How Selenium Protects Against Parkinson’s Disease—New Research

Simple dietary additions can boost selenium intake, making it easy for current patients and those at risk.

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Recent research sheds light on the promising connection between selenium, an essential mineral with antioxidant properties, and Parkinson’s disease. A cohort study published in May in BMC Geriatrics found that a moderate increase in selenium intake had a protective effect on Parkinson’s disease mortality.

The study’s findings suggest that including selenium-rich food in the diet positively influences the prognosis of the disease and may potentially mitigate the risk of developing Parkinson’s. The best part? Simple dietary additions can help increase selenium intake, making it an easily achievable goal for current patients and those at risk of developing the disease.

The Selenium and Parkinson’s Connection

The cohort study looked at data from 184 individuals ages 18 and older obtained from the National Health and Nutrition Examination Survey 2005–2006 to 2015–2016 and the National Death Index.

“We found that normal selenium intake had a positive effect on [Parkinson’s disease] prognosis compared with low selenium intake, but this effect disappeared when compared with high selenium intake,” the researchers wrote.

The authors concluded that Parkinson’s patients could benefit from increasing their intake of selenium-rich food or dietary supplements, but they noted that although patients with a low total daily selenium intake can benefit from a moderate increase, an excessively high intake from food or supplementation negates the protective effect.

Selenium may help protect against the development of Parkinson’s disease by reducing oxidative stress and inflammation in the brain. Research on the specific mechanisms is ongoing, but the protective effect of selenium on Parkinson’s disease has been demonstrated in animal models.

“Selenium administration increased levels of antioxidant enzyme and GSH [glutathione], reduced dopamine loss, maintains cellular DNA integrity and improved motor function recovery,” researchers wrote.

Selenium helps protect cells from damage caused by free radicals, which are harmful molecules that can contribute to the development of conditions such as Parkinson’s disease. Selenium acts as an antioxidant in the body, and antioxidants are known to counteract an imbalance of free radicals.

A cross-sectional study published in 2023 analyzed data from the National Health and Nutrition Examination Survey spanning from 2011 to 2020 for 15,660 people ages 40 and older. The results of the analysis were in line with the retrospective cohort study.

Analysis suggested a correlation between higher blood selenium levels and a lower incidence of Parkinson’s disease. The relationship between blood selenium and Parkinson’s showed a decrease in Parkinson’s risk being more significant at higher selenium levels than at lower concentrations. The rate of risk decline diminished notably as selenium levels increased.

Dr. Ramit Singh Sambyal, a general practitioner not associated with the study, told The Epoch Times in an email, “The association exhibited a non-linear pattern, with more pronounced risk reduction at higher selenium concentrations. [Parkinson’s] patients tend to have lower blood selenium levels compared to non-[Parkinson’s] patients.”

Additional research published in Nutrients in 2020 indicates that an imbalance of selenium—either too much or too little—may play a role in neurodegeneration. Conversely, Parkinson’s disease pathology could hinder the proper distribution of selenium in neurons.

Selenium deficiencies are rarely detected, but subclinically low levels of selenium may cause changes to cellular metabolism, including the gradual loss of neurons that produce dopamine, which may lead to neurodegenerative diseases such as Parkinson’s disease.

What Is Selenium?

Selenium is a trace mineral, meaning that the body needs it in small amounts. It is considered an essential micronutrient for humans—you must get it from food or supplements, as your body is incapable of making it. Selenium is a component of the amino acid selenocysteine. Selenocysteine is incorporated into selenoproteins, which have a variety of important functions in the body. They play a role in thyroid hormone production and DNA synthesis, among other duties.

Selenium is crucial for your brain’s development and overall health. Adequate selenium intake is important for cognitive function, memory, coordination, and overall neurological well-being, as it helps maintain the central nervous system.

What Is Known About Parkinson’s Disease?

Parkinson’s disease is the most common neurodegenerative disorder. Its prevalence worldwide increased by 74.3 percent between 1990 and 2016. Parkinson’s is a progressive nervous system disorder that affects movement. Its cause is unknown but believed to be a combination of genetic and environmental factors. The disorder usually develops gradually over many decades and commonly causes uncontrollable tremors and shaking, stiffness, loss of balance, and slowing of movement.

As it progresses, it leads to cognitive and mobility issues, usually coupled with mental health disturbances. There is no cure for Parkinson’s, but treatments include medications that increase dopamine production, affect neurotransmitter levels, and help with involuntary movements.

Dietary Sources of Selenium

The foods that are highest in selenium include Brazil nuts, seafood, and organ meats. The trace mineral is also found in water and soil, and the level found in plants is directly correlated to the content in the soil. North American soil tends to contain adequate amounts of selenium, although the majority of water sources do not. A case-control study published in 2017 found that high concentrations of selenium found in soil in 48 U.S. states benefited patients with Parkinson’s disease and helped reduce mortality from the disease.

Good ​​dietary sources of selenium include:

• Brazil nuts
• Fish (tuna, halibut, sardines, salmon)
• Shellfish (oysters, shrimp, crab)
• Meat (beef, liver, pork)
• Poultry (chicken, turkey)
• Eggs
• Sunflower seeds
• Mushrooms
• Brown rice
• Dairy products
• Beans
• Lentils

Additionally, evidence supports the neuroprotective effects of coffee.

There Is Too Much of a Good Thing

It is possible to consume too much selenium, and high levels of selenium are deemed to be toxic. Excessive intake of selenium can lead to a condition called selenosis, which can cause symptoms such as nausea, vomiting, hair loss, fatigue, and even nerve damage. In severe cases, it can lead to respiratory distress, heart problems, and even death. Consuming selenium within the recommended daily intake levels is important to avoid potential health risks.

The Recommended Dietary Allowance for selenium is 55 micrograms per day, which is roughly equivalent to three to four eggs or 6 ounces of turkey. The Tolerable Upper Intake Level is set at 400 micrograms per day, which can be crossed with just a small handful of Brazil nuts—so moderation is key.