A wealth of evidence shows that toxic metals can compromise the immune system, and damage the nervous system and brain. Raised levels are associated with decreased concentration and organisational skills, problems with speech and language comprehension, and lowered intelligence. Metals are implicated in autism, dyslexia and ADHD.

Deficient food Contributing to the ‘dumbing down’ of this generation is the poor state of our food. Nearly every study in the last century found that agricultural land, vastly overused and oversprayed with pesticides, is now depleted of minerals. The 1992 Earth Summit in Rio de Janeiro reported that US farmland was 85 per cent depleted of minerals while the overall worldwide depletion was 75 per cent. Manganese, zinc and iron were particularly low (FAO Soils Bull No 63, Rome, 1990).

It’s not just minerals that are lacking. Modern-day crops of wheat are around 9 per cent protein compared with 90 per cent in 1900. US Department of Agriculture handbooks reveal that the vitamin content of fruit and vegetables has also declined across the board, with the beta-carotene in broccoli and the vitamin C in cauliflower both down 50 per cent since 1963.

Vitamins and minerals are important in brain chemistry, and a deficiency in only one can result in a diminished mental capacity, mental and emotional disturbances, behavioural disorders and autism (Int J Bio Soc Res, 1981; 1: 21-41). It is not unreasonable, then, to consider at least a partial link between the decline in soil nutrients and the rise in learning difficulties.

Poor nutrition sets up a vicious cycle - it leads to the increased uptake of toxic metals which, in their turn, further interfere with the absorption of essential nutrients like magnesium, zinc, lithium, iron and the B vitamins. Brain cells, for example, absorb more toxic metals when the diet is low in calcium, iron, zinc, vitamin D and other essential nutrients.

What foods children do eat these days is often highly processed and filled with additives, many of which have proven links with conditions such as ADHD. One such additive is the artificial sweetener aspartame, which contains phenylalanine, a compound known to have a toxic effect on neurological functioning, with symptoms consistent with ADHD, if present at high levels in children. It can also affect children prenatally if ingested by the mother (Neuropsychology, 2003; 17: 458-68).

The best headstart for every child today, whether or not he is considered learning disabled, is a wholefood, unprocessed diet, rich in essential fatty acids, low in or free of gluten and dairy.

Michelle Clare and Lynne McTaggart