It isn’t just people who are affected by the Standard American Diet (SAD). It’s plants as well. And when we eat these non-nutritious plants—or the animals that are fed on them—it is our health that suffers.
Just as the Standard American Diet helps destroy the beneficial bacteria and fungi on which our bodies depend for proper functioning, what we are doing to plants is destroying the soil microbiome on which they depend.
All living things—animal or plant—live in synergy with friendly microorganisms and cannot live without them. In the case of humans, the microorganisms are both inside us and surround us in a cloud on our skin. For plants, the microorganisms are in the soil. In either case, we kill them off with antibiotics or, in the case of plants, with fertilizers and poisons.
We are just beginning to have an inkling how this works. For example, one friendly bacterium may be vital to our immune system but cannot itself survive without a second bacterium, which in turn requires the presence of a third, not to mention the right food. What we do know about all these relationships is tiny; what we don’t know is vast.
A fascinating article in Nautilus magazine details how key fertilizer ingredients like nitrogen, phosphorus, and potassium make plants grow faster and bigger, but not healthier, and the result is less nutritious food. Fertilizers have increased crop yields, for instance, but as a result plants have markedly lower levels of key nutrients and minerals. A 2009 study found a 5 to 40% decline in the mineral content of fruits and vegetables over the last 50 years.
It’s a problem natural health advocates have been aware of for some time, and one of the important reasons we need access to quality dietary supplements. But why exactly is this happening to our food?
Just as human health relies on our gut microbiota, so a plant’s health relies on the innumerable microbes (bacteria and fungi) that occupy the plant’s root microbiome, sometimes called the rhizosphere, which some think contains more life per unit area than anywhere else on the planet. The root microbiome delivers metabolites to the roots as well as minerals and nutrients from the soil.
In return, plants send exudates—a combination of carbohydrates, phytochemicals, and other nutrients—into the soil to nourish the root microbiome. When a plant sends exudates to the root microbiome, it gets nitrogen, phosphorus, and potassium in return, in addition to other compounds that aid in plant health.
The importance of the root microbiome cannot be understated. Well-nourished mycorrhizal fungi, for example, can mine minerals even out of rocks and deliver them to plants. These fungi can also double or triple a plant’s nutrient uptake per unit root length. Certain bacteria eat tryptophan and return it to the plant in the form of indole-3-acetic acid, a hugely important compound for plant growth that helps build an extensive root system that can absorb even more nutrients.
When plants are doused in nitrogen, phosphorus, and potassium from fertilizer, it becomes less necessary to send exudates to the root microbiome. Exudate production decreases, and as a result, the root microbiome produces fewer metabolites that are beneficial to plants. This results in a plant that may be growing steadily but has fewer of the nutrients and minerals, phytochemicals, and compounds it uses to stave off disease, heal injuries, and fend off pests and pathogens. Low exudate production also means the mycorrhizal fungi cannot aid in nutrient uptake.
Microbes in the soil are also hugely important in converting organic matter into a form that plants can use. Dead leaves, for instance, are slowly broken down by larger organisms into smaller pieces that are in turn eaten by smaller and smaller organisms, until microbes in the soil convert those compounds into forms that plants need.
In modern agriculture, however, the fertilizer may not kill off the microbiome. It may have already been killed off by pesticide and herbicide applications. Or the herbicide may be genetically engineered to be infused into the seed (as is the case with Monsanto’s Roundup Ready crops), so that both fertilizer and herbicide damage or destroy the microbiome together.
As all this makes clear that we are playing dangerous games with nature, with no idea how destructive we are to the soil on which we all depend.
Other articles in this week’s Pulse of Natural Health: