Selenium is a trace mineral essential for fertility, thyroid health, and pregnancy. It's also a powerful antioxidant that can protect your heart and mental health. While it's found in food, not everyone gets enough selenium from diet alone. It's incredibly important for women's health, but not everyone knows about it.
What is Selenium?
Even though selenium is an essential trace mineral, which means your body needs it in small amounts, it is important for keeping you healthy and protecting tissues and cells against damage, including DNA damage.
Selenoproteins are proteins made with selenium, which are involved in DNA synthesis, cellular repair and protection, and many other functions we will discuss below. Selenium is found in soil and water and absorbed by plants, but it can also be taken as a supplement.
What are the Benefits of Selenium?
The big-picture benefit of selenium is that it's a powerful antioxidant. This means it can help to protect cells in the body from damage caused by free radicals. But let's get into the details of some of the selenium benefits, especially as they relate to women's health.
May Reduce Oxidative Stress (Antioxidant)
The selenoproteins mentioned above (that are made with selenium) have antioxidant functions. Free radicals, which are unbound oxygen atoms that can cause damage, are generated from so many things we do or come into contact with daily, like pollution, stress, and even metabolism.
The balance of free radicals and antioxidants in the body matters. When free radicals overpower the antioxidants, it's called oxidative stress. Too many free radicals can cause damage to our cells which leads to inflammation, aging, and disease. Selenium helps to protect cells by reducing the amount of damage caused by excess free radicals.
Research shows that selenium increases total antioxidant levels in the body and helps to increase glutathione production in your body. Glutathione is often called the master antioxidant because it's so critical for detoxification, reducing inflammation, and protecting cells.
May Support a Healthy Immune System
Selenium's antioxidant function also supports a healthy immune system. By lowering inflammation and oxidative stress, selenium helps optimize immune function. Low levels of selenium are linked to a less-than-optimal immune response.
Cognitive Function and Mental Health
Oxidative stress, inflammation, and brain health are all interconnected. So, it's no surprise that selenium's ability to reduce these things also supports cognitive function and mental health. Diseases like Alzheimer's, dementia, and even depression have all been linked to oxidative stress. While there's no single silver bullet for any of these conditions, selenium could be part of the puzzle.
In one study, giving participants selenium—along with other antioxidants—improved memory and cognitive performance. And research suggests that there may be a connection between age-related cognitive decline and lower selenium levels.
Selenium has also been studied as a possible supportive supplement for depression. In a meta-analysis, researchers concluded that high selenium intake lowered the risk of postpartum depression and reduced depressive symptoms.
Selenoproteins may play an essential role in cardiovascular health by reducing oxidative stress and inflammation, which could damage blood vessels and lead to heart disease. People with lower selenium levels may be at a greater risk for heart disease, although there's still more research needed to understand the connection.
The link between oxidative stress and heart health is well-established, and selenium's ability to reduce oxidative stress could help to protect heart health. Selenium supplementation may also help lower C-reactive protein (CRP), a marker for inflammation. High CRP levels are linked to heart disease.
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Selenium for Thyroid Health
Selenium is critical for thyroid health. Without adequate selenium, the thyroid cannot function properly because the nutrient is needed to make thyroid hormone and convert T4 (inactive thyroid hormone) to T3 (active thyroid hormone), so your cells can actually use it. Thyroid tissue contains high amounts of selenium.
Its antioxidant activity also supports thyroid health by reducing oxidative stress and inflammation. This is especially important for people with Hashimoto's thyroiditis, the autoimmune thyroid condition where the immune system attacks the thyroid. Oxidative stress and inflammation are two of the underlying causes of autoimmune disease.
Studies show an inverse relationship between selenium levels and thyroid health in women, meaning as selenium levels go down, thyroid dysfunction goes up.
Helps Lower Thyroid Antibodies
Hashimoto's thyroiditis is characterized by high levels of thyroid peroxidase antibodies (TPOAb). These antibodies indicate that the immune system is attacking the thyroid, and supplementing with selenium has been shown to help lower thyroid antibodies.
