Selenium Needs: All Things Genetic

Importance Of Selenium

Selenium is a trace mineral that is essential for good health.

Its importance is mainly due to its role as a cofactor for the antioxidant enzymes known as glutathione peroxidases, which protect the body’s cells from oxidative damage.

Additionally, it plays a significant role in the human immune system and thyroid function.

Antioxidant Powerhouse

Selenium is incorporated into proteins to make selenoproteins, powerful antioxidants that help prevent cellular damage from free radicals.

Free radicals are natural by-products of oxygen metabolism that may contribute to the development of chronic diseases such as cancer and heart disease.

Selenoproteins help maintain the integrity of cellular structures and protect against inflammation, contributing to overall health and well-being.

Thyroid Function

Selenium is integral to the proper functioning of the thyroid gland, which produces hormones that regulate metabolism, growth, and development.

Selenium aids in the synthesis of thyroid hormones and protects the thyroid gland from damage.

Immune System Support

Selenium plays a crucial role in the health of the immune system.

This antioxidant helps lower oxidative stress in the body, which reduces inflammation and enhances immunity.

Studies have demonstrated that increased blood levels of selenium are associated with enhanced immune response.

Cardiovascular Health

Selenium may help keep the heart healthy by reducing oxidative stress and inflammation, which are linked to heart disease.

Some research suggests that oxidative stress and inflammation can lead to an increase in heart disease, so selenium’s role as an antioxidant and anti-inflammatory can help reduce this risk.

Cognitive Decline

Higher levels of selenium may be associated with a decreased risk of cognitive decline, as studies have shown that antioxidants like selenium can help reduce the risk of cognitive disorders like Alzheimer’s disease.

Section Summary

Selenium, though needed in small amounts, plays a vital role in many physiological functions of the body, making it an essential component of our diet.

Adequate selenium intake is necessary for maintaining overall health and well-being.

Why Do Humans Need Selenium?

Selenium is an essential trace element that is vital for several crucial biological functions in the human body.

Humans need selenium for the following reasons:

Role in Antioxidant Activity

Selenium is a key component of various enzymes known as selenoproteins, many of which function as antioxidants.

These antioxidants protect our cells from damage caused by free radicals, harmful compounds that can alter cell structures and DNA.

By mitigating oxidative stress, selenium helps protect against chronic conditions such as heart disease, cancer, and neurological disorders.

Thyroid Hormone Metabolism

Selenium is intricately involved in the production and metabolism of thyroid hormones.

It forms a part of enzymes that help convert the less active thyroid hormone (T4) to its more active form (T3).

This conversion is vital for maintaining normal metabolism and energy production in the body.

Additionally, selenium’s antioxidant role helps protect the thyroid gland from damage by oxidative stress.

Immune System Function

Selenium contributes significantly to the functioning of the immune system.

It enhances the body’s ability to fight off infections, illnesses, and diseases by promoting the growth and activity of immune cells.

Furthermore, selenium can help control excessive immune responses and chronic inflammation, which can potentially lead to autoimmune diseases.

Reproductive Health

Selenium also plays a vital role in reproductive health.

It contributes to the health and proper functioning of the male and female reproductive systems.

In men, selenium is necessary for sperm motility and may potentially improve fertility.

For women, selenium may support a healthy pregnancy.

Protection Against Toxic Metals

Research has shown that selenium can help mitigate the toxic effects of heavy metals like mercury, cadmium, and arsenic.

This protective role is especially important in areas where environmental exposure to these toxic metals is high.

Section Summary

Selenium is essential for humans due to its critical role in maintaining homeostasis in the body.

Despite being required in minute amounts, adequate selenium is vital for promoting health and preventing disease.

Selenium RDA

The Recommended Dietary Allowance (RDA) for selenium is 55 micrograms per day for adults.

This value is based on the amount of selenium required to maximize the activity of the selenoprotein glutathione peroxidase in plasma, which is thought to be a key indicator of selenium’s nutritional status.

Genetics And Selenium Levels

Selenium levels in the human body can be influenced by a range of factors, including diet, environmental exposure, and genetics.

While the former two are relatively well understood, the genetic factors that contribute to selenium levels are a topic of ongoing research.

The understanding of the genetic factors influencing selenium levels could provide valuable insights into individual susceptibility to selenium deficiency or toxicity.

Selenium Metabolism Genes

Selenium is incorporated into a variety of selenoproteins, which carry out many essential functions in the body.

The synthesis of these selenoproteins is regulated by a number of genes.

Mutations or variants in these genes can affect the efficiency of selenoprotein synthesis, potentially influencing an individual’s selenium status.

For instance, variants in the selenoprotein P gene (SEPP1), which is responsible for selenium transport, have been associated with variations in selenium levels.

Check your AncestryDNA, 23andMe raw data for the SEPP1 gene variants

Genes Involved in Selenium Absorption and Excretion

Selenium is absorbed in the gut and excreted through the kidneys.

Variants in genes involved in these processes, such as those encoding for certain transport proteins, could potentially influence the efficiency of selenium absorption and excretion, thereby affecting selenium levels.

Genetic Influence on Selenium Requirements

It’s also possible that genetic factors could influence an individual’s selenium requirements.

Some research has suggested that variants in certain genes could modulate the relationship between selenium intake and health outcomes.

This means that some individuals may require more or less dietary selenium to achieve optimal health.

However, it’s important to note that while the genetic influences on selenium levels are an exciting area of research, our understanding is still incomplete.

It’s also worth noting that the effects of these genetic factors are likely to be modest compared to the effects of diet and environmental exposure.

