WHAT FOODS CONTAIN THE MOST SELENIUM?
What are the benefits and harms of selenium? What is the result of a deficiency or excess of selenium?
Selenium is naturally found in soil and water and enters the human body with crop and livestock products. A deficiency and an excess of this mineral are dangerous for a person, so it is important to know how much selenium is in the foods in our diet.
THE ROLE OF SELENIUM
Regulates the production of thyroid hormones
Selenium is involved in the synthesis of T3 and T4. Selenium deficiency can lead to autoimmune diseases like Hashimoto’s and Graves’s. The body produces antibodies that attack the thyroid gland, causing it to become overactive (hyperthyroidism) or underactive (hypothyroidism).
Studies have shown that selenium reduces these antibodies and increases the activity of selenoproteins, which reduce inflammation. Thyroid hormones regulate metabolism and are responsible for hair and nails.
Protects the thyroid from oxidative stress
During the synthesis of thyroid hormones, hydrogen peroxide (H2O2) accumulates – a strong oxidant, and selenoprotein is an antioxidant. It neutralizes free radicals and protects healthy cells from damage.
Regulates iodine levels
Selenium promotes the absorption of iodine. The thyroid gland needs both minerals in sufficient amounts, and an excess of one can lead to a deficiency of the other. Therefore, food sources of selenium should be balanced with foods containing iodine.
Provides prevention of cardiovascular disease
Selenoproteins prevent platelet aggregation (clumping), reducing the risk of cardiovascular disease.
Supports the immune system
Selenium helps prevent the mutation of many types of viruses, thus protecting against repeated infections.
Reactivates vitamins E and C
Vitamins E and C act as antioxidants, neutralizing free radicals. They work without selenium, but selenium reactivates vitamins C and E back into their active state, thus enhancing the effect.
Responsible for spermatogenesis
Selenium protects sperm from damage or mutation. This mineral is present in the tail of spermatozoa, so these cells are sensitive to its deficiency.
Promotes brain activity
Serum selenium concentration decreases with age. The lack of this microelement negatively affects brain activity, especially in older people. Therefore, maintaining normal selenium levels is critical as we age.
The daily selenium intake depends on gender, age, and other factors, such as pregnancy. Men need 70 micrograms of selenium daily, and women – 55 micrograms daily. At the same time, pregnant and lactating women need about 60 and 70 mcg daily. Children should receive 10–50 micrograms of selenium daily. The maximum allowable intake of selenium is 300 micrograms per day.
As a rule, the content of selenium in foods (except Brazil nuts) does not cause an overdose of this trace element, but there is such a risk when taking dietary supplements with selenium.
WHAT DOES EXCESS SELENIUM LEAD TO?
Chronically high selenium intake can lead to health problems and serious consequences such as heart attack, respiratory failure, or kidney failure.
Symptoms of a selenium overdose: metallic taste, bad breath, nausea, diarrhea, hair loss, brittle or discolored nails, skin rash or redness of the skin, fatigue, irritability, and muscle soreness.
Brazil nuts are exceptionally high in selenium, even grown in soil that is low in this mineral.
One such nut contains more selenium than the recommended daily allowance. Eating too many Brazil nuts daily can lead to selenosis (an excess of selenium) and too much selenium supplementation.
HOW TO DETERMINE THE LACK OF SELENIUM IN THE BODY?
Groups at risk for selenium deficiency:
- People living in regions with low selenium content in the soil. Russia is one of the countries whose soil is poor in selenium.
- Vegetarians as they eat mainly plant foods.
- People with HIV. The virus can lead to diarrhea, malabsorption of nutrients, and reduced appetite.
- People with kidney failure on dialysis. This mechanical blood filtration process can remove some of the selenium. Dietary restrictions required in renal failure can also lead to a micronutrient deficiency.
Symptoms of selenium deficiency: nausea, vomiting, headaches, confusion, lethargy, and convulsions.
Severe selenium deficiency can cause Keshan disease (a type of cardiomyopathy or heart muscle disease) and Kashin-Beck disease (osteoarthritis).
PRODUCTS CONTAINING SELENIUM
Plants get selenium from the soil, while animals get it from the plants they eat. If we talk about selenium in food, it is enough in protein products of animal origin.
FOODS HIGH IN SELENIUM
|Product||Selenium content, mcg/100 g of product|
|Tuna, canned in oil||76|
|Sea bass cooked in the oven||46.8|
|Cold smoked mackerel||44.1|
|Beef, dried corned beef||32.4|
|Boiled chicken egg||32|
Selenium supplements have several benefits, including boosting immunity, supporting normal thyroid function, and improving hair and nail health. Sometimes they are combined with other antioxidant vitamins, such as vitamin E or C. Selenium is better absorbed with these vitamins.
But before taking supplements, check the level of selenium in the body since an excess of this trace element is just as harmful as a deficiency. You likely won’t need additional supplements if you know which foods are high in selenium and include them in your diet.