Glutamine is a nonessential amino acid. “Nonessential” means that the body can create its own supply if the diet is lacking in glutamine-rich sources, such as poultry, fish, and legumes. Few people who are basically healthy and follow a balanced diet are deficient in this amino acid, one of the most abundant in the bloodstream. But there are some important exceptions.
Glucosamine
Glucosamine, a sugar produced in the body and found in small amounts in foods, plays an important role in maintaining cartilage, the gel-like material that cushions joints. When taken as a dietary supplement, glucosamine may help to relieve the pain, stiffness, and swelling of osteoarthritis, a degenerative joint disorder that affects 12% of the population, in which cartilage has worn down. Rheumatoid arthritis sufferers report improvements with glucosamine supplements as well, as do individuals with other types of joint injuries. Some 70 countries around the world sanction glucosamine as a treatment for individuals with mild to moderately severe osteoarthritis.
Ginkgo Biloba
This popular herbal medicine is extracted from the fan-shaped leaves of the ancient ginkgo biloba tree, a species that has survived in China for more than 200 million years and now grows throughout the world. (The leaves are double, or bi-lobed; hence the name biloba.) Long used in traditional Chinese medicine, it is only in the last few decades that the medicinal uses for the herb have been studied in the West.
Ginger
Revered around the world for its pungent taste, ginger (Zingiber officinale) is a natural spice that is also widely prized for its medicinal properties. Since ancient times, traditional healers in a diverse array of cultures have used this plant primarily to help settle upset stomachs. Chinese herbalists have relied on ginger as a medicine and flavoring for more than 2,500 years. The early Greeks mixed it into breads (hence the first gingerbread), and North American colonists sipped nausea-quelling ginger beer, the precursor of modern ginger ale. Today, many cultures continue to rely on ginger for controlling nausea and also for reducing inflammation.
Garlic
Along with its well-earned reputation for discouraging friends and repelling potential lovers, this powerful herb has a storied culinary and medical history. Egyptian pyramid builders took it for strength and endurance. Medieval healers recommended it as protection against supernatural forces–vampires in particular. The French scientist Louis Pasteur investigated its antibacterial properties, and doctors in the two World Wars treated battle wounds with garlic juice when other drugs were unavailable. Most recently, garlic has been touted for heart health as well.
Garcinia Cambogia
The herb Garcinia cambogia, a diminutive purple fruit native to India and southeast Asia, has garnered a lot of attention as a popular natural weight loss aid. The reason is that the rind of the pumpkinlike fruit is rich in a substance called hydroxycitric acid, or HCA, closely related to the citric acid found in grapefruits and oranges.
Gamma-Oryzanol
Although it appears in grains such as barley and corn, gamma-oryzanol is extracted from rice bran oil for commercial purposes. In Japan, this concentrated mixture of ferulic acid and other compounds is commonly added to foods and beverages. The bulk of research on gamma-oryzanol’s health benefits has been done in Japan, although supplements are now available in the United States as well.
Forskolin
In India, practitioners of traditional Ayurvedic medicine have long used the herb Coleus forskohlii to treat asthma, heart disease, and a range of other ailments. The small mint-family herb is also found in Sri Lanka, Thailand, and Nepal.
Folic Acid
Folic acid, also called folate or folacin, is a B vitamin with a solid reputation for protecting against birth defects and heart disease. If adults were to get an adequate amount of this vitamin, it is estimated that 50,000 deaths from cardiovascular disease could be prevented each year in the United States alone. Moreover, common birth defects could be cut nearly in half. Other ailments, such as depression, Alzheimer’s disease, and certain types of cancer may respond to the effects of folic acid as well.
Flaxseed Oil
A source of fiber for linen fabric since ancient times, the slender flax plant (Linum usitatissimum) also boasts a long history as a healing herb. First cultivated in Europe, the plant’s brown seeds were regularly used to prepare balms for inflamed skin and healing slurries for constipation. Today, flaxseeds–also called linseeds–are best known for the therapeutic oil that is derived by pressing them. Rich in essential fatty acids, or EFAs, flaxseed oil has earned a solid reputation for treating a range of ailments, from heart disease to lupus.
Flavinoids
Flavonoids is the umbrella term given to some 4,000 compounds that impart the colorful pigment to fruits, vegetables and herbs. Also found in legumes, grains and nuts, flavonoids can act as effective antivirals, anti-inflammatories, antihistamines and antioxidants. They’re useful for reducing cancer risk and serve to prevent or treat a wide variety of conditions.
