There are three recent, prominent studies, examining the historical food composition data, covering time-frames of between 50 and 70 years. Davis, Melvin and Riordan (2004), in their study, highlighted that over the last 50 years, there have been many changes in the way vegetables and other crops have been grown and distributed in developed countries. The United States Department of Agriculture (USDA) suggested there had been an ‘alarming decline’ in food quality when looking at data in 12 common vegetables between 1975 and 1997.
Mayer (1997) argued that the historical reductions of minerals, described as the ‘dilution effect’ (the relationship between crop yield and mineral concentrations) is more difficult to quantify than suggested by Davis and is therefore open to a greater degree of interpretation, so she was more cautious in her conclusions. However, despite this caution, Mayer did find ‘marked reductions’ of seven minerals across 20 fruits and 20 vegetables, in a comparison of UK food composition data from the 1930s to the 1980s.
White and Broadley’s (2005) research arrives at a similar conclusion, suggesting that over the last 50 years there has been an apparent median decline of 5-40% in some mineral groups of vegetables and fruits. In some instances the dilution effect was found to be even greater.
At the time, U.S. and Canadian agricultural soils had lost 85% of their mineral content. Asian and South American soils were down 76% while throughout Africa, Europe and Australia, soils were depleted by 74%, 72% and 55% respectively (Marler and Walling, 2006).
If we are indeed altering the ecosystem as is suggested, through over-farming, pollution, deforestation, global warming, lack of replenishment of our soils and the contamination of water, then clearly anything that can offer some compensation for the impact this may be having on physical and psychological health needs to be taken seriously.
Added to the dilution effect, which essentially means we are eating more food yet getting less nutrients, is also the energetic expenditure that our food is costing. In other words, we are spending more energy in terms of our production costs for food, which means by the time something lands on our plate, it literally cost us more in terms of what was spent to create it than what we spent to purchase it. This position cannot be sustained – most of all by the planet and if the planet can’t sustain it, how are we to survive?
We have to start thinking more creatively about the future of food, because it’s our future too…