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Life Extension Magazine

LE Magazine July 1999

MEDICAL UPDATES

Studies from throughout the world that can help you live longer

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July 1999
Table Of Contents
 
  1. Green tea ingredient fights tumors
  2. Effect of resistance exercise on free radical production
  3. Garlic aids in fat burning
  4. Selenium protects against colon cancer
  5. How folic acid cuts heart risk
  6. Oxidation damage implicated in telomere shortening
  7. Animals fed CLA have a lower body fat content
  8. Soy genistein helps protect colon cells from bacterial invasion
  9. Growth inhibition of human leukemia cells by vitamin D3
  10. Melatonin for cluster headaches
  11. Faster mental decline in smokers
  12. High triglycerides risk for heart attack
  13. High stress may impair memory
  14. Choline supplementation boosts adult memory
  15. Raloxifene reduces heart risk
  16. Brain injury improves with hyperbaric oxygen
  17. DHA protects small intestine

  1. Green tea ingredient fights tumors

    Full source: Nature 1999;398:381-382

    A compound found in green tea can inhibit angiogenesis, the process in which blood vessel growth is stimulated. The finding suggests that the compound may be useful in fighting malignant tumors, which must form new blood vessels in order to grow. In addition, it may explain the observed preventive effects of green tea on a variety of tumors in humans. In this study, green tea, and one of its components, epigallocatechin-3-gallate (EGCG) significantly prevented the growth of new blood vessels in animals as well as in laboratory culture dishes. In a study of mice, drinking green tea was found to inhibit the growth of new blood vessels in the cornea of the eye. Blood vessel length and the area of vascularization were reduced by 55% and 70%, respectively, in tea-drinking mice compared with controls. Two or three cups of tea per day would be the human equivalent of the amount of tea given to the mice. Long-term consumption is very important to stop blood vessel growth, an effect that may be beneficial in the prevention of cancers as well as other angiogenesis-dependent diseases, such as diabetic retinopathy, an eye disease that is a common cause of blindness. People should not drink large amounts of tea where angiogenesis is important, as in pregnancy or in patients with healing wounds. This study supports the rationale of taking proper amounts of a high quality (organic and standardized) green tea extract everyday.



  2. Effect of resistance exercise on free radical production

    Full source: Medicine and Science in Sports and Exercise, 1998, Vol 30, Iss 1, pp 67-72

    The purposes of this investigation were to see whether free radical production changed with high intensity resistance exercise and, secondly, to see whether vitamin E supplementation would have any effect on free radical formation or variables associated with muscle membrane disruption. Twelve recreationally weight-trained males were divided into two groups. The supplement group received 1200 IUs of vitamin E once a day for a period of 2 weeks. The placebo group received cellulose-based placebo pills once a day for the same period. There was a significant difference in creatine kinase activity between the groups at 24 hours after exercise. The placebo group had a significant increase in creatine kinase (an enzyme usually elevated in plasma following myocardial infarctions) activity at 48 hour postexercise. This study concluded that high intensity resistance exercise increases free radical production and that vitamin E supplementation may decrease muscle membrane disruption.



  3. Garlic aids in fat burning

    Full source: Journal of Nutrition, 1999;129:336-342

    This study investigated the effects of garlic supplementation on triglyceride metabolism by measurements of the degree of thermogenesis in fat tissue, and noradrenaline and adrenaline secretion in rats fed two types of dietary fat, lard and shortening. After 28 days, body weight, blood triglyceride levels, and the weights of fat tissue and fat pads were significantly lower in rats fed diets supplemented with garlic powder. The content of mitochondrial protein and urinary noradrenaline and adrenaline excretion were significantly greater in rats fed a lard diet with garlic powder than in those fed the same diet without garlic. Differences due to garlic were significant in rats fed shortening, other than adrenaline secretion. The effects of various organosulfur compounds present in garlic on noradrenaline and adrenaline secretion were also evaluated. Administration of organosulfur compounds with allyl residues present in garlic significantly increased blood noradrenaline and adrenaline concentrations. However, the administration of the sulfides without allyl residues did not increase adrenaline secretion. These results suggest that the allyl-containing sulfides in garlic enhance thermogenesis by noradrenaline and adrenaline secretion.



