Dr. Weeks’ Comment: The seeds of most plants are not only 30x more nutrient dense than the flesh of the fruit or vegetable it grew in, but also the seeds fight cancer and grape seed extract (GSE) is very powerful. Use organic non-GMO seeds if you wish to join the revolution in nutrition! Note in the conclusion that the researcher propose that the seeds be used to AUGMENT conventional chemo and radiation therapy – they are too cowardly brainwashed to suggest that these natural agents might REPLACE the standard of care in chemo which is so destructive.
Anticancer and Cancer Chemopreventive Potential of Grape Seed Extract and Other Grape-Based Products1–3
Cancer is a global health problem with high morbidity and mortality and poses both economic and psychological challenges. Cancer cure and prevention therefore remain a high priority for the scientific community across the world. Insight gained into the etiology of cancer through various epidemiological studies encompassing various parameters such as geographical location, ethnicity, sex, age, and trans-migratory populations have collectively revealed that lifestyle is one of the major influencing factors (1–3). Other factors include environmental aspects such as automobile exhaust pollutants, solar UV radiation, occupational exposure to carcinogens and mutagens, bacterial/viral infection, and genetic susceptibility (4,5). Lifestyle factors are usually classified as modifiable risk factors and include diet intake, smoking, alcohol consumption, and physical activity and body mass. In general, physical activity instead of inactivity, abstinence from smoking and alcohol consumption, low body mass, and diets low in fat/calories are usually recommended for overall good health and have a positive influence on reducing the risk of cancer, especially breast and colorectal cancers (2,6). Because all these factors can be modified, they also provide us with leverage to use them as interventive/preventive measures. Accordingly, the American Cancer Society has suggested guidelines on nutrition and physical activity for the prevention of cancer. Broadly, recommendations suggest the intake of ≥5 servings of fruits and vegetables, chose whole grains instead of refined grains and sugars, limit the consumption of red meat or diets rich in fat, and finally maintain healthy weight by eating a diet that helps in maintaining proper weight. Other recommendations include guidelines for early detection/screening for cancers of certain sites (7).
Taking a cue from the epidemiological data indicating that dietary habits influence cancer risk, considerable scientific interest has been generated in developing various preventive measures based on diet, especially those involving fruits and vegetables (8–10). Fruits and vegetables, belonging to plant kingdom, represent a vast source of phytochemicals of varied chemical structure; many of them have already been studied extensively for their potential anticancer or chemopreventive efficacy (10). As such, interventions based on fruits and vegetables are not only “more natural” in lowering cancer risk without posing “any side effects” but also in maintaining good general health based on the fact that they are major sources of vitamins, minerals, and fiber.
A cancer chemopreventive agent could be effective at any of the classically defined stages of carcinogenesis: initiation, promotion, and progression (11–13). The scope of the efficacy of such agents could be profound, because the natural course of the development of full-blown clinically evident cancer is relatively long and sometimes takes a decade or so to develop from initial premalignant/precursor lesions. Because a primary aim of using these agents is the prevention of cancer occurrence where the general population is likely to consume them for a prolonged period, their safety assessment in terms of toxicity and/or other side effects is most vital. A wide range of studies over 2 decades has identified the presence of many potential chemopreventive agents in routinely consumed plant-based diets; mostly, they are nonnutritive phytochemicals spread over different classes based on their chemical structures and include phenolics (tannins, lignans, flavonoids), glucosinolates, terpenoids, carotenoids, and phytoestrogens (14,15). These agents have been found in fruits, vegetables, raisins, nuts, herbal extracts, and commonly consumed beverages such as wine, tea, and coffee. On average, almost 0.2–1 g/d of these agents are consumed as part of a regular healthy diet (16,17). These phytochemicals generate much scientific interest, because they fulfill basic requirements of an ideal chemopreventive agent, such as selective toxicity to cancerous or precancerous cells, efficacy against most types of cancers, oral route of administration, and acceptance by target human population and have a known mechanism of action (18).
In this review, we have focused our discussion on recent advancements largely in grape seed extract (GSE)6 and to a lesser extent on other grape-based products regarding their cancer chemopreventive and anticancer efficacy and associated molecular mechanisms. GSE is a nutraceutical agent that is commonly consumed as a health/dietary supplement and is sold as an over-the-counter product in the United States in the form of capsules or tablets (100–500 mg). The consumer interest in GSE has been primarily due to the high content of antioxidants in the form of proanthocyanidins in this extract. The antioxidant capacity of this extract has been shown to be greater than known antioxidants such as vitamin C and E (19).
Anticancer and chemopreventive efficacy of other grape-related products
Although the above-cited literature strongly suggests that grape seeds are a potential source of anticancer and cancer chemopreventive phytochemicals, the other parts of the grape such as the skin, the whole grape by itself, grape-derived raisins, and phytochemicals present within the grapes have also demonstrated potential anticancer efficacy in various preclinical and clinical studies, as summarized in Table 2. One such phytochemical is resveratrol, which is found abundantly in the skin of grapes; peanuts, itadori tea, and wine also contain resveratrol in appreciable amounts (59). With the discovery of the chemopreventive potential of resveratrol by Jang et al. (60) employing a mouse skin model, there have been thousands of publications showing anticancer and cancer chemopreventive efficacy of this natural product in numerous cancer models in cell culture and animals (61–64). Summarizing those is beyond the scope of the present review; however, some of the most recent findings are mentioned in Table 2.
In conclusion, prevention of cancer either by chemopreventive strategies based on naturally occurring agents or simply by advocating healthy dietary habits should have far reaching effects on lowering the incidence of cancer and reducing the socioeconomic burden, as these strategies are most cost effective and practical in their translational potentials. Additionally, being natural with increased affordability, they have much broader access to populations at large. Naturally occurring phytochemicals have shown promising chemopreventive effects in various in vitro and preclinical models and in several cases, their mechanisms of action at the molecular level have been characterized. However, most of them are in the infancy stage due to lack of extensive clinical studies yet to be conducted with these agents. Therefore, more studies are needed in high-risk populations for cancer of specific organs or sites with standardized GSE preparations to establish the dose regimen and to determine pharmacologically achievable levels of biologically active constituents in the plasma/target organ. These studies would also help establish any toxicity associated with long-term administration of GSE. Caution is also needed in the use of GSE and any other given agent in clinical settings until all of their adverse effects, even as a chemopreventive agent, are evaluated and established comprehensively. Once such information is available, it would also be helpful in using these agents as adjuvants to conventional therapeutic drugs to augment their therapeutic effect at relatively lower doses, thereby limiting their toxic side effects to some extent. Based on the evidence from currently available literature, vegetable- and fruit-based diets/extracts can be viewed in general as healthy and nutritive with the additional benefit of being cancer preventive. Together, it can be concluded that consumption of grapes and/or grape-related products in diets along with maintaining an active healthy lifestyle has both practical and translation potential in the fight against cancer and is thus beneficial to the general population.