LE Magazine September 2002
Studies from throughout the world that can help you live longer
September 2002 Table of Contents
1. Element of timing in breast cancer treatment
Approximately 200,000 American women develop breast cancer every year. Typically, chemotherapy and tamoxifen are used simultaneously after surgery. However, new research shows that when tamoxifen is given after chemotherapy, breast cancer is less likely to resurface. Tamoxifen (an anti-estrogen) is a drug that prevents breast tumor growth by blocking estrogen. A study was conducted with 1,477 postmenopausal women with early-stage breast cancer that had spread to the lymph nodes. Patients were divided into three groups: A) those treated with chemotherapy and tamoxifen simultaneously, B) those given chemotherapy followed by tamoxifen or C) tamoxifen alone. The results after eight years were encouraging. For those in group A, 67% remained free of breast cancer, compared to 62% in group B and 55% in group C. The women in group B were 18% more likely to remain disease-free than those in the other two groups. These results demonstrate the importance of starting tamoxifen after chemotherapy.
Initial results from 2002 INTERGROUP TRIAL, Loyola University Medical Center, IL
2. Calcium supplementation affects HDL levels
A new study shows that calcium supplementation significantly increases HDL cholesterol levels in postmenopausal women. The study consisted of 223 women (avg. age 72) who had not received prior treatment for hyperlipidemia or osteoporosis. The women were administered either calcium (1 g/day) or placebo for one year. The results showed that among women taking calcium supplements, HDL cholesterol levels and HDL:LDL ratio increased (7%) more than in the placebo group. In addition, LDL cholesterol was decreased by 6%. The concentrations of triglycerides showed no significant change. The results show the benefits of calcium intake on lipid levels, and encourage the use of calcium supplementation in postmenopausal women.
AMERICAN JOURNAL OF MEDICINE 2002;112:343-347
3. Sudden cardiac death linked to inflammatory protein
A study showed that levels of a protein in the blood called C-reactive protein (CRP), can predict the risk of sudden death due to heart disease. Inflammation is believed to play a key role in atherosclerosis (hardening and narrowing of arteries) that can lead to heart attack and stroke. Elevated CRP is a known indicator of inflammation. The immune system is activated during an infection and blood CRP levels rise significantly as CRP circulates through the body. A link has been found between chronic elevations of CRP and the increased risk of heart disease. The study analyzed blood from the arteries of 144 people who died due to sudden cardiac death. Approximately half of them had blocked arteries caused by plaque rupture or erosion. The placebo group died of causes unrelated to heart disease, and did not have any condition that would have raised their CRP levels. The results showed a modest elevation of blood levels of CRP in all those who died suddenly of heart-related causes. The study shows that an elevated level of CRP is a risk factor for sudden death and of vascular disease from atherosclerosis. High levels of CRP may be controlled by changes in lifestyle and with drugs like statins and aspirin.
JOURNAL OF THE AMERICAN HEART ASSOCIATION 2002;105
4. Vitamin C, E and arteriosclerosis in heart transplants
A recent study showed that supplementation with vitamins C and E slows the progression of arteriosclerosis in patients who have received heart transplants. Arteriosclerosis develops within three years in 70% of these patients. In this study, vitamins C (500 mg) and E (400 IU) were given twice daily for one year to a total of 40 patients who had heart transplants within the last two years. The results showed that after one year, the thickness of the coronary artery had increased by 8% in the group not given the vitamins. However, in the vitamin group, the artery thickness did not change significantly (0.8%). Vitamins C and E improved upon the benefits achieved with statin therapy. The results showed that the growth of plaque in the artery had been inhibited. The study demonstrates that vitamins C and E can reduce arteriosclerosis after a heart transplant. Since antioxidants slow arteriosclerosis in the hearts of people who have not had heart transplants, the results of this study are expected.
