Introduction What group of health-promoting nutrients is found in foods such as fruits and vegetables and beverages such as red wine, tea, and even cocoa? The answer is bioflavonoids. The most recent scientific breakthroughs confirm that these incredible nutrients are an important part of a healthy diet. Their healing properties promote longevity and play a role in the prevention of cancer and heart disease. They can even make you smarter and improve the appearance of your skin. So far 5,000 different types of flavonoids have been identified, and of these, a hundred or so have been shown to have biological effects in humans. These are called bioflavonoids. Several bioflavonoids, including quercetin, cathechin, and hespiridin, have scientific research backing their health benefits. In fact, many nutritionists believe that not getting enough of these precious substances from your diet may cause premature aging, degenerative diseases, and death. But by making a few simple nutrition choices and by taking the right bioflavonoid supplements, you can improve the quality of your life and perhaps extend your years. In “All About Bioflavonoids”, you will learn how these nutrients can prevent aging of the skin, relieve hemorrhoids, provide a natural way to help prevent breast cancer, and reduce the symptoms of premenstrual syndrome and menopause. You will also learn how certain bioflavonoids may help protect the prostate gland fro cancer. Section 1 provides you with some basics about bioflavonoids. Section 2 through 8 cover different bioflavonoids or bioflavonoid sources, including Pycnogenol, quercetin, grape-seed extract, green tea, citrus bioflavonoids, soy bioflavonoids, and more. The last section will guide you in choosing and using bioflavonoids. In other words, this book will help you select bioflavonoid-rich foods and supplements that will bring you the most complete health rewards for your investment. Section 1. Bioflavonoid Basics Bioflavonoids, which are sometimes referred to as flavonoids, are a group of naturally occurring plant compounds that act primarily as pigments, giving fruit, leaves, flowers, and other plant parts their vibrant colors. When ingested, bioflavonoids have numerous health-enhancing effects on the human body. In fact, this group of antioxidant nutrients-discovered in the 1930s-has always been an important part of the human diet. In this chapter, you'll learn the basics about these amazing bioflavonoids. Q. Why do plants contain bioflavonoids? A. One function of bioflavonoids is to give plants their various colors. Many of these colors, however, cannot be seen by humans or can be seen only under the illumination of ultraviolet light. Dr. John H. Crow, a botanist and ecologist at Rutgers University, suggests that bioflavonoids are involved in attracting insects to flowers, in which they tend to occur in high concentrations. Bioflavonoids also function as antioxidants in plants. You see, plants are exposed to direct sunlight all day long, and therefore receive a large dose of ultraviolet (UV) light. Bioflavonoids help protect the plant from these harmful UV rays and neutralize the free radicals-unstable molecules with an unpaired electron-which they produce. Bioflavonoids have this antioxidant effect in humans, too. Q. What are the health benefits of bioflavonoids? A. The main health benefits of bioflavonoids fall into two categories: health-promoting effects and therapeutic effects. The health-promoting effects include better eyesight; improved cardiovascular health; increased capillary strength; improved structure of connective tissues and appearance of skin; and a stronger immune system. In addition, bioflavonoids have a vitamin C and vitamin E enhancing effect, meaning that they can boost the function of these powerful antioxidant vitamins. Bioflavonoids also offer the health-promoting effect of lowering the risk of some diseases, such as atherosclerosis, cancer, arthritis, and gastrointestinal disorders. The therapeutic applications of bioflavonoids include treating a variety of diseases and disorders. Several of these are coronary heart disease, allergies, inflammation, hemorrhoids, respiratory diseases, viral infections, some types of cancer, and peptic ulcers-ulcerations of the mucous membranes of the stomach, esophagus, and upper small intestines. Q. How were the beneficial effects of bioflavonoids first discovered? A. Dr. Albert Szent-Gyorgyi, a famed Nobel Prize-winning researcher, was the first to discover a bioflavonoid effect during his research work on vitamin C. He found that vitamin C from lemon-juice extract was the most effective treatment for the fragile blood vessels caused by the vitamin-C deficiency disease, scurvy. He observed an improvement in capillary permeability, which appeared to reduce the bleeding he was trying to alleviate. This discovery led him to conclude that another vitamin factor was present in the lemon-juice extract, which he called "vitamin P." As Dr. Szent-Gyorgyi's research continued, it was determined that the vitamin-P factors were chemically related substances derived from a group of natural chemicals called phenols. Upon further investigation, he determined that the vitamin-P factors belong to a category of phenols called bioflavonoids. Shortly thereafter, the term vitamin P was discontinued because further research failed to establish that bioflavonoids are essential nutrients-meaning that they were not proven to be necessary for survival or required by the body to prevent nutrient-deficiency diseases. Despite their current nonessential status, bioflavonoids play an important role in health maintenance and disease