Nature's Pharmacopeia: A World of Medicinal Plants
Myriad seeds, stems, leaves, roots, and fruits—such as these for sale in a market in Kurseong, India—have a long history in the world’s culinary and medicinal traditions.
“Let food be your medicine and medicine be your food,” goes the oft-quoted capsule of advice attributed to the Hippocratic writers of ancient Greece.1
HERBAL DIETARY SUPPLEMENTS AND MEDICALLY ACTIVE FOODS
In many traditional medical systems, attention to diet is a core practice of healthful living, and illness might be rectified by changes in cuisine. A great number of herbs considered nutritive, flavorful, and wholesome have entered the pharmacopeia through the kitchen. Sometimes such plants, selected long ago, were ascribed various medicinal virtues and integrated into local conceptions of health. People gave these leaves, roots, fruits, and grains properties: they designated them as “warming” or “moistening,” said they were good sources of energy, remembered they could make a person feel better if taken in moderation or worse if taken in excess. People established rules and procedures to prepare herbs properly, to mix them with the right types of ingredients and in the correct proportions, to taste a certain way, to have certain effects on the body. The experiences of generations of food preparers yielded such knowledge. Codified in the medical texts and preserved in folklore, beliefs in the health-related properties of edible plants are grounded in the observations of countless food providers and the people they helped feed.
As peoples met across the great routes of human movement, they shared knowledge and entered into commerce that extended plants into new territories and under new caretakers. People began again to taste, observe, and speculate, taking account of what they had heard and assigning to each plant a set of properties that made sense to them. They further disseminated these plants across vast distances and down through the generations, sharing and evolving what they had learned: this herb is good for earaches, this one is binding and “drying,” this one is best in the winter. In this way, so many medicinal and culinary plants have come to the present, still serving their roles at the dinner table, and almost all awaiting the attention of biochemists and physiologists.
The inquisitive human spirit that gave rise to the diverse culinary traditions of the world, each incorporating so many flavorful, colorful, nutritious medicinal plants, is also evident in the countless roots, leaves, and seeds that made up the herbal teas, ointments, and other preparations people used to treat their illnesses and promote health. Generations of village elders, midwives, and physicians yielded a set of agents that, as part of and alongside cuisine, was believed to address the suite of maladies affecting a people. The traditional herbal pharmacy was enormous, and individuals relied on herbs both as part of a proper diet to maintain health and in directed medical treatment to deal with all types of ailments.
Drawing on numerous medical traditions, many in the West continue to look after their health through diet, giving attention to the timing, balance, and sourcing of their meals. Whether to treat particular acute complaints, address chronic concerns, or promote well-being in the broadest sense, people recognize that their choice of what to eat can influence their bodies in meaningful ways. They also choose to supplement their diets with readily consumed plant-based isolates and extracts, seeking health-related benefits and following an age-old practice of appealing to nature for help toward wellness. This chapter explores the lore and impact of several of the most popular herbal supplements and medically active foods. Some have come through thousands of years of Western herbal medical tradition; others have been adopted from the indigenous practices of Asia and North America. In a story common across so many herbal traditions, the cultural roles of these plants have changed over time, having been ascribed certain properties in antiquity and other properties that developed later, in new eras and locales. Today, these plants have been transformed yet again, shaped by new perceptions of their capabilities to modify health at the level of the body, tissue, cell, and molecule. Such herbs—encapsulated, extracted, and standardized—are modern products of the age-old pursuit of health through plants.
While previous chapters have addressed medicinal plants with unambiguous effects on human physiology (the strong stimulant properties of cocaine, from the coca plant, for example), many of the herbs in this chapter are proposed to have more subtle roles in health. These plants are thought to promote longevity, lighten the mood, and help resist infection, for instance, outcomes that can be harder to discern than those of products with more or less instantaneous effects. As a next large challenge for the study of herbal medicine, continued quantification and description of the properties of such popular supplements using objective measures will yield a great resource for practitioners and patients.
The oral and written records of traditional uses of plants provide much education to consumers and scholars, as generations of experience have delivered to modern researchers information about dosing, preparation, and particular uses of herbs. Human curiosity and government regulation demand also that medicinal products be subjected to scientific testing, to understand better the makeup and effects of plants and plant extracts on health. Such tests aim to characterize the chemical composition of herbal extracts to identify possible active principles, a task simpler for plant-derived agents with strong, immediate effects than for those with slower-acting effects. Some herbal compounds likely act as part of a mixture of chemicals, which calls for an analysis of some complexity. It is also important to recognize that experiments conducted in the laboratory using cell cultures or test animals (such as rodents) might not easily extend to the human being. Conducting clinical trials is a technically challenging and costly business, and many experiments investigating the possible effects of herbal supplements have been criticized for shortcomings of design. Ultimately, the most convincing data on the safety and efficacy of plant-based treatments will come from a consensus of scientifically sound experimental investigations that account well for dose, composition, mode of delivery, and specific, shared measures of health outcomes.