I n addition to nutrients, plant foods consist of phyto-chemicals, which may affect human health. Phytochemi-cals are the nonnutritive plant components with biological activity (Bennick 2001: 11). Fruits, vegetables, beverages, and several herbs and plant extracts contain these phyto-chemicals. There are numerous phytochemicals including carotenoids, flavonoids, indoles, and protease inhibitors, among others (Watson 2001: 3). Many research studies have determined that such chemicals have health benefits, naturally aiding the body in disease prevention and neutralizing chemical and hormonal imbalances. One study conducted estimated that plant based diets prevent 20-50 percent of all cancers (Nestle 1997: 11149). This medical research prompted doctors to begin prescribing diets rich in foods containing these phytochemicals. It did not take long until these ideas caught on in the fad-dieting and dietary-supplement worlds. Due to the new popularity of diets rich in phytochemicals, individuals are consuming these chemicals not only for health benefits but also for the prospect of losing weight and stubborn fat. Interestingly, the popularity of phytochemicals began among medical professionals due to results of medical research. However, more recently they have gained popularity with the public as a result of only partially or wholly unsubstantiated claims made by the creators of fad diets and supplements.
As a result of medical research, about thirty classes of phytochemicals have been described as having cancer-preventative effects (Watson 2001: 4). Several epidemiological studies suggest, "that micro chemicals present in our diet could be the most desirable agents for the prevention and/or intervention of human cancer incidence and mortality due to stomach, colon, breast, esophagus, lung, bladder, and prostate cancer" (Watson 2001: 3). The specific mechanisms of these phytochemicals that aid in cancer prevention are not yet fully known. However, there are many plausible reasons being investigated. For example, it is recognized that "phytochemicals can inhibit carcinogenesis by induction of phase II enzymes and inhibiting phase I enzymes, scavenge DNA reactive agents, suppress the abnormal proliferation of early preneoplas-tic lesions, and inhibit certain properties of the cancer cell" (Watson 2001: 3).
Much recent research has focused on the anticancer activity of phytochemicals found in soy products (Bennick
2001: 11). Early observations of the role of soybeans in prevention of human cancer developed from correlative investigations that were seeking explanations for the global differences in cancer between the Western and Asian countries (Birt 2001: 4). Research has shown that the Asian diet, which is richer in soy products and contains fewer fatty products than the typical Western diet, decreases incidence of cancer (Riulin 2001: 256). In addition, a large number of animal investigations have provided strong evidence for the role of soy in cancer prevention (Birt 2001: 5).
A subgroup of phytochemicals, phytoestrogens or plant estrogens, have been implicated as having additional disease-preventative and healthful effects. A high intake of these phytoestrogens may help alleviate the symptoms associated with the low estrogen levels that plague menopausal women. Phytoestrogens also may reduce the risk for diseases, such as cancer, associated with estrogen (Scholten 2006). For example, resveratrol, a phytochemi-cal in the skins of grapes and peanuts, was found to limit the growth and proliferation of human breast cancer cell lines, by inhibiting the binding sites of estrogen receptors in human breast cancer cells (Diamondis and Goldberg 2001: 173).
Since the discovery of these disease-preventative characteristics, many people have altered their diets for a healthier lifestyle. Doctors have strongly recommended that their patients incorporate more fruits and vegetables, which contain such nutrients and phytochemicals, into their diets. Foods that include these phytochemicals, other than soy, are dark green, leafy vegetables like spinach, kale and collards; citrus fruits, such as oranges, grapefruit and tangerines; and other red, yellow, and orange fruits and vegetables as well as their juices (Anon. (2005) "Phytochemicals"). Diets rich in phytoestrogens consist of soybeans, black cohosh, whole grains, legumes, tempeh, and flax seed (Scholten 2006).
