An analysis of the five editions of McCance and Widdowson’s Composition of Foods showed that:

• the mineral content of UK soil fell 1939-1991, in some cases dramatically. The falls are: (vegetables) Sodium 49%, Potassium 16%, Magnesium 24%, Calcium 46%, Iron 27%, Copper 76%, Zinc 59% (fruit) Sodium 29%, Potassium 19%, Magnesium 16%, Calcium 16%, Iron 24%, Copper 20%, Zinc 27%. The only mineral to rise was phosphorous, by 2%.

• Overall world soil mineral depletion was reported to the Rio Earth Summit (1992) by the US Senate as: North America 85%, South America 75%, Europe 72%, Asia 76%, Africa 74%, Australasia 55%

• As our science improves, more and more minerals are recognised as beneficial to health, e.g. Selenium 1957, Chromium 1959, Tin 1970, Vanadium 1971, Fluorine 1971, Silicon 1972, Nickel 1974, Arsenic 1975, Cadmium 1977 and Boron 1990. A good example is selenium. When Finland added it to fertilisers the rate of heart disease reduced and Finns now have an average three times the selenium content of people in the UK

• Because trees dig deeper for their minerals, tree products like nuts, fruit and leaves are a more reliable source

See also Organic soil more nutritous