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 The Latest In . . .
Human Cell Tests Beat Animal Tests An international research team has confirmed that human cell tests are better than lethal dose (LD-50) tests on rats and mice at predicting the dangers of drugs and industrial chemicals. Dr. Bjorn Ekwall and colleagues in the Multicenter Evaluation of In-Vitro Cytotoxicity (MEIC) trial based in Uppsala, Sweden, released final data from independent laboratories showing that while rat and mouse tests have been about 65 percent accurate in predicting human risk, a combination of three human cell tests predicted the toxicity of chemicals with 77 percent precision. “These tests can be used immediately in industry,” Dr. Ekwall wrote. After validation in practice, he said, they should be proposed for formal acceptance by government regulators. Lethal dose tests are not the only animal tests commonly used by drug and chemical manufacturers. Replacements for some of the others have already received government approval, but many chemical manufacturers still run animal tests for fear of liability suits should they omit them. Ekwall B, Barile FA, Castano A, et al. MEIC evaluation of acute systemic toxicity. Part VI. The prediction of human toxicity by rodent LD50 values and results from 61 in vitro methods. ATLA 1998;26:617-58. Capsules That Won’t Rot Your Brain Animal ingredients in medical and cosmetic products have come under intense scrutiny since the advent of mad cow disease, opening up a market for safer ingredients. Vegicaps, a plant-derived medicine capsule from GS Technologies, Inc., of Springville, Utah, replaces typical gelatin capsules produced from rendered animal remains. Manufacturers like the practical advantages of the nonanimal, preservative-free capsules. While gelatin capsules dissolve inefficiently when swallowed with cold beverages, Vegicaps dissolve easily at the full range of temperatures, due to the intrinsic properties of the vegetable fiber used to produce them.
‘White Meat’ Linked to Colon Cancer Eating meat, particularly chicken and fish, is linked to colon cancer in a new report in the American Journal of Epidemiology. Researchers at Loma Linda University examined the eating habits of 32,000 men and women between 1976 and 1982, and then monitored emerging cancer cases during the next six years. Among participants who generally avoided red meat but who ate white meat less than once per week, colon cancer risk was 55 percent higher than for those who avoided both kinds of meat. Those who had white meat at least once per week had more than three-fold higher colon cancer risk. Eating beans, peas, or lentils at least twice a week was associated with 50 percent lower risk compared to never eating these foods. Cancer researchers have long suspected that fat and cholesterol in meats contribute to colon cancer. However, in 1995 researchers at the National Cancer Institute found surprisingly high levels of cancer-causing heterocyclic amines in grilled chicken. These carcinogens are formed as animal proteins are heated. Grilled chicken registered 480 nanograms of heterocyclic amines per gram, 15 times higher than in beef. Meanwhile, Harvard researchers reported that diets rich in the B-vitamin folic acid cut colon cancer risk by 75 percent. Folic acid, found in beans, vegetables, and fruits, has also been shown to cut the risk of birth defects and heart disease. Singh PN, Fraser GE. Dietary risk factors for colon cancer in a low-risk
population. Am J Epidem 1998;148:761-74.
Chicken-Borne Bacteria Is Top Foodborne Illness The Centers for Disease Control and Prevention (CDC) report that campylobacter is the leading cause of foodborne illness. The bacteria are found in chicken feces and commonly contaminate chicken flesh during slaughter. Even a drop of fluid from a raw chicken can cause a serious infection. In a monitoring program in Minnesota, Oregon, California, Connecticut, and Georgia that covered about 6 percent of the U.S. population, CDC researchers found 3,974 culture-confirmed campylobacter infections among 8,576 cases caused by seven common bacteria. Since confirmed cases are only the tip of the iceberg, the CDC estimates that 8 million Americans are sickened by foodborne illness yearly. Americans eat approximately 1 million chickens per hour or 9 billion per year.
That’s One Big Banana Foods rich in potassium appear to cut stroke risk, according to a Harvard study of 44,000 men. Those whose diets included the most fruits, vegetables, or potassium supplements had 38 percent less stroke risk compared to those whose diets included lower intakes. Arizona State University researchers recently drew attention to another feature of fruits and vegetables—vitamin C. They found vitamin C deficiency to be surprisingly common among middle-class patients attending a clinic for routine check-ups. Blood tests showed that, of 494 participants, 30 percent were low in vitamin C and 6 percent were severely deficient. While most of us think of a vitamin C deficiency as increasing the risk of colds and cancer, the researchers were also concerned about more immediate symptoms, including fatigue and altered metabolism. While fruits and vegetables are loaded with vitamin C, meats, dairy products, and grains are virtually devoid of the vitamin. Ascherio A, Rimm EB, Hernan MA, et al. Intake of potassium, magnesium, calcium,
and fiber and risk of stroke among U.S. men. Circulation 1998;98;1198-204.
Milk Constipates Kids Milk continues to take a beating in scientific journals. After being linked to higher risk of fractures in the Harvard Nurses’ Health Study, then to possible higher risk of prostate and kidney cancer by the World Cancer Research Fund, it is now blamed for constipation. The New England Journal of Medicine reported on 65 children between 11 months and 6 years of age with chronic constipation treated unsuccessfully with laxatives. Switching to soymilk cured 44 of the children. Switching back to cow’s milk led to symptom recurrence within five to ten days. Cow’s milk can bother digestion in several ways. Lactose sugar is indigestible to most non-Caucasian older children and adults. Dairy proteins can also cause digestive reactions, starting with colic in infants. Also, dairy products fill kids up with calories derived mainly from fat (49 percent of calories) and lactose sugar (30 percent of calories) but supply no fiber at all. In these children, the researchers suggested, the problem was that milk caused perianal sores and severe pain on defecation, leading to constipation. World Cancer Research Fund. Food, Nutrition and the Prevention of Cancer: A
Global Perspective. American Institute for Cancer Research, Washington, D.C., 1997, p.
461.
HRT Doesn’t Help Heart Disease Hormone “replacement” therapy (HRT) has been promoted as a way to reduce the risk of heart disease, among other effects. But a new study of 2,763 postmenopausal women with coronary disease followed for an average of four years shows that, if anything, HRT may aggravate heart problems. Overall, there were as many heart attacks and related deaths among women treated with the combined regimen of estrogens and a progesterone derivative as among those receiving placebos, but the coronary problems occurred sooner in women taking hormones. Hormone-treated women were also more likely to develop dangerous blood clots and gallbladder disease. The study was paid for by Wyeth-Ayerst, the manufacturer of Premarin, which contains conjugated estrogens derived from pregnant mare’s urine. Last June an extensive review of previous studies by Graham Colditz in the Journal of the National Cancer Institute concluded that HRT substantially increases the risk of breast cancer. Hulley S, Grady D, Bush T, et al. Randomized trial of estrogen plus progestin
for secondary prevention of coronary heart disease in postmenopausal women. JAMA
1998;280:605-13. Leading Causes of Death The leading causes of death for the year 1997 were confirmed by the National Center for Health Statistics:
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