The health of livestock, humans, and landscapes is linked with plant diversity. Human and environmental health is enhanced when livestock forage on phytochemically rich landscapes, but it is reduced when livestock forage on pastures with few species or eat high-grain rations in feedlots, and health is greatly reduced when people eat ultra-processed diets. The global shift away from eating phytochemically and biochemically rich foods to ultra-processed diets encouraged 2.1 billion people to become overweight or obese and ballooned the incidence of type II diabetes, heart disease, and cancer. We can reverse these trends by learning to grow and eat wholesome foods that nourish human and environmental health. To do so, producers and consumers must become mindful that the health and wellbeing of the plants and animals we eat to nourish our bodies ultimately determines the health and the wellbeing of our families and our species. We are members of nature’s communities. What we do to them, we do to ourselves.
Let Feed Be Thy Medicine: Plant Diversity and Herbivore Health
Plants turn dirt into soil and diverse mixtures of plants turn soil into homes for herbivores, omnivores, and carnivores below and above ground. Landscapes with complex assortments of grasses, forbs, shrubs, and trees are nutrition centers and pharmacies with vast arrays of phytochemicals. Nothing is more important for health through nutrition than landscapes with a variety of foods for herbivores, omnivores, and carnivores below and above ground.
The Gravelly Range in southwestern Montana is home to incredibly diverse plant communities. Walking in the meadows of the Gravelly Range, I’m struck by the fragrances emanating from the bouquet. Gazing upon those multi-colored meadows makes me keenly aware of how complex mixtures of plant species create homes for myriad communities of animals. The resulting diversity is a model for how to create health and resilience in human communities.
The health of humans is linked to the diets of livestock through the chemical characteristics of the plants they eat. That includes not only the energy, protein, minerals, and vitamins, but the tens of thousands of other compounds plants create, collectively termed phytochemicals. This rich pool of compounds—including terpenes, phenolics, and carotenoids—promotes health in herbivores and humans. Through their many biological properties—anti-microbial, anti-parasitic, anti-inflammatory, anti-carcinogenic, cardioprotective, and immunomodulatory—phytochemicals bolster health and protect livestock and humans against diseases and pathogens.
A palate attuned to a landscape enables animals including humans to meet needs for nutrients and self-medicate through three interrelated processes: 1) access to phytochemically and biochemically rich foods, 2) learning in the womb and early in life to eat wholesome foods, and 3) biochemically mediated flavor-feedback associations where cells and organ systems, including the microbiome, alter liking for foods as a function of their needs. While we typically think we like foods because they taste good, we aren’t aware, because flavor-feedback associations occur at a subconscious level, that foods taste good when they are good for us.
These processes converge in wholesome ways when livestock learn to eat complementary combinations of forages on phytochemically rich landscapes, but they are thwarted when livestock forage on pastures with few plant species or are fed high-grain rations in feedlots. They are utterly commandeered and undermined when people learn to eat ultra-processed diets.
Compared with simple plant mixtures or feedlot diets, nutritional (macro and micronutrients), physiological (blood parameters indicative of health), and immunological (immune function) status improves when livestock forage on diverse mixtures of plants. While 3 to 5 plants typically make up the bulk of the diet in our meals, animals often eat 50 to 75 plants in a meal. Historically, we did not appreciate that the nutritional and pharmacological properties of these minor components of the diet—best eaten in small doses—enable health. Livestock foraging on phytochemically rich landscapes do not require antiparasitic drugs and antibiotics, yet they have low levels of morbidity and mortality compared with animals forced to forage on pastures with few species or in feedlots. When mixtures of plants include tannin-containing legumes, cattle gain weight more efficiently and can reach slaughter weight as quickly as animals in feedlots.
Complex mixtures of plants also enhance environmental health. For example, synergistic effects among different kinds of phenolic compounds (tannins) in legumes such as sainfoin and birdsfoot trefoil reduce emissions of greenhouse gases—methane and nitrous oxide. Pastures with tannin-containing legumes also have less emissions of nitrous oxide from soils. Assortments of phytochemically rich plants create healthy communities with no need for mechanical, chemical, or biological inputs. Yet, rather than grow diverse mixes of plant species, industrial agriculture declared fossil-fuel-based warfare on land mechanically (ploughing soil), chemically (herbicides, pesticides, fertilizers), and biologically (GMO technology). We can reverse ecological damage—from tillage, fertilizers, herbicides, and pesticides used to grow and protect crops in monocultures—by integrating livestock back into mixed-farming systems that build fertility, organic matter, and water-holding capacity of soil and enhance biodiversity.
