Selenium - Minerals - Vital Health Zone

Selenium
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Why selenium is good for you
Important selenium facts
Groups at risk of selenium deficiency
Symptoms of selenium deficiency
Selenium and health
Selenium in foods
Selenium recommended daily intake (RDI)
Selenium works best with
Overdosage, toxicity and cautions for selenium

Why selenium is good for you

Selenium is another important mineral for the health of the thyroid gland - it helps it to work properly and reduces goitre. It is helpful in fighting infections since it stimulates increased antibody response to infections and promotes more energy in the body. Selenium is a potent antioxidant.

One of the main activities of selenium is its anti-aging properties and its ability to help rid the body of free radicals, as well as toxic minerals such as mercury, lead and cadmium.

Selenium helps with alleviating menopausal symptoms in women and it also assists men in producing healthy sperm. Tissue elasticity and pancreatic function is also dependent on this mineral.

Important selenium facts

People living in areas where the soil is poor in selenium, should pay attention to their selenium intake
Selenium supplements should contain methionine as it detoxifies excess amounts of selenium
Sodium selenate is also less toxic than sodium selenite
Selenium is very important for the health of the thyroid gland and the heart

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Groups at risk of selenium deficiency

Men - men need more selenium than women as it is lost in the seminal fluid
Chronically ill patients - muscular weakness, muscle wasting, and cardiomyopathy (inflammation and damage to the heart muscle) have been noted in these patients.
People with large sections of their small intestine removed - these people have impaired absorption of selenium and may need supplementation
People with severe gastrointestinal problems, such as Crohn's disease - these people have impaired absorption of selenium and may need supplementation
People on specialised medical diets to treat metabolic disorders - people on these diets (ie one for as phenylketonuria - PKU), are often low in selenium due to the restrictions of their diet and may need supplementation

People in these groups at risk of deficiency should talk to a medical professional about selenium supplements BEFORE taking them.

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Symptoms of selenium deficiency

Selenium deficiency occurs when there is less than 40mcg intake of selenium per day. Selenium deficiency is associated with problems with the thyroid gland.

There are two main diseases that can occur with extreme selenium deficiency and both are very serious health conditions.

The following are two diseases which are caused by selenium deficiency:

Keshan's Disease:
This is a disease which affects the heart and it occurs mainly in selenium-deficient soils in certain regions of China. The acute form of Keshan's disease is characterized by the sudden onset of cardiac insufficiency, while the chronic form results in moderate to severe heart enlargement with varying degrees of cardiac insufficiency. The incidence of Keshan disease is closely associated with very low dietary intakes of selenium and poor selenium nutritional status. Selenium supplementation has been found to protect people from developing Keshan disease but cannot reverse heart muscle damage once it occurs.

Kashin-Beck Disease:
Kashin-Beck disease is characterized by the degeneration of the articular cartilage between joints (osteoarthritis) and is associated with poor selenium status in areas of northern China, North Korea, and eastern Siberia. The disease affects children between the ages 5 and 13 years. Severe forms of the disease may result in joint deformities and dwarfism, due to degeneration of cartilage forming cells. Unlike Keshan disease, there is little evidence that improving selenium nutritional status prevents Kashin-Beck disease.

Selenium and health

Cancer - in studies with animals it has been shown that high (therapeutic) levels of selenium reduces cancer in animals. Geographic studies have shown that people who live in areas with low soil selenium and also have relatively low selenium intakes have higher cancer mortality rates. In one trial undertaken in an area of China, higher selenium intake showed a 35% reduction in cancers. Other studies, in other areas have confirmed this result
The heart - selenium's antioxidant properties are helpful in making the blood less "sticky", which is helpful in preventing heart attacks and strokes
The immune system - selenium deficiency has been associated with impaired function of the immune system. Good selenium levels stimulate the immune system into action to protect the body from viral or bacterial (or other pathegen) infection
Viruses - some researchers have shown that in selenium-deficient animals a harmless virus can mutate into a virulent form capable of causing more severe ill health and death - this has also been followed up and confirmed by other studies

People who wish to take an selenium supplement should talk to a medical professional BEFORE taking it.

FUTURE RESEARCH

HIV/AIDS - there is evidence that selenium levels decrease as the disease progresses, even before malnutrition is presented. Several studies are underway and show some improvement in symptoms of people with HIV/AIDS with selenium supplement but do not decrease mortality or disease progression. More research is underway

People who wish to take an selenium supplement should talk to a medical professional BEFORE taking it.

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Selenium in food

FOOD	AMOUNT	selenium (mcg)
Crab meat	85g	40
Salmon	85g	40
Halibut	85g	40
Noodles, enriched	1 cup	35
Prawns (shrimp)	85g	34
Pork	85g	33
Brazil nuts	30g (6-8 nuts)	30
Chicken (light meat)	85g	20
Rice, brown	1 cup	19
Beef	85g	17
Whole wheat bread	2 slices	15
Milk	1 cup	5
Walnuts, black	30g	5

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Selenium recommended daily intake (RDI)

RDA	lifestage	age	amount
	INFANTS	0-6mths 7-12mths	15mcg 20mcg
	CHILDREN	1-3yrs 4-8yrs	20mcg 30mcg
	CHILDREN	9-13yrs 14-18yrs	40mcg 55mcg
	ADULTS	19-50yrs	55mcg
	SENIORS	51+yrs	55mcg
	PREGNANT	all ages	60mcg
	LACTATING	all ages	70mcg

TOLERABLE UPPER LIMIT	lifestage	age	AMOUNT
	INFANTS	0-6mths 7-12mths	45mcg 60mcg
	CHILDREN	1-3yrs 4-8yrs	90mcg 150mcg
	CHILDREN	9-13yrs 14-18yrs	280mcg 400mcg
	ADULTS	19-50yrs	400mcg
	SENIORS	51+yrs	400mcg
	PREGNANT	all ages	400mcg
	LACTATING	all ages	400mcg

Toxic Levels	>1000mcg

The tolerable upper limits should only be taken for short periods and only under medical supervision.

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Selenium works best with

Overdosage, toxicity and cautions for selenium

Toxicity >2mg - birth defects, dermatitis, fatigue, garlic breath odour, stomach upsets, irritated eyes, liver impairment, metallic taste in mouth, nausea, weakness, yellow skin

Last reviewed: 1 January 2010 || Last updated: 1 January 2010

references

USDA National Nutrient Database - provides nutrient values for foods (accessed 5 January 2005)
Osiecki, H. The Nutrient Bible. Bio-Concepts Publishing QLD, 2002
Whitney EN, Cataldo DB, Rolfes SR. Understanding Normal and Clinical Nutrition, 6th Edition. Wadsworth/Thomson Learning, 2002

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NOTE: Mega doses of vitamins, minerals, amino acids, or other supplements cannot cure illnesses and in fact can be very dangerous and produce toxic side effects and interfere with medicine you are taking. Always ensure you consult your doctor before taking any type of nutrient supplement.

Disclaimer: This guide is not intended to be used for diagnostic or prescriptive purposes. For any treatment or diagnosis of illness, please see your doctor.

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references