Selenium Benefits, Recommended Intake, Food Sources & Side Effects

Photo by Vitchakorn Koonyosying on Unsplash

Selenium is a trace element that is naturally present in certain foods, added to others, and available as a dietary supplement. It is only needed in small amounts but plays a major role in important processes in the body like metabolism and thyroid function. Let’s look at what selenium means to your health.

Health Benefits Of Selenium

1. Selenium for Reproductive System

Several studies have concluded that regular consumption of selenium can enhance fertility in both males and females. These studies have also confirmed that regular intake promotes sperm locomotion. It is considered as one of the essential minerals for your wellbeing and its deficiency can cause male infertility. Some studies even suggest that lack of selenium adversely affects fetal growth and female fertility.

2. Boosts the Immune System

The immune system keeps the body healthy by identifying and fighting off potential threats. These include bacteria, viruses, and parasites. Selenium plays an important 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. On the other hand, deficiency has been shown to negatively impact immune cells and may lead to a slower immune response. Studies have also associated deficiency with an increased risk of death and disease progression in people with HIV, while supplements have been shown to lead to fewer hospitalizations and an improvement in symptoms for these patients. Additionally, selenium supplements may help strengthen the immune system in patients with influenza, tuberculosis and hepatitis C.

3. Anti-Aging Properties

Free radical damage causes the cellular degeneration we know as aging. As a powerful antioxidant, selenium neutralizes the damaging effects of free radicals. One study revealed that selenium levels decline with age and low selenium contributes to cognitive decline in older adults. There is great interest in determining whether selenium supplementation can slow age-related mental impairment. Hopefully, we learn more soon.

4. Prevents Cancer

Selenium has been found to be an essential part of a number of cellular processes, and this includes the body’s response to cancerous activity. Studies have shown that a normal selenium intake can result in a serious decrease in cancerous cell formation, especially in regards to prostate, colorectal, and lung cancers. Selenium is an essential player in various enzymatic reactions that can induce apoptosis, also known as automatic cell death. It specifically kills all the dangerous cancer cells, without harming healthy cells. Free radicals, the byproducts of cellular metabolism that can cause cancer, damage DNA and mutate into the cancer cells. Selenium can boost DNA repair and prevent this mutation from occurring. Finally, glutathione superoxidase, an important anti-cancer compound in the body, utilizes selenium for its activity, making it all the more important.

5. Health of Heart

Heart diseases occur due to one’s unhealthy lifestyle. This is caused due to excessive amounts of fat accumulated in the body. Proper consumption of selenium in the diet can lower heart disease. Selenium can reduce oxidation of cholesterol and clotting of blood.

6. Prevent Hair Loss

A massive hair loss is one of the symptoms that we need more intake of selenium. Selenium is trace mineral that plays its important role for our healthy hair. Since our hair contains protein, we should consume rich-protein-food. Selenium digest the protein intake to our body. Besides, it also helps the synthesizing process of enzyme to increase its antioxidant reaction so that our hair can stay healthy and avoid us from free radicals that trigger our hair loss.

7. Thyroid Function

There is a clear link between low selenium levels and impaired thyroid metabolism. Selenium is highly concentrated in the thyroid gland where it acts as a catalyst for the production and metabolism of thyroid hormones. When selenium levels are low, the thyroid gland has to work harder to produce hormones, and the body has a trickier time converting these hormones into cells it can use. It also helps the body to recycle iodine, which is well known to support thyroid function.

8. Helps Reduce Asthma Symptoms

Observational studies have demonstrated that patients with chronic asthma may have lower levels of selenium. According to studies, when people with asthma took selenium supplements, they experienced less asthma-related symptoms than those who took a placebo. Experts think that selenium supplementation may be a useful add-on treatment to medication for patients with chronic asthma. However, more research is needed before this becomes a regular practice, as researchers have yet to determine selenium’s full effect on lung function.

Recommended Intake

The recommended dietary allowance (RDA) includes the total amount of selenium you should get from foods and from any supplements you take.

Life Stage

Recommended Dietary Allowance

Children 1-3

20 micrograms/day

Children 4-8

30 micrograms/day

Children 9-13

40 micrograms/day

Adults and children 14 and up

55 micrograms/day

Pregnant women

60 micrograms/day

Breastfeeding women

70 micrograms/day

Selenium supplements are available, but it is best to obtain any vitamin or mineral through food. It is not the individual vitamin or mineral alone that make certain foods an important part of our diet, but the way the nutrients work together. Isolating specific nutrients in supplement form does not necessarily provide the same health benefits as consuming the nutrient from a whole food. The daily requirements of any nutrient should first come from food.

Foods sources

Good natural food sources of selenium include:

Brazil nuts: 137% of the RDI in one nut (5 grams)
Halibut: 106% of the RDI in 6 oz (159 grams)
Yellowfin tuna: 77% of the RDI in 3 oz (85 grams)
Oysters: 77% of the RDI in 3 oz (85 grams)
Sunflower seeds: 62% of the RDI in 2 oz (56 grams)
Shiitake mushrooms: 51% of the RDI in 1 cup (145 grams)
Chicken: 50% of the RDI in 5 oz (140 grams)
Eggs: 44% of the RDI in 2 large eggs (100 grams)
Sardines: 36% in 4 sardines (48 grams)

The amount of selenium in grains and grain-based foods depends on the soil content where the grains grew.

Side Effects

The upper limit per day for selenium is 400 mcg for adults. Selenium toxicity due to overdose is rare, especially from dietary sources, but an overdose of highly concentrated supplements could have negative effects. These may include:

bad breath and a metallic taste in the mouth
→ brittle nails
→ mottled or decaying teeth
→ gastrointestinal problems such as nausea
→ neurological abnormalities
→ fatigue and irritability
→ skins lesions and rashes
→ hair loss
→ In extreme cases, it could lead to kidney failure, heart failure, and death.

Selenium supplements can also interact with some medications, including cisplatin, a chemotherapy drug. The use of this drug can reduce selenium levels in the body.

Sources & References:

Healthy Food MasterVitamins and Mineralsanti-aging,asthma,cancer,hair loss,heart,reproductive system,thyroid
Photo by Vitchakorn Koonyosying on Unsplash Selenium is a trace element that is naturally present in certain foods, added to others, and available as a dietary supplement. It is only needed in small amounts but plays a major role in important processes in the body like metabolism and thyroid function. Let’s look at...
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