During the past 70 years, people have grown crops such as corn and soybeans in vast monocultures to feed livestock confined in feedlots under conditions that violate the five freedoms of animal welfare. Livestock are moved from familiar environments (home) to unfamiliar social and physical environments (feedlots), which violates their freedom from fear and distress. Animals in feedlots are daily fed the same total-mixed ration, so high in grain they experience nausea, which violates their freedom from discomfort. Like us, animals come to dislike foods eaten too often or in excess, which causes stress and food aversions. Like us, individuals vary in their food preferences due to experiences in the womb and early in life. In feedlots, they have no chance to self-select their own diets, which violates their freedom to express normal behavior, maintain individual health, reduce stress, and prevent disease.
To counter the cumulative effects of grain-rich but phytochemically impoverished diets and unfamiliar, crowded conditions, animals are given antibiotics. Overuse of antibiotics in feedlots helped to create antibiotic resistance, a global health challenge. Our reliance on mass-produced meat also increases risk of pandemics. People in the U.S. now eat meat at nearly three times the global average. Reducing intake of meat from feedlots, while increasing intake of meat from livestock reared on phytochemically rich landscapes, could reduce what some consider excessive intake of meat and increase intake of biochemically rich meat, arguably of better quality.
Palates Link Plant Diversity, Herbivores and Humans
In Life in the Rocky Mountains, Warren Angus Ferris recounts his adventures along the headwaters of the Missouri, Columbia, and Colorado Rivers from 1830 to 1835. Back then, bison fed on diverse mixes of plants and Ferris’ crew fed on bison, as Indigenous people had done for ages. He notes bison in poor flesh were the worst diet imaginable, but as they became fat, no other meat could compare: “With it we require no seasoning; we boil, roast, or fry it, as we please, and live upon it solely, without bread or vegetables of any kind, and what seems most singular, we never tire of or disrelish it, which would be the case with almost any other meat.” His remarkable observations raise two questions: Why were bison in good flesh so nourishing? How is the flavor of bison affected by the phytochemical richness of their diets?
Human health is enhanced when livestock forage on phytochemically rich landscapes. The benefits to humans accrue as livestock directly assimilate some phytochemicals and convert others into metabolites that become muscle and fat, which in turn become biochemicals that can improve the health of humans. That is analogous to, but distinct from, benefits attained by eating phytochemically rich herbs, spices, vegetables, and fruits. This expanded pool of compounds—phytochemicals as well as metabolites produced by animals from plants—should be considered in attempts to understand health benefits to humans, such as dampening oxidative stress and inflammation linked with cancer, cardiovascular disease, and metabolic syndrome.
Diets influence the flavor and biochemical richness of meat. For instance, the flavor of blue grouse changes seasonally from early fall to winter as the birds switch from eating diets rich in grasses, forbs, and berries to diets higher in conifer needles, which give a subtle hint of terpene to the meat. Adding garlic or essential oils (terpenes) from juniper, rosemary, or clove to the diets of lambs and calves improves the flavor of their meat because each of these plant species contains a host of phytochemicals that benefit human health. Phenolic compounds (tannins) in herbivore diets improve the flavor of meat by reducing rumen bacteria that produce ‘off-flavors’ from skatole, a mildly toxic organic compound produced from tryptophan in the mammalian digestive tract. Among many other compounds, terpenes, phenolics, and carotenoids in herbivore diets can enhance the flavor and biochemical characteristics of meat and fat.
Herbivore diets also influence the flavors of milk and cheese. Phytochemically rich native pastures with diverse species of grasses, forbs, and shrubs produce complex combinations of terpenes and phenolics that positively influence the flavor of milk and dairy products. Plant diversity affects phenolics in cheeses such as L’Etivaz and Gruyere. Likewise, carotenoids in plants positively influence flavor and impart a yellow color to milk and cheese. Different compounds impart different flavors. Dairy cattle fed diets high in lipids produce milk with sweet, raspberry-flavors (γ-dodecalactone from oleic acid and γ-dodec-cis-6-enolactone from linoleic acid). Cattle fed diets low in lipids produce milk fat high in cheesy-flavored fatty acids and precursors of blue-cheese-flavors (methyl ketones) and coconut-peachy-flavors (δ-lactones).
