Thursday, October 25, 2007
HIV, the virus that causes AIDS, is epidemic in Africa. In some sub-Saharan countries, 35% of the population is infected. Every year, as many as 700,000 babies are infected with the virus during pregnancy, birth, or breast-feeding.
For 15 years, professional health organizations such as WHO have recommended that infected women in developing countries avoid breast-feeding to prevent transmission of the virus through breast milk.
But recent research from physician Nigel Rollins of the University of Kwazulu-Natal in South Africa has turned that recommendation on its ear.
There's no question that breast-milk can transmit the AIDS virus. But the realities of formula feeding in developing nations complicate the picture.
In Africa, women often don't have access to clean water or can't afford enough formula, and often wind up supplementing the formula with breast milk. And sadly, a mixed diet of formula and breast feeding turns out to be the worst possible recipe for AIDS transmission, worse than either alone.
That's because unclean water in the formula often irritates the lining of the baby's gut or makes sores in the baby's mouth - so that during subsequent breastfeeding, the HIV virus has an easier path into the baby's blood.
Rollins and his research team studied more than 2,700 women for 7 years, and published the results in the March 31 edition of the medical journal, Lancet. They found that babies fed only breast milk had only a 4% risk of infection from the ages of 6 weeks to 6 months. This was less than half the risk of HIV infection of babies fed with breast milk plus formula or other milk products. In addition, babies fed solids as well as breast milk were 11 times as likely to become infected as were breast-only babies. The solids were also found to inflame a baby's immature digestive system, thereby facilitating transmission of the virus through the gut wall into the baby's bloodstream.
Formula-feeding in developing nations has other problems as well. Babies fed formula or solids before 6 months of age don't get the full nourishment and disease-fighting benefits of breast milk, while being exposed to increased risks of gastrointestinal diseases and malnutrition from unclean water.
"We've reached remarkable consensus among experts" that exclusive breastfeeding is best during the first 6 months for babies of HIV-infected mothers in poor countries, says Jean Humphrey of the John Hopkins School of Public Health, speaking from Zimbabwe. "The issue really now is what to do after 6 months." WHO currently recommends that mothers wean babies rapidly after 6 months to avoid prolonged exposure to mixed feeding.
Carolyn Barry. "The Breast Solution: Nature's nutrition keeps HIV at bay." Science News. September 22, 2007. Some sections of the blog post above are direct quotes from the Science News article.
Keywords:: breastfeeding, breastmilk, breast feeding, breast milk, HIV, AIDS, Africa, malnutrition, infant nutrition
Thursday, October 18, 2007
Birds make tools - they even show handedness in making and using tools.
In the Oct 6 issue of Science News, there's an article about crows fitted with tiny "crittercams" that record the crows' use of plant stems to probe for food. These crows, from a South Pacific island, make several types of hooks and saw-edged probes from twigs and leaves.
I saw a film long ago that showed crows sitting on power lines and dropping nuts (or something with a hard shell, I forgot what) into traffic to be crushed by cars - then retrieving the contents when the stoplight stopped the traffic.
Last night, I went to the web site of one of the primary researchers of tool-use in crows, Gavin Hunt of the University of Auckland in New Zealand. I found it by googling "Gavin Hunt crow tools". He has an interesting site: http://language.psy.auckland.ac.nz/crows/our-research.htm.
Dr. Hunt says that crows show cumulative change in tool manufacture, which is very rare or even unique among the few animal species known to make tools. Chimpanzee and orangutan tool manufacture, for example, is often haphazard, and their tools show no evidence of incremental improvements over time. Just for perspective - current human technology is the result of a long series of cumulative changes, says Dr. Hunt. The ‘ratchet-like’ nature of humans' technological evolution means that design changes are retained by populations until new, improved designs arise. Animals other than humans have been generally presumed to lack the necessary cognitive sophistication for cumulative technological evolution.
The crows of New Caledonia (the South Pacific island) that Dr. Hunt studies manufacture two types of tool to capture invertebrates: one from twigs and the other from the long barbed edges of Pandanus leaves. The work of Dr. Hunt has revealed that these tools have four features previously thought to be unique to humans and our ancestors: a high degree of standardization, the use of hooks, “handedness”, and as mentioned above, cumulative changes in tool design. The cumulative changes involve three distinct tool designs using Pandanus leaves: wide tools, narrow tools, and stepped tools. w
Keywords:: tool use in birds, biodiversity, New Caladonia crows, Gavin Hunt
Friday, October 12, 2007
Like your chocolate dark? There's lots of evidence that it's very good for your health.
Cocoa naturally has flavonoids in it, which can give chocolate a bitter taste. To smooth the flavor, the flavonoids are often removed during the making of chocolate. Recent research, by Norman Hollenberg of Harvard Medical School, has shown that eating chocolate with the flavonoids intact can increase blood flow to the brain by 10 to 15%, with definite health benefits.
