Antioxidants May Not Be As Protective As Once ThoughtStudy Provides No Evidence For Heart Disease Prevention< June 25, 2003 >A new study in the medical journal The Lancet offers the best evidence yet that supplements containing vitamin E or beta-carotene, a form of vitamin A, do not protect the heart. The newest research study analyzed 15 major studies of nearly 220,000 people. "From high doses to low doses, in men and women of all ages, we found these supplements did not offer any benefits" in relation to deaths for any reason, or a decrease in the risk of death from stroke or heart disease, says study author Dr. Marc Penn, a cardiologist at the Cleveland Clinic Foundation. In the case of beta-carotene, Dr. Penn says the risk of death was slightly higher for those using the supplements. In commenting on the new study findings, New York University cardiologist Dr. Dan Fisher says, "What we believed to be true in the 1980s concerning the protective effects of antioxidant supplements simply did not hold up to scientific scrutiny." "And it's good to have this solid scientific validation of the conclusion that I and many doctors have come to realize," Dr. Fisher says. Benefit of Supplementation Not FoundWhile Dr. Fisher does not believe the book is completely closed on antioxidant protection, he adds, "Clearly, supplements of vitamin E and beta-carotene are not part of the solution." Dr. Penn suggests that "antioxidants will play some future role in protection from cardiovascular disease, but I don't think we know what that role is just yet. "And, more importantly, we don't know what kind of supplementation, if any, is going to provide that protection," Dr. Penn says. The Council for Responsible Nutrition, a Washington, D.C.-based trade association representing dietary supplement suppliers and manufacturers criticized the study. John Hathcock, the council's vice president for scientific and international affairs, says in a statement that the researchers were "making sweeping statements that are not justifiable based on the studies they reviewed." Hathcock said the researchers "discount the potential benefit of vitamin E for heart disease based largely on their review of secondary intervention trials on subjects with established heart disease. "But what many researchers refer to as the 'antioxidant hypothesis' is the belief that antioxidants may be effective in decreasing the risk of heart disease if consumed before the atherosclerosis develops," Hathcock says. Antioxidant Interest Started in the 1970sHow did all the attention to the power of antioxidant supplements get started? Dr. Penn believes it can be traced to several key developments. Dr. Penn says that in the 1970s scientists uncovered the power of oxidation, a physiologic process that works in tandem with blood fats like cholesterol to cause damage to the heart. Researchers set out to prove that taking antioxidants, vitamins such as E and beta-carotene, could stop or even reverse that damage. The concept was proven - but only in animal studies. "In translating those [animal] findings to clinical human practice, we didn't take into account that the animals had no lesions," Dr. Penn says. "And the findings could not be equated with giving vitamin E to people who had already experienced 20, 30, 40, or more years of oxidative damage to their body." A concern about earlier studies, Dr. Penn explains, was that the clinical studies showing the vitamins worked in people were not randomized (where the participants are assigned by chance to separate groups that compare different treatments). "What those patient questionnaires really told us was that vitamin E was a marker for people who took better care of their bodies," Dr. Penn says. "Overall, they exercised more, they ate better, they reduced stress. And those were the real reasons their risk of cardiovascular disease was lower, not the use of the supplements." The new research analyzed seven major randomized trials on vitamin E and eight on beta-carotene. The dose range for vitamin E was between 50 and 800 international units (IUs) daily, and beta-carotene dosing ranged from 15 milligrams to 50 milligrams daily. The follow-up on each study ranged from 1.4 years to 12 years. The study results showed the overall rate of death for those taking vitamin E was statistically no better than for those who did not use the supplements - 11.1 percent versus 11.3 percent. The death rate specifically related to cardiovascular disease was equal in both groups - 6 percent. And the death rate due to stroke was also nearly identical - 3.6 percent for the supplement users versus 3.5 percent for non-users. For those taking beta-carotene, the results were slightly worse. There was a small but significant increase in deaths from all causes in the group taking the supplement - 7.4 versus 7 percent. There was also a small increase in the number of deaths from cardiovascular disease compared to the control group - 3.4 percent versus 3.1 percent. Always consult your physician for more information. What Is a Dietary Supplement?A