The aim of food is to nourish us; to provide us with energy necessary for growth and health. But it is debateable whether growing food for nutrition has been the priority in our industrialised food system.
Professor Steve McGrath, head of sustainable agriculture sciences at Rothamsted Research, one of the oldest agricultural research institutes in the world, was part of the team that analysed 160 years’ worth of wheat samples to monitor and investigate changing nutritional values.
“It’s the longest experiment in the world,” McGrath explains. “The oldest samples are in huge bottles, they look like Victorian sweet jars that are sealed full of grain, and they’ve been sampled around every five years ever since.”
In their paper, McGrath and his colleagues found that the mineral density in wheat had decreased significantly over time.
“It was really quite a shock that the concentration of essential mineral micro-nutrients has decreased, and some of the macro-nutrients as well, things like protein concentration have decreased,” McGrath reveals.
“It made us realise that basically all of the efforts to increase yield through advances in crop breeding, crop protection and fertilisation, has led to this ‘dilution effect’.”
This dilution effect means that as the plant produces more wheat with higher yields, the concentration of nutrients decreases. According to McGrath, this is why organic produce might be more nutritious.
“Quite often they’re grown at a slightly lower yield level because the inputs are lower,” he explains. “That reverses this dilution effect that we talked about in the opposite direction, so when our crops have low yield, they tend to have higher concentrations of nutrients.”
McGrath points to the development of dwarf wheat varieties in the 1960s, also known as the Green Revolution, as a pivotal point in this downwards trend.
“The startling result was that as you through time, it looked fine up until the 60s and when yields really shot up, these micro-nutrient concentrations in the material went down.”
Since this obsession with yield is not confined to wheat production, could this apply to other crops? According to McGrath: “This is where we’ve got much less evidence. Nobody else has been keeping long term samples of vegetables or anything else you care to mention.”
This is something the Growing Real Food for Nutrition (GRFFN) programme hopes to rectify. Run by Matthew Adams and Elizabeth Westaway, a small team based at the Matara Centre in Gloucester, the mission is to accurately measure the nutrient density of food and investigate the contributing factors.
In collaboration with the US-based Bionutrient Association, the duo are developing a bionutrient meter that will test all types of food in real-time for its nutrient density.
Co-founder Matthew Adams says: “The intention is to set the standard for nourishing, nutrient dense fruit and vegetables so both growers and citizens can make informed choices about the quality of the food they grow and eat.”
Being able to make informed decisions is significant according to Adams, because not all fruit and vegetables are nutritionally equal. “To give you an example, in carrots we found that with antioxidants and polyphenols, there were 200 times more in the best samples compared to the worst samples.”
The machine shines an LED light on the carrot, and it gives a unique signature based on its chemical makeup and density.
Using carrots as an example; conventional nutritional analysis of hundreds of different carrots in a lab is necessary to translate the different signatures into nutritional information.
Once enough data is collected, and a lot will be required for accurate sampling, it could be available to consumers to test for nutrient density themselves.
Would access to this knowledge be a game changer for consumers? Westaway certainly thinks so. “It’s going to massively increase transparency in the supply chain,” she says.
“It’s probably going to end up as an app, so it’s going to be really easy to use. It will enable [them] to make an informed choice of whether to buy that carrot with poor nutritional value.”
Freely admitting that nutrition is a misunderstood and highly complex realm, in a parallel project GRFFN is exploring more holistic ways of measuring and growing food of high nutritional value.
GRFFN want to define food of excellent nutrition based on four criteria; good taste, resistant to pests and disease, high yield and uniformed growth, and longer shelf life, which they are trialling by growing food in four different ways within one quadrant.
According to Adams, when produce fulfils these four requirements, this is when we can start to consider this as nutrient dense food.
“Nutrition is really tricky to nail down in terms of what is good nutrition. In garlic, there are over 20,000 discrete nutrients,” says Adams.
“How do you describe what is nutritious? It’s a total package. We’re a society that thinks in silos. We need to be thinking more holistically, we need to be looking at everything.”
While verging on social philosophy and inference rather than hard science, the logic rings true. Food is meant to provide us with energy and good health, but it also nourishes us in other ways; it can delight the senses, bring us together as communities, create biodiverse habitats for species, and even mitigate climate change.
It’s time to look beyond yield and profit as the barometer of success and start to focus on nourishing ourselves, in all senses of the word.
Nutritionally enhanced or Frankenfoods?
Vitamin D enriched mushrooms. In 2016, Tesco launched a mushroom grown under enhanced light to contain more Vitamin D due to deficiency concerns.
Healthy heart tomatoes in Japan. Using the controversial technology genome editing, Japanese seed company Sanatech have recently introduced a tomato that contains high levels of gamma-aminobutyric acid (GABA), an amino acid believed to aid relaxation and help lower blood pressure.
Genetically modified golden rice. Developed by the Rockefeller Foundation and agrochemical giant Syngenta to increase Vitamin A in diets. It has been approved for use in the Philippines, USA and Canada.