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The Link Between Soil and Human Health

E. Bader
April 25, 2023

“You are what you eat.”

This catchphrase first appeared in advertising campaigns in the 1920s, an adaptation of French physician and the author of “The Physiology of Taste” Jean Anthelme Brillat-Savarin’s 1823 statement: “Dis-moice que tu manges, je te dirai ce que tu es.” Tell me what you eat, and I will tell you what you are.

Over the past 200 years, the phrase has become an unwavering mantra for nutrition advice. While the connection between health and what we eat has taken root in our culture, if not our medical system, we have yet to connect the nutritional content of our food and what it “eats.”

Not all broccoli is created equal. Here’s why.

Our current food system is a system built for quantity and based on commodities and yield. Food security is tied to the ability to produce as many calories as possible as efficiently and as certainly as possible. In this system, varieties of crops are selected for yield, not flavor or nutrition. Crop management is reduced to a prescribed amount of nitrogen, phosphorous, and potassium (NPK), plus additional chemicals to control weeds and pests.

We have a similar reductionist approach to nutrition science. In this system, nutrients are traded commodities. Food labels list macronutrients such as carbohydrates, protein, and fats and micronutrients including vitamins and trace minerals. Nutrition is interchangeable units of recommended daily allowances and calories. One apple is the same as another, and vitamins and minerals can be added to make a processed, apple-flavored muffin and an apple appear equally “healthy.”

But what if the scale in the grocery store aisle could measure quality, not just quantity? We could easily weigh one head of broccoli against another for its impact in our health. Of course, to use this scale, we first need to understand what it measures.

Nutrition quality and the food-eater synergy

Over a century ago, scientists first connected deficiencies in vitamins and minerals to diseases like rickets. The discoveries dramatically improved lives. However, the new field of isolating and chemically synthesizing vitamins gave rise to the billion-dollar supplement industry and our current reductionist approach to nutrition and vitamin-fortified, processed foods.

Fortunately, nutrition science is evolving. One newer concept is “hidden hunger,” the recognition that deficiencies of micronutrients can occur even with adequate calories. The primary cause of hidden hunger is a decline in food nutritional value from unsustainable agriculture practices and nutrient-deficient soils.

Another nutrition evolution is “food synergy.” Simply put, food synergy is the idea that a food is greater than the sum of its parts. Food synergy is relationship-based. The concept includes how the building blocks of a given food work together and how these work within us, the eater, including how we digest them and how they affect us down to our cellular level.

Food synergy studies compare the nutrition in foods created by technology or biology. The findings are clear: a vitamin-fortified apple-flavored muffin is not equal to an apple. Biology is better, and plants are the best chemical engineers.

The soil-plant synergy

Plants produce various phytochemicals in response to their environment. They actively manage their relationship with a soil microbiome by secreting chemicals from their root systems. The richer the soil’s microbiome and mineral content, the more active the plants become in the uptake of nutrients, production of phytochemicals, and building of health and defense systems. 

For plants to uptake minerals and micronutrients, the soil must contain the nutrients plants need. Soil “macronutrients” may be nitrogen, phosphorus, and potassium, but plants, like people, need micronutrients as well. These soil micronutrients include calcium, magnesium, iron, and zinc. Soil nutrients must also be in a form that plants can uptake, or bioavailable. If the soil is compacted or waterlogged, or if the soil’s biology is poor, the nutrition in the soil will be less available to the plant.

Excessive use of inorganic fertilizers and pesticides reduces soil biodiversity, including mycorrhizal fungi. These fungi have a mutualistic relationship with plants and support mineral uptake by the plants’ roots. When a plant needs more nutrients from the soil, it releases more phytochemicals from its roots to recruit fungi. When easy synthetic fertilizer is present, a plant becomes dependent. It produces fewer phytochemicals and takes in fewer nutrients from the soil. Fertilizers increase aboveground plant biomass, but that yield comes at the cost of nutrition quality, soil health, and phytochemical content. 

Phytochemicals are potent compounds. For example, stress and pathogens trigger plants to produce defensive phytochemicals, including salicylic acid, the active ingredient in aspirin. Plants’ chemical defense systems are the basis of many other medicines, including the cancer drug paclitaxel, painkillers like morphine, and the anti-malarial drug artemisinin. Phytochemicals also include phytonutrients, which have potent and positive effects on our health. 

Phytonutrients are the chemicals that give plants their color, flavor, and odor. The compounds include flavonoids, carotenoids, and anthocyanins associated with powerful antioxidant and anti-inflammatory health benefits in food. The healthier the soil – the minerals and nutrients plants “eat” – the more phytonutrients, micronutrients, and minerals plants can contain.  

The soil-plant-eater synergy

Nutritionists define food synergy as the relationship between the constituents of food and eater. A more complete food synergy exists between soil, food, and eater.

For the past few decades, the food production and nutrition debate centered on conventional versus organic practices. In 2012, a widely publicized meta-study compared findings from 223 studies of the nutritional content of organic and conventional produce. The analysis found significantly higher levels of pesticides and nitrates in conventional produce, but unclear nutritional difference between conventional and organic produce. The study considered only macro- and micronutrients. The meta-study data identified variation between nutritional content for both conventional and organic produce, but the study did not analyze why the data was inconsistent.

Long-term, controlled studies identified the why: the boundaries of organic versus conventional systems do not define the variables linked to increased food nutrition. One variable is the crop variety, or cultivar. For example, a purple tomato can have up to six times the beta carotene and lutein as a red tomato. Whether it is beta carotene in broccoli or folate in beets, different cultivars vary widely in micronutrient and phytochemical density.

Soil health is linked to all the other variables. Organically managed soil generally has better biodiversity than conventionally managed soil. But both conventional and organic systems rely on tillage. Organic systems often use tillage for weed control. Tillage degrades soil organic matter and reduces soil life and biodiversity, decreasing mineral uptake and phytochemical production in the crop. No-till management increases soil carbon and biodiversity while reducing reliance on fertilizer and pesticides.

Soil health and biodiversity rely on soil carbon stock, which takes time to build. Thus, the length of time land was managed with organic and conservation practices also impacts the nutrient density in crops. The rate of soil carbon sequestration also varies significantly with management practices, soil type, and climate.

Biodiversity, aboveground and in the soil, is also linked to nutritional content. Farms with diversified crops and soils that host a rich microbiome produce higher quality food and increased micronutrient and phytonutrient density.

No-till, reduced reliance on fertilizer and pesticides, and building biodiversity are all considered regenerative practices. Regenerative systems, including regenerative organic management, produce foods with the highest micronutrient and phytonutrient density. How we manage the soil and produce food determines our role in the soil-plant-health synergy.

That relationship can be extractive, focusing only on the quantity we take. Or it can be mutually beneficial in which we care for the living soil that, in turn, produces quality food. By regenerating the soil and our relationship to the food we consume, we regenerate our health.

Check our sources.

We love intellectual curiosity and critical thinking. If you want to read more, here are the sources of information for this article.

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