What's Hot
What's Hot
 |
| October 1999
Medicines from Microbes, Prescriptions from Plants Natural products researchers at the University of Arizona College of Pharmacy are expanding their research into potential drug discoveries from plants and microbes in Latin America with a grant from the National Institutes of Health (NIH) and the National Science Foundation (NSF). The five-year project holds promise for developing prescription medicines that may aid in the treatment of infectious diseases, cardiovascular, central nervous system and gastrointestinal disorders, cancers, and women's health problems. The project involves discovery and development of pharmaceuticals from plants of arid and semi-arid ecosystems in Chile, Argentina and Mexico. A unique new component of the research will examine microbes, the microscopic organisms that grow on plants. Microbes are the source of antibiotics such as penicillin, but there never has been a detailed study of them in the dry lands of Latin America. Headed by principal investigator Barbara N. Timmermann, Ph.D., the project is an extension of research she began in 1993 with the Latin American International Cooperative Biodiversity Group (ICBG). The Latin American program is one of six ICBG projects worldwide exploring natural products and the only project dedicated to desert plants. —D Dye
Pycnogenol seen as protection from heart attacks and strokes A trademarked natural supplement derived from pine bark called Pycnogenol may help provide protection from heart attacks and strokes, according to a recently published study by a researcher at the University of Arizona College of Medicine. Ronald Watson, Ph.D., professor of public health research at the Arizona Prevention Center at the UA College of Medicine, is one of the authors of the study published in Thrombosis Research (vol. 95, issue No. 4, pages 155-161, 1999). Titled, "Inhibition of Smoking-Induced Platelet Aggregation by Aspirin and Pycnogenol," the study involved 38 healthy smokers at the UA and at the University of Munster in Germany, the latter under the direction of Peter Rohdewald, PhD. Pycnogenol significantly reduced platelet aggregation, a condition that occurs when the smallest blood cells stick together and form clumps in the blood. Clumped cells in an artery feeding a region of the brain can produce a stroke, while aggregated platelets in narrowed vessels feeding the heart can lead to a heart attack. Study participants were given a single dose of 100-120 mg of Pycnogenol or 500 mg of aspirin. They then smoked to increase platelet aggregation prior to having their blood drawn. Within two hours after taking the supplement, participants were evaluated to measure the effects of Pycnogenol or aspirin in reducing smoking-induced platelet aggregation. The study focused on smokers because it is easier to measure their increased clumping of platelets. Results showed that both Pycnogenol and aspirin reduced platelet aggregation significantly. But a single, smaller dose of the natural supplement was as effective as five times as much aspirin. —D Dye
Vitamin E May Protect Against Macular Degeneration The October issue of the Archives of Ophthalmology reported findings by Dr. Cecil Delcourt of the National Institute of Health and Medical Research in Paris that antioxidant status is strongly related to the prevalence of macular degeneration. Dr. Delcourt and members of the POLA study group evaluated information provided by 2,584 persons aged 60 or older. Blood levels of glutathione and vitamins A, C and E were assessed as well as the eye health history, lens opacity and visual acuity of each individual. Color fundus photographs of the macular area of the eyes were taken for each patient. Of the group, 38 had late age-related macular degeneration. Persons older than eighty years of age experienced a higher prevalence of the disease. Individuals having the highest vitamin E to lipid ratios were found to have an 82% decrease in the incidence of the disease. They were also found to have fewer early signs of age-related macular degeneration. Although the investigators remarked that the study was observational, they stated that the results suggest a protective effect of vitamin E against age-related macular degeneration. —D Dye
Blueberries For The Brain In addition to being delicious, blueberries could improve age-related memory, balance and coordination problems. In a recent National Institute on Aging (NIA) and U.S. Department of Agriculture funded study, rats fed a blueberry-extract diet for 8 weeks experienced fewer age-related motor changes than rats on a regular diet or those receiving strawberry or spinach extracts. Researches noticed a marked reversal of age-related impairments within a short period. The groups fed fruit and vegetable extracts scored better on memory tests and showed signs of the key antioxidant Vitamin E in their brains. Blueberries are rich in natural antioxidants, which may protect against oxidative stress. As cells turn oxygen into energy, they release free radicals that when produced in normal quantities remove