When dairy cows dine on botanically diverse pastures, rather than a total-mixed ration of cultivated forages and grains, both the flavor and biochemical richness of their milk and cheese are greatly enhanced. Local people in Italy and France prefer the flavors of milk and cheese from dairy cows grazing on the botanically diverse swards. Consumers in those countries select cheeses based on season of production and the mix of plant species in particular landscapes, for example cheese made from high elevation summer pastures in the Alps. Their palates are linked —beginning in the womb and early in life—with soil, plant diversity, and herbivore diets.
People also prefer meat they are accustomed to eating. When Spanish milk/concentrate-fed lambs and British grassfed lambs were assessed by Spanish and British taste panels, both panels found British lamb had higher flavor intensity, but the Spanish panel preferred milk/concentrate-fed lambs, while the British panel preferred grassfed lambs. Families in Mediterranean and European countries—Greece, Italy, Spain, France, UK, and Iceland—also differ in preference for meat depending on whether they are familiar with lamb fattened on grain or pasture.
Most Americans are conceived and raised eating grain-fed beef, so taste panels of consumers, as well as experts trained to evaluate sensory features of meat, typically find grain-finished beef more palatable than grass-finished beef. Inconsistent ratings for grass-finished beef in studies reflect differing past experiences of consumers and differences in how animals are fattened. These studies show why the generic label “grassfed” tells a consumer little about how the phytochemical richness of an animal’s diet contributes to the flavor of meat or health, and they create an opportunity for producers to develop artisanal meats that link local soils, plant diversity, grazing practices, and environmental health with the palates of consumers.
Let Food Be Our Medicine: Plant Diversity, Livestock Diets and Human Health
Most humans are omnivores who satisfy their needs for nutrients with both plant and animal foods. Our needs for some nutrients are better met by plants, while our needs for other nutrients are better met by meat. Plant and animal foods thus function symbiotically to nurture human health. For example, plants can more readily meet needs for magnesium and plants are high in folate, manganese, thiamin, potassium, vitamin E, and a wide array of phytochemicals. On the other hand, meat provides high-quality protein (a balanced mix of all of the essential amino acids) and micronutrients such as iron, zinc, and vitamin B12. Eating 30 g of dry beef can meet daily needs of a healthy 70-kg adult human for taurine and carnosine and provide creatine, anserine, and 4-hydroxyproline to improve overall health of cells and organ systems.
While soy or pea proteins in plant-based faux meat alternatives have similar digestibilities to proteins in meat, they are not converted as efficiently into cells and organ systems. That is why, compared with plants, people need to eat less meat to meet needs for protein and some essential nutrients. That is also why, as Warren Angus Ferris experienced, meat obtained from bison fattened on phytochemically rich diets nourishes and satiates. That also helps to explain an apparent paradox: vegetarians report a lower desire to eat meat compared to omnivores, but brain scans of their neural activity reveal a craving for meat. Their verbal reports and neural scans highlight a conflict between inherent needs for nutrients in meat and acquired beliefs.
A common contention and belief is that eating too much red meat promotes oxidative stress and low-grade systemic inflammation—characterized by elevated plasma levels of pro-inflammatory markers such as C-reactive protein, serum amyloid A, tumor necrosis factor alpha, and interleukin 6—implicated in cancer, cardiovascular disease, metabolic syndrome, insulin resistance, and type 2 diabetes. These diseases allegedly are due to ingesting excesses of compounds such as heme iron in red meat and nitrate/nitrite in processed meat.
Inferring the health impacts of dietary patterns from associative (epidemiological) studies is problematical due to multiple confounding factors, many of which are not known or taken into account, including how the phytochemical diversity of herbivore diets affects the biochemical characteristics of meat and milk. Studies that find inverse associations between eating red meat and health do not distinguish between meat from livestock fed high-grain diets in feedlots and livestock foraging on phytochemically rich mixtures of plants. Nor do these studies address how herbs, spices, vegetables, and fruits eaten in a meal with meat can enhance health.
