By Emily Bernstein, Graduate Student at Nutrition Therapy Institute. Emily is passionate about soil health and the potential it has to improve nutrient-density in crops and reduce greenhouse gases.
Let’s talk about the little critters living in our soil, and why we should care. To simmer down a complex subject –there are microorganisms living in soil that have a symbiotic relationship with plants. When this relationship is faltered, perhaps by the application of a pesticide, herbicide or fungicide, the plants that produce our food suffer. This results in many unwanted consequences, but amongst the most threatening is the drastic reduction of vitamins and minerals in our food supply. Fortunately, practices that increase the health and diversity of these microorganisms in the soil can ultimately restore the much needed vitamins and minerals in our food1.
As a nutritionist, I bite my tongue before saying, ‘you just need to consume more fruits and vegetables’. Unfortunately, this simple, gold standard advice has become much more complex with the rise of conventional agricultural practices and environmental toxins. These factors make ‘being healthy’ a lot harder. The reason for this is two-fold. First, the loss of nutrients in our soil –and consequently our food– deprives us of the necessary ‘internal defenses’ to properly handle and breakdown toxins in the body. Secondly, the rise in environmental toxins sets us up for an uphill battle that we’re not prepared to fight.
Selenium, for example, is a mineral found in soil that is an integral part of our body’s antioxidant defense system. Antioxidants help the body combat oxidation, which is responsible for inflammation, damaged tissue, aging, amongst other harmful effects. Selenium protects the body so much so that populations deficient in this mineral become more vulnerable to certain viruses2. One scientific journal article predicts that the impact of conventional agriculture and climate change will decrease Selenium concentrations in farmland soil, increasing people’s risk of deficiency3. The article also states that the same factors contributing to Selenium loss in the soil will most likely impact other trace mineral concentrations4. This prediction is supported by other research, as a study in 1997 found significant reductions of Calcium, Copper, Magnesium, and Potassium in our food from 1930-19805. Another study found that 43 fruits and vegetables had nutrient losses when comparing the food in 1950 to 1999 (these nutrients included Calcium, Phosphorus, Iron, Vitamin C, Vitamin B2, and protein)6. The authors attributed these losses to modern agricultural practices depleting the nutrients from the soil. I can only imagine with the rise of fossil fuels and monoculture agriculture that these nutrient disparities have grown.
Now, I’m not saying we should cut out vegetables because of the reduced nutrient content. In fact, the opposite is true. To better equip us for the battle for our health, we need to bulk up on fruits and vegetables to get the necessary vitamins, minerals, antioxidants, and phytochemicals into our body. Vegetables and fruits contain much more of these nutrients than other food groups, making them an important staple in the diet –but make sure to buy from farmers that you know prioritize soil health and take good care of the soil microbiome!
To address the other reason why our health is compromised by modern farming practices, it’s only appropriate to start with pesticides and herbicides. The soil contains a living community of microbes, similar to our own gut. For both environments, the health of the landscape is dependent on the diversity of the microbial community7. This knowledge gives context as to why agrochemicals, including chemical fertilizers, are such a threat to our health. Since pesticides and herbicides kill the microbes in the soil8, then the chemical residue on food we’re consuming is also killing the microbes in our gut9. According to a well respected scientific journal, the disruption of the human gut microbiome from pesticides and ubiquitous chemicals in our environment (leachate from plastic packaging, for example), result in decreased microbial biodiversity, an increase in lipid metabolism, and systemic inflammation10. Decreased microbial biodiversity in the gut directly impairs the functioning of the digestive and immune system11. In addition to these harmful long-term effects, there are also acute dangers to be aware of. There have been thousands of pesticide-related deaths and poisonings in North and South America, where these chemicals are heavily used12,13.
Heavy metals like Arsenic and Cadmium have also increased in the soil and groundwater (due to modern industry)14. Even in low amounts, these heavy metals have been shown to alter gut biodiversity and increase the risk of Type 2 Diabetes15.
I know this all looks grim and dim, but there is a light at the end of the tunnel. Practices like regenerative agriculture focus on restoring soil health and the ecosystem in which the farm exists. This results in a healthier environment and crop through carbon sequestering16, increased soil biodiversity17, and thus more nutrient-dense food. Soil may not seem like a sexy topic, but it’s a topic you should care about because ultimately the health of humans is dependent on the health of the soil.
