Our nutrient density research revealed a vast amount of complexity in how plants respond to different environments
Most Acres U.S.A. readers are experienced farmers, gardeners, or other industry professionals who have been involved in growing plants for many years. But how many of us can honestly say we’ve taken a critical look at the nutritional value of the crops we’re growing or eating? That’s the uncomfortable reality I faced a few years ago after meeting Dan Kittredge from the Bionutrient Food Association.
After having been a professional farmer, college instructor and certified consultant for over 20 years — someone who was keenly interested in food quality — I realized that despite having done plenty of Brix testing over the years and having tested tens of thousands of soil, plant, fertilizer and irrigation water samples, I’d never really tested the crops themselves. It was one of those moments in life when you take a step back and realize that something you should have thought of years ago seems so obvious.
After a brief moment of humility, our team at Apical decided to put a plan together to test crop quality. We began digging into the concepts of food quality by analyzing the mineral and other metabolic contents of crops and comparing the results with those crops’ growing practices. This involved talking with nutritional labs around the country about analysis methods and current practices in lab sampling and processing, and wading through research journals to identify what work was being done on the topic. To our surprise, the answer was very little in terms of useful information for consumers — and even less for farmers eager to improve the nutritional value of their crops.
Gaps in Existing Data
USDA does have some basic mineral data for crop nutrient standards, but these are relatively incomplete and out of date. Additionally, there are many crops for which we could only find incomplete nutritional profiles for minerals — let alone solid standards for metabolic compounds or molecules of interest from a medical perspective. After digging through research journals for a full winter, our lab team concluded that there needed to be a data-gathering stage in which we could build nutrient profile targets for a number of crops.
For the next 12 months, we tested dozens of crops, hoping to build some basic nutrient profiles while we scoured all published literature on the nutritional value of more than 60 crops. By mid-2024, we had what appeared to be a basic analysis method — a skeleton of mineral target values for various crops and some key metabolite categories to monitor that related to nutrient flows in the plant. At this point, I happened to come across some information on nutritional contamination in soils related to heavy metals as a major concern in a number of foods, so we decided to add a low-detection-level heavy metal component to the tests. But as we ran more tests, patterns started to emerge.
The Complexity
Last fall, we quietly started beta testing our Crop Nutrient Analysis, a ~$100 laboratory analysis that gives growers insight into the report card nature is giving them. The initial intent of the test was to show growers how their produce stacks up, primarily from a mineral perspective, with other growers. For example, how many carrots do my customers need to eat from my competitors to equal 10 of mine? We’ve since found that while this is possible, there’s a lot more going on that relates to growing practices, as well as what we’re all eating generally, that’s probably more significant. Additionally, we’ve found that making claims of nutritionally dense or “better” may be more complex than we originally anticipated.
It’s pretty amazing that there’s been so little attention to the analysis of the produce we eat for the past 50 years. In a casual summary of the analysis, we’ve discovered some great information and some interesting truths.
Specifically, each crop (fruit, vegetable, grain, nut, etc.) has a unique blend of minerals, proteins, sugars and other metabolites based on location, weather, genetics, growing practices and a host of other factors (harvest timing, post-harvest handling, storage, etc.).
Similar to the work of the BFA, we’ve noted differences from 10 to multiple hundreds of percent difference in any given mineral in any given crop. In other words, “not all food is created equal” is the rule rather than the exception, contrary to what USDA has led us to believe all these years.
Also, once we started looking closely at minerals in crops, we noticed that since there are a couple dozen minerals of interest, it would make sense that not all of them are higher or lower in a given sample; rather, each crop is individually different and contains a different blend of minerals.
Unfortunately, we’ve also found high levels of various metals in random samples of produce across all types. Various non-metallic antimicrobial compounds such as chlorine (chloride) or nitrate can often be found in random samples in 10x quantities. We also see large spikes in polyphenols in crops that have high levels of metals contamination.
Interestingly, we’ve also noted less than statistically significant differences between minerals in a lot of produce from different growers. In other words, growers who were growing organic unknowingly used the wrong inputs. While they had fewer pesticides in the crop, they had mineral levels significantly similar to conventional crops, though with higher Brix and contamination of heavy metals.
Lastly, and perhaps most alarmingly, some growers using sewage sludge years ago who thought they were doing the right thing for the environment made one wrong move and contaminated their whole crop and soils with heavy metals for years to come.
Patterns in Nutrient Uptake
Over the past nine seasons, we’ve analyzed tens of thousands of leaf sap tests for growers and have identified significant patterns in leaf mineral uptake related to soil health. We can now confidently assert that mineral health (or sickness) of soils can be transferred from soils to plants to fruit. But as often happens when we start examining something more closely, new insights have started to arise.
The first is that by studying minerals, heavy metals, organic acids, proteins, sugars and polyphenols, there seems to be some sort of innate system in how plants manage each of these independently as well as concurrently. Plants appear to have mechanisms for managing their own health in startlingly innovative ways.