These doctor-recommended healthful diets that incorporate phytochemicals have become the basis for fad diets that proclaim they promote health and weight-loss. For example, the Mediterranean Diet has become increasingly popular as people have become aware that good health is linked to a good diet (Watson 2001: 217). This diet is based on the "historic" food intake in the Mediterranean region, which includes larger amounts of vegetables, fruits, beans, and grains, as well as olive oil as the main source of fat and moderate amounts of protein, primarily from fish and poultry. Such views of "traditional"
cuisine as being innately healthy have their historical rationale in the claims that "natural" foods are consumed by "natural" society and therefore show the innate superiority of such groups over "modern," globalized society and its production and consumption of foods. The Mediterranean Diet prescribes that people eat certain proportions and combinations of these foods, each with their own phytochemicals, throughout the day. The fad diet also uses cooking methods similar to those used several decades ago around the Mediterranean Sea. It is considered the model of a healthful diet and has attracted attention because of the low rates of chronic diseases and the high life expectancy noted in countries of the Mediterranean region. This diet is found to produce beneficial effects on blood lipid profiles and protect against oxida-tive stress and carcinogenesis ("Watson 2001: 217).
Additionally, some cuisine of the Mediterranean diet is believed to contain minor metabolites, like limonene, that are thought to speed weight loss. This diet is easily accepted by most people due to this possibility of weight loss combined with the hundreds of recipes that conform to the rules of the diet (Watson 2001: 224). It has gained vast popularity, for it provides the best chance for influencing people to abandon unhealthy foods in favor of fresh and less saturated-fatty foods (Watson 2001: 217).
Although the diet in the Mediterranean region has been linked with reduced frequency of disease among inhabitants of the lands around the Mediterranean Sea, the Mediterranean Diet sold as a fad diet. The diet has not been sufficiently studied or proven to reduce disease or induce weight loss. It is based on the author's perception of the diets of inhabitants of the Mediterranean and, thus, is not an exact replica of their eating practices. For instance, Watson argues that "there is no single typical Mediterranean diet. Defining and understanding the Mediterranean diet is not easy because there are several countries that border the Mediterranean Sea" (Watson 2001: 218). Also, prescribing the diet of a certain region alone is not necessarily enough to mimic the lifestyles of the people of that region. The diet fails to take into account other factors in Mediterraneans' living, such as their physical activity level. Because this fad diet does not account for the differences between it and the precise diet and activities of the Mediterraneans, it may be mistaken in claiming that its prescription of certain foods and their associated phytochemicals actually reduce the incidence of diseases and overweight as they actually do in the Mediterranean region.
Phytochemicals have also justified the "science" behind some dietary supplements that claim their products help individuals achieve leaner bodies and/or increase disease prevention. For example, the makers of a supplement called EstroX, containing naturally occurring estrogen inhibitors, claim that their product along with a diet rich in natural estrogen-inhibiting foods, such as certain vegetables, whole grains, and fatty fish, will help individuals lose weight. The product advertisement claims that individuals who have been subject to hormone therapy or who have been exposed to the "unhealthy estrogenic environment" of everyday life have too much estrogen in their bodies. The makers claim that too much estrogen, rather than playing its usual role as an antioxidant and anticancerous compound at normal levels, instead converts into toxic compounds that are stored as fat and are thought to contribute to the formation of breast, ovarian, and prostate cancers. Therefore, by taking their supplement, which contains the "superior" proportion of three estrogen inhibitors derived from bee propolis, broccoli, tobacco, passiflora, and chamomile, the makers of EstroX claim that individuals suffering from excess estrogen will decrease their estrogen levels and thus achieve leaner bodies and healthier lives (Hofmekler 2006).
It at first seems as though the makers of EstroX have done their medical research. However, the creators use vague language about the extent to which their claims are scientifically supported. As with all supplements, ExtroX is not required to pass FDA or any other government regulations in order to make certain claims or break into the supplement market.
Phytochemicals can be found in a wide variety of foods and beverages people consume. Considering their abundance, it is no wonder that these phytochemicals have become famous as a result of the medical discoveries tying their consumption to a healthier lifestyle. However, much of their popularity has grown due to the unsubstantiated claims of the more public fad dieting and dietary supplement worlds that have embraced phyto-chemicals as a new phenomenon in health and weight loss. There is no question that it will take more years of research into phytochemicals and the effects of the phyto-chemical products claiming miraculous results, before these non-established declarations are proven.
See also Natural Man; Risks Associated with Dieting
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