Is selenium really able to slow down ageing and increase our lifespan?
Selenium supports a host of different metabolic processes and serves as an antioxidant that protects our cells. According to recent studies, selenium also has anti-ageing properties that protect us against cardiovascular disease, cancer, dementia, and other age-related diseases. According to a review article published in Medical News Today, selenium also helps against impaired immunity and counteracts chronic inflammation, which is typically seen in connection with ageing processes. A Swedish study of healthy seniors has even showed that supplementation with selenium and Q10 has a positive effect on heart function, quality of life, and life expectancy.
Selenium is a trace element, which means it is a compound that we only need in relatively small quantities. Despite our limited need for selenium, the nutrient is essential because it supports over 25 different selenoproteins that control things like DNA synthesis, energy turnover, thyroid hormones, fertility, immune defense, and regulation of inflammatory processes.
Selenium is also a vital part of important antioxidants such as GPX (glutathione peroxidase) and TDR (thioredoxin reductase) that protect cells and tissues against free radicals.
Free radicals are highly reactive molecules that the body produces as part of its energy metabolism, cell signaling, the immune system’s attacks on microbe, and various other physiological processes. Free radicals, however, must be kept on a tight leash. Left uncontrolled, they tend to set off chain reactions that can cause damage to cholesterol, cell membranes, and DNA. This can eventually result in cellular damage, inflammation, premature skin ageing, and a number of age-related diseases. The only thing that can defend the body against free radical damage are antioxidants. The antioxidants that are supported by selenium are particularly important. They carry out functions that no other antioxidants can handle.
- Free radicals are produced naturally by the body in connection with different metabolic processes.
- The free radical burden is increased by ageing processes, poisoning, inflammation, smoking, and UV rays from the sun
- Oxidative stress is a state where protective antioxidants are outnumbered by free radicals
- Selenium-containing antioxidants have essential functions that no other antioxidants can handle
Selenium’s anti-ageing advantages
Biological ageing processes are complex and involve molecular damage, metabolic imbalances, atherosclerosis, changes to the immune system, increased sensitivity to stress factors in the environment, and a number of age-related ailments.
According to a review article from 2018, selenium has the ability to counteract ageing processes and prevent different age-related diseases such as cardiovascular disease, cancer, and neurological diseases. This is because selenium counteracts chronic inflammation, which is typically seen in old age. Chronic inflammation is also linked to increased vulnerability to infections like COVID-19 and influenza.
Other studies show that selenoproteins account for a number of health benefits. For example, a review article from 2021 has found hat selenoproteins play a key role in clearing out misfolded proteins that tend to accumulate in the body as we age. Experts have found that misfolded proteins are a normal sign of age-related diseases like type 2 diabetes and Alzheimer’s disease. What scientists have also observed is that selenium-containing antioxidants like GPX and TDR protect our skin against UV rays from the sun. TDR is located in our keratinocytes, which are the most prevalent cells in our epidermis.
A study from 2020 found that increased selenium intake is related to increased telomere length. Telomeres are protective “snippets” at the end of chromosomes. Each time a cell divides, the telomeres become slightly shorter, so they are determining for the number of times a cell can divide and when it perishes. Some scientists use telomere length to assess the ageing process, and many researchers are convinced that higher selenium levels in the blood are linked to a longer lifespan. Scientists have found that older people with high levels of selenium in their blood have significantly lower all-cause mortality than those with low blood levels of the nutrient.
It has also ben observed that centenarians have higher levels of selenium and iron and lower levels of copper in their blood compared with others.
Studies have shown that selenium protects against many age-related conditions, as listed below:
Selenoproteins and their anti-ageing mechanisms
- Support of different metabolic processes
- Important for energy turnover and optimal utilization of Q10
- Important for DNA synthesis and removal of misfolded proteins
- Important for telomere length
- Important for immune defense and inflammatory processes
- Support of various antioxidant systems
- Protection of cells and tissues against oxidative stress
- Protection of the skin against UV rays
- Repair of oxidative damage
Cardiovascular disease is the leading cause of death. A meta-analysis has found that low selenium levels in the blood are linked to a higher rate of cardiovascular disease. Truth be told, some studies have failed to show that selenium supplementation can reduce cardiovascular mortality. On the other hand, there is not much point in taking extra selenium if your selenium intake and selenium levels in the blood are already adequately high, which is typically the case in countries like the United States where there is plenty of selenium in the soil. The quality and bioavailability of selenium supplements also affect the outcome of studies and should be taken into account.
The Swedish KiSel-10 study was carried out with a combination of selenium and Q10 given to healthy seniors. European farmland contains very little selenium. Also, the body’s synthesis of Q10 decreases with age. Therefore, older people often lack both nutrients. The participants were given daily supplements of selenium yeast (200 micrograms/day) and Q10 (200 mg/day). Both supplements were pharmaceutical-grade. The entire study lasted five years and showed that the supplemented group had a 54 percent lower cardiovascular mortality rate and substantially a substantially lower hospitalization rate compare with the group that got placebo.
A 12-year follow-up of the study showed that supplementation with selenium and Q10 even had a long-term effect on heart function and lifespan. It is plausible that continued use of the supplements would lead to an even more pronounced effect.