Fish Oils
Heralded for its heart-healthy actions, fish oils offer high concentrations of polyunsaturated fats called omega-3-fatty acids. While all fish contain these fats, cold-water fish–salmon, sea bass, tuna, trout, mackerel–are particularly rich sources because of their diet: plankton packed with omega-3s. Interestingly, the colder the water, the more omega-3s in the plankton. Cold-water fish also boast the most potent forms of omega-3s: the essential fatty acids known as eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). Consumed as part of a fish-filled diet or in supplement form, omega-3s have myriad healing powers.
Fiber, soluble
Most foods contain a mixture of soluble and insoluble fiber, which together make up the dietary fiber family. Compounds that dissolve or swell when put into water are called soluble fibers and include pectins, gums, mucilages, and some hemicelluloses. These compounds are found inside and around plant cells and exist as gum arabic, guar gum, locust bean gum, and pectins. Soluble fiber is found in cereals and a variety of foods such as salad dressings, jams, and jellies.
Fiber, insoluble
Insoluble fiber is a subclass of dietary fiber. Like its soluble cousin, insoluble fiber differs from starch because the chemical bonds that join individual sugar units can not be digested by enzymes in the human gastrointestinal tract. Insoluble fiber is considered a “noncarbohydrate carbohydrate” since the components that make up insoluble fiber are lignins, cellulose, and hemicelluloses. All of these compounds form the structural parts of plants and do not readily dissolve in water and are not metabolized by intestinal bacteria. Bran fiber is rich in hemicelluloses, while a cotton ball is pure cellulose.
Feverfew
For centuries, healers relied on the feathery green leaves of feverfew (Tanacetum parthenium) to treat headaches, stomach upset, rheumatoid arthritis, and menstrual problems. The bright yellow and white blossoms of this flower, which grows wild throughout Europe and South America, emit a powerful aroma that was once thought to purify the air and prevent disease. Feverfew has also long been used in gardens to repel bees and various insects. And as its common name suggests, it was once popular for reducing fever.
Fennel
Most cooks–even unadventurous ones–can easily identify the yellowish-brown crescents known as fennel seeds. That’s because these tiny seeds, which actually represent the dried ripe fruits of the aromatic fennel plant (Foeniculum vulgare), have been handed down through the ages as a spice and food preservative. Their heady and memorable flavor, reminiscent of licorice and anise, is familiar to most people because fennel seeds are routinely used in rye bread.
False Unicorn Root
Over the centuries, countless women have turned to false unicorn root (Chamaelirium luteum), a tall perennial native to eastern North America, to remedy menstrual and uterine problems. (It should not be confused with Aletris farinosa, another member of the lily family, commonly referred to as “true” unicorn root.) Therapeutic compounds called steroidal saponins were identified in false unicorn root some time ago, but whether these exert hormonal activity in women that would help regulate the menstrual cycle remains unclear.
Evening Primrose Oil
Evening primrose oil is extracted from the evening primrose plant (Oenothera biennis), a wildflower found in North America, Europe and parts of Asia. The plant’s pale yellow flowers open in the evening–hence its common name–and its seeds bear the special fatty oil that is used in healing today.
Eucalyptus
From cough cure to tension-reliever, the woody scented oil and leathery leaves of the stately eucalyptus tree have found myriad uses over the centuries. Australian aborigines relied on this native evergreen for soothing painful joints and healing skin lesions. And settlers to the continent dubbed eucalyptus the “fever tree” in recognition of its disease-fighting powers. While these early users ascribed its potency to the tree’s brisk aroma, it is now known that the thirsty roots were responsible: They kept the surrounding ground relatively dry and thus free of malaria-carrying mosquitoes.
Elderberry and Elderflower
Famed as a source of the blue-black berries used to make elderberry wine and jelly, both the berries and flowers from the elder shrub (Sambucus nigra L.) have been used medicinally for centuries to fight off respiratory infections and other ailments. American elder (Sambucus candensis L.) is found in the eastern part of North America. What accounts for the plant’s therapeutic action is not well understood, but its healing properties are thought to derive from substances called flavonoids. These substances act as in the body in a variety of ways. As antihistamines, bioflavonoids can be helpful in the treatment of allergies. As antioxidants, they counteract the cell destruction caused by toxic molecules called free radicals. But it is the third property of flavonoids, an antiviral effect, that seems to make elderberry a clinically useful plant.