Evolutionary Association, Chapter 8: Fertiliser

Plants do not grow all by themselves - they need nutrients from the soil - and we humans supply them with some of those.

The Dietary Change

Industrial agriculture needs fertiliser for its high yields - and fertiliser is normally⁽¹⁾ readily and universally available.

At the beginning of the 20th century the Haber-Bosch process⁽²⁾ was developed, which allows ammonia - the valuable base material for nitrogen fertiliser - to be produced on an industrial scale. Practically the entire demand for ammonia is met by this process today - and according to Wikipedia, this one process alone accounts for 1.4 to 3 % of annual global CO₂ emissions and 1 to 2 % of annual energy consumption.

But nitrogen alone is not enough, so further substances are mixed in, for example in NPK fertiliser⁽³⁾. This gives plants plenty of the nutrients they need in order to grow. Just like microorganisms, they can build amino acids (the building blocks of protein) out of those components, and the harvest turns out larger than it would be without fertiliser.

On top of that, the dietary guidelines recommend that we take in more than half of our required energy in the form of carbohydrates - and we recall: those are the substances that get broken down into sugar - glucose, strictly speaking - and thus drive blood sugar and insulin levels up.

A wheat-field with horizon (Credits on the linked page)

Nutrient Density

A surprising effect in the intake of nutrients, showcased on Magnesium from Wheat. Why more isn’t always better…

New ND Simulation

The Phenomenon

Ever since mineral fertiliser came into use, every patch of farmland has been yielding more and more. Breeding new varieties (faster growing, larger) together with the use of fertiliser means that more and more is harvested. Even though hunger sadly remains an issue in some parts of the world: in many parts of the world (and I am writing this article from a German perspective) there is food in sufficient quantity.

Despite this generally good food supply, there are more and more signs of deficiency. They show up, for example, as night-time calf cramps, muscle tension (“my back’s playing up”), heart rhythm disturbances, a population that sleeps badly, and plenty of other symptoms.

The Biochemical Association

Larger agricultural yields from the same area also mean that more nutrients are taken out of the soil. Mineral fertilisers are there to make up for that. Unfortunately they contain plenty of the substances that allow a larger harvest with more macronutrients, but they do not raise the share of micronutrients in the soil (minerals, for example) - quite the opposite: the fertiliser-induced extra plant growth pulls those out of the soil faster than was previously the case.

Let us take magnesium as an example - it is not part of N-P-K fertilisers, and a collective deficiency in this mineral leads to exactly the symptoms I listed above⁽⁴⁾. Soils are by now considered low in magnesium.

This has in fact been recognised, both by the food industry and by agriculture: magnesium is one of the best-selling food supplements, and in some cases it is added back to the soil as well. Neither in the field nor in the human body is this straightforward, because what matters is bioavailability: whatever comes in a form that plant or human cannot make use of is money down the drain.

But that falls short: magnesium is not the only micronutrient we need. This same story has to be repeated for every other micronutrient. For all the known ones, and for all the unknown ones. Because what is not in the soil does not end up in the plant either, and consequently not in the human being.

And even that can be topped: the bigger, the more “inflated” the crops turn out, the lower the concentration of micronutrients, simply because the same amount of a substance is spread across a larger volume (of harvest). The soils need not even be depleted for that - but after a few harvest cycles without replacement, they likely will be.

We can see the difficulties that follow from this, can’t we?

What does magnesium actually do?

Many people will know the home remedy for cramp: magnesium. It is involved in around 300 enzyme reactions in the body⁽⁵⁾ - sometimes as part of the enzyme, sometimes as a coenzyme - and it is needed in particular for the relaxation of muscles and nerves, as well as acting as a catalyst in providing energy via ATP (the body’s actual “energy currency”).

In breaking down glucose, magnesium is involved in some 30 steps. There are so many of them (glycolysis⁽⁶⁾, citric acid cycle⁽⁷⁾, electron transport chain⁽⁸⁾) that, chapter title notwithstanding, I will spare you the actual biochemistry at this point. In some places this sounds like consumption - but it is “only” a catalyst (or an enzyme component), which is precisely what does not get consumed.

But even that is not all I am getting at. Given that the dietary guidelines encourage us to eat plenty of carbohydrates, there is of course one more aspect that cannot be missing on butterbei.de:

Sugar (glucose) and magnesium

When blood sugar and insulin levels are high, the reabsorption of magnesium in the kidney stops working properly⁽⁹⁾. The two act independently of each other: blood sugar even without raised insulin, insulin even without raised blood sugar. As a result more magnesium is excreted in the urine and is therefore no longer available to the body at all. So even if farmers use the more expensive magnesium-enriched fertiliser on their fields, or we supplement magnesium ourselves, we can excrete it again right away when our blood sugar and insulin levels are too high.

Elsewhere I like to grumble about antinutrients, which see to it that micronutrients are not absorbed by the body - here a (nonessential ) macronutrient (glucose, carbohydrate) sees to it that micronutrients already present get excreted again, and that a deficiency can arise by that route.

Once again I recommend the simulator for getting a feel for blood sugar and insulin levels. In this case the comparison feature, which lets you compare a healthy metabolic profile with a prediabetic or diabetic one. You can see straight away how much higher the curves are in the two comparison cases.

The solution: more fertiliser?

At first you might say: great - we know about it, so we take our magnesium on the side, or spread it on the field along with the NPK fertiliser.

Then we remember the fourth Rumsfeld quadrant, “we don’t know what we don’t know”, and ask ourselves what else besides magnesium we would have to tip onto the field, and whether other micronutrients meet a similar fate inside the body.

Anyone with a similarly sarcastic inner voice, and motivated enough to move away from social norms (bread + pasta), has another option and lowers their blood sugar - a ketogenic diet helps enormously with that, and makes sure the body at least does not flush out the magnesium it has already taken in.

“Phenomen-al”: actually measured

While researching this article, one point took on a sharper shape - one I had already touched on in Chapter 6 on Sourdough: the varieties being grown. There I wrote about dwarf wheat, which “also brings other properties with it”. Here is one of them:

At Rothamsted in England, a wheat field trial has been running since 1843, and its harvests have been archived - so the grains from 1845 and those from today can be analysed in the same laboratory using the same method⁽¹⁰⁾. The result: zinc, iron, copper and magnesium stayed stable until the mid-1960s and only fell after that - precisely from the introduction of the new, high-yielding dwarf wheat varieties. In the soil of those same fields, by contrast, the concentrations stayed the same or even rose⁽¹¹⁾. So it was not the depleted soil. It was the yield, or rather the variety being grown⁽¹²⁾.

The authors themselves supply the reason:

However, modern plant breeding has been historically oriented toward higher agronomic yield rather than the nutritional quality.

That is not a conspiracy, it is a target⁽¹³⁾. Breed for yield and you get yield. Nobody ever selected for magnesium.

And here too: magnesium is only one example - the same holds for all the other micronutrients. For the known ones, and for the unknown ones.

Conclusion

It seems that, in the effort to provide the population with enough calories, we lost sight of the fact that “fuel” is by no means the only reason we eat. But as long as a harvest is measured and paid for by weight rather than by quality, the prevailing incentives in the system simply do not match what I expect from my food.

The wheat/magnesium example given here looks to me like the perfect storm: “eat things that supply little magnesium and at the same time get the body to excrete more of it.”

That wholegrain health halo: could I have another look at it, please? My vision seems to have gone a little cloudy.