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L-Selenomethionine is a highly bioavailable, organic source of selenium used in many dietary supplements.
Selenium is an essential trace mineral that we must obtain from dietary sources in order to meet our needs. While selenium deficiency is rare, there are times when increasing intake of this mineral could promote health.
People use L-selenomethionine supplements to support thyroid function, immunity, promote healthy cholesterol levels, protect the heart and as a natural antioxidant.
Selenium is also purported to have benefits for prostate health and other organs. It plays an important role in detoxification pathways in the body and is an essential component of glutathione which protects cells from damage caused by reactive oxygen species.
According to one clinical review of selenium supplements, L-selenomethionine is easier for the body to utilize than other known forms of selenium. [1]
Anti-Oxidant
Immunity
Thyroid Function- Cofactor for antioxidant enzymes
- Supports thyroid function & metabolism
- Promotes immune function & fertility
Top Selenium Products* ❯L-Selenomethionine Supplements
L-selenomethionine is the left-handed enantiomer of the naturally occurring amino acid, selenomethionine.
Selenomethionine has a similar structure as the amino acid methionine, but with a selenium atom attached in place of a sulphur atom.
According to NIH, selenium is used to produce various selenoproteins that are important for DNA synthesis, protection from infection and oxidative damage, metabolism of thyroid hormones, and reproduction. [2]
There are inorganic and organic forms of selenium. In chemistry, organic molecules have a carbon backbone and contain hydrogen in their chemical structure while inorganic molecules do not.
Inorganic forms include selenite and selenate. Organic forms include selenomethionine and selenocysteine. NIH states that both forms can be used to meet dietary selenium requirements in humans.
Some sources recommend using both organic and inorganic forms of supplements for certain health goals as they exhibit some different mechanisms of action in the body.
The majority (28% to 46%) of the human selenium pool is stored in skeletal muscles. It is stored in the form of selenomethionine. From the muscles, this molecule can be used to synthesize proteins chains from amino acids. [2]
The three most commonly used forms of selenium supplements are L-selenomethionine, selenium-methyl L-selenocysteine and sodium selenite. [3]
L-Selenomethionine Uses
L-selenomethionine has several advantages as an ingredient in dietary supplements compared to other versions of this supplement. It is more bioavailable, meaning it is better absorbed by the body.
People use selenium supplements for a wide range of reasons. Based on user reviews posted online, some of the common reasons for taking this supplement include detoxification of heavy metals, supporting mental focus, metabolism, energy levels, and weight loss.
NIH states that most common reasons for selenium supplementation include: [2]
- Supporting the function and health of the thyroid gland;
- Supporting the immune system;
- Managing healthy blood lipid levels;
- Avoiding selenium deficiency;
- Normal blood clotting;
According to the Natural Medicines Comprehensive Database, there are other uses for selenium supplements in traditional medicine as well. Some of these include mood disorders, hypothyroidism, autoimmune diseases, Hashimoto Autoimmune Thyroiditis, dermatitis, diabetes, swine flu, cataracts and preventing miscarriage. [4]
While selenium is used for different reasons, it has not been approved as a drug the FDA for the prevention or treatment of any medical conditions. More research is needed to validate many of the therapeutic uses for this supplement.
L-Selenomethionine for Cancer
One of the reasons people take L-Selenomethionine supplements is to improve defences against the development of cancer. However, there is mixed evidence on this use and it has not been approved by the FDA to prevent or treat cancer.
Selenium is important for detoxification pathways in the body. It is noted to reduce levels of ROS (reactive oxygen species), can cause oxidative damage in the cells. Some examples of ROS include singlet oxygen, peroxides and the free radical superoxide. [3]
Oxidative damage compounds over time is associated with the onset of chronic disease, including cancer. Because of its strong antioxidant properties, selenium continues to be studied for its anticancer and chemopreventive properties. [2]
Selenium supplementation has been studied in various types of cancer including liver, thyroid, bladder, colorectal, esophageal, gastric, lung, ovarian, prostate, skin and pancreatic cancer. [4]
According to research from the University of Illinois at Chicago, organic selenium compounds acts on multiple pathways to “attack cancer on many different fronts, at many different stages.” [5]
Some of these include:
- Activating Phase II liver enzymes that neutralize carcinogens;
- Detoxifying heavy metal residues;
- Reducing oxidative stress and free radical damage;
- Inducing programmed cell death (apoptosis);
- Inhibiting DNA mutations;
Population studies have found correlations between higher selenium levels in the body and decreased risk for prostate cancer, but have not found correlations for lung cancer, ovarian cancer or colorectal cancer.
A number of large-scale clinical trials have been conducted to determine whether this dietary supplement can reduce risk factors for developing cancer. Many of these studies have found no significant change in cancer risk from consumption of this supplement.
There may be a reduction in cancer risk for men from supplementation. Another study found that 100mcg of selenium with 200mg of synthetic allitridum decreased risk in women, but not men.
According to the Natural Medicines Comprehensive Database, “although selenium may not reduce the overall risk of developing cancer, an analysis of multiple clinical studies shows that selenium supplements may decrease cancer mortality by 22% compared to respective controls.”
Currently, there is insufficient reliable evidence to rate the efficacy of selenium for cancer. More studies are necessary to determine whether it works or not.
Dietary Sources of L-Selenomethionine
Some of the best food sources of L-selenomethionine include Brazil nuts, unrefined sea salt, certain types of seafood, eggs, organ meats and shiitake mushrooms.
If you live in North America and eat a healthy diet, selenium deficiency is rare. Most people obtain at least the Recommended Dietary Allowance (RDA) for selenium of 55 micrograms (mcg) per day.
This is the average daily intake level established by the US FDA that is sufficient to meet the nutrient requirements of almost all healthy people.
However, supplementation may have benefits for certain individuals. Users report taking L-Selenomethionine supplements to address the following:
- Support for gastrointestinal function;
- Heart health;
- Immunity;
- Improving fatigue;
Seek medical advice before beginning to use any dietary supplement, especially if you have pre-existing health conditions, or use prescription medications of any type.
L-Selenomethionine Side Effects
The NMCD rates selenium supplements as Likely Safe when used orally and appropriately in short-term periods. This mineral has a tolerable upper intake level (UL) of 400 mcg/day.
According to WebMD, getting too much L-selenomethionine can cause you to feel irritable, fatigued and/or nauseous. It may also cause hair and/or nails to fall out and/or become brittle. [6]
Getting more than 400 mcg/day is not recommended except in cases of close medical supervision. Consuming too much cause a condition called selenosis (selenium toxicity).
Some research has suggested that taking low-dose selenium supplements over more than 7 years increases the risk for diabetes and insulin resistance. [2, 6]
Ask your healthcare provider about the benefits and safety of taking an L-selenomethionine supplement before beginning to use this product to determine whether it is appropriate for you.
Article last updated on: July 5th, 2018 by Nootriment