Silicon intake and plasma level and their relationships with systemic redox and inflammatory markers in rheumatoid arthritis patients

Anna Prescha,Halina Grajeta,Sylwia Płaczkowska,Daiva Gorczyca,Katarzyna Zabłocka-Słowińska,Anna Łuczak

doi:10.17219/acem/105380

Abstract

The nutritional significance of silicon for the human body is highlighted by a continually growing body of evidence. In conditions of excessive reactive oxygen species and upregulated immune response, silicon has been observed to provide benefits, but its role in redox and inflammatory status has not yet been examined in rheumatoid arthritis (RA). The aim of this study was to assess the relationship of silicon intake and plasma level to systemic indices of redox status and inflammation in patients with RA. Silicon intake and plasma levels were measured in 115 RA subjects and 129 control subjects. Serum antioxidant and oxidant levels, antioxidant enzyme activity, and albumin, uric acid, TBARS, hs-CRP, and IL-6 levels were measured and compared to the intake and plasma levels of silicon. Silicon intake and plasma silicon levels were higher in RA subjects than in the controls. In the RA group, a generally favorable correlation to redox and inflammatory markers was found for silicon in diet and in plasma; however, albumin level, smoking status, and gender interfered with these results. In the control subjects, a significant relationship was observed only between plasma silicon and non-enzymatic markers of redox status. There are suggestions of silicon's involvement in managing redox and inflammatory status in RA, though further studies are warranted.

Highlights

A growing body of evidence suggests that silicon is essential to the human body, supported recently by the identification of the cellular silicon influx and efflux system.[1,2] Orthosilicic acid diluted in water and soluble dietary silicates are both absorbed by the intestines
Silicon intake and plasma silicon levels were higher in rheumatoid arthritis (RA) subjects than in the controls
In the RA group, a generally favorable correlation to redox and inflammatory markers was found for silicon in diet and in plasma; albumin level, smoking status, and gender interfered with these results

Summary

Introduction

A growing body of evidence suggests that silicon is essential to the human body, supported recently by the identification of the cellular silicon influx and efflux system.[1,2] Orthosilicic acid diluted in water and soluble dietary silicates are both absorbed by the intestines. Solid plant foods, such as cereals and certain vegetables, provide silicon in the form of the less absorbable phytolytic silica, but the high silicon content makes them important dietary sources of this element.[3,4] The food industry utilizes silicon compounds as food additives, in the form of food-grade amorphous silica, silicates, and polymethylosiloxane, which can substantially increase the amounts of silicon in one’s diet.[5] The body retains silicon mainly in connective tissues, including bone, cartilage, skin, and the aortal wall.[1] Orthosilicic acid circulating in the blood is thought to be predominantly unbound to protein.[6]. In conditions of excessive reactive oxygen species and upregulated immune response, silicon has been observed to provide benefits, but its role in redox and inflammatory status has not yet been examined in rheumatoid arthritis (RA)

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