Selenium's Role in Brain Health

The Role of Selenium in Neurological Health

In this episode of The Dr. Ardis Show, Dr. Brian Ardis presents a comprehensive review of medical literature suggesting that a single mineral—Selenium—is critical in preventing and reversing symptoms of Alzheimer’s, Parkinson’s, and Multiple Sclerosis (MS). Dr. Ardis argues that Selenium deficiency is a primary driver of cognitive decline and that supplementation can mimic the neuroprotective benefits of exercise.

The Mechanism: Oxidative Stress and Neurogenesis

Dr. Ardis explains that the brain is highly susceptible to oxidative stress, a key factor in neurodegenerative diseases. Selenium is required to synthesize selenoproteins and glutathione peroxidase, which act as the body’s primary defense against oxidative damage and inflammation.

Furthermore, research cited in the episode highlights that Selenium stimulates neurogenesis (the growth of new neurons) in the hippocampus, the area of the brain responsible for memory and learning.

Key Research Findings

• ** The Exercise Connection:** Studies on mice revealed that physical exercise improves brain function by increasing the transport of Selenium to the brain. Crucially, researchers found that administering Selenium without exercise resulted in the same increase in neural precursor cells—effectively doubling or tripling the number of new neurons. This suggests Selenium is a viable therapy for elderly or disabled individuals unable to exercise.

• Alzheimer’s Disease: A systematic review of human studies showed that Alzheimer’s patients consistently exhibit lower Selenium levels in their plasma and red blood cells compared to healthy controls. Supplementation significantly increased Selenium levels in the Cerebral Spinal Fluid (CSF) and improved cognitive test scores (such as the MMSE and ADAS-Cog), often outperforming multivitamins that contained lower doses.

• Parkinson’s Disease: The transcript details how Selenium protects the nigrostriatal pathway, a dopamine pathway essential for motor control.



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Degeneration in this pathway leads to Parkinson's symptoms like tremors and rigidity. Studies indicated that Selenium deficiency exacerbates damage to dopamine neurons, while supplementation reduced DNA damage and improved motor function.

Thyroid and General Health

Dr. Ardis reiterated a foundational point regarding thyroid health: the thyroid cannot synthesize hormones (T3 and T4) without three specific components—Selenium, Iodine, and the amino acid Tyrosine. He suggests that many thyroid conditions are actually untreated Selenium deficiencies.

Dosage and Recommendations

The episode concludes with practical advice on dosage. While the FDA recommends a daily limit of roughly 200–400 mcg, Dr. Ardis discusses the safety of higher doses for therapeutic purposes, citing experts who suggest up to 1.2 mg may be safe. However, the standard recommendation provided is 200 mcg per capsule, suggesting 2 capsules (400 mcg) daily for those with neurological concerns to restore cognitive function and protect against oxidative stress.

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Annotated Bibliography: Selenium and Neuroprotection

Akbaraly, T. N., Hininger-Favier, I., Carrière, I., Arnaud, J., Gourlet, V., Roussel, A. M., & Berr, C. (2007). Plasma selenium over time and cognitive decline in the elderly. Epidemiology, 18(1), 52–58.

Transcript Context: Referred to as the "EVA Study" (Epidemiology of Vascular Aging), this 9-year longitudinal study followed 1,389 elderly participants in France. Key Findings: The study established a longitudinal link between falling selenium levels and cognitive decline. Researchers found that participants with the greatest decrease in plasma selenium over the 9-year period had the highest probability of cognitive decline. Conversely, those who maintained or increased their selenium levels showed a protective effect against cognitive deterioration.

Cardoso, B. R., Ong, T. P., Jacob-Filho, W., Jaluul, O., Freitas, M. I., & Cozzolino, S. M. (2010). Nutritional status of selenium in Alzheimer's disease patients. British Journal of Nutrition, 103(6), 803–806.

Transcript Context: Dr. Ardis discusses this study to highlight the deficiency of selenium in diagnosed patients. Key Findings: This case-control study compared 28 elderly patients with Alzheimer’s Disease (AD) to 29 healthy controls. It found that selenium concentrations in plasma, erythrocytes (red blood cells), and nails were significantly lower in the Alzheimer’s group. The authors concluded that selenium deficiency is strongly associated with the pathology of AD, potentially due to the brain’s inability to combat oxidative stress without adequate selenoproteins.

Leiter, O., Zhuo, Z., Rust, R., Wasielewski, J. M., Grönnert, L., Kowal, S., ... & Walker, T. L. (2022). Selenium mediates exercise-induced adult neurogenesis and reverses learning deficits induced by injury and aging. Cell Metabolism, 34(3), 408–423.

Transcript Context: This is the foundational mouse model study cited regarding "exercise vs. supplementation." Dr. Ardis refers to the lead researcher, Dr. Tara Walker. Key Findings: The study discovered that the cognitive benefits of physical exercise are mediated by the transport of selenium to the brain via the protein selenoprotein P. Crucially, the researchers demonstrated that selenium supplementation alone (without exercise) could replicate these effects, tripling the number of neural precursor cells in the hippocampus and reversing cognitive deficits caused by aging and hippocampal injury.

Pereira, M. E., Souza, J. V., Galvao, J., & Oliveira, C. S. (2022). Effects of selenium supplementation in patients with mild cognitive impairment or Alzheimer’s disease: A systematic review and meta-analysis. Nutrients, 14(15), 3205.

Transcript Context: Dr. Ardis uses this systematic review to argue for the efficacy of selenium supplementation in humans. Key Findings: A meta-analysis of 11 clinical studies involving selenium supplementation. The review found that supplementation significantly raised selenium levels in the blood and cerebrospinal fluid (CSF). It also noted that patients taking selenium alone often showed greater improvements in cognitive scores (such as the MMSE and ADAS-Cog) than those taking selenium as part of a broader multivitamin, possibly due to dosage or absorption competition.

Solovyev, N. D. (2015). Importance of selenium and selenoprotein for brain function: From antioxidant protection to neuronal signalling. Journal of Inorganic Biochemistry, 153, 1–12.

Transcript Context: Cited to explain the biochemical mechanisms of selenium in the brain, specifically regarding the "nigrostriatal pathway" in Parkinson's and protection against neurotoxins. Key Findings: This review paper details how selenoproteins (like glutathione peroxidase) protect neurons from oxidative damage and modulate neurotransmission. It highlights selenium’s specific role in preserving the dopamine pathways involved in Parkinson’s disease and its ability to chelate and protect against neurotoxins like mercury and lead.

Hashtags: #Selenium, #BrainHealth, #Alzheimers, #Parkinsons, #Neuroprotection