Eating any food causes a transient inflammatory response following the meal. When people eat meat and fat, protein oxidation and lipid peroxidation cause inflammation. Yet, when herbivores eat phytochemically rich diets, compounds in their diets protect meat and dairy from the protein oxidation and lipid peroxidation that cause inflammation. Phytochemical richness may be one reason why people have decidedly lower inflammatory responses following a meal of meat from kangaroos foraging on diverse mixtures of native plants (a traditional hunter-gatherer meat meal) compared with a meal of meat from wagyu cattle fed high-grain diets in feedlots (a modern meat meal). Despite the potential significance of these findings, no other studies have assessed how the phytochemical richness of forages herbivores eat affects the phytochemical and biochemical richness of meat and fat and how that affects inflammation.
Historically, Native Americans used wild berries—such as serviceberry (Amelanchier alnifolia), highbush cranberry (Viburnum trilobum), silver buffaloberry (Shepherdia argentea), and chokecherry (Prunus virginiana)—for food and medicine. They also combined berries with dried meat and fat to make pemmican. Eating wild berries (and some vegetables and fruits) can reduce risks of type 2 diabetes, cardiovascular disease, cancer, and all-cause mortality. Wild berries contain phytochemicals that protect against metabolic syndrome, diabetes, diabetic microvascular complications, hyperglycemia, and inflammation. Phenolic compounds in berries (proanthocyanidins, anthocyanins, and phenolic acids) can moderate high levels of glucose in blood (hyperglycemia) and inhibit chronic inflammation associated with disease. Carotenoids inhibit aldose reductase, an enzyme involved in diabetic microvascular complications.
Eating processed meats is associated with higher incidence of colorectal cancer, allegedly due to compounds such as nitrates used in processing. People who eat processed meats high in nitrates as well as large amounts of vegetables high in nitrates—beets, celery, lettuce, radishes, and spinach—may have greater risk of cancer, though some contend eating modest amounts of foods enriched with nitrate and nitrite provide health benefits with little risk. Yet, people who eat traditionally processed meats in Morocco do not have increased risks of colon cancer. One explanation is that the complex combinations of herbs and spices used to process meats, such as Kaddid in Morocco, promote health. Kaddid is ribs of beef, lamb, or camel cut in thin slices mixed with olive oil, herbs and spices such as cumin, garlic, coriander, salt, vinegar.
Cooking hamburger can generate reactive oxygen species that cause oxidative stress and inflammation associated with heart disease and cancer. However, adding polyphenol-rich antioxidant spices such as oregano and rosemary to hamburger enhances flavor and reduces levels in meat, plasma, and urine of malondialdehyde (MDA), a marker for oxidative stress. Likewise, drinking polyphenol-rich red wine while eating red meat cutlets reduces by 75% the levels of MDA, which can rise by 3-fold after a meal of cutlets alone. That is one reason why drinking a glass of red wine complements a meal with steak.
Phytochemically rich herbs and spices added to foods enhance palatability, satiation (when a meal ends), and satiety (length of time between meals). Why? Because herbs and spices are good for the health of cells and organ systems. They can counter the seven hallmarks of cancer: selective growth and proliferative advantage, altered stress response favoring overall survival, vascularization, invasion and metastasis, metabolic rewiring, an abetting microenvironment, and immune modulation. Little wonder they complement meat and vegetable dishes and that people eat less of foods that provide greater sensory pleasure from added herbs and spices than they do of a blander version of the same food. These flavor-feedback relationships occur as cells and organ systems, including the microbiome, are nourished by phytochemicals in herbs and spices. Ironically, no research has assessed how palatability, satiation, and satiety are affected by the phytochemical and biochemical richness of meat or of meat with herbs and spices.
