Low blood selenium: A probable factor in essential hypertension

The possible association between selenium and essential hypertension was investigated in this study. Blood selenium (BSe) and plasma glutathione peroxidase (plGSH-Px) activity were measured asbiochemical markers of selenium status of 103 hypertensive patients (44 males and 59 females) and 88 apparently healthy subjects (40 males and 48 females). The hypertensive patients were classified intothree groups based on the severity of the disease namely: mild (Group 1), moderate (Group 2) and severe (Group 3). The healthy and the hypertensive subjects were recruited from Abeokuta and Ibadan(South-Western Nigeria). The mean age of the hypertensive patients was 41.9 ± 10.3 (range 21 – 68) years, while the mean age of the healthy subjects was 37.8 ± 8.6 (range 18 – 52) years. The weight,height, blood pressure and pulse rates of all subjects were measured and their body mass indices (BMI) computed. BSe was determined by atomic absorption spectrophotometry (AAS) while plGSH-Px activitywas measured by spectrophotometric method. The mean BSe concentration was significantly lower in the hypertensive patients (0.136 ± 0.028 mg/L) than in the healthy group (0.188 ± 0.026 mg/L) (P < 0.001). However with respect to plGSH-Px activity, there was no statistically significant difference between the hypertensive patients (0.126 ± 0.019 U/mL) and the healthy group (0.127 ± 0.022 U/mL). Blood Selenium concentration was found to decrease with the severity of the disease. The difference in BSe concentration of Group 1 and Group 2 patients was not significant. However, there were significantdifferences in the BSe levels of Group 2 and Group 3 patients (P < 0.05) and Group 1 and Group 3 patients (P < 0.05). The observed low BSe in hypertensive subjects implies that low BSe is probably a predisposing factor to essential hypertension or a consequence of the disease. The severity of the disease was also observed to be inversely related to the level of BSe, suggesting that BSe level may have a role in the prognosis of the disease. Alteration in BSe status appears to confirm the elemental basis of the aetiopathogenesis of certain diseases. Despite the reduction in BSe level in the hypertensive patients, it was still adequate to maintain plGSH-Px activity at a level comparable to thoseof the healthy group. This suggests that BSe may exist in another functional form, which plays a role in the pathogenesis or prognosis of the disease