Did you know that the gold in your body is worth 1 euro cent? It is not much, although it is not that we have very large nuggets in our body: 0.7 milligrams at most and it does not play any biological role. Quite the opposite happens with the rare molybdenum, for which they would give us 0.0004 euros but without which we would not produce uric acid, the way our body has to get rid of unwanted nitrogenous material. Or the also rare vanadium, of which we have 0.1 mg, mainly in the tissues , and is thought to play a role in those enzymes that regulate the functioning of sodium in our body. For this we must maintain the daily needs of this element: 2 millionths of a gram per day, which we take from potatoes, lettuce and rice.
There are many elements that we can find in our body. Of some we only find minute traces, practically undetectable, and with names as little known as dysprosium, erbium, gadolinium, holmium, lutetium… that enter our body with water and food. Others, like lithium, of which we have 7 milligrams, we ingest it with plants , such as nightshades (the family to which potatoes belong) and in much less quantity with oranges and lettuce, among others. In us it does not seem to play any role, but it has been found that a lithium deficiency in goats makes them weigh less than those that do have lithium in their diet. Of course in quantities of a few parts per million, nothing to stuff yourself with a gram of this element so common in the batteries of our mobile phones. And what about cobalt, a tremendously important metal at a commercial level -it is involved in alloys for magnets, razor blades, ceramics, various catalysts in the chemical industry…-? We could not live without it because it is at the very heart of vitamin B12 and is an example of one of the rarest examples of bonding in nature: that of carbon with a metal.
Of course, and as an intelligent machine in the movie Star Trek said, we are units of carbon: a person who weighs 70 kilos will have 16 of this chemical element. But being purists, what we really are is an oxygen unit: nothing less than 43 kilos of the gaseous element, for which they would give us only about 86 euros. This high amount is explained by the fact that we are more than 60% water and because it also participates in the processes of bone formation. And this structure-support that is our skeleton weighs on average about 9 kilos, which explains why calcium and phosphorus are high on the list of abundances of chemical elements in the human body. But if we look carefully, of all the chemical elements that we can find inside our cells, which is practically all the elements that exist on the planet, we only need 25 for our body to function properly.
Interestingly, we absorb more useless strontium (about 320 milligrams) than other necessary elements . And all for one simple reason: because it resembles calcium. However, the fact that it is not useful for humans does not mean that it is not useful for other species. Some sea creatures use it in their shells, and a deficiency of this element in seawater causes 7 species of cephalopods to move uncontrollably. Furthermore, sea slugs such as Aplysia californica are sensitive to variations in strontium concentration as small as 1 part per million. Rocky corals also use it and that is why it must be added to aquariums.
The opposite happens with selenium, which in 1975 was discovered to be part of the enzyme glutathione peroxidase, which has an antioxidant effect. Of others, such as tin, it is still debated whether they play a role in the body. In the case mentioned, it has been found, for example, that rats with a dietary deficiency of this metal prevent them from growing normally. It is difficult to discover the influence of each chemical element that we have in our body, if any. Much remains to be investigated on the functioning of a body that, by weight and its components, would not give us more than 1,200 euros .