LANCET 2002 Mar 30;359(9312):1108-13
5. Coenzyme Q10 and kidney failure
Coenzyme Q10 (CoQ10, ubiquinone) is an essential antioxidant that is highly efficient in protecting cell membranes from free radicals. CoQ10 also helps convert food into energy. CoQ10 is produced naturally in the body. However, a deficiency of CoQ10 occurs in heart failure, cardiomyopathies, gingivitis, hypertension, muscular dystrophy, AIDS and kidney problems. In older people, low levels of CoQ10 are more common. In a recent study, 11 patients with chronic kidney failure were given 60 mg of CoQ10, 3x/day. In the CoQ10 group, there were significantly fewer people (36.2%) on dialysis, compared to the placebo group (90.0%). Blood levels of vitamins A, E, C and beta-carotene rose significantly, and stress indicators were reduced considerably. Thus, CoQ10 supplementation improves the functioning of the kidneys and reduces free radicals in those with kidney failure.
JOURNAL OF NUTRITIONAL AND ENVIRONMENTAL MEDICINE, 2000;10:281-8
6. Preconditioning the heart with resveratrol
Resveratrol is a grape-derived polyphenolic antioxidant that has been found to protect the heart from ischemic-reperfusion injury. A study looked at the mechanism of heart protection by investigating the ability of resveratrol to precondition the heart. Preconditioning of the heart with resveratrol provided protection, as evidenced by improved heart functional recovery (developed pressure and aortic flow), and reduced size of heart attacks and death of heart cells. The results demonstrate that resveratrol can pharmacologically precondition the heart.
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 2002;282(6):H1988-H1995
7. Vitamin C, vasoconstriction and vasodilation
High tension in arteries due to blood oxygen increases vascular resistance. This is possibly related to an interaction between oxygen free radicals and vasoactive factors derived from the endothelium (layer of cells of membranous tissue lining the heart and vessels of the circulatory system). Vitamin C is a potent antioxidant capable of reversing dysfunction of the endothelium caused by increased oxidant free radical stress. A study determined whether vasoconstriction (decrease in diameter of blood vessels) due to hyperoxia (excess oxygen) would be prevented by vitamin C, and whether vasodilation (increase in diameter), mediated by acetylcholine (transmits nerve impulses to excitable membranes), would be blunted by hyperoxia and then restored by vitamin C. The participants were 11 healthy subjects and 15 congestive heart failure (CHF) patients. The CHF group was characterized by endothelial dysfunction and oxidative stress. Vitamin C prevented the hyperoxia-mediated increases in forearm vascular resistance in both healthy subjects and CHF patients. Vitamin C also prevented the impairment by hyperoxia of acetylcholine-mediated increase in forearm blood flow in healthy subjects. The addition of vitamin C during hyperoxia augmented forearm blood flow responses to acetylcholine. Thus, it was shown that vitamin C prevents the effects of hyperoxia. The results also suggest that vasoconstriction due to hyperoxia is mediated by free radical oxidative stress, and that hyperoxia impairs acetylcholine-mediated vasodilation in normal cell function.
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY 2002; 282(6):H2414-H2421
8. Potassium level and risk of CVD
A study sought to determine the association between blood potassium concentration and cardiovascular disease (CVD) risk in 3,151 participants (avg. age 43; 48% men). They were free of CVD, were not taking medications affecting potassium homeostasis, and had blood potassium levels measured (1979-1983). After 16 years, there were 313 CVD events, including 46 CVD-related deaths. The results show that blood potassium level was not significantly associated with the risk of CVD or disease-related death. Thus, in a community-based sample of individuals free of CVD, blood potassium level was not associated with risk of cardiovascular disease.
ARCHIVES OF INTERNAL MEDICINE 2002;162(9):1007-12
9. New water-soluble vitamin E inhibits atherosclerosis
A new form of vitamin E that is water soluble, 2-(alpha-D-glucopranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), was evaluated for its ability to inhibit the development of atherosclerosis in hyperlipidemic (high lipid levels) or cholesterol-loaded rabbits. The results showed that although TMG rapidly entered the circulation blood after oral administration, the blood TMG concentration remained low, while neither TMG nor its metabolites appeared in the low-density lipoprotein (LDL) fraction. TMG did not decrease total blood cholesterol, VLDL or HDL. However, TMG did reduce the blood concentration of thiobarbituric acid-reactive substances (TBARS; an indicator of lipid peroxidation) in cholesterol-loaded rabbits but not in the hyperlipidemic rabbits. Nonetheless, TMG did inhibit atherosclerosis of the aorta as effectively as probucol (a lipid lowering drug). The results indicate that TMG opposes the progression of atherosclerosis by preventing oxidation of LDL, and by presently unknown mechanisms. Thus, even an antioxidant that is not fat soluble, and thus not absorbed by LDL, apparently can inhibit development of atherosclerosis despite a very low blood concentration.