  4. Selenium protects against colon cancer

    Full source: Journal of Nutrition, 1/99

    There is increasing evidence that selenium can protect against tumorigenesis or preneoplastic lesion development induced by chemical carcinogens. This study examined whether selenite, selenate or selenomethionine would be protective against DNA adduct formation in the liver and colon of rats. It sought to delineate the mechanism for the protective effects of the different chemical forms of selenium against aberrant crypt formation (a preneoplastic lesion for colon cancer). After injection of a carcinogen (DMABP), two DNA adducts were identified in the liver and colon of rats. Supplementation with selenium diet as either selenite or selenate resulted in significantly fewer (53-70%) DNA adducts in the colon, than in rats fed a selenium-deficient diet. Rats supplemented with selenomethionine had greater blood and liver selenium concentrations and glutathione peroxidase activity than those supplemented with selenite or selenate; however, they also had more DMABP-DNA adducts. The protective effect of selenite and selenate against chemical carcinogen induced DNA adduct formation apparently is not a result of alterations in blood or liver selenium concentrations or altered glutathione activities. It may be related to differences in the metabolism of the different forms of selenium.



  5. How folic acid cuts heart risk

    Full source: Nature Structural Biology 1999;6:293-294, 359-365

    It has long been known that folic acid reduces the risk for birth defects and heart disease by lowering blood levels of homocysteine. Folic acid is a B vitamin found in green, leafy vegetables, orange juice, beans, and fortified grains. Until now, scientists did not know exactly how folic acid worked to reduce homocysteine levels. This study reports that folates, derivatives of folic acid, work by activating an enzyme called methylenetetrahydrofolate reductase (MTHFR). MTHFR regulates blood homocysteine by producing methyltetrahydrofolate, a compound that plays an important role in regulating blood homocysteine levels. The study provides insight into the cause and treatment of high blood levels of homocysteine, a condition associated with cardiovascular disease in adults and neural tube defects in newborns. Current guidelines urge all adults to consume 400 micrograms of folic acid through diet and a daily multivitamin. For pregnant women and women planning to become pregnant, the recommendation increases to 600 micrograms a day. "Our findings about the action of folates are strong reinforcement for the current recommendations for folic acid intake. We must all pay attention to folate intake and supplementation," said the team leader. It is difficult to obtain optimal folic acid intake (for prevention of heart attacks, strokes, and Alzheimer's disease) through diet alone. 1,200 mg of folic acid can be taken daily among other vitamins and minerals. A yearly blood test for homocysteine should be as important as cholesterol lipid panels.



  6. Oxidation damage implicated in telomere shortening

    Full source: Ann N Y Acad Sci 1998 Nov 20 854 318-27

    It appears that telomeres being on the more vulnerable ends of highly folded chromosomes are subject to easier free radical attack and are not as well repaired as in the rest of the genome. This damage then causes the telomeres to either break off ahead of time and/or to excessively shorten when next the cell divides. Accumulation of such telomeric fragments could also provoke senescent cellular changes. Therefore, controlling the oxidative load onto DNA, in general, and, especially, onto telomeres might become a major factor to influence the rate of aging.



  7. Animals fed CLA have a lower body fat content

    Full source: Department of Animal Sciences, Oregon State University, Corvallis OR 97331 and Hill's Pet Nutrition, Inc., Topeka, KS 66601

    This study shows how CLA helps prevent excess fat accumulation. Conjugated linoleic acid (CLA) is a group of isomers of linoleic acid. CLA is the product of rumen fermentation and can be found in the milk and muscle of ruminants. Due to the way cattle and dairy cows are fed today, the content of CLA in whole milk and beef is much lower than in early days. Nonfat milk is devoid of CLA. The objective of this study was to establish the possible mechanisms by which CLA affects the production of fat. The results showed that CLA inhibited fat cell proliferation. This implies that fat reduction caused by CLA treatment may be attributed to CLA's inhibition of both proliferation and differentiation of fat cells in animals.



  8. Soy genistein helps protect colon cells from bacterial invasion

    Full source: Department of Laboratory Medicine and Pathology, Department of Surgery, and Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis, MN 55455-0385

    The soy isoflavone, genistein is the focus of much research involving its role as a potential therapeutic agent in a variety of diseases, including cancer and heart disease. Genestein is one of the unique health-promoting phytochemicals of soy. It has numerous functions to benefit our health; this research report demonstrates how genistein helps prevent colon bacteria from entering the cells that line our colon. This colonic loss of integrity, allowing bacteria to bypass cell membranes, has been demonstrated by electron microscopy in patients with colon cancer. Genistein helps prevent this bacterial cellular invasion from occurring. Taking a daily standardized soy extract containing proper levels of genistein is the best way to obtain adequate genistein, because the usual soy milk, tofu, etc. contain relatively little or no genistein, or other soy isoflavones.



