The science linking healthy soils with healthy bodies is becoming ever more compelling. Will it be the epiphany that pushes nature-friendly farming into the mainstream? By Nick Hughes.
Eating carrots is good for us.
As dietary statements go, this is about as uncontentious as it gets. Carrots are rich in vitamins and minerals like beta-carotene and potassium, they are full of antioxidants and a good source of fibre. Carrots are unequivocally on the positive side of the nutrition ledger.
But what if all carrots aren’t created equally? What if a carrot produced on one farm is better for the human body than a carrot produced in different soil a mile down the road? And what if science can prove this is definitively the case?
Welcome to the world of microbiomes: a nascent but fast-growing area of scientific research which seeks to establish clear links between the health of the soil in which food is produced and the wellbeing of our bodies.
The essential idea is this: every piece of soil has a unique microbiome made up of diverse communities of bacteria, fungi and other microorganisms. So too does the human body, the most studied being the gut microbiome. The microbes contained in our gut metabolise the food we eat and determine how we feel. A healthy, diverse microbiome keeps us feeling well; a depleted microbiome is a marker of poor health.
It is generally accepted that we can alter our gut microbiome somewhat by the food we eat. The science is complex but in (very) simple terms (and not withstanding individual biological needs), eating unprocessed fruit and vegetables, legumes and wholegrains is good for our gut; eating lots of highly processed foods, particularly those high in fat, sugar and salt, is bad.
Where the science gets even more interesting concerns the relative health benefits of the same food produced in different soils. This year’s Goodwood Health Summit, held in October, explored the intricate relationship between the soil microbiome and the human microbiome. The thesis up for discussion across three panel sessions was that as the diverse microbes from healthy soils are transferred to the gut via food, our bodies benefit more than if the same food was produced on poor quality land degraded by intensive agricultural practices like frequent tillage, monocultures and overuse of chemical inputs.
Many believe this relationship between soil and human microbiomes is the next frontier in the ‘one health’ movement that seeks to show how human health, so often studied in isolation, is intimately connected to animal, plant and environmental health.
It may also be what ultimately pushes regenerative agriculture into the mainstream by cutting through to the public in a way the environmental benefits of nature-friendly farming may never do for the population at large.
Journey of discovery
The science around microbiomes is relatively new and experts admit there is much we don’t yet know about the human and soil microbiomes and how they interact. Yet there is also a keen sense of urgency around the journey of discovery.
“The way to think about the gut microbiome is there’s almost a parallel extinction event happening in our guts that reflects what’s happening in our natural environment,” said Dr Federica Amati, a medical scientist and public health nutritionist, speaking at the Goodwood Health Summit. “We’ve seen a huge decrease in the variety of microbes that live in our guts, with loss of species, variety and also the diversity we see.”
Amati referenced research showing how the Hadza tribe of people who live in a hunter-gatherer community in Tanzania have twice the number of different species of microbes in their gut than people living in developed Western economies. “What’s really worrying to see is that there’s this depletion of the gut microbiome, especially in children, and while you can influence your gut microbiome composition later in life there is a really important time in the first 1,000 days, and actually in the first year of life, where key species are established and that gut microbiome is basically put together,” she said.
Alongside a lack of nutritious food, experts increasingly believe diet-related ill health, which is estimated to cost the UK economy £268bn every year in healthcare funding and productivity losses, is inextricably linked with planetary breakdown, including poor soil health and the presence in the natural environment of toxins like micro-plastics and PFAS (forever chemicals). “The [human] microbiome conceptually, figuratively and literally connects us to our planet. If our planet is sick, we are sick,” said Dr James Kinross, head of colorectal surgery at Imperial College London and a leading expert in the gut microbiome.
Food produced in a way that heals both bodies and landscapes promises to deliver a huge range of economic and social benefits – lower spending on healthcare, and more productive, resilient farmland to name but two. The challenge to-date has been in proving that food produced in healthy soils is indeed of far greater nutritional value than food produced in overexploited soils – something pioneers of the organic and regenerative farming movements, and many buyers of their products, have intuitively believed for years.
Nutrient density
Dan Kittredge is at the vanguard of a global movement to define, measure and track nutrient density in foods and prove that crops grown in regenerative systems are higher in micronutrients than those grown conventionally. Kittredge is a US-based regenerative farmer and founder of the Bionutrient Food Association (BFA). He told the audience at Goodwood how his research is showing the nutritional quality of food produced across multiple continents correlates with the quality of the soil microbiome – “the more life in the soil, the more nutrients across the board”.
The BFA’s work includes developing physical tools that measure real nutritional value. These include a handheld bionutrient meter (Kittredge described it as like a “Star Trek ray gun”) that, with a flash of light, can provide nutritional information about food, crops and soil by taking readings for a number of biomarkers. The results, Kittredge said, show a “powerful diversity” with the sulphur content in carrots, for example, varying by a ratio of 4:1, polyphenol content by 20:1 and antioxidant content showing up to a 40:1 difference between soil types. “The level of function of the soil microbiome correlates profoundly with the level of nutrients in food,” he said.
Although he is deep into the science of the soil microbiome, Kittredge believes humans have an innate ability to decipher the nutrient quality of food by using our senses – specifically taste and smell. The “profound variation in flavour” between a tomato bought from a supermarket in January and one picked from your own garden in August “is your sophisticated, whole body system conveying to you, in a categorical fashion, that this is [more] beneficial”, he explained.
Still, food businesses looking to source and sell more nutrient dense products will need hard evidence that the science stands up to scrutiny or risk charges of greenwashing (or ‘healthwashing’) that have already been levelled against elements of the regenerative agriculture movement. Speaking at this year’s Groundswell Festival, Imogen Royall, co-founder of Northern Pasta, said being able to evidence greater nutrient density from its regeneratively-grown spelt would be helpful in the brand’s marketing, but added: “I am so cautious about throwing out claims. It’s up to us to make sure [of the evidence].”
Business opportunity
Kittredge said “big business” has already engaged with the BFA and has a common cause. “I would propose that big corporates who want to work to provide food of a higher nutritional calibre are going to make more money because they’re going to get more market share. What the people want is food with nutritional calibre. So, it’s not an ‘us [versus] them’ dynamic. It’s a ‘we’re all in this together’ opportunity.”
One audience member noted how farmers are not currently incentivised through the supply chain to produce food with higher nutritional value. But if at some point buyers decide to make nutrient density part of a product’s specification, alongside standard specifications like volume, price and size, it would provide a clear market incentive for growers to adopt regenerative, organic or other nature-friendly farming systems.
Kittredge believes consumer demand will play a similarly key role in driving a focus on nutritional quality once there is transparency over how different products measure up. “The idea basically is if people begin to understand that this brand of carrots is better than that one, or this brand of milk is better than that one, and they begin to pull that off the shelf and leave on the shelf that which is less good, the economic incentive to the supply chain is then to focus on nutrition as opposed to volume.”
The idea of good nutrition is relative of course. Getting people who already eat carrots to eat a slightly better carrot is unlikely to move the dial on diet-related ill health in the same way as converting those that don’t eat carrots to become carrot eaters. Kinross, although a strong advocate for the connection between human and planetary health, said about the people visiting his clinic in a deprived area of London: “I don’t care what tomato they eat, I just care that they eat a tomato.”
Yet there’s no denying the appeal in Kittredge’s utopian vision in which we’re all eating nutritious food from nutritious soils that in turn supports healthier bodies and a healthier planet. That surely is a goal worth pursuing with vigour, however complex the science and however long and challenging the journey to get there.