prevention. Q. What is the current thinking concerning bioflavonoids? A. Contemporary researchers believe that bioflavonoids actually play important roles in the promotion of health and longevity. Since the early nutrition research by Dr. Szent-Gyorgyi, many researchers have turned some of their attention to the so-called nonessential or semi-essential nutrients in the human diet-nutrients that serve to enhance the structure, function, and health of the human body, but are not absolutely required for existence. A large portion of the research on bioflavonoids is epidemiological-a type of research that examines health statistics of populations and looks for relationships between diet and health. Epidemiological studies are usually starting points that later lead researchers to conduct experiments in an effort to understand how a particular food or substance causes the observed effects. Scientists then begin to conduct a barrage of other studies; some to identify, isolate, purify, and reproduce the substances in foods that may be causing the beneficial health effects. Q. What are some common terms that refer to bioflavonoids? A. During the course of determining the various effects that different flavonoids exert on living systems, the term bioflavonoid was adopted by some researchers to differentiate between the health-promoting flavonoids and the thousands of other flavonoids that do not have a proven biological role. Unfortunately, scientists who study bioflavonoids are often at odds in agreeing on their terminology and classification. (This is sometimes the case when dealing with such a large group of chemical compounds.) For our purposes, know that bioflavonoids-which are as diverse as vitamins-are categorized by their chemical structure. Think of them as a group of plant compounds that have a similar primary structure with slight differences. Though individual bioflavonoids can be sorted into several subgroups, the entire group of bioflavonoids falls under a larger group of plant chemicals known as phenolic compounds. These compounds contain one or more phenyl rings in their structure. Bioflavonoids contain at least two. The different subgroups of the bioflavonoids include the catechins, anthocyanidins, leucoanthocyanidins, flavonones, flavones, flavanonols, flavonols, isoflavones, flavans, dihydrochalcones, aurones, and chalcones. In turn, specific types of bioflavonoids belong to one of these classes. For example, the bioflavonoid quercetin belongs to the flavonol class; genistein belongs to the isoflavone class; catechin belongs to the catechins class; and cyanidin belongs to the anthocyanidins class. But don't become too concerned about memorizing these categories. Instead, stay focused on the big picture-the types of foods and supplements that contain these health-promoting bioflavonoids. Q. Why aren't bioflavonoids considered essential nutrients? A. In order for a nutrient to be classified as essential, a deficiency of the nutrient must cause symptoms of disease. Currently, there are no clearly established bioflavonoid-deficiency conditions that result in obvious symptoms or sudden death. Some researchers speculate that an absolute essential function of bioflavonoids hasn't been determined because it's difficult to completely eliminate this group of nutrients from the diet. Other researchers argue that low bioflavonoid intake leads to a slow death from degenerative diseases, such as cancer and coronary heart disease. There is also scientific evidence that bioflavonoids positively influence the behavior of genes-the biological blueprints that direct the behavior of the cells of the body. While bioflavonoids are not essential by the strictest sense of the word, they are very beneficial. Q. Are there any studies that link bioflavonoid intake to disease prevention? A. Many studies-some of which will be discussed in later chapters-have linked bioflavonoid intake to disease prevention. The Zutphen Elderly Study is one of the more popular studies. In this study, Michael Hertog and coworkers set out to see if there was a connection between bioflavonoid intake and a reduced risk of coronary heart disease. To accomplish this, the researchers assessed the bioflavonoid intake of 878 men, age sixty-five to eighty-four, at the beginning of the study in 1960 and again in 1985. The bioflavonoid content of various foods, including black tea, onions, and apples, was determined. Total consumption of bioflavonoids averaged 25.9 mg per day. At the end of the study, the researchers found that those men who regularly consumed bioflavonoids in their diets reduced their risk of death from coronary heart disease. The researchers hypothesize that one way bioflavonoids play a role in reducing coronary heart disease is by reducing the formation of oxidized LDL-cholesterol (the "bad" cholesterol), which would then inhibit the formation of cholesterol deposits in the arteries. In addition, bioflavonoids inhibit the cyclooxygenase pathway, which plays a role in blood platelet aggregation. This results in a reduced risk of thrombosis-a type of blood-vessel clot formation. Q. What exactly are antioxidants? A. Antioxidants are chemical substances that control or prevent oxidation, or free-radical damage, by neutralizing free radicals before they can harm the cells and tissues of the body. As the field of antioxidant research has grown, antioxidants, as a group, have come to include compounds that protect against many types of oxidants, or reactive chemicals, including super oxide radicals, hydrogen peroxide, hydroxyl radicals, as well as the more mild oxygen molecules. Oxidation in your body can alter