  9. Growth inhibition of human leukemia cells by vitamin D3

    Full source: British Journal of Cancer, 1998, Vol 77, Iss 1, pp 33-39

    Vitamin D-3 is a potent inducer of differentiation in leukemia cells. Differentiation is a progressive diversification of embryonic cells and tissues, unlike undifferentiated cells in cancer tissue. However, its clinical use is limited due to it causing a high concentration of calcium compounds in the blood. This study examined the ability of vitamin D3 in combination with several anti-cancer drugs to inhibit the proliferation of, and to cause differentiation in human leukemia cells. Three antineoplastic agents which inhibit or prevent development of tumors (hydroxyurea (HU), cytarabine and camptothecin) showed effective synergism with vitamin D3, effectively causing the differentiation of monoblastic leukemia cells. Among the anticancer drugs examined, HU had the greatest synergistic effects with vitamin D3, with regard to growth inhibition and differentiation induction in leukemia cells. The researchers concluded that as vitamin D-3 preferentially acts on monocytic cells, it might be useful in the treatment of acute monocytic leukemia, both alone and in combination with HU.



  10. Melatonin for cluster headaches

    Full source: CNS Drugs, 1998, Vol 9, Iss 1, pp 7-16

    Cluster headaches are excruciatingly painful and occur in cluster periods lasting weeks or months that are separated by remission periods of months or years. The cause of cluster headaches is still unknown. Usually, cluster periods begin in spring or autumn when there is a rapid rate of change of the quantity of daylight, and, often the attacks recur on a daily basis with "clockwork" regularity. The periodic nature of cluster headache suggests involvement of the hypothalamus, the site of the biological pacemaker. Melatonin production is under the control of this hypothalamic pacemaker. A number of studies have shown that melatonin levels are reduced during cluster periods, suggesting that the disorder is associated with a periodic dysfunction of hypothalamic structures. In this article, some of the biological functions of melatonin are reviewed in light of their possible relevance to the mechanisms that cause cluster headache. These include the role of melatonin in the regulation of circadian rhythms and the possible implications of its effects on gamma-aminobutyric acid (GABA) and serotonin receptors, intracellular levels of calcium ions and prostaglandin production. Results showed that in a double-blind, placebo-controlled clinical study, melatonin effectively prevented cluster headache in 50% of patients. This finding suggests the possible utility of melatonin as a second-line prophylactic agent in cluster headaches, and provides additional evidence of a periodic central dysfunction.



  11. Faster mental decline in smokers

    Full source: Presented at the American Academy of Neurology meeting.

    Elderly smokers have a more rapid decline in mental faculties over time compared with their nonsmoking peers. The take home message is "don't start smoking and if you have started, quit." "It is never too late to quit." This study took place in the Netherlands A multinational team of researchers looked at four large studies containing a total of 9,223 healthy men and women over age 65. The subjects were tested for cognitive function-a catchall term for memory, learning and language skills-an average of every 2 years. About 22% were current smokers, 36% were former smokers, and 42% were never smokers. The researchers found that the average annual decline on a test of cognitive function was greater in smokers (-0.25 points) than in former smokers (-0.13 points) and never smokers (-0.03 points). There was no statistically significant difference between the former smokers and never smokers in terms of cognitive decline. However, the test results can't be directly related to everyday tasks, such as losing one's keys. For example, one cannot conclude that for a given decline it is more difficult to count change or make a telephone call or remember your friends' names. Even results from more sophisticated neuropsychologic tests are difficult to translate directly into daily activities as they are designed to test specific aspects of brain function. However, brief and more detailed neuropsychologic tests can indicate problems and in nondemented (people) may predict later dementia. It's not clear exactly why smokers would score more poorly on tests of cognitive function. However, it's possible that smoking, which increases the risk of stroke, may be causing small, silent strokes that don't have obvious symptoms. The silent strokes are caused by several mechanisms, including atherosclerosis that blocks the blood flow to the brain, eventually causing hypoxia (reduced oxygen) and ischemic damage that leads to neuronal death and small infarcts (damaged areas) in the brain.