toxins. But in excess, the free radicals damage tissues and cells. Scientists consider this oxidative stress to be a factor in aging and the development of neurodegenerative diseases. Researchers concluded that blueberry and strawberry extract offered brain tissue the best protection from oxidative stress. Fruits, yellow and orange vegetables, and whole grains contain natural antioxidants. In addition to antioxidant activity, phytochemicals found in fruits and vegetables help nutrients and chemical signals enter and exit cells, decreasing tissue inflammation. Researchers will investigate how long the blueberry-induced reversal of age-related impairments lasts and if the results hold true for people. Ongoing NIA-funded clinical trials are comparing cognitive declines in women taking over-the-counter antioxidants with those who do not. —D Dye
Thiamin Essential For Brain Function The readily available vitamin thiamin may help brain function in older adults who have lost their appetite, don't care about the quality of their diets or forget to eat. Poor nutritional habits put those seniors at risk for two neurological disorders more commonly associated with alcoholism: Wernickes encephalopathy and Korsakoffs Syndrome. The diseases can be fatal. Wernickes causes memory impairment, confusion, vision disturbances, muscle weakness and an unsteady gait. Treatment includes thiamin replacement. Without the vitamin, memory loss can become permanent. This amnesia marks Korsakoffs, which is usually considered incurable. Australian researcher Dr. Clive Harper at the University of Sydney says doctors often misdiagnose the diseases. Researcher Edith V. Sullivan, Ph.D., at the Stanford University School of Medicine says the results of the study indicate the importance of nutritional factors in brain condition and cognitive well-being. Sensitive muscle and nerve tissue, including the brain, start to deteriorate without sufficient vitamins, minerals and other nutrients. In the United States and other countries, food manufacturers often add thiamin to bread flour. Japan enriches its rice. The water-soluble B vitamin is found naturally in organ meats and whole-grain breads, cereals and pastas. Although deficiencies are rare, the possibility should be investigated in people experiencing memory loss or dementia. —D Dye
FDA To Issue Statement on Soy The FDA is expected to issue a statement that soy protein may reduce the risk of heart disease. The expected announcement is the result of a petition by Protein Technologies International to allow health claims for soy. The FDA is expected to state that "consuming 25 grams of soy protein a day as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease." Actually, a diet high in soy protein reduces heart attack risk regardless of diet. This has been proven since at least the 1940s when studies on types of protein and how they relate to heart disease began in earnest. Casein (animal protein) consistently produces heart disease, whereas soy (vegetable) does not. In studies on monkeys, lesions in the arteries typical of heart attacks were 90% less in animals fed soy protein compared to animal protein. The phytoestrogen part of soy is important, though not critical, for the heart-saving effect of the protein. Phytoestrogens work like calcium channel blockers. In addition, they act as antioxidants and keep platelets from sticking together. Bill Stewart, CEO of Naturade, a manufacturer of soy products, calls the FDA's announcement the "Great Soy Protein Awakening". It took awhile for the FDA to wake up--soy's heart benefits have been proven for at least 10 years. And although the agency is only allowing low fat/low sodium products containing 6.25 grams of soy protein per serving to make the heart claim, tofu, soy milk and other soy products are also good for the heart. Anthony MS, et al. 1997. Soy protein versus soy phytoestrogens in the prevention of diet-induced coronary artery atheroslerosis of male cynomolgus monkeys. Arterioscler Thromb Vasc Biol 17:2524-31. Williams JK, et al. 1998. Dietary soy isoflavones inhibit in-vivo constrictor responses of coronary arteries to collagen-induced platelet activation. Coron Artery Dis 9:759- 64. Chiang CE, et al. 1996. Genistein directly inhibits L-type calcium currents but potentiates cAMP-dependent chloride currents in cardiomyocytes. Biochem Biophys Res Commun 223:598-603. —D Dye