A study examining pregnant women with elevated thyroid peroxidase antibodies (TPOAb) found that supplementing with 200 mcg of selenium daily during pregnancy and postpartum significantly reduced TPOAb levels. It also lowered the overall incidence of hypothyroidism compared to those who only took a placebo.
Supplementing with selenium is also associated with lower thyroid antibodies in women with Hashimoto's who aren't pregnant. It also may help with mood and overall feelings of well-being.
Selenium and Fertility
All the cells and tissues in our body are vulnerable to free radical damage, but reproductive tissues are especially susceptible. This makes selenium's antioxidant activity critical for fertility and pregnancy.
Selenium's Role in Preconception
Once again, the antioxidant power of selenium helps protect the delicate balance of hormones needed for conception and eggs and sperm from free radical damage. On the other hand, selenium deficiency is closely linked to infertility.
For the partner with sperm, selenium helps to protect sperm from free radical damage, supports healthy sperm motility and shape, and is needed for normal sperm function. A selenium deficiency could even impact testosterone levels and sperm health. Plus, sperm are susceptible to damage from free radicals, so they need all the antioxidant support they can get.
Adequate selenium is needed for follicle development and ovarian function. Follicles are the sacs that house and protect eggs as they mature. And like sperm, eggs are also susceptible to free radical damage, so selenium can protect and help mitigate oxidative stress.
A review of seven studies looking at selenium and female fertility concluded that selenium supplements could improve fertility, especially in women with low selenium levels. A small study on men with Hashimoto's and low sperm quality also found that supplementing with selenium improved sperm and thyroid health after six months.
Selenium During Pregnancy
You probably won't be surprised to learn that selenium also supports a healthy pregnancy and developing baby by acting as an antioxidant. Selenium even helps to protect the placenta from free radical damage.
Thyroid health is also essential during pregnancy, and as we know, selenium is critical for thyroid hormone production. So adequate selenium is needed to become pregnant, stay pregnant, and maintain a healthy pregnancy.
A systematic review of 16 studies concluded that supplementing with selenium was linked to a significantly lower risk of pre-eclampsia, a serious pregnancy complication. Selenium supplementation could be an effective and safe way to help prevent this condition.
Another study looked at pregnant women with gestational diabetes and found that selenium supplementation improved antioxidant status and helped to protect against free radical damage.
How Much Selenium Per Day Do Women Need?
Depending on the stage of life, women need different amounts of selenium. You can get selenium from foods like brazil nuts, seafood, or organ meats. Still, the amount of selenium in food can vary, especially with plant-based sources, where it can depend on the soil where the food was grown.
Recommended Daily Allowance of Selenium
The RDA for adults is 55 mcg/day, but this goes up to 60 mcg/day during pregnancy and 70 mcg/day while breastfeeding.
However, the RDA is only meant to prevent deficiency, and sometimes we need more than the RDA to support optimal health. As mentioned above, several studies suggest that 200 mcg/day is a more beneficial amount for fertility, thyroid, and pregnancy health.
Keep in mind that too much selenium isn't good for you either, so don't go over 400 mcg/day.
Selenium is found in stand-alone supplements or as part of a multivitamin or prenatal formula. Food is always the best way to get nutrients, but sometimes supplementation is needed to reach optimal levels. Just be sure to consider the total amount of selenium you're getting from food and supplements to ensure you're not exceeding the upper limit.
Products That Contain Selenium
While 200 mcg is ideal for fertility and pregnancy health, the amount found in most prenatal formulas is lower, around 50-100 mcg. Prenatal Plus formula contains 200 mcg of selenium from selenomethionine to support a healthy pregnancy.
Women's Twice Daily, a multivitamin for women who can't take iron or are in menopause, also contains 200 mcg of selenium from selenomethionine.
You'll also find 50 mcg of selenium in all-in-one thyroid supplements, like Thyroid Support, to optimize thyroid function.
Selenium may not be top of mind, but this critical mineral plays many vital roles in women's health, from fertility to thyroid health to pregnancy. If you're not getting enough selenium from diet alone, consider supplementing with a high-quality multivitamin or prenatal formula.
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