Health Impacts of Regenerative Agriculture
Guest post from Jenny Pethan, MS Candidate in Agriculture, Food and Environment, Tufts University Friedman School of Nutrition Science and Policy and Zero Foodprint Climate Smart Agriculture and Health Promotion Intern Emeritus
Regenerative agriculture, a way of farming that builds soil health and climate resilience, has been gaining interest in recent years and for good reason. This method of farming has been proven to sequester carbon, replenish depleted soils, restore biodiversity, and enhance resistance to climate extremes. An emerging field of research, however, is showcasing that regenerative agriculture goes a step further by offering the potential to improve health outcomes. It turns out that, as a result of restoring soil health and sequestering atmospheric carbon, such practices can increase the nutrient density of our food. As a result, embracing regenerative agriculture offers promising prospects for enhancing public health by promoting sustainable farming practices that nourish both the land and people.
Nutrient Density
Regenerative agriculture prioritizes soil health by incorporating practices such as composting, reduced or no tillage, cover cropping, crop rotations, and rotational grazing. Rooted in indigenous ecological knowledge, this way of farming recognizes that the health of people and our planet begins with healthy soils.
Healthier soils with improved soil structure, organic matter, and other physical and chemical properties lead to greater microbial and fungal diversity. This enhanced biodiversity plays a major role in helping plants unlock access to nutrients. The plant roots, bacteria, and fungi develop a symbiotic relationship wherein the bacteria and fungi enhance the plants’ ability to access nutrients and water from the soil which in turn (Colin Averill)(Nat Geo).
Recent research is showing that how we farm is directly linked to the nutritional quality of our food. Most notably, in a 2022 study comparing regenerative and conventional agriculture practices, the authors, David Montgomery and Anna Bikle, found that the regeneratively grown crops had:
34% more vitamin K
15% more vitamin E
17% more vitamin B2
11% more calcium
17-23% more zinc
15% more total carotenoids
20% more total phenolics
22% more total phytosterols
Their results show that across the board, crops grown in regeneratively farmed soils had greater nutrient content than conventional and even organic production systems. In some cases, when compared directly to conventionally grown crops, the regenerative crops had 50% more zinc and magnesium, almost 50% more carotenoids, and 60-70% more total phenolics. An even more recent 2023 review supports some of these claims in finding that in 15 out of 16 studies, rice grown under increased organic inputs, such as compost, cover crops, crop rotation, reduced tillage, and sustainable water management, showed significant increases in grain zinc (Zn) concentration. The researchers also found that vitamin C concentration of tomato fruit increased in ~50% of studies when plants were grown under increased organic inputs, and in 76% of studies when plants were grown under deficit irrigation. These studies assess the collective impact of regenerative farming practices on nutrient density, but we can also look at the impacts that specific practices have.
Organic Inputs
The use of organic inputs, including compost, green or animal manure, and fungal and/or bacterial inoculations, has been shown to help increase mineral uptake and phytochemical content of crops. This is largely due to increases in soil biodiversity associated with plant nutrient uptake. Studies at a variety of institutions have reported that levels of zinc, iron, manganese, potassium, vitamin C, and an array of phytochemicals increased after applying compost rich in symbiotic fungi and bacteria to plants. For example, a 2012 Italian study inoculated tomato plants with mycorrhizal fungi and saw an increase of almost 30% more zinc and almost 20% more lycopene and other antioxidants. Lycopene, a carotenoid–a family of pigments that give fruits and vegetables their red, orange, and yellow coloring–is a powerful antioxidant that has demonstrated promising anti-cancer effects (Harvard Health). Additionally, a study found that the annual application of municipal solid waste provided the greatest enhancement in the nutritional content of crops when compared to biennial or no application. Such findings led the authors to conclude that compost application to plants may be a cheaper alternative to grow and biofortify food plants to promote healthy diets and human well being.