  12. High triglycerides risk for heart attack

    Full source: Circulation 1998;97:1027-1028, 1029-1036

    A high blood level of triglycerides-the most common type of fat found in food-is a strong risk factor for heart attack among middle-aged and elderly men, independent of other factors such as total cholesterol levels. This study in Denmark, analyzed blood levels of triglycerides for 2,906 white men, 53 to 74 years of age, with no history of heart disease. Over an 8-year follow-up period, 229 of the men had a first heart attack-163 survived, 66 died. Then the researchers divided the subjects into three groups, according to the triglyceride levels obtained at the beginning of the study. Men with higher levels of triglycerides appeared to be at greater risk of heart attack, irrespective of their high density lipoprotein (HDL) level, which is believed to play a protective role against heart disease. However, the researchers also found that the highest risk of heart disease was in men who had blood triglyceride levels between 1.6 to 2.5 millimoles per liter (mmol/L), with risk appearing to decrease at higher triglyceride levels. This was true although, in general, subjects with the highest triglyceride levels also had a high prevalence of other risk factors for heart attack, such as high blood pressure and high cholesterol levels. The researchers suggest that the decreased cardiac risk for men with a triglyceride level over 2.5 mmol/L may be because these men have lipoproteins in their blood that are less likely to cause arterial disease. The conclusion was that blood triglyceride level was "a stronger risk factor than total cholesterol" and that such a test of blood triglyceride level taken after a patient had fasted "should be included in risk factor profiles." Serum triglycerides can be lowered by consumption of omega-3 essential fatty acids (fatty fish or organic flaxoil), cutting alcohol consumption, and reducing simple carbohydrates in the diet, increasing dietary fiber, eating more protein, taking niacin supplements, and possibly supplements of chromium picolinate.



  13. High stress may impair memory

    Full source: Nature Neuroscience (1998;1(1):3-4, 69-73)

    Elderly people who have consistently high blood levels of cortisol don't score as well on memory tests as their peers with lower levels of the stress hormone. What's more, high levels of cortisol are also associated with shrinking of the hippocampus, a region of the brain that plays an essential role in learning and memory. Cortisol is a steroid hormone released in response to stress by the adrenal glands, which sit on top of the kidneys. The findings suggest that even cortisol levels in the normal, "healthy" range can actually accelerate brain aging. The study results now provide substantial evidence that long-term exposure to adrenal stress hormones may promote hippocampal aging in normal elderly humans. Over a 5- to 6-year period, researchers at the Geriatric Institute of Montreal measured 24-hour cortisol levels in 51 healthy, volunteers, most of whom were in their 70s. The participants could be divided into three subgroups: 1) those whose cortisol progressively increased over time and was currently high (increasing/high); 2) those whose cortisol progressively increased over time and was currently moderate (increasing/moderate); 3) and subjects whose cortisol decreased, but was currently moderate (decreasing /moderate). The researchers tested the volunteers' memory and conducted magnetic resonance imaging (MRI), a type of brain scan, on six people in the increasing/high category and five people in the decreasing/moderate group. The increasing/high cortisol group had impairment on delayed recall tests and took longer to complete simple and complex mazes compared with those in the decreasing/moderate group. The total volume of the hippocampus in those in the increasing/high group was 14% lower than those in the decreasing/ moderate group, although there were no differences in other brain regions. The results suggest that brain aging can be accelerated by levels of adrenal hormones that are not generally regarded as pathological and that variation within this normal range is correlated with variation in the rate of brain aging. This further suggests that chronic stress may accelerate hippocampal deterioration.



  14. Choline supplementation boosts adult memory

    Full source: Neurophysiology (April 1998)

    High levels of the nutrient choline during pregnancy may enhance memory and learning capacity in the fetus, according to the results of a study in rats. Choline is one of the B complex vitamins, and occurs in foods such as eggs, meat, fish, nuts, legumes, and soy, as well as in human breast milk. Choline is also an important component of the neurotransmitter acetylcholine, the chemical messenger that many nerve cells use to communicate. Scientists believe choline is an important "building block", essential to the healthy development of various types of cell membranes (including neural membranes) during fetal gestation. The study compared the development of the neural membranes of rats born to mothers placed on one of three types of diets: 1) a "normal" diet; 2) a diet supplemented with 4 to 7 times as much choline; 3) or a choline-deficient diet. The researchers say they discovered real cellular differences in brain tissue samples obtained from the three groups. Specifically, they say that fetal choline supplementation was linked to "enduring alterations" in adult rat brain structure "that may underlie changes in spatial memory capacity." Related behavioral studies have also revealed that animals from supplemented mothers "seem to have a larger memory capacity. They're able to hold more items in memory without forgetting them." These animals also displayed lifelong improvements in their ability to remain attentive during a variety of tasks. Study co-author Dr. Christina Williams, a behavioral neuroscientist at Duke University in Durham, North Carolina, believes the study findings demonstrate, "pretty conclusively, that supplementation with choline during the last third of pregnancy has fairly dramatic and long-lasting effects on the memory of offspring." Furthermore, she said researchers have "just now discovered that animals that got five days of extra choline during early development actually don't show the same age-related declines in memory that you see in normal animals. Therefore, these animals actually have better brain-health for the rest of their lives. We have old animals whose memory function is very much like young adults." It's very easy for our diet to vary a lot in choline. Selecting choline-rich foods or using supplements quickly boosts daily intake of the compound to recommended levels. New government recommended daily allowance guidelines (RDA), published recently by the National Academy of Sciences, suggest that pregnant women consume at least 450 milligrams of choline per day.



