Effects of Selenium Supplementation in Patients with Mild Cognitive Impairment or Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Abstract

Elevated levels of oxidative stress could cause and aggravate Alzheimer’s disease (AD). Selenium (Se) is a trace element with antioxidant and anti-inflammatory activity with neuroprotective effects. To evaluate the effects of Se supplementation in patients with AD or mild cognitive impairment (MCI) through a systematic review and meta-analysis, data were searched and collected from four electronic databases, including clinical trial studies published until December 2020, following the PRISMA guidelines. Statistical analysis was performed by RevMan, and the risk of bias was assessed using the Rob 2 tool. A total of 1350 scientific papers were collected, and following evaluation 11 papers were included in the systematic review and 6 of these were used in the meta-analysis. Studies that evaluated only Se supplementation observed an improvement in Se levels, glutathione peroxidase (GPX) activity, and in some cognitive tests in MCI patients; similarly, improvement in Se levels and mini-mental score was also observed in AD patients. Regarding supplementation of Se plus other nutrients, improvement in cognitive tests was observed in both AD and MCI patients. Therefore, Se supplementation is a good alternative for patients with AD and MCI for improving Se levels and GPX activity. More detailed studies are required to further evaluate the effects of Se on the cognitive deficit and oxidative stress associated with AD and MCI.

First-in-Class Selenium-Containing Potent Serotonin Receptor 5-HT6 Agents with a Beneficial Neuroprotective Profile against Alzheimer’s Disease

“…Condensation reactions were carried out according to a method described previously, 40,51 utilizing purification on flash chromatography, crystallization from water, or transformation into the corresponding crystalline hydrochloric salts. Spectral ( 1 H, 13 C, 77 Se NMR) and chromatographic (LC/MS) analytical methods confirmed the structures and purity (>95%) of the final compounds.…”

“…1 H NMR and 13 C NMR spectra were routinely recorded in DMSO-d 6 at 500 and 126 MHz, respectively, in the basic form of final compounds (except 9, 10, and 15, for which spectra were recorded for hydrochlorides) on an FT-NMR 500 MHz JEOL (JNM-ECZR500 RS1 version ECZR) apparatus. 77 Se NMR spectra were recorded in DMSOd 6 at 95 MHz on an FT-NMR 400 MHz Bruker Avance spectrometer. Spectroscopy was carried out at ambient temperature using the solvent signal as an internal standard.…”

“…The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.jmedchem.3c02148. Synthesis of compound 15O; HPLC traces, mass spectra, and 1 H, 13 C, and 77 Se NMR spectra of final compounds 3, 6−15, 15O, and 17; Table S1…”

“…Indeed, selenium plays various roles in the progression of some neurodegenerative diseases such as AD. , It is crucial for the activity of glutathione peroxidase (GPx), which is responsible for protecting organisms from oxidative damage; studies show that supplementation with this element is beneficial for patients with AD and mild cognitive impairment . The toxicity of organoselenium compounds strongly depends on the selenium oxidation state and types of substituents .…”

The role of nutrition in the prevention of cognitive decline

“…Concerning carotenoids, a recent meta-analysis showed a statistically significant improvement in cognitive functions after the administration of carotenoids in healthy individuals [41]. Regarding selenium supplementation (alone or with other nutrients) in Alzheimer's disease and MCI individuals, some cognitive improvements were observed but were not statistically significant according to the meta-analysis findings (Table 1) [42 ▪▪ ].…”