Essential Poisons for a Balanced Diet
Nitrogen is present in the proteins used to build up the muscle and collagen from which our bodies are constructed.
Calcium and phosphorus are essential to the structures of bones and teeth. Sodium and potassium are employed in the transmission, along the nerves, of electrical signals from the brain. Though we require only a few milligrams of iron, zinc and magnesium each day, our requirements are still large enough for our diets, sometimes, to be deficient in them.At the lower end of the scale, a handful of elements are needed in such tiny amounts that we are never likely to be short of them. Indeed the opposite problem can occur. If we eat these to even slight excess, they become quite poisonous.
Uses and Toxic Effects of Selenium
Selenium belongs to the same family of elements as oxygen and sulphur. Our daily requirement is probably as little as 10 micrograms (millionths of a gram), while a balanced diet, containing fish, liver, nuts and bran, probably contains five or six times that amount. In addition, a large reservoir is available in our bones, hair and kidneys, that can be drawn upon in the unlikely event of a shortage in the diet.
Selenium performs several jobs in the body. It provides a measure of protection against high blood pressure, anaemia, arthritis and some forms of cancer. It also appears to be important in the formation of hormones in the thyroid gland, and may ease some of the effects of iodine deficiency. In addition, it helps protect the body against highly toxic metals like mercury, cadmium, arsenic and lead.If the daily intake of selenium rises above 450 micrograms, then its toxic nature becomes apparent in symptoms such as hair loss, nerve damage and digestive disorders.
A single intake of 5 milligrams would be dangerous and 50 milligrams probably fatal.Certain plants, like vetches can absorb high concentrations of selenium from the soil. Animals fed on these show erratic behaviour, known as staggers, as a result of selenium poisoning. If the body does contain excess selenium, then this is excreted through the breath and skin as a foul-smelling methyl selenium compound.
Cobalt, the Element Vegans May Miss
Cobalt metal is essential for the formation of vitamin B12, the lack of which causes pernicious anaemia, in which there are insufficient red blood cells to carry oxygen around the body. As plants have no need for cobalt, animals have to eat at least some animal products to obtain enough in their diet. Liver, eggs and oily fish are rich in vitamin B12, though a balanced diet contains more than enough to fulfil requirements. Only vegans, who eat no animal products, are likely to suffer from cobalt deficiency.Cobalt salts cause dermatitis if applied to the skin, while excess in the diet can cause cancers, as well as damage the heart and thyroid.
Chromium, Molybdenum and Manganese
Anyone who has seen the film ‘Erin Brockovitch’ will be aware of the toxic nature of chromium compounds. As well as causing cancers, these can also lead to ulcers on the skin and in the stomach. Yet traces of chromium are needed for the efficient metabolism of glucose, and a lack of the metal can lead to diabetes.Chromium is present in common foods such as eggs, nuts, beans and apples.
Root vegetables, like potatoes and carrots are able to absorb chromium from the soil.Molybdenum, a close relative of chromium, is found in bones, skin, liver and kidneys and can be obtained by eating pork, lamb, eggs and green beans. Fruit contains very little molybdenum. Though the daily requirement may be as low as 50 micrograms, it is present in no fewer than twenty enzymes. One of these helps in the conversion of nitrogen compounds into uric acid prior to their excretion in urine.
Another aids the breakdown of alcohol in the body. People with low levels of this are very easily intoxicated.Molybdenum begins to become toxic at about 400 micrograms and sustained intake above this level can lead to convulsions and mental retardation and deformities in unborn children.Manganese appears to be involved in the operation of vitamin B1 and in the metabolism of glucose. It may also be present in an enzyme that helps prevent the damage to cells caused by free radicals.
As manganese is widespread in the soil, and is the 12th most abundant element in the earth’s crust, it is unlikely to be lacking in the diet. It becomes toxic at intake levels above 20 milligrams.Our daily requirements of these trace elements are so tiny that a balanced diet is very unlikely to be deficient in any of them. Dietary supplements rarely do any good, as the excess is generally excreted as surplus to our bodies’ needs.
Find more on:
Healthdiet
Tagged with:
#vitaminb12 #vitamin #chemical elements #oxygen #liver
Comments
Post a Comment