Hollenberg's research team has been studying the Kuna people who live on islands off the Caribbean coast of Panama. In the early 1990's, the team noticed that the Kuna have a lower incidence of high blood pressure than Americans, and lower risk of diseases associated with high blood pressure, such as heart attacks, diabetes, strokes and some kinds of dementia. They also found that the Kuna drink several cups of cocoa per day. Kuna cocoa is minimally processed, leaving large quantities of flavonoids in the cocoa. Kuna who moved off the island and drank cocoa without the flavonoids did not have the same health benefits.
Recently, Hollenberg conducted an experiment in the United States to look for a connection between the flavonoids and the low blood pressure. He gave one experimental group cups of cocoa with flavonoids every day, while the other group received cocoa without flavonoids. The group that drank the flavonoid-rich cocoa had 10 to 15% more blood flow to the brain, and less high blood pressure. The other group showed no changes in blood flow.
How can you as a consumer find flavonoids? Some chocolate-bar and cocoa manufacturers are make dark chocolate using a method that retains 95% of its flavonoids. The labels of dark chocolate bars will often say so. Dove Dark Chocolate bar is one example of flavonoid-rich chocolate that was used in a similar experiment at UC San Francisco with similar results, by Mary Engler, PhD, RN. (See the URL to the full online article below.)
When you choose chocolate bars, it pays to look for brands that advertise flavonoids. They may provide valuable health benefits.
Dark chocolate is better for the environment too, because dark chocolate is often made without dairy products, or with less. Dairies are among the biggest sources of nutrient pollution of surface waters and ground water in the U.S. A single dairy cow creates 120 pounds of waste per day! That's more than twice as much as a steer raised for beef, because beef cattle are slaughtered before full maturity.
But back to chocolate. Can't you get more and better flavonoids from other foods? Not really. Dr. Engler of the UC San Francisco study says that dark chocolate contains more flavonoids than any other food, including green tea, black tea, red wine, and blueberries.
While a little dark chocolate is good, a lot is not necessarily better. Chocolate still has a lot of calories. If you eat more chocolate than you have been eating, you'll need to cut out something else, or get more exercise. The key to heart health includes a balanced diet with lots of fruits and vegetables, little saturated fat, and lots of activity.
1. Daniel J. DeNoon. WebMD Medical News. "A Dark Chocolate a Day Keeps the Doctor Away."
2. "Cocoa compound increases brain's blood flow." Science News. March 3, 2007.
Friday, October 05, 2007
2. If you don't have a bird bath, put a bowl on the ground - but only if you can put in an open area where cats cannot ambush birds. I'm guessing that a cat can ambush a bird from any sort of hiding place within 10 feet of the water bowl. Maybe more than that. If you have natural areas in your yard, squirt them occasionally with the hose. Squirrels and rabbits and chipmunks will come to a bowl on the ground, but snakes, toads, mice etc, that are burrowed in the leaf litter need moisture too. And they generally won't come to a bowl to drink.
3. Offer seeds and fruits to birds, such as slices of orange. Drought affects not only the water available, but it affects the insects and plants that birds and animals eat. As above, make sure the feeder is not a bird-trap for the local house cat, by elevating it or placing it on the ground with a wide circumference of open area. Keep it clean by scrubbing it regularly.
4. For the long term, native plants withstand drought much better than introduced plants and ornamentals, many of which are from tropical rainforests. So landscape your own yard with native plants, which can be found at plant nurseries, even Home Depot (ask the plant manager there). If not, google Native Plant Society and your state name to find a local source for native plants. Don't dig up native plants in protected woodlands for your own yard - tempting but damaging to wildlife. You might find a friend who propagates native plants and will give you a few seedlings or seeds. For a good guide to landscaping with native trees, shrubs and perennials in North Carolina, see www.ncwildflower.org. Most states have such organizations now. Some of the most attractive native plants for landscaping in North Carolina are eastern redbud trees, purple coneflower, black-eyed Susans and eastern columbine. Animals love shrubs and trees that produce berries and fruits, such as mulberry, dogwood, and persimmon. Ask at your local native plant society or nursery about which varieties are native to your area.
5. Keep your house cat indoors. Birds and small animals weakened by hunger and thirst may be more vulnerable than ever to house cats, all of which prey on birds or small mammals - whether you witness it or not. Not only will the birds and other animals be better off, but your house cat will be safer too. For more info on how to make your cat a happy indoor cat, local cat laws, and resources, visit www.abcbirds.org/cats.
Key words::5 top ways to help birds, wildlife and dry weather, effect of drought on animals, house cats, housecats and predation, 5 top ways to help birds, wildlife and dry weather, effect of drought on animals, house cats, housecats and predation, keep cats indoors, small mammals