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 The Latest In . . . By Kristine Kieswer
Kids' Hearts Show Blockages A study of teenagers' hearts shows that one in six has at least one significant blockage, according to a report at the American Heart Association Scientific Sessions on November 9, 1999. The study was conducted on transplanted hearts from child donors who had died in accidents, using ultrasound shortly after the hearts were placed in recipients. The study was led by E. Murat Tuzcu, M.D., of the Cleveland Clinic.
Vegetables and Fruits Cut Stroke Risk Vegetables and fruits reduce the risk of ischemic stroke, the kind of stroke caused by a blocked artery to the brain, according to data on 570 men and women participating in two Harvard studies. The strong-est benefits were seen with green leafy vegetables, cruciferous vegetables (e.g., broccoli, cauliflower, and cabbage), citrus fruits, and fruit juices. The actual risk reduction could be calculated by multiplying the number of daily servings by 3 percent in women and 5 percent in men (e.g., four servings cut risk by roughly 12 percent and 20 percent, respectively). Risk was further reduced to the extent that vegetables and fruits were not simply added to the diet but actually displaced meats and trans fats. Joshipura KJ, Ascherio A, Manson JE, et al. Fruit and vegetable intake in relation to risk of ischemic stroke. JAMA 1999;282:1233-9.
OJ Boosts Good Cholesterol Orange juice boosts the level of high density lipoprotein (HDL) in the blood. HDL is known as the "good cholesterol" because it carries cholesterol out of the body. University of Western Ontario researchers gave volunteers up to three glasses of juice daily for 12 weeks. HDL levels rose 21 percent and were still high (27 percent above beginning values) five weeks after stopping the juice. The results were presented by Elzbieta M. Kurowska, Ph.D., at the American Heart Association meeting in Atlanta on November 10. The study was funded by Tropicana.
Golden Arches Lead to Pearly Gates A westernized diet spells heart attacks, according to Chinese researchers who compared villagers in Pan Yu, a town 100 miles from Hong Kong, to westernized Chinese living in Hong Kong, Sydney, and San Francisco. Using ultrasound, the researchers measured the wall thickness of the carotid arteries, which carry blood to the brain and are a good indicator of heart health. The average carotid inner wall was a healthy one-fifth thinner among villagers than among the westernized Chinese. Dr. Kam Woo of the University of Hong Kong credits the Chinese diet. "Hardly any ham, bacon, sausage, or scrambled egg is eaten in the typical Pan Yu breakfast meal," Woo said. Westerners, he said, "should think about drinking more green tea, eating more vegetables, and eating less meat and dairy products." The study supports findings of Cornell University researcher and PCRM Advisory Board member Colin Campbell, Ph.D., whose research has shown dramatically low cholesterol levels and low heart disease risk among those following a traditional Chinese diet.
New Method Replaces Animals in Skin Tests Many manufacturers test the corrosivity of chemicals and household products by painting them on the skin of rabbits and watching for a burning reaction. A federal agency has finally permitted a nonanimal test to be used instead. In the new test, called Corrositex, chemicals are applied to artificial skin, and a color change indicates the degree of corrosivity. "Since there are more than 2,000 chemicals introduced each year, this could result in a considerable reduction in the use of laboratory animals," said William Stokes of the National Institute for Environmental Health Sciences. If a chemical is found to be an irritant with Corrositex, no further testing is required. Unfortunately, the government still calls for chemicals that look safe in the Corrositex method to have backup testing on rabbits. The animal tests are not designed to protect consumers. They are used to determine whether products should carry warning labels. Corrositex is manufactured by In Vitro International of Irvine, Calif.
Breast-fed babies' IQs are three to five points higher than those of formula-fed babies, according to a new report in the American Journal of Clinical Nutrition, which compiled the results of 11 previous studies and adjusted for factors that could affect results, such as parental intelligence or income. Breast-fed babies also showed more rapid maturation of visual and motor systems and fewer behavioral problems. The benefits are thought to be due to the type of fats in breast milk, which are somewhat different from those in cow's milk formulas. An IQ benefit has also been demonstrated with vegetarian diets.
Vitamin A for Very-Low-Birth-Weight Babies When premature babies weigh less than 1,000 grams, their lungs are vulnerable to infections and other complications. A multicenter research trial has shown that vitamin A can cut the risk slightly. Of untreated infants, 56 percent had chronic lung disease, compared to 47 percent of those treated with vitamin A. No toxicity was reported.
E. coli Threat Grows The deadly E. coli O157:H7 bacteria may be found in as many as half of cattle carcasses, according to Tom Billy, administrator of the U.S. Department of Agriculture's Food Safety and Inspection Service. Once ingested, the bacteria release a toxin that causes a devastating illness with multiple organ failure and a high death rate. The worrisome new estimates came as inspectors began using a new and more sensitive testing method. Meanwhile, the Centers for Disease Control and Prevention report that human infection with the deadly bacteria may also be more common than previously believed. Many cases, apparently, had never been reported because the affected individuals had recovered without medical care. Anderson JW, Johnstone BM, Remley DT. Breast-feeding and cognitive development:
a meta-analysis. Am J Clin Nutr 1999;70:525-35.
Give It a Rest People are sleeping less now than they did a century ago, thanks to the widespread availability of electric lighting and the shift to an urban, industrialized economy, not to mention late-night television. The result is a disruption of basic body metabolism. Karine Spiegel and colleagues at the University of Chicago asked research participants to stay in bed just 4 hours per night for six nights, then 12 hours per night for the next seven nights. Under sleep deprivation, blood sugars, cortisol, and sympathetic nervous system activity rose, and thyrotropin, which regulates thyroid function, fell. In other words, chronic sleep deprivation forces the body into a fight-or-flight response, pushing blood sugars and other hormone-related functions out of kilter. Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt on metabolic and endocrine function. Lancet 1999;354:1435-9.
MS, Arthritis, and Crohn's: Caused by Infections? From our good friend Gabe Mirkin, M.D., comes an important review showing that infections may play an important role in at least some cases of MS, arthritis, and Crohn's disease. For MS, suspicion has been cast on human herpes virus 6 (HHS-6), which may be treatable with gancyclovir or foscarnet, and on chlamydia pneumoniae, which is treated with doxycycline. Many rheumatoid arthritis patients are infected with mycoplasma, which is treated with the antibiotic minocycline. Inflammatory bowel disease may result from an infection by cytomega- lovirus or Epstein-Barr virus. While all of these are under continuing investigation, patients should consider anti-infective treatments, particularly given the often poor results of conventional treatment. Dockrell DH, Smith TF, Paya CV. Human herpes virus 6. Mayo Clinic Proc
1999;74:163-70. |
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Breast-Feeding Boosts IQ