As with many aspects of human biology, selenium levels are influenced by a complex interplay of both genetic and environmental factors.

Below is an example of some SNPs in genes related to selenium metabolism, along with their potential effects.

Please note that this is a simplified summary and doesn’t represent the complete picture of how genetics influence selenium levels.

Actual effects can depend on a combination of multiple SNPs, lifestyle, and other environmental factors.

SNP	Gene	Potential Effect
rs3877899	SEPP1	Variants in this SNP have been associated with differing levels of selenium in the body, potentially affecting the risk of selenium deficiency or toxicity.
rs7579	SEPP1	This SNP might influence the transport of selenium within the body, as the SEPP1 gene codes for a protein that carries selenium.
rs1050450	GPX1	This SNP in the gene for glutathione peroxidase, an enzyme that uses selenium, might influence the body’s antioxidant defenses.
rs713041	GPX4	Variations in this gene, which also codes for a selenium-dependent enzyme, could potentially influence selenium’s role in preventing oxidative damage.
rs4880	SOD2	While not directly related to selenium, this gene codes for a different type of antioxidant enzyme. Variations might interact with selenium-related genes and influence overall antioxidant status.

It’s important to remember that genetics is only one part of the equation. Diet and environmental factors play a substantial role in selenium levels, and even individuals with the same genetic makeup can have different selenium statuses depending on these factors. Genetic information can be a useful tool for personalizing dietary recommendations, but it should always be interpreted in the context of the individual’s overall health, lifestyle, and nutritional status.

Non-Genetic Factors

Several non-genetic factors can influence selenium levels.

These include diet, age, sex, health status, and environmental exposure.

For instance, people living in regions with selenium-rich soil may have higher selenium levels due to the selenium content in locally grown foods.

Selenium Deficiency

Selenium deficiency is rare in most parts of the world but when it does occur, it can lead to serious health issues.

Symptoms can include fatigue, mental fog, weakness, hair loss, weakened immune system, and fertility problems in men.

Severe selenium deficiency can lead to Keshan disease, a potentially fatal form of cardiomyopathy.

Can You Get Too Much Selenium?

While selenium is important for health, too much can lead to selenosis, a condition characterized by symptoms such as gastrointestinal upset, hair loss, white blotchy nails, garlic breath odor, fatigue, irritability, and mild nerve damage.

How Can You Identify Selenium Levels?

Yes, selenium levels in the body can be measured through blood tests. The test can help identify both selenium deficiency and selenium toxicity.

Ideas To Make Your Diet Selenium-Rich

Incorporating selenium-rich foods into your diet is an effective way to ensure that you’re getting enough of this essential mineral.

Here are a few tips on how to add more selenium to your diet:

Add Seafood to Your Menu

Seafood, especially fish like tuna, halibut, and sardines, are high in selenium.

Shellfish, including oysters, clams, and shrimp, are also good sources.

Incorporating seafood into your meals a couple of times a week can boost your selenium intake significantly.

Eat More Organ Meats

Organ meats such as liver and kidneys are rich in selenium.

If you enjoy these types of foods, they can be a great way to increase your selenium intake.

Include More Poultry and Red Meat

Chicken, turkey, and red meats like beef and lamb are good sources of selenium.

Using these meats in your main dishes or as additions to salads and pastas can increase your selenium levels.

Enjoy Whole Grains

Whole grains such as brown rice, oatmeal, and whole wheat bread contain selenium.

Replace refined grains with these healthier alternatives whenever possible.

Snack on Nuts and Seeds

Brazil nuts are one of the richest dietary sources of selenium.

Other nuts and seeds, such as sunflower seeds, also contain this mineral.

A handful of these as a snack can provide a good portion of your daily selenium requirement.

But remember, Brazil nuts are so high in selenium that it’s possible to exceed the recommended daily intake by eating just a few too many, so moderation is key.

Use Selenium-Rich Dairy Products

Dairy products such as milk, yogurt, and cheese contain selenium.

They can be easily incorporated into your diet as a part of meals or snacks.

Incorporate More Legumes

Legumes, including beans, lentils, and peas, are good sources of selenium.

Adding them to salads, soups, and stews can increase your selenium intake.

Use Selenium-Enriched Foods

Some foods are fortified with selenium.

These can include certain bread and cereals.

Check the labels to see if selenium has been added.

Section Summary

While ensuring adequate selenium intake is important, it’s equally important not to consume too much.

Excessive selenium could lead to selenosis, a condition with symptoms such as hair loss, gastrointestinal upset, and irritability.

It’s best to aim for a balanced diet that meets all your nutritional needs.

If you’re unsure about your selenium intake, consider seeking advice from a healthcare provider or a nutritionist.

Summary

Selenium is a crucial micronutrient that supports various bodily functions. It is necessary to obtain an adequate amount of selenium through diet or supplements, while also avoiding excessive intake. Both genetic and non-genetic factors can influence selenium levels, which can be tested through a blood test. Regularly consuming a variety of selenium-rich foods can help maintain optimal selenium status for overall health.

References

1. Office of Dietary Supplements – Selenium. National Institutes of Health.
2. Rayman MP. (2012). Selenium and human health. Lancet.
3. Tinggi U. (2008). Selenium: its role as an antioxidant in human health. Environ Health Prev Med.
4. Fairweather-Tait SJ, Bao Y, Broadley MR, Collings R, Ford D, Hesketh JE, Hurst R. (2011). Selenium in human health and disease. Antioxid Redox Signal.
5. Labunskyy VM, Hatfield DL, Gladyshev VN. (2014). Selenoproteins: molecular pathways and physiological roles. Physiol Rev.