Browsing the fresh produce aisle, you might look for freshness, colour, and perhaps an organic label. But what about nutrient density? We assume a carrot is a carrot, equally as nutritious regardless of how it was grown. But new evidence suggests otherwise.
Dan Kittredge, founder of The Bionutrient Institute, a collective of scientists and researchers working together to define nutrient density, has tested thousands of samples of fruit and veg and found large variations in the nutrients they contain. For example, some carrots contained 40 times more antioxidants than others, meaning you would need to eat 40 of the lowest scoring carrots to match the antioxidant benefits of just one highly nutritious carrot.
Why? While they’ve looked at many variables, it all comes down to soil health. ‘There is a direct relationship between the health of the soil, the health of the environment and the nutritional calibre of the food that soil produces,’ says Kitteridge. He asserts that healthy soil, teeming with life and nutrients, grows healthy plants, which taste better and are better for human health.
Is organic produce more nutritious?
The scientific evidence is mixed, with some studies suggesting that organic fruit and veg may contain higher levels of certain nutrients, such as vitamin C and polyphenols. As polyphenols are defence chemicals that plants produce, it makes sense that organic crops, grown without pesticides and artificial fertilisers, would experience more challenges, and perhaps produce more of these defence chemicals, which are also fantastic for our health.
Other studies however, have found no significant difference. For Kitteridge, who grew up on an organic farm and is deeply embedded in the organic movement, organic isn’t a guarantee of nutrient density.
‘I think one of the key points that we’ve pretty much categorically confirmed is that just because its organic, doesn’t mean it’s necessarily more nutritious,’ he says.
Organic farms are all meeting the standards for certification, but the health of the soil will vary dramatically, depending on individual farming practices, soil type and how the land was previously cultivated. But the best organic farms will be striving to build their soil to maintain long term fertility, and so it seems – the nutrient levels in their crops.
How do we choose nutrient dense food?
Imagine walking into any shop and being able to compare the nutrient density of the produce on offer – not just generic data on the label, but actual measurements of vitamins, minerals and polyphenols in each item – and choose food that provides the most nourishment.
This is exactly what Kittredge is working on. The Bionutrient Institute has developed a handheld spectrometer, which uses light to measure nutrient levels in food, soil and plants. Each substance, or nutrient, absorbs light at different wavelengths; this absorption spectrum is unique and acts as a fingerprint for each nutrient. The device can estimate nutrient density by comparing this data to lab tested samples.
As revolutionary as it sounds (and it is) this technology is still in its infancy. For the device to deliver meaningful readings, they need more data on nutrient variations. A lot more testing – and funding – is needed. But if realised, it has potential to drive real change in the food system, especially if this technology was available via an app on your phone, which is Kittredge’s ultimate vision.
For now, we still have one very powerful tool to help us discern whether food is nutritious. Ever tasted a tomato, straight from the vine in summer? Compare that to a bland, watery tomato you might have experienced from the supermarket, out of season. The contrast is stark, but could you be tuning into the nutrients those tomatoes contain?
Kittredge thinks so: “We’ve evolved with the most sophisticated nutrient-monitoring systems that can ever be expected to exist – our noses and tongues,” he says.
It’s true that some nutrients influence flavour. Sugars like fructose and sucrose add sweetness, while acids such as citric acid provide tartness; amino acids like glutamate enhance umami flavour, and minerals affect taste perception and balance between sweet, bitter, and umami. Phytonutrients can affect bitterness and aromatic complexity in foods such as herbs, dark chocolate, olive oil, and of course, wine.
Over the last 60 years, studies show that the nutrient density of fruit, vegetables, and other food crops has declined significantly. Why? A 2024 scientific review identified the degradation of soil – the loss of biodiversity and fertility – as the main culprits. The same intensive farming practices that we are concerned about from an environmental perspective, are also depleting all important nutrients in our food supply. Leaving us with food that looks the same, but offers less nourishment.
Soil health isn’t a consideration for the vast majority of consumers when they are buying food, but nourishing themselves and their families? Definitely higher on the agenda. As we gain a deeper understanding of the complex connection between the two, could the demand for nutritious food incentivise farmers and food producers to move towards practices? Benefiting both human and planetary health.
Hannah Neville-Green is Riverford’s Nutritional Therapist.
Hello, We are Good Gardeners International and we are the originators of the No Dig system in the United Kingdom. We hold 30 years of research and history into the No Dig system. Our recent developments are that we now have a revolutionary system that turns useful nutrients from organic wastes into optimum fertiliser in 90 days. We have been selling it in shops for 25 years. This includes all kinds of farm waste, pet wastes and all forms of human effluent. There are nutrients in all of these that are currently lost due to modern systems of recycling and we have the technology that reveals how to do this. TNR Total Nutrient Recovery. see ggi.org.uk
I think that the health-giving value of produce MUST come down to a combination of both its nutritional value and its toxic load. After suffering severe food poisoning decades ago, leading on to M.E., I was unable to put even a forkful of cooked standard supermarket vegetable into my mouth without feeling sick and turned off by it. So I turned to growing my own vegetables, organically for health, and found that I could eat whole platefuls without any problem. It was a revelation and I’ve never looked back.