RECURSOS NATURALES

Perhaps the most astounding thing about paclitaxel’s discovery was its extremely ordinary origin. Yew trees are neither exotic nor endangered, yet they produce chemicals that effectively combat two of the most serious diseases women face. Likewise, many seemingly unremarkable plants have been identified as possessing unusual heal-ing properties. Herbalists—people who know the uses of plants for medicines and cosmetics—kept this knowledge alive even when lab-oratory-produced drugs took a dominant role in health care. In some nations, particularly those of Asia, physicians incorporated both traditional medicines and Western drugs as they treated patients. In other lands, herbalists became part of an alternative medical culture.

In the 1970s and 1980s, people began taking an interest in the work of herbalists and in the general subject of alternative medicine, and medical scientists started examining these centuries-old healing plants.

It is difficult to say exactly why herbal remedies became so popular during this time. One reason might have been that people were becom-ing disenchanted both with the risbecom-ing cost of modern medicine and with the side effects that accompany modern pharmaceuticals. At the same time, though, such social movements as the trend toward organic farming and the criticism and distrust of synthesized chemicals may also have made people more receptive to these alternative treatments.

Whatever the cause, store shelves began filling up with such products as Saint-John’s-wort, which was touted as a natural antidepressant, and echinacea, a flower that yielded a chemical that supposedly could pre-vent colds, or at least cut them short.

In addition to herbal remedies, vitamin and mineral supplements became popular as people started exploring ways to prevent illness.

Vitamins are catalysts for other chemical reactions in the human body, maintaining functions that range from the assembly of DNA molecules in cells to the creation of new skin over wounds and sores. Human beings need 13 vitamins in order to stay alive: Vitamin A, or retinol;

eight vitamins known as the B complex; vitamin C, also called ascorbic acid; vitamin D, or cholecalciferol; vitamin E, or tocopherol; and vita-min K. Most people get almost all the vitavita-mins that they need if they eat a healthy, balanced diet. The exceptions include three of the B vita-mins: biotin, niacin, and pantothenic acid; vitamin K, which the intes-tinal bacteria produce; and vitamin D, which the skin makes when exposed to sunlight.

As catalysts, vitamins do not so much do things in the body as ensure that things get done. Vitamin A helps the body maintain the health of the eyes, the skin, the urinary tract, and the linings of vari-ous organ systems. Vitamin C allows the body to grow and replace various tissues, as well as to heal wounds. The lack of some vitamins can have drastic effects. Scurvy, a disease in which wounds heal slowly, gums bleed, and victims become extremely weak, is the result of a severe vitamin C deficiency. This disease was especially common Traditional herbal

medicines have been in use around the world for millennia. Here, herbalists prepare drugs in a 1950s Chinese hospital. (World Health Organization photo, courtesy of the National Library of Medicine)

among sailors during the age of wind-powered ships, when weeks or months passed without access to fresh fruits or vegetables. The first clue that a lack of some nutrient was responsible for scurvy came when a Scottish physician named James Lind discovered that eating oranges and lemons could cure the disease. Lind also found that lemon or lime juice could keep scurvy at bay, and he convinced the British Royal Navy to provide a daily ration of juice to its sailors starting in 1795.

American sailors found a different cure for the disease: vitamin-C-rich cranberries.

One of the best-known advocates of the healing power of vitamins was Dr. Linus Pauling, an American chemist who won the 1954 Nobel Prize in chemistry and the 1962 Nobel Peace Prize. Though he won his 1954 prize for his analysis of how atoms bond to form chemical compounds, Pauling later examined how vitamins, particu-larly vitamin C, affected the health of the human body. He believed that huge amounts of vitamin C, which he called megadoses, could help people treat ailments such as the common cold and cancer.

Indeed, scientists who followed up on Pauling’s theories showed that large doses of both vitamin C and vitamin A seemed to prevent some forms of cancer. However, other studies either failed to show any benefit from taking megadoses of vitamins or provided inconclusive results.

Similar studies have yielded similar results regarding the disease-preventing abilities of some minerals, particularly zinc. Minerals are chemical elements such as zinc, calcium, iron, and iodine that the body uses for such functions as building bones, making blood cells, and reg-ulating metabolism. Diets that contain too little or too much of one or more minerals can cause a variety of illnesses. Too little iodine, for instance, causes the thyroid gland to swell to many times its normal size, creating a condition called a goiter.

Like vitamins, some minerals have been touted as being able to pre-vent or cure some illnesses. Perhaps the best-known of these medicinal minerals is zinc, a metal that supposedly can suppress the activity of viruses that cause the common cold or sinus infections. Over the years, zinc has appeared in many products designed to increase the amount of the metal present in the body: tablets, chewing gum, nasal sprays, and health and energy drinks. Despite its popular reputation, though, there have not been many studies analyzing the actual health benefits of zinc supplements and remedies. The few studies that have been conducted have returned varying results, leaving the important question—does the stuff work?—unanswered so far.