From the Guardian.uk (via Common Dreams):
Mineral Levels in Meat and Milk Plummet Over 60 Years
· Study blames the decline on intensive farming
· Food industry contests comparative methods
The mineral content of milk and popular meats has fallen significantly in the past 60 years, according to a new analysis of government records of the chemical composition of everyday food.
The levels of iron recorded in the average rump steak have dropped by 55%, while magnesium fell by 7%. Looking at 15 different meat items, the analysis found that the iron content had fallen on average by 47%. The iron content of milk had dropped by more than 60%, and by more than 50% for cream and eight different cheeses. Milk appears to have lost 2% of its calcium, and 21% of its magnesium too.
Most cheeses showed a fall in magnesium and calcium levels. According to the analysis, cheddar provides 9% less calcium today, 38% less magnesium and 47% less iron, while parmesan shows the steepest drop in nutrients, with magnesium levels down by 70% and iron all gone compared with its content in the years up to 1940.
Scientists at the University of Newcastle's agriculture school have looked at differences in the fat and vitamin composition of milk produced in different farming systems. "We know that the faster grass grows the more you dilute the uptake of trace elements," Gillian Butler, a researcher, said. Another explanation might be that in traditional farming, clover, which is higher in minerals than grass, also played a greater part in feeding animals.