What is selenium good for?
On the other hand, a deficiency in selenium is linked to a range of health problems, but thankfully selenium is found in many foods, and is also easily available in supplemental form for those who may be deficient.
Selenium functions as an antioxidant, and it is studied in relation to oxidative stress, the immune system, and conditions such as inflammatory disease, stroke, heart disease, Alzheimer's disease and cancer, as well as premature aging.
Role in cancer research
In fact, a review of 69 studies that included over 350,000 participants found that high blood levels of selenium were associated with lower rates of certain cancers, including breast cancer, lung cancer, prostate cancer and colon cancer.
Cardiovascular health
Likewise, a review of 16 studies including over 433,000 participants that suffered from heart disease found that selenium supplementation was associated with a lower key inflammatory marker for the condition. A further analysis of 25 studies looked at blood levels of selenium and heart-disease risk.
Brain health
Regarding Alzheimer's disease specifically, research has found that people who have lower blood levels of selenium are more likely to develop the disease, and diets rich in antioxidants like selenium, such as the Mediterranean diet, have been studied for memory in people with Alzheimer's disease.
One interesting study found that taking one single selenium-rich Brazil nut a day reported improvements in speech and mental functions in patients that were suffering from mild cognitive impairment.
Role in thyroid function
Selenium is also very important for proper thyroid function, and thyroid tissue actually contains more selenium than any other tissue in the human body. The selenium is known to protect the thyroid against oxidative stress, and also plays a crucial role in our metabolism and hormone production.
A deficiency in selenium is linked to an increased risk of hypothyroidism, a condition where our own immune system attacks the thyroid, while selenium supplementation has been studied for the symptoms of the condition.
When should I take selenium?
Multiple foods are known to negatively affect the absorption of selenium, and some studies have shown that taking selenium on an empty stomach results in maximum absorption, although there is no specific time of day that appears to be optimal.
What does selenium combine well with?
Selenium with piperine, taken together, for increased absorption
Piperine is the active ingredient in black pepper, and is known for its absorption-increasing properties when taken together with a variety of compounds, including selenium.Selenium with Vitamin E, taken together, for antioxidant protection
Vitamin E is also known to promote absorption of the mineral selenium, so you may want to consider this if you want to get the most out of your selenium supplementation. Not only that, but selenium is also known to work together with vitamin E, as they both function as antioxidants.Selenium with kelp or iodine supplements, taken together, for thyroid function
Selenium is part of the deiodinase enzymes that turn thyroid hormone into the form your body uses, and iodine is the element those hormones are built from. Selenium also belongs to glutathione peroxidase, which protects the thyroid gland from the oxidative stress of making hormones, so the pair covers production and conversion in one routine.Sea moss and Kelp's high iodine content also make them a contender for companions to selenium, although bear in mind that you should only ever really have one source of iodine (if any) at a given time.
What else pairs well with selenium?
Also taken with beta-carotene, for antioxidant activity
Selenium's antioxidant properties are also known to be reinforced in the presence of beta-carotene.Also taken with saw palmetto and lycopene, for prostate and urinary tract health
One study reported that selenium, when combined with saw palmetto extract and lycopene, offered greater anti-inflammatory results in people that were suffering from reduced urinary flow, including benign prostatic hyperplasia (BPH), than when the supplements were taken individually.Also taken with zinc, for antioxidant research
Both selenium and zinc have been studied in cancer research, and their combined supplementation is often taken together, especially in prostate cancer research.What should I avoid taking selenium with?
Avoid taking selenium at the same time as niacin (vitamin B3)
Selenium is known to interact with niacin (vitamin B3), so it is advised to take these separately, at least three hours apart. This includes B-complex.Avoid taking selenium at the same time as astragalus
It is also known that some species of astragalus can naturally contain high levels of selenium, due to the plant's ability to absorb it from the soil, so you would be advised to avoid taking selenium supplements together with astragalus in order to avoid excess selenium intake.Avoid taking selenium at the same time as l-glutathione
Also, lower levels of glutathione are associated with an increased absorption of selenium, so it may be a good idea to take these separately.What are natural sources of selenium?
If you are interested in obtaining your daily selenium through your diet, you can often find it in:
It's worth noting that a single brazil nut could contain up to 100mcg of selenium, which is almost twice the minimum recommended dietary allowance of 55mcg.
Who should avoid taking selenium?
Before taking selenium supplements, check with your trusted healthcare professional if any of the following apply to you:
- Selenosis
Remember to always discuss any vitamins or supplements with your trusted healthcare professional if you are suffering from any health conditions.
Possible side effects of selenium
Possible side effects from taking selenium supplements may include (but are not limited to) the following:
- Hair loss
- Garlic breath
- Nerve damage (excess)
There is a fine line between just enough selenium and too much. The adult upper limit is 400 mcg a day, and prolonged intakes above this limit can lead to a condition known as selenosis, resulting in hair loss, brittle nails, a garlic breath and a skin rash. Brazil nuts are the food that pushes people over the line without a supplement, since a single nut can carry more selenium than even a tablet.
If you are experiencing negative side effects from taking selenium supplements, stop taking them immediately and reach out to your trusted healthcare professional.
Drug interactions with selenium
The medicines listed below are the ones most often named in interaction reports for selenium, but it is by no means a comprehensive list:
- Antacids
- Antibiotics
- Chemotherapy & radiotherapy
- Hormone therapy
- Statins
Antacids, statins, birth control or chemo drugs
Selenium could potentially interact with other medicines and supplements, such as certain antacids, chemotherapy drugs, corticosteroids, statins, or birth control pills, so you should check with your doctor before starting selenium supplementation if you are currently taking any medication.If you are taking any prescription drugs or medication, check with your trusted healthcare professional before taking selenium supplements.
Can I take selenium while pregnant or breastfeeding?
Selenium needs rise only slightly during pregnancy, to 60 mcg a day, and it supports the thyroid enzymes that handle the extra hormone production of these months. Brazil nuts, fish and eggs cover it easily, and a single Brazil nut can carry a day's worth. Just remember to review all your sources of selenium so you never exceed the daily 400 mcg upper limit.
Remember to always discuss any vitamins or supplements with your trusted healthcare professional while pregnant or breastfeeding, or while attempting to conceive.
What are deficiency symptoms of selenium?
Possible signs of selenium deficiency may include (but are not limited to) the following:
- Heart muscle disease
Ordinary mixed diets usually cover selenium.
If you are experiencing abnormal symptoms, reach out to your trusted healthcare professional as soon as possible.
Where should I store selenium?
For optimal shelf life, it is recommended to keep selenium supplements stored in the cupboard. Always make sure the bottle or container is tightly closed, and kept away from sources of light, heat and humidity.
Selenium data sources & further reading
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