Plants don’t seem to treat proteins, sugars and organic acids as isolated pools; rather, they use them as interchangeable currencies that maintain physiological processes. A few examples are redox balance; energy distribution (root/shoot/fruit allocations); carbon/nitrogen ratio management; osmotic regulation; mineral chelation and movement; immune-defense chemistry; reactive oxygen species management; and biological communication with bacteria, fungi and other symbiotic (or non-symbiotic) microbes.
We’ve looked at redox, C:N, minerals and immune regulation for years in leaf sap and soils, but incorporating the data from analyzing fruits and vegetables has led to new understandings of how plants are managing these functions and how we can be part of that process as farmers.
Obviously, sugars are regulated by photosynthesis, source/sink needs, stress and daylight signals, but when we see crops grown under high light, low light, drought or waterlogged conditions, these sugar flows are enhanced or disrupted in various ways. When needed as a defense system, sugars can bioaccumulate in plant organs (roots/fruits), but if they are disrupted in their flow (by untimely N applications, for instance), they can’t perform their job.
Similarly, protein — and nitrogen as its precursor — is tightly regulated and managed throughout the seasonal and daily lifecycles. Proteins act as nitrogen storage and as the execution of metabolic triggers within their structure. Proteins are the end use of the majority of the plant’s nitrogen budget and are conserved and only used for specific functions. Proteins require key minerals to develop and tend to break down when carbon is scarce or the plant encounters even the slightest stress.
Organic acids seem to manage the regulation of mineral uptake, respiration and oxidation by allocating dynamic carbon flows into plant organs. When in deficiency (soils or the plant itself) or when the plant encounters high light or mineral imbalances, they can also be useful in managing osmotic pressure within intracellular and extracellular fluids.
Plant Flexibility and Farmer Decision-Making
The even more interesting revelation is that plants apparently maintain flexibility by constantly converting between pools. In other words, plants can shift carbon, mineral and nitrogen uptake, assimilation, allocation, consumption and distribution based on weather, soil health, water availability, light levels and so on. Taking it one step further, plants are doing all of this in a way that optimizes the health of their offspring (fruits, vegetables, grains).
This manifests in crops when, for instance, we see them grown in poor soils or under high metals stress. The plant will upregulate and concentrate ultra-high levels of polyphenols to account for the deficiency in organic acids or mineral cofactors. Conversely, when plants are grown under conditions of high nitrogen fertilization, they tend to develop high to excessive levels of stress proteins to overcompensate for their inability to synthesize sugars or defense molecules such as polyphenols. Plants appear to be constantly adapting their uptake, regulation, distribution, assimilation and management of organic molecules based on the weather, soil health and other factors.
This information becomes timely and relevant in the context of all the fancy new biostimulants on the market today, as well as in helping us connect to deeper layers of biological agronomy. For instance, if we need to create residue digestion in a soil through bacterial digestion but know that bacterial digestion will also release a large amount of protein, we can supplement polyphenols, elicitors or microbes that can help upregulate plant N conversion into healthy proteins instead of stress proteins by diversifying the plant’s diet.
These biostimulant applications (surfactants, amino acids, organic acids, microbial metabolites, flavonoids, etc.) support the plant development pathways already being stimulated by the weather conditions, but with a more diverse and complete nutritional profile that makes up for the gaps induced by environmental conditions.
What begins to take shape when you combine leaf sap analysis with nutrient analysis of crops is a management system that can not only manage plant stress but can alleviate that stress in various ways to solve for a crop’s nutritional response in the field in real time. In other words, as weather changes, so should biostimulant applications to preserve the nutrition of the crop.
Implications for Human Health
All of this pales, perhaps, in comparison with some curious research that has come to light recently about how humans may not be accessing nutrition from fruits and vegetables and grains in similar ways.
In recent years, there have been many news articles about the rise in food allergies, gluten intolerance and similar issues. Now research is coming out that says that specific individuals are susceptible to an inflammation (immune) response from varying foods. This goes way beyond allergies and gets back to individual food preferences — but this time from a biochemical perspective, not just because these people are picky eaters.
What’s more, relatively normal human systemic conditions (chronic stress, insomnia, gut microbiome health) can predispose or prevent an inflammation response to certain foods based on a person’s genetics. I’ve seen this in friends and family members who seem to gradually develop allergies over time.
While this information is way out of our league as farmers, what it can do is help us manage the growth of our crops for our customers. For instance, if we know our crops are being grown in depleted, low-organic-matter soils with high levels of metals, we can proactively manage for the health of our customers by supplementing organic acids, antioxidant elicitors and trace minerals to offset the imbalances native to our growing environment. This subtle shift repositions the farmer in the driver’s seat of the healthcare industry — not as just another victim of it.
We’ve all seen the various approaches to biofortification proposed over the years in the news — often by major NGOs in ambitious developing-world projects promoting questionable genetic modifications. Now a similar murmur is spreading within the ag and healthcare industries as growers, consumers and health professionals start to connect the dots between food, health, disease, longevity and the environment.
While it is refreshing to see interest in treating food as medicine, let’s ensure farmers are a big part of the conversation and process on how crop quality is measured for the grower as well as the consumer.
