  RESULTS
  The group of patients with chronic myofascial pain, compared with the control group, showed a lower erythrocyte concentration of selenium (79.46 ± 19.79 μg/L vs. 90.80 ± 23.12 μg/L; p = 0.041) and zinc (30.56 ± 7.74 μgZn/gHb vs. 38.48 ± 14.86 μgZn/gHb, respectively; p = 0.004). In this study, a compromised food intake of zinc was observed in the majority of the subjects in both groups. The selenium intake was considered to be safe in 80% of the subjects in both groups; however, the likelihood of inadequate intake of this mineral was twice as high in group I (49.5% vs. 24.4%, respectively). In the logistic regression analysis, the erythrocyte concentration of zinc was associated with the presence of pain. In each additional 1 mg of Zn2+ per gram of hemoglobin, a reduction of 12.5% was observed in the risk of the individual having chronic myofascial pain (B = -0.133; adjusted OR = 0.875, 95% CI = 0.803 to 0.954, Wald = 9.187, standard error = 0.044, p = 0.002). Physical inactivity and obesity were noted more commonly in group I compared with the control group.
  
  
  CONCLUSIONS
  In this study, patients with chronic myofascial pain showed lower intracellular stores of zinc and selenium and inadequate food intake of these nutrients.
authors.affiliation: College of Nutrition, Federal University of Alagoas, Maceió, Alagoas, Brazil.
authors.forename: João Araújo
authors.initials: JA
authors.lastname: Barros-Neto
authors.affiliation: Institute of Health Sciences, Federal University of Bahia, Salvador, Bahia, Brazil.
authors.forename: Adelmir
authors.initials: A
authors.lastname: Souza-Machado
authors.affiliation: College of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil.
authors.forename: Durval Campos
authors.initials: DC
authors.lastname: Kraychete
authors.affiliation: College of Nutrition, Federal University of Bahia, Salvador, Bahia, Brazil.
authors.forename: Rosangela Passos de
authors.initials: RP
authors.lastname: Jesus
authors.affiliation: Multidisciplinary institute in health, Federal University of Bahia, Vitória da Conquista, Bahia, Brazil.
authors.forename: Matheus Lopes
authors.initials: ML
authors.lastname: Cortes
authors.affiliation: Multidisciplinary institute in health, Federal University of Bahia, Vitória da Conquista, Bahia, Brazil.
authors.forename: Michele Dos Santos
authors.initials: MD
authors.lastname: Lima
authors.affiliation: University Center Estácio FIC, Department of Nutrition, Fortaleza, Ceará, Brazil.
authors.forename: Mariana Carvalho
authors.initials: MC
authors.lastname: Freitas
authors.affiliation: Federal Institute of Alagoas, Maceió, Alagoas, Brazil.
authors.forename: Tascya Morganna de Morais
authors.initials: TM
authors.lastname: Santos
authors.affiliation: College of Pharmacy, Federal University of Bahia, Salvador, Bahia, Brazil.
authors.forename: Gustavo Freitas de Sousa
authors.initials: GF
authors.lastname: Viana
authors.affiliation: College of Pharmacy, Federal University of Bahia, Salvador, Bahia, Brazil.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Menezes-Filho
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D015992:Body Mass Index; D016022:Case-Control Studies; D002908:Chronic Disease; D004032:Diet; D004435:Eating / Q000502:physiology*; D004912:Erythrocytes / Q000737:chemistry*; D015444:Exercise; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D010146:Pain / Q000473:pathology*; D012643:Selenium / Q000032:analysis / Q000097:blood*; D012907:Smoking; D015032:Zinc / Q000032:analysis / Q000097:blood*
chemical_list: D006454:Hemoglobins; D012643:Selenium; D015032:Zinc