Mercury – sources and types.

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The problem with mercury toxicity is recognising it.  The symptoms are many and various since a good dose of mercury can affect the thyroid, the central nervous system, the brain and the cardiovascular system.  So mercury toxicity can mimic almost every disease from heart attacks, to an underactive thyroid to dementia.  It can also cause depression and leaky gut.

I was lucky enough to have a lecture on mercury toxicity from Dr Shade, interviewed in the above video.  He gave about a 5 hour lecture in an hour and a half, so his wpm was astronomical.  As the gun went off at the start of his lecture, he told us he is an extremely laid back kind of guy.    The above relaxed Dr Shade was not the Christopher Shade motoring through his lecture in Boston a couple of weeks ago!  Dr Shade’s lecture was extremely good and in this blog and the next, I shall expand a little on what he says above.

There are two main sources of mercury toxicity: big oily fish and amalgams.  Dr Shade also points out the air we breathe and vaccines as the other sources.  I really do find it extraordinary that this extremely toxic metal should be put in our mouths or injected into our babies.  But then I’m not a doctor or a dentist, so what do I know?  Fortunately the amount of mercury being added to vaccines is reducing.  As for the air we breathe: don’t live near a coal powered power station and avoid erupting volcanoes, don’t suck in petrol or diesel fumes and do look after the detoxification systems in the body.

Mercury comes in different forms, which have different effects upon us.  The form found in oily fish is called methylmercury, an organic mercury.  When we eat dark tuna meat or swordfish, our body confuses the methylmercury we eat with an amino acid1 making the mercury highly bioavailable – meaning the body gobbles it up mistaking it for useful stuff.  Once inside us, there is a 95% uptake across the blood/brain barrier, so tuna fish sandwiches for lunch is a good way to fry the brain.  Methylmercury also accumulates in the liver.

The fish to avoid are the big ones, high up the food chain; so shark; swordfish; king mackerel – these are found off the coast of America, off the UK coast we find the common mackerel, much smaller and less toxic; dark tuna meat and the mysterious tilefish.  Tilefish is rarely eaten, but when the four most contaminated fish were named and shamed, the tuna fish lobby discovered that the most contaminated fish in the world is the tile fish, thus knocking tuna off named and shamed status.  As far as tuna fish is concerned, apparently the light meat is not so bad, but the dark tuna meat should be avoided.  All oily fish salmon sized and smaller are OK to eat as part of a widely varied diet.

The other common, and more dangerous, source of mercury comes from our amalgam fillings.  From what I have found out, amalgam fillings comprise 50% mercury mixed with silver, tin, copper a bit of zinc and some other trace metals.  The mercury in amalgams is inorganic and not particularly bio-available. In theory amalgams are stable in our mouths.  In practice it has been found that whenever we chew, we release mercury vapour.  Some say it evaporates slowly all the time.  Without doubt, a broken amalgam filling is releasing mercury vapour all the time. Inorganic mercury may not be particularly bio-available, but mercury vapour most certainly is.  Its a different kettle of fish altogether.2

The mercury we ingest from our fillings is even more toxic than methylmercury from fish, having a significant effect on our guts and immune system.  It tends to get caught in our detoxification organs, so the kidneys, liver and gut. It can also play havoc with our mitochondria, the tiny powerhouses in our cells, and so cause chronic fatigue symptoms.  And once in our body, it is hard to dislodge.

As Dr Shade says, although many people have amalgam fillings and many people eat tuna fish, not everybody suffers from mercury toxicity.  The reason lying in our ability to detoxify mercury and the other heavy metals cadmium and arsenic.3  This ability is is mainly genetic but also environmental: as we get older our detoxification abilities start tanking, as Dr Shade memorably put it.  Along with everything else, it seems.

So if we have chronic stuff going on: depression, underactive thyroid, leaky gut problems, heart problems – the list is depressingly long – and we have amalgam fillings (or eat plenty of tunafish), there is a high chance that we have  inherited a system detoxifies mercury inefficiently.  Cutting out the tuna is not difficult.  Sorting out the amalgams is.  To have an  amalgam filling removed is a serious undertaking; if we want to do that we need to track down a biological dentist who can remove the amalgams with a care for both our and their health, helping reduce the resulting mercury vapour and giving detoxification help to our bodies.  It won’t be cheap.

The next blog will go more into the detoxification of mercury and the various ways of detecting it.


  1. Whole proteins break down into amino acids.  The amino acids it confuses mercury with are the cysteines. []
  2. Sorry for the terrible joke. []
  3. Lead, incidentally follows a different detox pathway. []

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