What is selenium good for? Thyroid, immunity and the daily amount

Ingredient spotlight · Selenium in Health Royals’ Peak Performance, multivitamin for women with omega 3 · 7 min read

Selenium contributes to normal thyroid function, to the normal function of the immune system, to the protection of cells from oxidative stress and to the maintenance of normal hair and nails. The reference intake is 55 µg a day. Swedish soils are low in selenium, so Swedish grain and vegetables provide less than in many countries; fish, eggs and Brazil nuts are the richest sources. In Peak Performance Formula, Health Royals uses 27.5 µg of selenium as L-selenomethionine, the form found in food.

Selenium is needed in only very small amounts and is easy to overlook. Inside the body, though, it becomes part of specialised proteins involved in cellular protection, the metabolism of thyroid hormones and the immune system. Its importance does not come from quantity. It comes from where the mineral is used.

This article covers what selenium is good for, why Sweden is a special case, how much you need, and why we at Health Royals chose L-selenomethionine at 27.5 µg a day for Peak Performance, our daily multivitamin for women with omega 3 from algae. With selenium, more clearly than with most nutrients, the dose matters as much as the raw material.

Selenium at Health Royals

Peak Performance contains 27.5 µg of selenium per daily dose as L-selenomethionine, 50 per cent of the nutrient reference value. Selenium contributes to normal thyroid function, to the normal function of the immune system and to the protection of cells from oxidative stress. The amount is deliberately moderate, because selenium also comes from food and the margin upwards is short.

See Peak Performance, multivitamin for women with omega 3

What is selenium good for?

Selenium is an essential trace mineral with four authorised functions in the EU. Selenium contributes to normal thyroid function. Selenium contributes to the normal function of the immune system. Selenium contributes to the protection of cells from oxidative stress. Selenium contributes to the maintenance of normal hair and normal nails.

Once absorbed, selenium is used to build specialised proteins known as selenoproteins, among them enzymes that manage oxidative reactions and enzymes that process thyroid hormones. Selenium is not simply stored as a mineral. It becomes part of proteins that carry out specific biological work.

Dietary sources include fish, seafood, eggs, meat, dairy products, grains and Brazil nuts. The amount in plant foods varies a great deal, because it depends on how much selenium is in the soil they were grown in.

How does selenium help protect cells?

Everyday metabolism, exercise and environmental exposure produce reactive compounds, and the body has its own systems to keep that chemistry in balance.

Several selenium-containing enzymes take part in those systems. Among the best known are the glutathione peroxidases, which help the body process certain peroxides formed during normal metabolism. This is why selenium contributes to the protection of cells from oxidative stress.

The wording is precise for a reason. Selenium supports enzyme systems the body already uses, and a larger dose does not add protection beyond them.

Why is selenium connected with thyroid function?

The thyroid helps regulate metabolism through the hormones it produces, and selenium-containing enzymes convert those hormones between their different forms. Selenoproteins also form part of the protective systems inside thyroid tissue. This is why selenium contributes to normal thyroid function.

Selenium and iodine have different roles. Iodine is used to build thyroid hormones. Selenium-dependent enzymes help process and regulate them.

Selenium supports the normal biology of the thyroid as part of an adequate intake. Symptoms that may come from the thyroid belong with a doctor, and a food supplement does not treat thyroid disease.

What does selenium have to do with immunity?

Immune cells depend on tightly controlled metabolic and oxidative processes, and selenoproteins take part in the systems that help those cells keep their balance. Selenium therefore contributes to the normal function of the immune system.

The role is nutritional: an adequate, regular supply supports the cellular systems that normal immune function depends on. In Peak Performance, selenium works alongside vitamin D and zinc, which also contribute to the normal function of the immune system.

How much selenium do you need, and can you get too much?

The EU nutrient reference value is 55 µg a day. Sweden is a special case, because Swedish soils are low in selenium, so Swedish grain and vegetables provide less than in many countries.

Selenium is also a nutrient where balance matters particularly clearly. It contributes to the maintenance of normal hair and nails, but more is not better: a high intake over time can itself cause hair loss and brittle nails. Brazil nuts can contain a great deal of selenium, with amounts that vary widely from nut to nut. If you combine products, count the selenium in all of them.

What we do know makes the choice straightforward. The need is small, it needs to be met regularly, and the upper margin is short. That points to a moderate, precisely defined daily amount.

Why did we choose L-selenomethionine at 27.5 µg?

Because it is the form found in food, it is clearly defined, and the dose is set to add to the diet rather than to exceed it.

In selenomethionine, selenium is built into the amino acid methionine. It is one of the principal selenium forms naturally present in food. The body can also absorb selenium from other recognised forms, such as selenium-enriched yeast, sodium selenite and sodium selenate. We chose L-selenomethionine because it gives Peak Performance a clearly defined selenium source that matches the form in the diet.