No or Reduced Tillage, Cover Crops, and Crop Rotations
When practiced together, reduced or no tillage, cover cropping, and crop rotations have the greatest positive effects on soil health. These practices play a major role in promoting plant and soil health which leads to improved nutrition. For example, heavy tillage can cause mineral depletion and the release of organic carbon, an essential food source for microbes (Nat Geo). In contrast, the rotation of crops within fields can improve the nutrient content of subsequent crops (Nat Geo). The Rodale Institute, in its study spanning since 1981, compared conventional and organic farming approaches, revealing that the latter, which incorporates cover cropping, reduced tillage, crop rotations, and organic inputs in lieu of synthetic additives, experienced increased yields. Within the first five years of the study, the conventional plots saw no increases in soil organic carbon (SOC) or soil organic nitrogen (SON) levels, while the organic plots saw significant improvements in SOC and SON content. This led researchers to study the effect of soil improvement on crop nutrition, uncovering notable mineral content increases in organic oats—ranging from 8% for potassium to an astounding 74% for boron, averaging at 32.3%. Antioxidant analyses for tomatoes, carrots, and jalapeno peppers displayed parallel trends, with respective increases of 36.3%, 28.9%, and 18.1%. These findings align with the Montgomery and Bikle study, corroborating an average 19% rise in nutrient content for regenerative crops and spotlighting cover-cropped wheat's gains in mineral density, including boron (41%), magnesium (29%), calcium (48%), zinc (56%), molybdenum (quadrupled), potassium (26%), manganese (35%), and two-thirds as much nickel, thereby encapsulating the transformative potential of regenerative practices.
Rotational Grazing
Fat Composition
Greater nutrient density from regenerative practices doesn’t only apply to crops, it also affects animal products. A study comparing regenerative pasture-raised to conventional feedlot beef and pork found major differences in omega-3 fats. Regenerative beef had 3 times more omega-3 fats, and more than 6 times more of the essential omega-3, alpha linolenic acid (ALA). Similarly, the regeneratively produced pork had more than 9 times as many omega-3s, more than 11 times as much ALA. When analyzing the nutrient density of regeneratively pastured animals, studies consistently show a lower ratio of omega-6 to omega-3s. To put that ratio into perspective, humans evolved on diets that contained equal amounts of omega-6 and omega-3 fats. However, a typical Western diet now consists of a ratio anywhere from a 10:1 to 20:1, which contributes to chronic inflammation in the body that underlies many metabolic diseases prevalent today (Harvard). In comparison to animals fed grain and raised in confinement, animals raised on regenerative pastures consistently prove to be nutritionally superior.
Phytonutrients
Animal products aren’t often recognized as sources of phytochemicals, but research shows that livestock, specifically those raised on diverse pastures, can provide benefits to human health. One study analyzed the levels of phytonutrients found in meat and dairy products of agroecological pasture-raised animals. What they found was significant differences in the presence of anti-inflammatory, antioxidant, antiviral, and anticarcinogenic properties. Goats that were grazed on a wide variety of grasses, legumes, and forbes had 5-fold more terpenoids, powerful antioxidants, in their milk compared to goats consuming a limited number of grasses. Additionally, certain phenols, another group of beneficial antioxidant compounds, were present only in the milk of goats grazed on pasture and were undetectable when goats were fed concentrates in confinement.
When looking at milk obtained from cattle grazing diversified forages, there were 6-23x more terpenoids than the milk of cattle fed concentrates. Additionally, the researchers found that the grazing cattle had a flavonoid content, a phytochemical recognized for its anti-inflammatory, antioxidant, antiviral, and anticarcinogenic properties, that was 6-fold higher. These findings suggest that products from animals raised on regenerative pastures could provide a source of beneficial compounds in our diets.
As Montgomery and Bikle put it in their book, What Your Food Ate, regenerative practices that rebuild soil health (composting, no till, cover cropping, crop rotations, rotational grazing) help ensure our bodies acquire adequate supplies of phytochemicals that underpin lifelong health. Moreover, phytonutrients contribute to our food’s distinct flavors and aromas, making them more delicious and enjoyable to eat!
Nutrition Security and Health Outcomes
Although there is limited research on the direct linkages between nutrient density and regenerative agriculture practices, researchers are suggesting that the population-level health benefits through improved dietary micronutrient supply could potentially be large (2023). This is primarily due to the fact that, despite an overabundance of calories available, inadequate micronutrient intake is seemingly widespread in the US (PubMed). A recent analysis of publicly available dietary surveys showed that even in affluent countries, more than three quarters of the adult population do not achieve the recommended intakes for a large number of vitamins (PubMed). While we also know that most Americans, 9 in 10 adults, are not consuming the daily recommended servings of fruits and vegetables, for those that do, the previous results suggest that they now have to consume more in order to meet their micronutrient Recommended Daily Allowance. For example, in 2018, the Bionutrient Institute conducted a study of 648 samples from a variety of sources (farms, farmers markets, grocery stores) and found significant variation (up to 200:1!) in antioxidants, polyphenols, and minerals in carrots and spinach.