lipids, proteins, and other biomolecules, damaging their structure and function. You should note, however, that these potentially harmful reactions are vital to ordinary body functions. That's why the body produces its own antioxidants, including glutathione peroxidase, coenzyme Q10, alpha-lipoic acid, and super oxide dismutase (SOD). Together with dietary antioxidants, these endogenous antioxidants help to protect the body against the thousands of free-radical hits that each cell experiences daily. With all of these biochemical reactions going on in the body, it's easy to understand why the extra intake of antioxidants, including bioflavonoids, can promote a healthier internal environment. Q. Are bioflavonoids very powerful antioxidants? A. The antioxidant activity of bioflavonoids is quite diversified and actually complements the more traditional antioxidants, which include vitamin C, vitamin E, and beta-carotene. Bioflavonoids work with the other antioxidants to offer a sort of group protection. And on their own, bioflavonoids have the ability to deactivate several types of free-radical compounds that exist in or infiltrate your body. Free radicals damage the body in many ways, and are the underlying causes of many degenerative diseases, including cancer and arthritis, and also may speed up the aging process. Different bioflavonoids seem to have individual preferences for the different types of free radicals they neutralize. Additionally, bioflavonoids-due to their individual structures-display an attraction to certain body parts where they carry out their antioxidant activities or other health-promoting functions. For example, the herb bilberry affects vision; green tea plays a beneficial role in gastric cancer; and Pycnogenol and grape-seed extract have positive effects on coronary heart disease. Q. How do antioxidants help to prevent diseases? A. There is growing evidence that free-radical damage plays a causative role in diseases, such as cancer and coronary heart disease, and leads to other age related disorders, such as cataracts and arthritis. And as you've learned, antioxidants neutralize free radicals before they can cause damage. For example, by preventing LDL-cholesterol from becoming oxidized by free radicals, antioxidants can prevent the resulting artery-clogging plaque that can lead to heart disease. In the case of cancer, the oxidation of DNA can lead to cellular mutations and cancerous tissue growth. By limiting free-radical damage to DNA, antioxidants inhibit the growth of abnormal cells and tumor cells. As for arthritis, antioxidants help to control the increased amount of free radicals in inflamed arthritic tissues. The formation of cataracts, because they are the result of free-radical damage to proteins in the lens of the eye, can be decreased with adequate antioxidant intake. Q. Can bioflavonoids really help to prevent cancer? A. In a recent article entitled "The Prevention of Cancer," Bruce Ames and Lois Swirsky Gold reported that dietary factors can have a major effect on reducing cancer rates. In particular, hundreds of epidemiological studies have shown that adequate consumption of fruits and vegetables-plant foods that are typically high in bioflavonoids-is associated with lower cancer rates. Therefore, people who have cancer or who are at risk for cancer may experience some anticancer health benefits by eating fruits and vegetables and by taking bioflavonoid supplements. Note, however, that cancer is associated with many other factors, including aging, toxic chemicals, and metabolic waste products. Moreover, this is a very serious disease, so strict medical supervision is mandatory to insure that every available prevention therapy and treatment option is being considered and properly utilized. Q. Can taking antioxidants, such as bioflavonoids, slow the aging process? A. Slowing the aging process with nutrition has recently become a major focus of medical research. Free radicals, as you've learned, can damage cells and cause the body to breakdown on the cellular level. You've also learned that antioxidants can reduce the amount of damage caused by free radicals. Therefore, antioxidants, such as bioflavonoids, act to slow cellular breakdown-a major factor in the aging process. Researchers-including Bruce Ames, Kenneth Beckman, and Denham Harman-who study the adverse effects of free radicals and other chemicals on the body, point out that the free radicals produced during normal body processes cause accumulative damage over the course of a lifetime; eventually leading to disease, aging, and death. An increase in antioxidant consumption should therefore significantly decrease the amount of free-radical damage that an individual accumulates over the years. Q. What are good sources of bioflavonoids? A. Bioflavonoids are abundant in virtually all plant foods. However, the greatest dietary sources of bioflavonoids are tea leaves, onions, apples, grains, grapes, potatoes, roots, herbs, fruits and their juices, soybeans, vegetables, cocoa, coffee, beer, and most wine. Remember, however, that it's a good idea to limit your intake of alcoholic and caffeine-containing beverages. Bioflavonoids are also available as dietary supplements. Scientists have developed special concentrated forms of bioflavonoids with the hope of enhancing their health benefits. Pycnogenol, quercetin, grape-seed extract, green tea, and soy isoflavones are just a few examples of the bioflavonoid products available in health food stores, pharmacies, supermarkets, and through mail-order catalogs. See Section 9 for some guidelines on boosting your bioflavonoid consumption. To Section 2. Pycnogenol |
