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Nutrient levels in food supply eroded by pursuit of high yields
When we sit down to a meal of supermarket-bought produce, we like to think we’re getting a reasonable cross-section of the body’s nutrient requirements, but studies are showing that our chemical intensive monocrop farming systems are not delivering the vital ‘secondary nutrients’ that our ancestors enjoyed. Plants ‘flourishing’ on fast, soluble chemical fertilisers get ‘lazy’ and do not develop the deep, healthy root systems that pull additional elements out of the soil. In addition, the soil micro-organisms that break down organic matter and minerals to feed to plant roots are being slaughtered through chemical bombardment and violent mechanised manipulation of their environment.
Essentially, we’re getting robbed, and having to pay for it in reduced health/vitality/longevity and increased medical bills.
Actually, if you understand a little about soil science and plant health, the information in the recently released report – Still No Free Lunch – should be obvious to all. But, for many of us, the closest we get to the land is when we take a walk down the aisles of our local shopping centre.
American agriculture’s single-minded focus on increasing yields over the last half-century created a blind spot where incremental erosion in the nutritional quality of our food has occurred. This erosion, modest in some crops but significant in others for some nutrients, has gone largely unnoticed by scientists, farmers, government and consumers.
Government data from both America and the United Kingdom have shown that the concentration of a range of essential nutrients in the food supply has declined in the last few decades, with double digit percentage declines of iron, zinc, calcium, selenium and other essential nutrients across a wide range of common foods. As a consequence, the same-size serving of sweet corn or potatoes, or a slice of whole wheat bread, delivers less iron, zinc and calcium.
Fewer nutrients per serving translate into less nutrition per calorie consumed. This erosion in the biological value of food impacts consumers in much the same way as monetary inflation; that is, we have more food, but it’s worth less in terms of nutritional value.
… Agronomic practices have worked hand-in-hand with plant breeding in setting the stage for this nutrient decline. Together, the tactics farmers use to increase yields—including close plant spacing and the widespread use of chemical fertilizers, irrigation and pesticides—tend to create big plants that grow fast, but do not absorb a comparable quantity of many soil nutrients. The plants are dependent on highly soluble, readily available sources of nutrients applied by the farmers, as opposed to those distributed through each acre’s layer of topsoil. In fact, recent studies have shown that crops grown in poor quality, low organic matter soil sometimes have higher rates of root disease, and can struggle to absorb nutrients even when the nutrients are present at high levels in the soil profile – Executive Summary, Still No Free Lunch: Nutrient levels in U.S. food supply eroded by pursuit of high yields (PDF)
Nitrogen, Phosphorus, and Potassium on the Menu
The main ingredients in the chemical soup poured onto our fields are Nitrogen (N), Phosphorus (P) and Potassium (K). Plants will grow on little more than this, but like a kid fed only on chocolate all his life, the plant’s growth is not matched with corresponding vitality. Essential nutrients are missing from the diet and this shows up in poor plant health (remember, you are what you eat). Plants become vulnerable to disease – necessitating further applications of chemicals – and they perish faster, which has contributed to the birth of the concept of food irradiation. These additional polluting and resource/energy intensive practices are simply patching holes in the globalised monocrop farming system, a system that will inevitably collapse.
The report shares the results of studies that show organic farming practices, conversely, produce crops with higher nutritional value – including boosted rates of cancer-preventing antioxidants:
Some studies have reported even more dramatic differences in concentrations of specific phytochemicals—for example, nearly twice as much of two common antioxidants in organic tomatoes compared to conventional tomatoes. Organic forms of fertilizer, like manure or cover crops that offer more balanced mixes of nutrients and release the nutrients more gradually, encourage plants to develop more robust root systems that more aggressively absorb nutrients. At the same time, for a wide range of fruits, vegetables and grains, reducing pesticide use has been shown to boost phytochemical content, sometimes dramatically.
… High levels of readily available nitrogen tend to reduce nutrient density and the intensity of flavors, and sometimes make crops more vulnerable to pests. Nutrients in compost, manure, cover crops and other soil amendments tend to be released more slowly in step with crop needs, and often help to boost crop nutrient levels, the efficiency of nutrient uptake, and flavor profiles. The large amounts of organic matter returned to the soil in organic farming systems encourage healthier, more robust roots, higher levels of available micronutrients, water infiltration and retention, and below-ground microbial activity that can help increase crop nutrient density.- Executive Summary, Still No Free Lunch: Nutrient levels in U.S. food supply eroded by pursuit of high yields
If you are not already growing your own food, then, as you transition, do support local growers that are working with natural systems – and experience the benefits. The advantages of food grown with a focus on soil health are more than just being able to eat ‘chemical free’ produce. Truly organic food is not just a subtraction of a negative, but also an addition of many positives — health-giving and disease-preventing nutrients are not the least among these.