Is it Safe to Use Antioxidant Supplements with Chemotherapy?

10/10/02 - Healthnotes Newswire—A new clinical trial published in the Journal of Clinical Oncology (2002;20:3478–83) provides the clearest evidence to date that taking antioxidant supplements does not interfere with the efficacy of cancer chemotherapy. This new study involved 52 people being treated for advanced colon cancer with a chemotherapy drug called oxaliplatin. Half of these individuals also received intravenous treatment with an antioxidant called glutathione (at an average dose of approximately 2,500 mg each time they received chemotherapy), while the other half received a placebo. The participants receiving intravenous glutathione had a significantly lower incidence of chemotherapy-induced nerve damage than did the control group, allowing more of the chemotherapy drug to be safely administered. Perhaps more important, the addition of glutathione to the treatment regimen did not reduce the ability of the chemotherapy to shrink the size of the colon tumors. In fact, the people who received the glutathione treatment were slightly (but not significantly) more likely to have tumor shrinkage.

Antioxidants During Chemotherapy: A Hot Topic
Antioxidants, including glutathione, are agents that protect the body from damage by unstable molecules called free radicals. There are many dietary antioxidants, including vitamins C and E, beta-carotene and coenzyme Q10. Many commonly used herbs also contain antioxidants. Glutathione is present in small amounts in the diet, but it appears to be poorly absorbed; however, glutathione is also synthesized in the body from certain amino acids, and it appears to be one of the most important antioxidants in various tissues in the body. Because several of the common cancer treatments (including radiation and many types of chemotherapy) work in part by producing free radicals, many doctors and researchers have voiced concern that antioxidants may reduce the beneficial effect of these therapies. However, there is very little evidence from scientific research that this interference actually occurs. In fact, the overwhelming majority of test tube, animal, and preliminary human studies have concluded either that there was no effect of the antioxidant on the tumor-fighting ability of the cancer treatment, or that the antioxidant enhanced the anticancer effect of the therapy. In addition, antioxidants often protected against some of the most common side effects of cancer treatment, such as organ damage, low blood counts and diarrhea. Critics of the concurrent use of antioxidants and chemotherapy often point to the lack of clinical trials in humans. Previous preliminary clinical trials, however, have concluded that the antioxidants ginkgo (Ginkgo biloba), melatonin, coenzyme Q10 and N-acetylcysteine did not appreciably reduce the effect of cancer therapies. Pharmaceutical antioxidants such as amifostine and mesna have also been extensively studied in conjunction with chemotherapy and radiation, and have not appeared to cause a negative interaction. Many prominent cancer scientists believe that the dietary and pharmaceutical antioxidants prevent some of the worst side effects of cancer treatments.

Should People Undergoing Chemotherapy Take Glutathione?
Glutathione is available as an oral supplement, although only a small amount of orally administered glutathione is absorbed intact into the blood stream. At present there is no evidence that taking glutathione orally would have the same effect as that reported for intravenous glutathione in the new study. Unfortunately, this clinical trial doesn’t answer the question of whether it is safe or desirable to use glutathione with other types of chemotherapy. It also doesn’t address the issue of using other antioxidants with chemotherapy. However, the results of the new study, when combined with those of previous research, provide a strong rationale for intensive research on the risks and benefits of combining antioxidants with conventional cancer therapy. People interested in using antioxidants along with conventional cancer treatment should talk this issue over with their doctors.

—Matt Brignall, N.D.Matt Brignall, N.D., is a graduate of the University of Michigan and Bastyr University. He works at the Seattle Cancer Treatment and Wellness Center, where he specializes in complementary medicine approaches to cancer. He has been published in several journals, including Alternative Medicine Review, Coping With Cancer and the Journal of the National Cancer Institute. Dr. Brignall also teaches clinical nutrition at Bastyr University in Kenmore, WA. He is a regular contributor to Healthnotes, Healthnotes Newswire and the Healthnotes Quick!Reference series

Radiation-induced Cancer in Cockpit Crew Member

A cohort study evaluated 3,877 cockpit crews accruing 61,756 person-year at risk for radiation-induced cancer. Both malignant melanoma and skin cancer were found in excess in cockpit crew members with a long flying history. There was also a significant increase of acute myeloid leukemia in male cockpit crew members in jets flying more than 5,000 hours.

Gundestrup M, Storm HH. Radiation-induced acute myeloid leukemia and other cancers in commercial jet cockpit crew: a population-based cohort study. Lancet. 1999;354:2029-2031.

(Address: Dr. Hans H. Strom, E-mail: Hans@cancer.dk)

Teaching is Hazardous to One's Health, Study Finds

In a Proportional mortality study, proportional mortality ratios showed that elementary and secondary schoolteachers have a higher incidence of autoimmune disease compared to people in other professional occupations. According to the researchers, teachers experience an occupational exposure that increases risk of autoimmune diseases.

Walsh SJ, DeChello LM. Excess autoimmune disease mortality among school teachers. J Rheumatol. 2001;28:1537-1545.

Obesity and Diabetes in US Continues to Climb

Despite efforts to sound the alarm about obesity and diabetes in the US, rates of both conditions continue to skyrocket. Researchers at the Center for Disease Control and Prevention (CDC) in Atlanta, Georgia report that in 2000, nearly 20% of American adults were obese, 7.3% had diabetes, and about 3% suffered from both conditions. The current findings indicate that most US adults (more than 56%) are overweight, about 1 in 5 is obese, and 7.3% have diabetes. They note that diabetes rates could be as high as 10% if undiagnosed cases are considered.

Colorado had the lowest rate of obesity, with about 14%, while Mississippi topped the scales with 24.3% obesity or nearly 1 in 4 adults with a BMI of 30 or more.