The dose is 27.5 µg a day, 50 per cent of the reference value. Food already provides selenium, and the distance between enough and too much is comparatively short, so we stopped at half the reference value on purpose. For us, the dose matters as much as the raw material. Health Royals works with specialist manufacturers, researchers and supplier networks when raw materials are chosen, as we explain in branded and non-branded ingredients.

Why is selenium part of Peak Performance rather than a tablet on its own?

Selenium can be bought on its own. Our question was a different one: which nutrients belong together in one daily dose for a woman in Sweden, and at what level?

The answer started with intake data. In Riksmaten, Livsmedelsverket's national dietary survey, the nutrients where intakes often fall below the recommendation are vitamin D, folate and iron, with selenium as a fourth, as we set out in what Riksmaten shows. Omega 3 is the other gap, since ordinary multivitamins leave it out. So selenium sits in Peak Performance with:

• Vitamin D3, 25 µg, as Quali-D® from dsm-firmenich, and vitamin K2, 90 µg, as MenaQ7®.
• Folate, 200 µg, as Quatrefolic® 5-MTHF, and vitamin B12, 10 µg, as MecobalActive® methylcobalamin.
• OMEGATEX® algal oil, 500 mg, providing 375 mg of omega 3, of which 300 mg DHA and 50 mg EPA.
• Selenium, 27.5 µg, as L-selenomethionine, zinc, 5 mg, as L-OptiZinc®, and chromium, 20 µg, as chromium picolinate.
• Thiamin, 1.1 mg, and niacin, 16 mg.
• Hytolive® olive fruit extract, 150 mg, providing 15 mg of hydroxytyrosol, with 450 mg of extra virgin olive oil, and Extramel® melon extract, 10 mg.

Hytolive® and Extramel® are at the daily amounts used in their own human studies; the vitamins and minerals, selenium included, are at a nutritional level. Selenium contributes to the normal function of the immune system. Vitamin D contributes to the normal function of the immune system. Zinc contributes to the normal function of the immune system.

Peak Performance contains no calcium, magnesium or iron; iron is a question for a blood test. That is what we mean by fewer jars, more thought: one jar instead of several, each ingredient there for a reason, the doses published. The jar is amber glass with a scented core, made to stay out on the shelf, and a subscription sends refill pouches after the first jar.

We have done the selection so that you do not have to. Peak Performance gives you selenium as L-selenomethionine at 27.5 µg a day, together with vitamin D3, folate and omega 3 from algae, at doses we can explain. You can stop looking.

See Peak Performance, multivitamin for women with omega 3

Further reading

• Guide: wellbeing from within
• Nutrient deficiency in Sweden: what Riksmaten shows
• Zinc for hair, skin and immune function
• D2 or D3, and why we chose Quali-D®
• SOD from melon, Extramel®
• Hydroxytyrosol, the olive polyphenol
• Branded raw materials and what the name guarantees
• Peak Performance, multivitamin for women with omega 3

Frequently asked questions

Do you need a selenium supplement?
It depends on the diet. Selenium in plant foods follows the soil, and Swedish soils are low in selenium, while fish, seafood, eggs, meat and dairy contribute more consistently. In Riksmaten, selenium is one of the nutrients where intakes often fall below the recommendation, which is why Peak Performance contains a moderate amount.

Does selenium help with thyroid problems?
Selenium contributes to normal thyroid function as part of an adequate intake. A food supplement does not treat thyroid disease, and suspected thyroid symptoms belong with a doctor.

Can you get too much selenium?
Yes. The distance between enough and too much is comparatively short, and a high intake over time can cause hair loss and brittle nails, among other effects. Count food and other supplements when adding up the day.

Why does Peak Performance contain 50 per cent of the reference value?
27.5 µg is an addition to the selenium the diet already provides, not the whole daily requirement in one capsule. With a short margin upwards, a moderate amount is the considered choice.

References

European Commission. EU Register of nutrition and health claims made on foods: authorised health claims for selenium.

European Food Safety Authority. Scientific opinion on dietary reference values for selenium. EFSA Journal. 2014;12(10):3846.

European Food Safety Authority. Scientific opinion on the tolerable upper intake level for selenium. EFSA Journal. 2023;21(1):7704.

National Institutes of Health, Office of Dietary Supplements. Selenium: fact sheet for health professionals.

Disclaimer: This article is intended for general information and educational purposes only and does not constitute medical advice. It summarises nutrient functions and published scientific information. Individual needs and experiences may vary. Consult a qualified healthcare professional with questions about selenium intake, supplementation, medication or personal health.