Rather than growing and eating wholesome combinations of phytochemically and biochemically rich foods, our ailing society (adults in the U.S.: 75% overweight or obese, 50% pre-diabetic or diabetic, only 12% metabolically healthy) succumbs to the allure of multimillion-dollar supplement industries that claim to be the foundations of health. We are captivated by the allure of their recommendations to take supplements alleged to improve our health—our single-nutrient obsession. Omega-3 fatty acids are an example. Human health is enhanced as the phytochemical and biochemical richness of our diets increases from individual omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), to diverse mixtures of omega-3 fatty acids, to mixtures of wholesome foods such as oily fish, meat and milk, vegetables and fruits that contain tens of thousands of bio-active compounds in addition to omega-3 fatty acids. That is why increased intake of fish, as opposed to supplemental omega-3s, is more consistently associated with lower inflammatory responses in people with metabolic syndrome.
Our understanding of how diet affects health is limited to a mere 150 nutritional components, including energy, protein, minerals, and vitamins. These compounds are a fraction of the more than 26,000 biochemicals in the human foodome. Learning in the womb and early in life to eat phytochemically and biochemically rich combinations of foods, not single compounds, is foundational in health. Sadly, during the past century, we’ve extracted the culture from the landscape, the diet from the culture, the whole foods from the diet, and the compound from the food and we now have no notion whatsoever of how palates link peoples with landscapes.
During the past 70 years, we incentivized eating ultra-processed foods and disincentivized eating fruits and vegetables. To our detriment, the flavors of ultra-processed foods have become irresistible as the food industry learned to link familiar flavors with a blast of energy from refined carbohydrates to condition strong preferences for their products. On the other hand, the flavors of fruits and vegetables have become bland and unpalatable because their phytochemical richness has declined from 10% to 50% during that same time. We selected varieties for production, growth, appearance, and sweetness rather than phytochemical richness. By contrast, wild fruits and vegetables still contain complex mixture of different phytochemicals that nourish and satiate. In addition, we fertilize and irrigate crops, which often favors growth at the expense of phytochemical richness. For instance, phenolics and terpenes are typically higher in plants grown on drier sites than on wetter sites and higher in plants grown on less fertile sites than on highly fertile sites. Finally, fruit is picked green, shipped, and ripened with ethylene gas—the fruit-ripening hormone—rather than ripened to full phytochemical richness on the vine. These same issues apply to beef and chicken: we selected animals that grow quickly on feedlot diets that diminish favor because they are utterly lacking in phytochemical richness. Phytochemical richness also affects bees and honey as well as chickens and eggs.
The global shift away from eating phytochemically and biochemically wholesome diets to ultra-processed foods encouraged nearly one third (2.1 billion) of the human population to over-eat and become overweight or obese. This was illustrated in a study where people fed ultra-processed foods (white bread, sugary cereals, and reconstituted meats) ate an additional 500 calories daily compared with people offered wholesome foods (e.g., fresh fruits and vegetables, whole grains, and unprocessed meat), even though the two diets were matched for energy, protein, sugar, fat, sodium, and fiber. Compared with wholesome foods, ultra-processed foods do little to induce satiation (physical and biochemical processes that bring a meal to an end) or satiety (processes that inhibit eating between meals). Thus, people overeat and gain weight.
Steadily embedding ultra-processed foods in our diets for the past 70 years has been an experiment of sorts. Replicate this study over generations—in the womb, childhood, teen, and adult years—and we now have a pandemic of chronic diseases linked with excess weight. Given modern dietary trends, it is foolish to think that introducing more ultra-processed foods (faux meat) in our diets will reverse the burden of diet-related diseases. Our past experiences provide a good idea of the likely outcome: a sustained rise in intake of ultra-processed foods, which is now greater in young vegetarians and vegans than in meat eaters, and diet-related diseases. Ironically, champions of faux meat purport to address issues of human and environmental health, created in part by industrial agriculture, with more ultra-processed foods reliant on industrial agriculture.
Conversely, circumstantial evidence supports the hypothesis that plant diversity—manifest as plant diversity and phytochemical richness of landscapes—affects the biochemical richness of meat and dairy as well as human and environmental health. Future studies should enhance understanding of how plant diversity influences flavor and biochemical richness of meat and dairy; how phytochemically rich herbs, spices, vegetables, and fruits complement meals that contain meat; and how the aforementioned affect the health of people and the planet.