1. Lal R. Soil degradation as a reason for inadequate human nutrition. Food Security. 2009;1(1):45-57. doi:10.1007/s12571-009-0009-z
2. Guillin O, Vindry C, Ohlmann T, Chavatte L. Selenium, Selenoproteins and Viral Infection. Nutrients. 2019;11(9):2101. doi:10.3390/nu11092101.
3. Jones GD, Droz B, Greve P, et al. Selenium deficiency risk predicted to increase under future climate change. Proceedings of the National Academy of Sciences. 2017;114(11):2848-2853. doi:10.1073/pnas.1611576114.
4. Jones GD, Droz B, Greve P, et al. Selenium deficiency risk predicted to increase under future climate change. Proceedings of the National Academy of Sciences. 2017;114(11):2848-2853. doi:10.1073/pnas.1611576114.
5. Mayer A. Historical changes in the mineral content of fruits and vegetables. British Food Journal. 1997. 6. Davis, D., Epp, M. and Riordan, H., 2004. Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999. Journal of the American College of Nutrition, 23(6), pp.669-682. 7. Blum, W., Zechmeister-Boltenstern, S. and Keiblinger, K., 2019. Does Soil Contribute to the Human Gut Microbiome?. Microorganisms, 7(9), p.287.
8. Huang, Y., Xiao, L., Li, F., Xiao, M., Lin, D., Long, X. and Wu, Z., 2018. Microbial Degradation of Pesticide Residues and an Emphasis on the Degradation of Cypermethrin and 3-phenoxy Benzoic Acid: A Review. Molecules, 23(9), p.2313.
9. Reygner, J., Joly Condette, C., Bruneau, A., Delanaud, S., Rhazi, L., Depeint, F., Abdennebi-Najar, L., Bach, V., Mayeur, C. and Khorsi-Cauet, H., 2016. Changes in Composition and Function of Human Intestinal Microbiota Exposed to Chlorpyrifos in Oil as Assessed by the SHIME® Model. International Journal of Environmental Research and Public Health, 13(11), p.1088.
10. Blum, W., Zechmeister-Boltenstern, S. and Keiblinger, K., 2019. Does Soil Contribute to the Human Gut Microbiome?. Microorganisms, 7(9), p.287.
11. Blum, W., Zechmeister-Boltenstern, S. and Keiblinger, K., 2019. Does Soil Contribute to the Human Gut Microbiome?. Microorganisms, 7(9), p.287.
12. Joyce, S., 1997. Growing pains in South America. Environmental Health Perspectives, 105(8), pp.794-799.
13. Calvert, G., Beckman, J., Prado, J., Bojes, H., Schwartz, A., Mulay, P., Leinenkugel, K., Higgins, S., Lackovic, M., Waltz, J., Stover, D. and Moraga-McHaley, S., 2016. Acute Occupational Pesticide-Related Illness and Injury —United States, 2007–2011. MMWR. Morbidity and Mortality Weekly Report, 63(55), pp.11-16.
14. Li, X., Brejnrod, A., Ernst, M., Rykær, M., Herschend, J., Olsen, N., Dorrestein, P., Rensing, C. and Sørensen, S., 2019. Heavy metal exposure causes changes in the metabolic health-associated gut microbiome and metabolites. Environment International, 126, pp.454-467.
15. Li, X., Brejnrod, A., Ernst, M., Rykær, M., Herschend, J., Olsen, N., Dorrestein, P., Rensing, C. and Sørensen, S., 2019. Heavy metal exposure causes changes in the metabolic health-associated gut microbiome and metabolites. Environment International, 126, pp.454-467.
16. Yang, Y., Tilman, D., Furey, G. and Lehman, C., 2019. Soil carbon sequestration accelerated by restoration of grassland biodiversity. Nature Communications, 10(1).
17. Yang, Y., Tilman, D., Furey, G. and Lehman, C., 2019. Soil carbon sequestration accelerated by restoration of grassland biodiversity. Nature Communications, 10(1).
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