Vitamins C and E Reverse the Effects of Homocysteine on Blood Vessels Meat-and-potatoes types may want to pay attention to research from Italy. An amino acid found abundantly in meat dramatically damages blood vessels. Methionine is an amino acid that turns into homocysteine during metabolism. Homocysteine is deadly to blood vessels. Researchers gave volunteers a big dose of methionine, and then measured the effects. Homocysteine levels almost tripled after methionine (100 mg/kg of weight). Dramatic increases in substances that damage blood vessels were also evident, including prothrombin and plasminogen activator. Normally, the amino acid L-arginine has a beneficial effect on blood vessels. But in the presence of so much homocysteine, L-arginine could not protect vessels. Instead, it actually turned foe and made things worse. Researchers believe that homocysteine interferes with L-arginine's ability to create nitric oxide, a blood vessel-friendly substance that reduces oxidative stress inside arteries. Antioxidant vitamins C and E can reverse the negative effects of homocysteine if given at the same time as the methionine is ingested. One thousand milligrams of C plus 800 IUs of vitamin E are required. Researchers believe that homocysteine overwhelms arteries with free radicals that damage their inner lining. Years of damage leads to heart attacks and strokes. Vitamins that break down homocysteine were not tested in this study which looked solely at damaging substances generated by oxidative stress. Nappo, F, et al. 1999. Impairment of endothelial functions by acute hyperhomocysteinemia and reversal by antioxidant vitamins. JAMA 281:2113-118. —D Dye
Ginkgo May Help Glaucoma Ginkgo is known for getting blood to the brain. Researchers believe it may also help the eyes. Eleven people treated with ginkgo biloba extract for two days showed a 23% increased blood velocity in the main eye artery (40 mg three times a day). The speedy blood came with no side effects. This is good news for anybody with eye problems relating to impaired blood flow. Ginkgo works by interfering with the ability of blood cells to stick together. It especially works in tiny blood vessels known as capillaries. In one study, the blood flow to fingernail capillaries was increased 57%. While it's nice to grow nails, it's better yet to see, think, and remember. If this new research on eyes holds up, ginkgo will have a new role to play in the extension of the brain known as the eyes. Chung HS, et al. 1999. Ginkgo biloba extract increases ocular blood flow velocity. J Ocul Pharmacol Ther 15:233-40. Jung F, et al. 1990. Effect of ginkgo biloba on fluidity of blood and peripheral microcirculation in volunteers. Arzneimittelforschung 40:589-93. —D Dye
Vitamin C for Gastritis People who constantly reach for the antacids may have something more serious than they realize. Helicobacter pylori is an unwelcome bacterium linked to stomach ulcers. But it also causes chronic gastritis that can, if left untreated, turn into cancer. Five major studies are currently underway to verify the connection. Three of them are investigating whether vitamin C can inhibit both the bacterium and the cancer. Previous studies show that vitamin C slashes the risk of gastric cancer by 50%. Researchers believe the vitamin may work by counteracting n-nitroso compounds (NOC). NOCs form in the stomach when food containing nitrate or nitrite interacts with stomach acid. NOCs promote cancer. Nitrates are abundant in processed meat like bacon, hot dogs and lunch meat. Vitamin C scavenges cancer-promoting free radicals caused by NOCs. It appears, however, that H. pylori keeps vitamin C from doing its job. Unlike uninfected people, those infected with H. pylori, show no stomach secretion of vitamin C. As a result, they are far more likely to get stomach cancer. H. pylori thrives in stomachs that don't have enough acid to maintain the proper environment. Taking ascorbic acid (vitamin C) at 1 to 2 grams a day may help eradicate the bug, and keep cancer at bay. Reed PI. 1999. Vitamin C, Helicobacter pylori infection and gastric carcinogenesis. Int J Vitam Nutr Res 69:220-27. —D Dye
CLA and Vitamin A Counteract Aging Immunity Certain supplements reverse age-related declines in immunity. There is new evidence that CLA (conjugated linoleic acid) and vitamin A reverse the effects of aging on immunity. Immunity is a prime place for aging to show up. Reversing aging here can have effects throughout the body. Researchers at Tufts recently reported that CLA jump-started the immune system of old mice by increasing a chemical messenger known as IL-2. IL-2 decreases with age in both mice and humans. This decrease has been linked to all kinds of adverse effects including inflammation throughout the body. Researchers don't know how it works yet. In a different study, researchers at Penn State were able to show that a lack of vitamin A causes decreased IL-2 in rats. This decrease went along with increases in CD8, a type of immune cell not conducive to IL-2. Young rats (and humans) have a good balance between CD4 which produces IL-2 and CD8 which produces other kinds of immune stimulators. Aging causes CD8 to become top-heavy, with CD4 and IL-2 dwindling. Reversing age-related declines in IL-2 is important for maintaining the ability to fight off infection and cancer. Not only that, but IL-2 keeps a check on other immune stimulators that cause inflammatory substances like prostaglandins to be manufactured in the body. Dawson HD, et al. 1999. Chronic marginal vitamin A status affects the distribution and function of T cells and natural T cells in aging Lewis Rats. J Nutr 129:1782-90. Hayek MG, et al. Dietary conjugated linoleic acid influences the immune response of young and old C57BL/6NCrlBR mice. J Nutr 129:32-38. —D Dye
|