My colleagues (Stephen van Vliet, Scott Kronberg, Pablo Gregorini) and I are comparing faux meat, meat from feedlots, and meat from animals eating phytochemically rich diets. To do so, we are conducting: 1) metabolomic analyses that assess the phytochemical and biochemical richness of meat and dairy; 2) feeding trials to assess inflammatory responses of people, as researchers in Australia did when they compared postprandial inflammation in people fed meat from kangaroos and wagyu cattle; and 3) clinical trials to assess satiation, satiety, inflammation, and health.
Findings from these studies will achieve three ends. First, they will illustrate relationships among liking for the flavor of meat and dairy, the ability of phytochemically and biochemically rich meat and dairy to satiate, and the value to cells and organ systems, including the microbiome, of phytochemically and biochemically rich foods for humans. Second, they will underscore how we can create human and environmental health by growing and eating wholesome foods, rather than treating the symptoms of diet-related diseases. Finally, they will help people appreciate how palates link soil and plants with animals and environments.
Palates linked with wholesome foods would obviate the need for much modern nutrition and medicine. Health through nutrition was, of course, the point Hippocrates made roughly 2,400 years ago. That was also the point Roger Williams made in Biochemical Individuality, first published in 1956, when he discussed the implications of individuality for medicine and nutrition. He noted correctly that treatments (and diets) will need to be tailored to individuals and the importance of “body wisdoms” concluding “If this wisdom were universally possessed by all members of the human family, there would be no need to study nutrition and the only deficiency diseases would be those induced when suitable foods were not available.”
Unfortunately, nowadays most people are sick as a result of nutrition and medicine not appreciating the wisdom of the body and how that is linked with healthy soil, plant diversity, and the biodiversity of landscapes. These systems in conjunction with industrial agriculture have created the health crises whose symptoms medicine and pharmacy now treat at great expense.
During the past century, farmers and ranchers valiantly attempted, using the best intent and knowledge available during that time, to feed a human population that has burgeoned from 2 billion to nearly 8 billion people—a global population that is increasingly exceeding the carrying capacity of the planet. In the process, industrial agriculture and food processing have inadvertently wreaked havoc on soils, plant diversity, populations of animals below and above ground, and humans. We are now experiencing a pandemic of diet-related diseases from obesity at one extreme to malnutrition at the other end of the spectrum, all signs of societies detached from the landscapes that sustain our wellbeing. We can reverse these trends in part by integrating livestock back into mixed-farming systems that can provide wholesome meat and produce to nourish populations while building the health of the ecosystems that nurture us.
We made an art form of dining, but tabled the larger questions. Eating is participating in endless transformation as plants and animals are killed and eaten. As I eat, energy and matter in someone—plants and animals alike are conscious and sentient—becomes this entity I call “me” which will, in the flicker of a cosmic eye, return to Earth as soil, plants, and animals. In pondering this mystery, we may realize that all life is sacred. The wellbeing of the plants and animals we eat as food to nourish our bodies determines our health and that of the communities that sustain life on this planet. We’ve forgotten that we are members of nature’s communities: what we do to them, we do to ourselves. Only by nurturing them can we nurture ourselves. And we do that by declaring love—not war—on one another and the communities we inhabit.
Further Reading
This article is derived from the book Nourishment: What Animals Can Teach Us about Rediscovering Our Nutritional Wisdom and a subsequent article (also derived from Nourishment), which was published in March of 2019 in Frontiers in Nutrition titled Is Grassfed Meat and Dairy Better for Human and Environmental Health? That article is available for free online: https://www.frontiersin.org/articles/10.3389/fnut.2019.00026/full.
For additional details and a complete list of scientific references please refer to that book and article.
About the Author
Fred Provenza grew up in Salida, Colorado, working on a ranch and attending school in Wildlife Biology at Colorado State University. He is professor emeritus of Behavioral Ecology in the Department of Wildland Resources at Utah State University where he worked for 35 years, directing an award-winning research group that pioneered an understanding of how learning influences foraging behavior and how behavior links soil, plants, herbivores, and humans.
He is the author of three books, including Nourishment: What Animals Can Teach Us about Rediscovering Our Nutritional Wisdom; Foraging Behavior: Managing to Survive in a World of Change; and The Art & Science of Shepherding: Tapping the Wisdom of French Herders (co-authored with Michel Meuret). He has published over 300 research papers in a wide variety of scientific journals. He has been an invited speaker at over 500 conferences.