diet is a plan or strategy for eating with certain foods included and eliminated. Adding anything to your regular diet to improve your health or healing is considered a dietary supplement. It is considered alternative therapy when it is offered outside the medical care setting and the proponents make claims that it will produce a medical benefit. Most of your nutritional needs should be met by eating a balanced diet. Not all medications and dietary supplements available over the counter are proven to be safe. The US Food and Drug Administration (FDA) does not require manufacturers of these products to print potential side effects on their labels. And if they do receive complaints, the FDA cannot take a dietary supplement or herbal product off the market unless scientists can prove that the product is unsafe. Each dietary supplement is different. Because most are scientifically untested, the side effects are unknown. Always consult your physician for more information. Online Resources(Our Organization is not responsible for the content of Internet sites.) Centers for Disease Control and Prevention (CDC) National Cancer Institute (NCI) |
Advanced MRI Finds Prostate Cancer that Has Spread to Lymph NodesA new method for determining whether prostate cancer has spread to the lymph nodes is being hailed as a breakthrough by many experts in the field. The technique uses a high-contrast agent with high-resolution magnetic resonance imaging (MRI). This agent is able to detect even tiny metastases in the lymph glands of men who have already been diagnosed with the cancer. Prostate cancer is the most common cancer among men, excluding skin cancer. The American Cancer Society (ACS) estimates for 2003 include 220,900 new cases of prostate cancer and 28,900 deaths from prostate cancer in the US alone, making it the second leading cause of cancer death in men. The study, reported in the New England Journal of Medicine, used an iron oxide-containing contrast agent that is not yet approved by the US Food and Drug Administration (FDA), but is currently being evaluated. In this study, all the participants had a preliminary high-resolution abdominal MRI. They then received intravenous infusions of the high-contrast agent, and 24 hours later, another set of MRI studies. "This technology provides potentially a revolutionary, very exciting approach toward the detection of metastatic cancer," says Dr. W. Marston Linehan, chief of urologic surgery at the National Cancer Institute. "I imagine this technology is going to be applicable to a number of different kinds of cancer." Dr. Gilbert J. Wise, director of urology at Maimonides Medical Center in New York City, says, "Anything that improves diagnosis and minimizes invasive procedures for established diagnoses in cancer or any other disease process is obviously a step forward." Right now, finding out if cancer has spread to the lymph nodes is an imprecise endeavor. "It's very hard for us, even with our best imaging, to determine whether the nodes are affected or not," Dr. Linehan says. Technological advances have made the job easier, but it's still not foolproof. "It's a probability," Dr. Wise says. And whether or not a cancer has spread to the lymph nodes is crucial information because it determines how treatment will proceed. "There are three main ways that patients can be treated with prostate cancer. The patient can either go for surgery, radiation, or hormonal therapy," explains study author Dr. Mukesh Harisinghani, a radiologist in the abdominal imaging division at Massachusetts General Hospital in Boston. "When the disease is confined to the prostate gland, surgery is an option because you want to take the primary cancer out and prevent it from spreading," he says. "If the tumor has spread to the lymph nodes, that precludes going to surgery because it is assumed the cancer has already spread." "We continue to see an alarmingly high mortality rate," confirms Dr. Daniel Shasha, co-director of genito-urinary oncology for Continuum Health Partners in New York City. "Why are all these patients failing while so few are presenting with radiographic metastases?" asks Dr. Shasha. "One of the reasons is the nondiagnosis of microscopic metastatic cancer, and that's where this study becomes very, very important." However, there are practical problems with implementation of MRI for detecting prostate cancer metastasis. For one thing, it is not yet FDA-approved. But if and when that happens, there are not nearly enough MRI scanners to go around. Always consult your physician for more information. Stages of Prostate CancerWhen prostate cancer is diagnosed, tests will be performed to determine how much cancer is present, and if the cancer has spread from the prostate to other parts of the body. This is called staging, and is an important step toward planning a treatment program. As defined by the National Cancer Institute (NCI), the stages of prostate cancer include the following: stage 1 stage 2 stage 3 stage 4 recurrent Always consult your physician for more information. |
