STUDY: Once-daily treatment cuts in half the risk of passing on the infection
JOURNAL: American Society for Microbiology
AUTHORS: Dr. Lawrence Corey
ABSTRACT: For the first time, a drug widely used to treat genital herpes has been shown to prevent its spread as well, offering a new way of curbing an infection already carried by one in five Americans.
COMMENTARY: A study released Friday found that a once-daily Valtrex — known generically as valacyclovir cut in half the risk of passing on the infection when taken by people with herpes simplex virus type 2, the primary cause of genital herpes.
Until now, the only advice for avoiding herpes during sex has been to use condoms. While no one knows which is more effective, condoms are clearly not foolproof, since the virus spreads by contact with herpes sores, and condoms may not cover them all.
The latest research suggests a new use for Valtrex in so-called discordant couples — those in which one partner is infected and one is not. The drug is already widely prescribed to prevent and treat herpes flare-ups.
The Centers for Disease Control and Prevention estimates that 45 million American teenagers and adults are infected with the type 2 virus, which is almost always spread during sexual contact. The other herpes simplex virus, type 1, is much more common and causes cold sores. However, it too can cause genital infections if spread through oral-genital contact.
Usually, the type 2 virus causes only mild symptoms or no obvious sores at all. In fact, 90 percent of infected people do not realize they have it. Nevertheless, an unlucky minority suffers recurring painful genital sores.
STUDY: No Link with Vit A and Bone Loss
JOURNAL: Journal of Nutrition 2002;132:1169–72
ABSTRACT: Contrary to a report published earlier this year in the Journal of the American Medical Association, supplementation with moderate amounts of vitamin A does not cause bone loss, according to a study in the Journal of Nutrition (2002;132:1169–72).
COMMENTARY: In the new study, 80 healthy men between the ages of 18 and 58 years were given a vitamin A supplement (25,000 IU per day) or placebo for six weeks. Blood tests taken at the beginning and end of the study revealed that vitamin A supplementation had no effect on various measures of bone breakdown and bone formation.
Thus, at least in the short term, taking a moderate amount of vitamin A is unlikely to promote bone loss.
Previous studies showed that increasing vitamin A intake is associated with an increased risk of hip fracture; however, the relevance of those studies is questionable. The main sources of vitamin A in the diet are vitamin A-fortified foods such as margarine, sugary breakfast cereals, and milk and circumstantial evidence suggests that some or all of these foods can promote the development of osteoporosis for reasons unrelated to their vitamin A content. If that is the case, then vitamin A was a victim of “guilt by association.”
Although taking too much vitamin A can cause a wide range of adverse effects (including neurological disease, liver damage, and even death), bone loss has not been mentioned as a consequence of chronic vitamin A poisoning.
Studies suggest that a safe level of intake of vitamin A is 25,000 IU per day for most healthy adults and 15,000 IU per day for individuals over the age of 65. Larger amounts, which are used by some doctors to treat acne, some cancers, menstrual irregularities, or other problems, should be taken only with medical supervision. Early warning signs of vitamin A excess include headaches, joint pain, muscle aches, bone pain, dry skin, and hair loss. These signs disappear if the vitamin is discontinued.
Preliminary research suggests that pregnant women should not take more than 10,000 IU per day, though not all studies agree on this point. Although the body converts beta-carotene into vitamin A, taking large amounts of beta-carotene does not lead to vitamin A toxicity. That is because there is a limit to the amount of beta-carotene that can be converted to vitamin A.
STUDY: You can't believe anything anymore
ABSTRACT: -- Coca-Cola's brand of bottled water, Dasani, was pulled from shelves in Britain Saturday when it was found to contain bromate, a cancer-causing chemical.
COMMENTARY: Earlier this month, it was revealed the advertised "pure" water in Britain was nothing more than tap water taken from the bottling plant in Kent.
The legal limits are set to have a wide margin of safety, and the Food Standards Agency said that while Dasani contained illegal levels of bromate, it did not present an immediate risk to the public, the Guardian reported Saturday.
"Any increased cancer risk is likely to be small. However, the levels are higher than legally permitted in the U.K. and present an unnecessary risk. Some consumers may chose not to drink any Dasani they purchased prior to its withdrawal given the levels of bromate in it," the FSA said.
STUDY: Breast Best
ABSTRACT: The longer white infants from low-income families are breast-fed, the less likely they will be overweight as young children.
COMMENTARY: The study of more than 177,000 children from low-income families who visited U.S. public health clinics between 1988 and 1992 found that formula-fed infants and babies breast-fed for less than a month were more likely to develop weight problems by age 4 than infants breast-fed for longer periods.
However, the correlation between breast-feeding duration and healthier weight was limited to whites in the study, and did not apply to Hispanics or blacks, who made up nearly one-third of the participants.
U.S. obesity rates among children and adults have been climbing, with Hispanics and blacks the most likely to be overweight.
The report, which was published in the journal Pediatrics, speculated that different dietary habits among low-income Hispanics and blacks overwhelmed breast-feeding's benefits.
Among the possible reasons behind the correlation are that breast-fed children seem to be better able to self-regulate their eating at mealtimes compared to formula-fed children, the report said. Breast-fed babies likely exert more control over when to stop suckling, while babies fed formula might be urged to finish off a bottle or were left wanting more.
Breast-fed children also have been found to make an easier dietary transition to vegetables than formula-fed children, wrote study author Laurence Grummer-Strawn of the U.S. Centers for Disease Control and Prevention in Atlanta.
And compared to breast milk, formula provokes a greater insulin response that may lead to early deposits of body fat.
Breast-feeding is known to provide valuable nutrients and to strengthen the bond between mother and child. The American Academy of Pediatrics, which publishes Pediatrics, recommends mothers breast-feed for at least a year, and the World Health Organization recommends two years.
In 2001, only 69.5 percent of new American mothers said they had ever breast-fed their newborns and just 32 percent were still breast-feeding at six months. Low-income mothers were the least likely to breast-feed.
In the study, less than one-third of the children were ever breast-fed, and only 6 percent were breast-fed for more than six months.
Among whites, 14.5 percent of infants who had never breast-fed became overweight, compared to 7 percent of those breast-fed at least a year. The proportion of overweight Hispanic children in the study ranged from 22 percent to 29 percent, and among blacks between 13 percent and 19 percent, with duration of breast-feeding having little impact.
JOURNAL: Gastroenterology 0204
ABSTRACT: So-called "good bacteria" in the intestines, which may help people with inflammatory bowel disease, allergies and some forms of cancer, work even when they're inactive.
COMMENTARY: Called probiotics, they are bacterial organisms that contribute to the health and balance of the intestinal tract. Recent studies have proven the health benefit of these bacteria.
The effectiveness of probiotics has been attributed to their live, metabolic activity. But active probiotics are used in only a small number of food products, such as yogurt. Active probiotics are unsuitable for most food products because they induce fermentation, which changes the taste, texture and freshness of food on an hourly basis.
This new study, by researchers at the University of California, San Diego School of Medicine and the Shaare Zedak Medical Center in Jerusalem, found probiotics contain immune system-stimulating DNA that makes them just as effective when they're inactive.
The finding offers the potential to use inactivated probiotics in a variety of food products.
The study also outlines a method to determine and select which probiotic bacteria provide the most benefit for people with inflammatory bowel disease.