Earlier this month after 2 years of consideration the EAT-Lancet Commission published its report in the medical journal the Lancet. The project set out with admirable aims, to pull together the thoughts and evidence base from a large group of experts to see if they could identify a ‘healthy diet from sustainable food systems’. General media opinion since publication has been positive and there are many commendable aspects to the report, but as with many big data driven reports some of the underlying subtleties have been missed out or glossed over.
One in particular relates to the geographic variability in the potential for crop and livestock rearing and the other key point and linked to these is the denuded state of the soil in terms of its phytobiome – the soils equivalent to our microbiome named by Nobel prize winner Joshua Lederberg to describe our ecological community of commensal, symbiotic and pathogenic microorganisms found on our mucosal surfaces, including the eye, mouth, lungs, and the gut.
The phytobiome consist of plants, their environment, and their associated communities of organisms embedded in the soil. Interactions within phytobiome’s have profound effects on soil, plant and agroecosystem health. i.e in much the same way that our microbiome has direct effects on our function and health, so does the plants – and if plants are not supported, their nutrient content and ability to transfer healthful elements to animals and to us will also be poor.
Soil health, also referred to as soil quality, is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. Sound familiar? Our microbiome fulfils a similar job and, in both cases, they need to be fed appropriate, nutrient dense material. A failure to manage soils and allied phytobiome will also reflect in a failure to manage gut diversity, microbial redundancy and functionally in humans.
It has already been proposed based on studies exploring the microbiome of our nearest living hunter gatherers and comparing them to western urban dwellers that we may have lost as much as 50% of our diversity. Research indicates that gut microbial community diversity is positively associated with diet diversity and the proportion of calories derived from plant material and that increases in both should increase the number of available nutritional niches. However, whilst it is very likely that loss of diversity will influence functionality, its not yet completely clear that ‘more is better’.
However, the industrialisation of agriculture over the last 100 years has also seen a change in soil and human bacterial populations – effectively changing our and the soils microbial heritage to which we and plants have been exposed through millions of years of evolution. Industrialisation is substantially correlated with reduced human microbiota diversity. The gut diversity of South American Amerindians is ∼2-fold that of healthy people in the United States and likely the UK also.
Learning how to manage the microbial communities in our digestive tract and elsewhere is the challenge for many people and represents an ongoing clinical challenge. People in industrialised and developing countries from across the world can be classified into two overall groups: low and high intestinal bacterial diversity, respectively. Industrialisation encompasses many influences on the microbiota, including a highly processed water supply, refined diets, and altered environmental exposure—which may affect the microbiota through bi directional effects on the immune system—and the presence of medical care, including pre-, peri-, and postnatal antibiotics; caesarean section delivery; and bottle-feeding—all of which reduce the transmitted and maintained microbial diversity, especially during the critical window of early-life development.
But there are many other opportunities for loss and restoration of the microbiota – despite the challenges of soil depletion. Its one of your challenges to find the most effective way to heal your soil and your gut.