- KiSel-10 is different from other studies in that it focuses on healthy people and things they can do to maintain good health
It is commonly known that factors like smoking, being overweight, eating processed meat, drinking alcohol, and exposing yourself to UV rays from the sun can increase the risk of cancer. Still, there are examples of people who stick with the official guidelines for healthy living and still manage to contract cancer. A contributing – and often overlooked – factor may be lack of selenium. Several large studies have revealed differences in selenium levels in blood samples and nail clippings from cancer patients and healthy controls, and these differences are detectable long before the disease starts to develop.
Selenium has a number of anti-cancer mechanisms such as controlling and activating countless genes. Selenium-containing antioxidants protect against DNA damage and mutations. Selenium is also important for the immune defense and helps it destroy abnormal cells. Selenium also regulates inflammatory processes that often occur in connection with cancers.
A host of studies have shown that selenium helps prevent common cancers such as breast cancer, prostate cancer, and colorectal cancer.
The so-called SELECT study, however, failed to show a protective effect on cancer but that stands to reason. First of all, the study participants already had high selenium levels in their blood. Secondly, the scientists did not use selenium yeast with a variety of different selenium species but gave the participants a single selenium source called selenomethionine in combination with synthetically manufactured vitamin E.
- Decades of research shows a clear relation between selenium deficiencies and common cancers.
Thyroid disorders are becoming increasingly common and are linked to a number of different symptoms that are often misdiagnosed. The thyroid gland contains more selenium than any other tissue in the body, suggesting that selenium has a vital role in the body’s metabolism. The thyroid gland produces two thyroid hormones. One is named T4 (and contains four iodine atoms), while the other is named T3 (and contains three iodine atoms).
T4 is passive. Different selenoproteins (deiodinases) must activate it first by removing a single iodine atom, thereby converting it into active T3. This conversion is handled in step with the body’s metabolic rate. The selenium-containing GPX antioxidants also protect the hard-working thyroid gland against oxidative stress.
Thyroid disorders such as Hashimoto’s thyroiditis that causes the metabolic rate to slow down (hypothyroidism) are very common. Graves’ disease that does the opposite and speeds up the metabolic rate is not quite as common. Both types of thyroid disorders are autoimmune. Studies show that daily supplementation with 200 micrograms of selenium given to patients with autoimmune thyroid disorders can have a positive effect within a period of 3-6 months. Two large, ongoing studies (CATALYST and GRASS) are looking into the effect of giving 200 micrograms of selenium daily to thyroid patients who fail to benefit from conventional therapies.
The number of seniors is constantly increasing, and so is the rate of people with cognitive decline. Alzheimer’s disease is the leading cause of dementia. The different selenoproteins have an important role in the central nervous system. The GPX antioxidants counteract oxidative stress, which is very important because the brain is particularly vulnerable to free radical attacks due to its large blood supply and its high content of iron and unsaturated fatty acids.
A selenium deficiency can lead to deficiencies of different neurotransmitters, which increases the risk of neurological diseases. It has been observed that Alzheimer’s patients have selenium concentrations that are around 60 percent lower than selenium levels in healthy controls. A team of scientists from Munich has looked closer at the mechanisms used by the selenium-containing GPX4 antioxidants to protect brain neurons against a type of cell death known as ferroptosis.
- Levels of selenium in the blood normally drop with increasing age. Reduced selenium status is therefore believed to impair brain function
Selenium levels in the blood and their impact on mortality
For decades, the British professor, Margaret Rayman, has addressed the alarming European selenium deficiency. She published a study in The Lancet in 2012, which looks at selenium’s anti-ageing properties. The study shows a link between mortality rates and selenium levels in the blood.
Selenium levels in blood serum
- Below 105 micrograms per liter = increased mortality
- 105-170 micrograms per liter = mortality below average
- 130-150 micrograms per liter = lowest mortality
The average selenium level in Europe is between 80-100 micrograms per liter. This level is associated with an increased risk of early death
Selenium in food and supplements
We get selenium from fish, shellfish, offal, eggs, dairy products, and Brazil nuts. European crops contain very little selenium because of the nutrient-depleted farmlands. This is one of the main reasons why Europeans lack selenium. Older people may have an increased need for selenium due to the fact that their enzymes are sluggish, and older people are also more exposed to oxidative stress.
The recommended selenium intake (reference intake level) in Denmark is 55 micrograms per day, but only around 20 per cent of the population gets that much. Studies indicate that we need around 100 micrograms of selenium in order to saturate selenoprotein P, the selenoprotein that is used as a marker of the body’s selenium status. Many of the studies that have looked at cardiovascular diseases, cancer, and thyroid disorders have been conducted with daily doses of 200 micrograms per day. The European Food Safety Authority (EFSA) has set the daily safe upper intake level at 300 micrograms.
Selenium-containing compound and its function:
- Deiodinase type 1-3: Thyroid hormones
- 1-6 (Glutathione peroxidase): Powerful antioxidants
- Selenoprotein S: Regulation of cytokines and inflammatory response in cells
- Selenoprotein P: Antioxidant and selenium transport in the body
- Selenoprotein R and N1: Antioxidants with several other functions
- Selenoprotein M: Large concentrations in brain tissue. Its function is not fully understood
- Selenoprotein T: Involved in cellular structure and proteins
- TXNRD 1-3: Antioxidants, mitochondrial energy turnover, and metabolism
- MSRB1: Repairs oxidative damage
- Methyl selenol: Counteracts uncontrollable production and transportation of problematic NKG2D ligands
- TDR (thioredoxin reductase): Antioxidant that protects against UV rays from the sun
Even a marginal selenium deficiency may prevent all of the selenoproteins from functioning optimally.
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