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Got milk? Contrary to popular belief, what causes those milk moustaches in the dairy industry’s ad campaign may play a role in helping to prevent obesity in children and adolescents. “There’s a myth that consuming fat from dairy products makes you fat. Lots of people believe that. Lots of doctors believe that. It’s not completely true,” reported Lynn Moore, a MED associate professor, at a recent meeting of the North American Association for the Study of Obesity.

Moore’s most recent study showed that those whose diet was low in dairy products when they were young children were more likely, not less likely, to develop excess weight and body fat as teenagers than their counterparts whose diet as children was rich in dairy products. Using data from the Framingham Children’s Study, whose participants are third and fourth generation descendants of the original Framingham Heart Study participants, Moore tracked 99 children, beginning at ages three to five, over a 12-year period. Using diet records collected several times a year for each participant, she divided the children into three groups: those with high, moderate, and low dairy consumption. She compiled and analyzed common measures of stored body fat (body mass index and skinfold measurements) for each group. The children who consumed the fewest servings of dairy products in the preschool years had 45 percent more subcutaneous fat as measured by the sum of four skinfolds than did children in the highest dairy intake group.

Moore hypothesizes that several factors may contribute to this effect. Dairy foods are a rich source of calcium and magnesium. Insufficient calcium may trigger the body to store energy in the form of fat; similarly, magnesium deficiency has been shown to promote insulin resistance -- preventing the body from efficiently metabolizing nutrients. She suggests that other biologically active compounds in dairy foods may affect weight regulation and metabolism. Also, children who consume more dairy products may drink fewer sugary drinks and other high-calorie snacks.

According to Moore, only 30 percent of children get the minimum recommended amount of dairy products. Because whole milk products can contribute to weight gain, she suggests that reduced-fat or skim milk would probably supply the benefits without the calories and the saturated fat.


Glacial quakes. Earthquakes, characterized by seismic waves -- waves of energy that travel within the earth much as sound waves travel in air -- are most often the result of movement on faults when one large section of the earth’s crust quickly slides past another.

Geoffrey Abers, a CAS associate professor of earth sciences, working with a team led by Göran Ekström at Harvard, has discovered that sudden movement of glaciers may also produce substantial earthquakes, with signals similar to those of earthquakes having magnitudes as large as 5.1. (The 1989 earthquake near San Francisco measured 6.9.)

Ekström had been researching unusual earthquake signals that seemed unrelated to the usual sources. These signals lasted longer and were of lower frequency than those of normal earthquakes, making them difficult to detect with traditional seismographs, instruments used to detect earthquake signals.

The strongest signals came from near Mount McKinley in Alaska, an area where Abers had been collecting data for three years in a project funded by the National Science Foundation called BEAAR (Broadband Experiment Across the Alaska Range) with instruments that are sensitive to lower frequency signals.

Abers’ array of seismographs produced, in his words, “among the strangest signals that I have ever seen. They had some similarities to signals generated by trucks or trains, but were seen nearly simultaneously at sites 250 kilometers (155 miles) apart.” The research group traced the source of the signals to an area next to the Dall Glacier.

“The signals are best explained by something dragging horizontally on the earth’s surface,” Abers says. “The kind of drag or push is exactly what one might expect from a glacier suddenly surging or sliding, and the direction matches what one would expect were the Dall Glacier to move.”

The researchers are seeking additional confirmation of this hypothesis through direct surveys of glaciers or satellite imagery.

Their research appears in the October 24 journal Science.

"Research Briefs" is written by Joan Schwartz in the Office of the Provost. To read more about BU research, visit http://www.bu.edu/research.

       

15 May 2003
Boston University
Office of University Relations