Now more than ever we’re able to recognize the role nutrition plays in preventing and even reversing chronic diseases. Research in the field of food is medicine is growing rapidly as the prevalence of nutrition-sensitive conditions such as obesity and type 2 diabetes has increased substantially in the US during the past 30 years (JAMA). At the same time, the nutrient content of our food, most notably protein, calcium, phosphorus, iron, vitamin A, vitamin B2 and vitamin C, has declined consistently over the past 70 years (Davis, D. R). The epidemic of diet-related diseases coupled with the declining nutrient density of our food demonstrates the critical role regenerative farming practices play in improving public health nutrition.
However, not everyone has an equal risk of developing these diet-related conditions. Hidden Hunger, wherein an individual has sufficient daily caloric intake but suffers from malnutrition, disproportionately impacts populations in the U.S. including:
People of low socioeconomic status or those experiencing food insecurity
Women, particularly those of childbearing age
BIPOC
Older adults
Individuals with certain medical conditions or disease states
Individuals with low-nutrient diets or on restrictive diets
Long time users of medications that inhibit one’s ability to absorb nutrients (IFM)
Such disparities in diet quality among US adults is a growing concern as it is well recognized that unhealthy diets are one of the top contributors to poor health (Zhang). According to Dariush Mozaffarian, nutrition is the most powerful determinant of health for everyone and in the U.S., with an estimation of 45 percent of deaths from heart disease, stroke or diabetes linked to poor diet.
Much of the attention has been given to the term “food security”, having consistent access to enough food for every person in a household to live an active, healthy life, but much of the dialogue has begun to shift toward “nutrition security”, having consistent access, availability, and affordability of foods and beverages that promote well-being and prevent (and if needed, treat) disease, instead. What this demonstrates is that the quality of our food matters and that we must seek to achieve food security in a changing climate through good nutrition as opposed to merely ensuring the availability of sufficient calories (Maysoun A). It has been stated that developing effective strategies to improve the diet quality and nutritional status of high-risk populations is important for the prevention of diet-related chronic disease (PubMed), and we are seeing more and more that regenerative farming can be a part of that solution. With studies showing that consuming nutrient dense foods decreases the risk of CVD, diabetes, and all-cause mortality, the nutrient density approach is looking to be promising (Troesch, B.).
Colin Averill Jennifer M. Bhatnagar, Michael C. Dietze, Stephanie Kivlin. 2019. Global imprint of mycorrhizal fungi on whole-plant nutrient economics. PNAS. https://doi.org/10.1073/pnas.1906655116
Davis, D. R., Epp, M. D., & Riordan, H. D. (2004). Changes in USDA food composition data for 43 garden crops, 1950 to 1999. Journal of the American College of Nutrition, 23(6), 669–682. https://doi.org/10.1080/07315724.2004.10719409
Institute for Integrative Medicine. https://www.ifm.org/news-insights/micronutrient-malnutrition-not-limited-developing-nations/
Maxfield L, Shukla S, Crane JS. Zinc Deficiency. [Updated 2022 Nov 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493231/
Troesch, B., Biesalski, H. K., Bos, R., Buskens, E., Calder, P. C., Saris, W. H., Spieldenner, J., Verkade, H. J., Weber, P., & Eggersdorfer, M. (2015). Increased Intake of Foods with High Nutrient Density Can Help to Break the Intergenerational Cycle of Malnutrition and Obesity. Nutrients, 7(7), 6016–6037. https://doi.org/10.3390/nu7075266
van Vliet Stephan, Provenza Frederick D., Kronberg Scott L. Health-Promoting Phytonutrients Are Higher in Grass-Fed Meat and Milk. Frontiers in Sustainable Food Systems. Volume 4. 2021. DOI: 10.3389/fsufs.2020.555426
Washington Post - Why Food Security Needs to Become Nutrition Security