Peak soil: Why nutrition is disappearing from our food

The secret to good health may start with dirt

Tomato harvest
(Image credit: (Joe Raedle/Getty Images))

The fountain of youth may be made of dirt.

So supposes Steve Solomon in The Intelligent Gardner: Growing Nutrient-Dense Food. He asserts that most people could "live past age 100, die with all their original teeth, up to their final weeks, and this could all happen if only we fertilize all our food crops differently." It's a bold statement, but mounting evidence suggests that remineralization could be the definitive solution to our nutrient-light diet.

Concerns about the quality of our food tend to focus on the many evils of modern industrial farming, but 10,000 years of agriculture have created a more insidious problem. The minerals and phytonutrients historically derived from rich soil are diminishing in our produce and meat. It takes 500 years for nature to build two centimeters of living soil and only seconds for us to destroy it. While pesticides, chemical-rich fertilizers, and agro-tech exacerbate the problem, even natural gardening can leach soil of vital minerals. When the same land is constantly re-cultivated without replenishing phytonutrients it yields more disappointing and nutrient-deficient crops.

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Jo Robinson of The New York Times writes:

Studies published within the past 15 years show that much of our produce is relatively low in phytonutrients, which are the compounds with the potential to reduce the risk of four of our modern scourges: cancer, cardiovascular disease, diabetes and dementia. The loss of these beneficial nutrients did not begin 50 or 100 years ago, as many assume. Unwittingly, we have been stripping phytonutrients from our diet since we stopped foraging for wild plants some 10,000 years ago and became farmers. [New York Times]

This is the same reason new gardeners often see generous harvests in their first few years, followed by diminishing results. The natural ecosystem is based on wild and diverse plant life, which creates more balanced and healthy soil. Agriculture, by nature, is designed to reap the maximum yield of crops, a process that has been honed and perfected over the centuries. It's quantity at the expense of quality, in other words.

As Nafeez Ahmed, executive director of the Institute for Policy Research & Development, notes:

Over the past 40 years, about two billion hectares of soil — equivalent to 15 percent of the Earth's land area (an area larger than the United States and Mexico combined) — have been degraded through human activities, and about 30 percent of the world's cropland have become unproductive. But it takes on average a whole century just to generate a single millimetre of topsoil lost to erosion. Soil is therefore, effectively, a non-renewable but rapidly depleting resource. [The Guardian]

Many experts believe the depletion of nutrients in our soil is responsible for many of the degenerative diseases that are more prevalent now than they were in our ancestors. Our predecessors had shorter lifespans than we do, but their primary cause of death was injury and infection. Research indicates that even those who lived into their seventies were far less likely than we are to die from degenerative diseases.

Solomon offers a solution: Remineralization. The process is relatively simple in concept. Through soil-testing, farmers can determine which minerals are deficient and regularly reintroduce them into their farmland. But the economics of it are quite challenging. At current food prices, artificially reduced by government subsides, the cost of remineralization could put many commercial farmers out of business.

Take phosphorus, for example. Vegetables and fruits grown in phosphorus-abundant soil have less starch and sugar, and feature higher concentrations of other important minerals and nutrients. Yet, the nutrient-rich produce looks the same as if it had been grown in phosphorus-deficient soil, making it difficult for consumers to rally behind the cause. Getting a critical mass of consumers is especially important because the cost of reintroducing a healthy supply of phosporus into just an acre of soil is about $10,000.

That's the crux of the problem for remineralization. While reintroducing phytonutrients and minerals into our soil would require a widespread commitment to invest more in our food, rallying the masses to get behind soil enhancement poses some unsurprising challenges. As David Montgomery, author of Dirt: The Erosion of Civilizations says, "Unfortunately, saving dirt just isn't a very sexy issue."

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