10. Green tea protects against alcohol-induced liver injury
A study examined the antioxidant polyphenolic extract of green tea against early alcohol-induced liver injury. Rats were fed high-fat liquid diets with or without alcohol and green tea (300 mg kg/day) continuously for four weeks. After four weeks, the blood ALT (sign of liver damage) levels were increased significantly from 35 to 114 (four-fold over placebo group values). However, the inclusion of green tea extract in the diet significantly blunted the increase to 65. The alcohol also caused severe fatty accumulation, mild inflammation and tissue death in the liver. However, with green tea extract, the increase in tissue death caused by alcohol were significantly reduced, while not affecting fat accumulation or inflammation. Alcohol also significantly increased the accumulation of protein adducts (products of lipid peroxidation and an indication of oxidative stress). However, green tea extract blocked this effect almost completely. Green tea extract also blunted the increase of TNFalpha (causes inflammation) protein levels in the liver by alcohol. The results indicate that dietary antioxidants, such as those found in green tea, prevent early alcohol-induced liver injury, most likely by preventing free radical stress.
BIOLOGICAL CHEMISTRY 2002;383(3-4):663-70
11. Effect of multivitamins on immune system
A study looked at the effect of regular intake of low doses of a multivitamin on the free-radical-producing activity of peritoneal (membrane of abdomen) macrophages under conditions resembling a possible infection in vitro. (Macrophages are long-lived cells that engulf bacteria, protozoa, and tumor cells, and stimulate other cells of the immune system.) For two weeks mice were fed a basic diet, with or without supplementation of a multivitamin. Multivitamin supplementation increased the number and activity of macrophages. This effect persisted for two weeks after higher doses of supplementation were stopped. Multivitamin supplementation lowered the steady-state free radical concentrations of the liver and spleen and increased their antioxidant reactivity. Thus, when taken regularly, low doses of multivitamin supplementation may have a beneficial effect on the body's immune system.
BRITISH JOURNAL OF NUTRITION 2002;87(5):501-8
12. Effects of Chinese herbal extracts on lung cancer
A study examined lung cancer cells treated with four extracts of Chinese herbal medicines taken by many cancer patients. They exposed normal cells, drug-sensitive cells, and multidrug-resistant lung cells to extracts from two plants used in Chinese herbal medicine for lung cancer: 1) Glycorrhiza glabra (GLYC) and 2) Olenandria diffusa (OLEN). The cells were also exposed to extracts of two commercially available combinations of Chinese herbal medicines, 3) SPES (15 herbs) and 4) PC-SPES (8 herbs). Cell toxicity was measured in terms of the inhibition of cell growth. The results showed that the four herbal extracts were equally cytotoxic to all the drug-sensitive cells tested. All four extracts induced DNA fragmentation in the lung cancer cells. The cancer cells treated with OLEN, SPES and PC-SPES showed increased expression of several genes involved in the normal cell death cascade. Therefore, the Chinese herbal medicine extracts OLEN, SPES and PC-SPES are cytotoxic to both drug-resistant and drug-sensitive lung cancer cells. The extracts show some tumor cell specificity (interaction with tumors only) compared to their effect on normal cells. Thus, the herbal extracts help initiate apoptosis, as measured by DNA breaks and gene expression. The reaction of the tumor cells to these herbal extracts was similar to their reaction to conventional chemotherapeutic drugs.
CANCER CHEMOTHERAPY AND PHARMACOLOGY 2002;49(4):261-26
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