Agricultural science has delivered some remarkable advances in yields, but inadvertently created some perverse outcomes that practitioners like Carole Hungerford believe are trashing health and health budgets around the world.
CSIRO research published last year found that simply adding superphosphate to a wheat crop reduced zinc levels in the wheat grains by 33-39 per cent – to the point where people who got most of their zinc from the wheat in their diet would become deficient in the nutrient.
The research suggested the phosphate destroyed arbuscular mycorrhizal fungi (AMF) in the soil.
AMF are a key to how grasses like wheat access zinc from the soil.
Long fallows and canola crops, both hard on AMF, produced a similar depeletion of zinc in wheat grains.
A US Department of Agriculture study published in 2006 looked at changes in nutrient levels in hard red winter wheat as new varieties were introduced from 1873 to 2000.
They found that compared to 130 years ago, modern varieties deliver 36pc less selenium, 34pc less zinc and 28pc less iron.
From 1919, when wheat hybridisation began in earnest, the USDA researchers calculated that "...the amount of wheat farmers harvested from a given field increased by about 1pc each year, (but) the amount of these micronutrients in the harvested grain declined by .16 to .38pc each year".
And a University of Texas study of 43 fruits and vegetables, published in 2004, found nutritional quality declined in the 50 years between 1950 and 1999.
Six out of 13 nutrients studied showed apparently reliable declines, including protein, calcium, phosphorus, iron, riboflavin and ascorbic acid.
The declines ranged from 6pc for protein to 38pc for riboflavin.
"Perhaps more worrisome would be declines in nutrients we could not study because they were not reported in 1950—magnesium, zinc, vitamin B-6, vitamin E and dietary fiber, not to mention phytochemicals," lead researcher Donald Davis was reported as saying.
For more coverage see this week's The Land.
Email a friend