  15. Raloxifene reduces heart risk

    Full source: The Journal of the American Medical Association, May 13th

    Postmenopausal women who take Raloxifene (trade-named Evista) to lower their risk of osteoporosis may also be reducing their risk of heart disease. However, the study's authors say Raloxifene's cardiac benefits may still not match those of traditional hormone replacement therapies (HRT). The researchers concluded that the response (after Raloxifene treatment) paralleled that of HRT, although not necessarily of the same magnitude. Raloxifene, already approved by the FDA for use in reducing osteoporosis risk in postmenopausal women, has recently been shown to help prevent breast cancer in women at high risk for the disease. Now, the latest research suggests that the drug could reduce certain heart disease risk factors in postmenopausal women as well. If so, Raloxifene might prove an effective alternative to HRT, which reduces cardiovascular risks but increases a woman's chances of developing ovarian or breast cancer. The researchers reported that Raloxifene favorably alters several markers of cardiovascular risk. However, they also found that the most important of these beneficial changes were not equal in magnitude with those caused by HRT. Compared with the placebo group, women taking Raloxifene saw their blood levels of LDL ("bad" cholesterol, because it increases heart risk) drop by an average of 12% compared to 14% in HRT users. In addition, HRT pushed HDL levels 10% higher than the placebo, whereas Raloxifene had no impact on raising blood levels of HDL (the "good" cholesterol). Raloxifene also reduced levels of lipoprotein(a), another blood fat associated with an increased risk of heart disease, by about 8% compared with an HRT-linked reduction of 19%. Raloxifene may become the drug of choice in women who don't wish to take HRT, but want to strengthen their bones, lower their risk for breast cancer, and reduce the risk for heart disease. This drug should be a part of a prudent plan of exercise, proper diet and nutritional supplementation (including phytoestrogens) .There never has been a prospective, double-blind, placebo-controlled study to show the value of HRT in preventing heart disease.



  16. Brain injury improves with hyperbaric oxygen

    Full source: Presented in Seattle at the Undersea and Hyperbaric Medical Society 1998 Annual Scientific Meeting

    Patients with long-standing traumatic brain injury show a general improvement of speech, memory and attention after undergoing a series of hyperbaric oxygen therapy treatments. Hyperbaric oxygen therapy is a technique in which patients breathe pure oxygen in a chamber with a higher-than-normal atmospheric pressure. Hyperbaric oxygen therapy is commonly used to treat people suffering from carbon monoxide poisoning or divers with decompression sickness. Initially, five of the 11 patients, at least 3 years post-brain injury had 80 sessions in a hyperbaric unit. After a 5-month rest period, those five patients underwent another 40 hyperbaric sessions. The remaining six patients, serving as controls, did not undergo hyperbaric oxygen therapy. There was no change in the blood flow of the six control patients during the study period. However, patients who did receive the hyperbaric oxygen therapy showed increased blood flow in specific areas of the brain, as well as improvements in speech and memory functions. The improvements in these patients peaked at 80 hyperbaric oxygen sessions, and repeating the therapy every one to two weeks maintained improvement. The therapy sessions were also used to treat individuals with stroke, cerebral palsy, dementia, near-drowning and chronic carbon monoxide poisoning patients. Those patients were treated a year after the brain injury occurred. The patients had no other treatment options. Patients with the least loss of function following injury showed the greatest improvement with hyperbaric oxygen therapy. According to the researchers, it's not clear why hyperbaric oxygen therapy helped patients. "There is clinical and animal data to suggest that it might help, but the studies are not conclusive," said the president of the Undersea and Hyperbaric Medical Society. It's fertile ground for research.



  17. DHA protects small intestine

    Full source: Life Sciences, 1998, Vol 62, Iss 15, pp 1333-1338

    Oral administration of methotrexate (MTX) to mice causes the damage of the small intestine. The permeability of a typically poorly absorbable compound (FITC-dextran) through the small intestine increased in the MTX-treated mice. However, oral administration of DHA (docosahexaenoic acid) ethyl ester protected the small intestine from the increase in the small intestinal permeability induced by the MTX treatment. The MTX treatment also decreased retinol concentration in the blood of mice and the coadministration of DHA maintained its concentration to the level of mice untreated with MTX. The present study showed that DHA protected the small intestine of mice from the MTX-induced damage.

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