Supplementation with selenium and Q10 has a positive effect on metabolism, circulation, and lifespan

Selenium is involved in enzymes that activate thyroid hormones. It is also part of several antioxidants that protect cells and the circulatory system from damage caused by free radicals. Additionally, selenium is crucial for the optimal utilization of Q10, which plays a role in cellular energy metabolism. However, selenium intake in many European countries is too low, mainly due to depleted soil. At the same time, the body’s endogenous production of Q10 declines significantly with age. This can lead to metabolic disorders, atherosclerosis, fatigue, and other deficiency-related conditions. According to a follow-up study published in BMC Medicine, supplementation with selenium and Q10 has a positive effect on thyroid hormones, circulation, quality of life, and lifespan.

The thyroid gland is the organ that contains the highest concentration of selenium relative to its weight. This is because selenium is a component of enzymes called deiodinases, which convert the inactive thyroid hormone T4 into the active T3 hormone. T3 then allows oxygen into the cells so they can produce energy as needed. Selenium is also part of antioxidant enzymes called GPX (glutathione peroxidases), which protect the thyroid gland from oxidative damage caused by free radicals. This function is particularly important since the active thyroid gland receives about five liters of oxygen-rich blood per hour, increasing its exposure to free radicals.
A large Chinese population study involving 6,100 participants found that selenium deficiency, which is widespread in certain regions of China, increases the risk of hypothyroidism, autoimmune thyroid diseases such as Hashimoto’s and Graves' disease, and goiter, where the thyroid gland becomes enlarged.
Selenium deficiency is also widespread in Europe, mainly due to depleted soil. This deficiency negatively affects the body's ability to utilize coenzyme Q10.
Q10 exists in two forms. One form, ubiquinone, is crucial for cellular energy production by converting dietary calories into energy using oxygen. This process occurs in the cellular powerhouses – the so-called mitochondria. The other form, ubiquinol, functions primarily as an antioxidant that protects cells and cholesterol from oxidative damage caused by free radicals. In this process, selenium plays a key role in the enzyme TXNRD, which ensures that Q10 can transition between its two essential forms.
However, the body's own production of Q10 gradually declines after the age of 20, and by the age of 80, the heart’s Q10 levels have been reduced by about half. This means that elderly individuals living in selenium-deficient regions face an increased risk of cardiovascular diseases and other conditions due to deficiencies in both selenium and Q10. The purpose of the new follow-up study was to examine the relationship between selenium levels in the blood and various thyroid hormones, as well as to investigate whether supplementation with selenium and Q10 could influence thyroid hormone concentrations, mortality rates, and quality of life.

Supplementation with selenium and Q10 benefits metabolism, circulation, and lifespan

The researchers used data and blood samples from a previous groundbreaking study called KiSel-10, which involved 443 elderly Swedish men and women aged 70–88. All participants were relatively healthy and living independently. They were divided into two groups, with one group receiving a daily supplement of 200 micrograms of selenium yeast and 200 mg of pharmaceutical-grade Q10, while the other group received a placebo. All participants continued taking any prescribed medication.
Throughout the study, participants’ blood pressure and heart function were monitored, and more than 50,000 blood samples were frozen for future analysis.
At the start of the study, both groups had a low average selenium level of 67 µg/L in their blood. This corresponds to a daily selenium intake of 35 µg, which is far too low. At baseline, it was found that participants with the lowest selenium levels had significantly higher levels of thyroid-stimulating hormone (TSH), which stimulates the thyroid gland’s hormone production. They also had significantly lower levels of free T3, the active thyroid hormone. High TSH and a low T3 levels indicate an imbalance in thyroid hormones and a sluggish metabolism.
The study lasted for 48 months, and in the new follow-up study, researchers found that participants who took selenium and Q10 supplements experienced significantly lower TSH levels and significantly higher T3 levels, as well as other signs of improved metabolism. There were no significant differences in the placebo group.
Additionally, a low concentration of free T3 was associated with higher levels of C-reactive protein (CRP), an inflammation marker. Chronic inflammation, often associated with aging, leads to increased oxidative stress, which can damage cells and the circulatory system.
The researchers also found that participants in the placebo group with higher TSH levels had an increased risk of death over the next 10 years. Other studies have reported that patients with subclinical hypothyroidism are at greater risk of developing cardiovascular diseases.
On the other hand, lower TSH levels were associated with a lower risk of death from cardiovascular diseases and an improved quality of life.
The positive effects of selenium and Q10 supplementation on thyroid hormones are largely attributed to selenium’s role in deiodinase enzymes, which are crucial for converting the inactive thyroid hormone T4 into the active form T3. The researchers also concluded that a significant portion of the study participants suffered from subclinical thyroid dysfunction due to insufficient selenium intake.
This new follow-up study, which specifically focuses on thyroid hormones, has been published in BMC Medicine. The KiSel-10 study and other follow-up studies have previously shown that supplementation with pharmaceutical-grade selenium and Q10 can extend lifespan and improve quality of life through various mechanisms, including the regulation of oxidative stress, chronic inflammation, and multiple biomarkers related to heart health and circulation.

References:

Urban Alehagen et al. Supplementation with selenium and Q10 in an elderly Swedish population low in selenium – positive effects on thyroid hormones, cardiovascular mortality, and quality of life. BMC Medicine 2024

Urban Alehagen et al. Improved cardiovascular health by supplementation with selenium and coenzyme Q10: applying structural equation modeling (SEM) to clinical outcomes and biomarkers to explore underlying mechanisms in a prospective randomized double-blind placebo-controlled intervention project in Sweden. European Journal of Nutrition. 2022

Alehagen U, et al. Cardiovascular mortality and N-Terminal-proBNP reduced after combined selenium and coenzyme Q10 supplementation. Int J Cardiol. 2013.