Mississippi also heads the list as the state with the highest rate of diabetes, at nearly 9%. Alaska had the lowest rate, 4.4%. The researchers explain that their findings are conservative, largely due to the fact that overweight people tend to underestimate their weight and all people are likely to overestimate how tall they are. In other findings, investigators report that 27% of those surveyed said that they did not engage in any physical activity and 28% said they were "not regularly active."

The good news is that both obesity and diabetes are largely preventable, and even small reductions in weight can have big health benefits. For instance, the authors point to a recent study conducted in Finland where researchers found that diet and exercise counseling resulted in a 58% reduction in diabetes risk among people who were prime candidates for developing the condition, which is associated with obesity and sedentary lifestyle.

In that study, even modest weight loss conferred a much lower risk of diabetes. Those who participated in 4 hours of exercise per week-even if they did not achieve their weight-loss goal-had a reduction in diabetes risk.

Mokdad AH, Bowman BA, Ford ES, et al. The continuing epidemics of obesity and diabetes in the United States. JAMA. 2001;286:1195-1200.

SCIENCE, STUDIES & REGULATORY NEWS

• A study conducted by Swedish Researchers on 370 individuals over the age of 75 found that supplementing their diets with vitamin B12 and folic acid may help prevent the onset of Alzheimer's disease, according to an article on the Berliner Morgenpost web page. The results, which were published in a recent issue of Neurology, found that over the three years the patients were followed, signs of dementia set in for the group not taking the supplements.
  
  
• The National Integrative Medicine Council issued a press release calling on the U.S. Congress to stop cuts in medical education programs. The group feels doctors do not receive enough education about alternative methods of treatment and as such too often recommend surgical interventions. The group said it is working with members of the Appropriations committees from both the Senate and the House.
  
  
• The National Nutritional Foods Assn. said it would publish guidelines for members on how to convey the benefits of low-glycemic foods for consumers on low carbohydrate diets. The group says the U.S. Food and Drug Administration currently has no position on how glycerin metabolizes differently and as such how it should be labeled differently than other carbohydrates. The group also said the FDA rejected its earlier proposals to make the labeling distinct.

NERVE TISSUE DAMAGE RELATED TO MULTIPLE SCLEROSIS
CAN BE REPAIRED, UC IRVINE SCIENTISTS FIND
Discovery May Lead to Possible Human Therapies for Debilitating Nervous System Disease

Irvine, Calif., Oct. 1, 2001 -- UC Irvine researchers may have discovered how to reverse the disabling nerve tissue damage affecting persons with multiple sclerosis, a finding that may produce treatments for those who have the debilitating disease.

In animal tests, UCI biologists Thomas Lane, Michael Liu, and Hans Keirstead successfully stopped a process called demyelination, a disintegration of the fatty myelin tissue insulating nerve fibers that impairs the signaling function of the central nervous system. Through removing the factors causing the damage, the scientists found that the insulating tissue began to regenerate and normal nerve function began to return.

"We are excited by these findings because they show that the insulating tissue is capable of repairing itself if the causes of demyelination are removed," said Lane, an assistant professor of molecular biology and biochemistry. "While this doesn't represent a potential cure for multiple sclerosis, it does show that there are real possibilities to address the debilitating symptoms of this disease."

Demyelination is a central feature of multiple sclerosis, a chronic central nervous system disease that can cause blurred vision, poor coordination, slurred speech, numbness, acute fatigue and, in its most extreme form, blindness and paralysis. Some 350,000 Americans have this disease. Its causes are unknown, and symptoms are unpredictable and vary greatly in severity.

Lane and his colleagues targeted a set of molecules called chemokines, which work with immune response mechanisms in the body. When functioning properly, chemokines send signals to T lymphocyte cells (T cells), which respond to repair injury and promote recovery from illness. However, in the instance of multiple sclerosis, an excessive amount of two specific chemokines, called CXCL-9 and CXCL-10, exist in the central nervous system and correlate with the inflammation of the myelin tissue covering nerve axons. In response to increasing amounts of CXCL-9 and CXCL-10, an overwhelming number of T cells may respond and begin to destroy myelin tissue, which leads to a disruption of nerve signaling. In persons with multiple sclerosis, this process of demyelination can come in relapsing attacks or in a slow, degenerating process.

Lane and his colleagues used a mouse model of multiple sclerosis that is triggered by infecting the animals with a mouse hepatitis virus. After the mice began to show the effects of demyelination, including partial hind limb weakness and paralysis, they were injected with antibodies designed to block the activity of the CXCL-9 and CXCL-10 molecules in the central nervous system.

While treatment with antibodies specific for CXCL-9 showed no effects, application of antibodies specific for CXCL-10 blocked signaling to the T cells. The researchers then began to notice a reversal in demyelination followed by a regeneration of the myelin tissue. Soon after that observation, crippled mice began to resume normal hind limb function. However, when Lane and his colleagues ceased to apply the CXCL-10 antibodies to these mice, demyelination resumed and limb weakness and paralysis returned.

"Because of these results, we believe that there is strong evidence that the CXCL-10 molecule is the key in starting the process of demyelination," Lane said. "The results also document the feasibility of treating demyelinating diseases with antibodies, which will be our next research direction."

Lane and his colleagues are following these findings by exploring the molecular mechanisms of myelin repair. A patent is pending on the research method. The National Institutes of Health, the National Multiple Sclerosis Society, and the Reeve-Irvine Research Center at UCI supported the research.

Liu MT, Keirstead HS, Lane TE. Neutralization of the chemokine CXCL-10 reduces inflammatory cell invasion and demyelination and improves neurological function in a viral model of multiple sclerosis. J Immunol. 2001;167:4091-4097.