Teens With Bulging Bellies at Increased Risk for Hypertension
Armed with nothing more complicated than a tape measure and a scale, researchers are perfecting the art of estimating levels of dangerous body fat in teenagers.
The technique simply combines measurements of body-mass index (BMI) and the waist-to-height ratio. The two measurements, which otherwise independently are imperfect probes of measuring body fat, surprisingly predict the amount of fat floating in the blood and accumulated on bodily organs, which ultimately can lead to diabetes, heart disease and cancers.
The dual method is an inexpensive proxy to body fat measurements using blood tests and whole body scans. Researchers from University of Toronto and the Hospital for Sick Children in Ontario, Canada, report these findings today (April 2) in the journals Archives of Pediatrics Adolescent Medicine.
The problem with measurements
BMI, the ratio of a person’s weight to height, is the most common measurement to determine whether a patient is overweight, yet it comes with numerous limitations: BMI cannot differentiate between lean muscle and unhealthy fat; it doesn’t account well for different body-frame types, often categorizing short, chubby people as “healthy weight” and tall, muscular people as “overweight;” and it can be a poor indicator of obesity in teenagers, who are growing rapidly.
Waist circumference can be more predictive of abdominal fat, which is generally unhealthy and indicative of fat accumulating on organs such as the liver, kidneys and heart. A person can have a large frame with a large waist, however, and not have excess visceral fat on the organs. Regardless, waist circumference — essentially one’s pants’ size — rarely is measured during a medical exam.
Faced with the limitations of BMI, the Canadian researchers decided to examine the added role that waist measurements can have in predicting fat levels and subsequent health risks. They examined more than 3,000 teens ages 14 to 15 in Ontario, collecting waist, height and weight measurements along with blood pressure and blood samples.
For obese teens in particular, a high BMI coupled with a large waistline was associated with high blood pressure and high levels of circulating fat in the blood. Increases in waistline were directly correlated with increases in blood pressure and internal fat. These adolescents are at risk for diabetes and liver and heart disease, the researchers said.
Obese and overweight children with moderate waistlines had only slightly elevated fat levels. Those who had BMIs in the normal to overweight range, but had normal waist measurements, had healthy blood pressure and no excess levels of circulating fat.
Contention among researchers
Despite their simplicity, BMI and waistline measurements are the subject of much contention. Some researchers desire to eliminate them from the vernacular, claiming they are of little value to individuals wondering if they are overweight. BMI, for example, was a tool first used for population studies and only recently became associated with individual dieting goals and a healthy weight range. [5 Diets That Fight Diseases]
Data presented at the 2009 Endocrine Society annual meeting, from the University of Tennessee Health Science Center in Memphis, suggests that BMI and waistline measurements overestimate obesity among African-Americans. A paper published in August 2011 in the Journal of Adolescent Health stated that waist circumference was not a predictor of diabetes risk and shouldn’t be collected.
Other papers have compared the predictive powers of one measurement over another, be it BMI, waist circumference or to the waist-to-height ratio.
This latest Canadian study, led by Michael Khoury of the University of Toronto, is among the first to look at how simple measurements of weight, height and waistline can complement each other. The sum is greater than the parts, the researchers concluded, and they recommend that the basic measurements become routine in medical exams.
The researchers hope to expand their analysis with a larger sample size to better represent race, body types, age and puberty stage.
Christopher Wanjek is the author of the books “Bad Medicine” and “Food At Work.” His column, Bad Medicine, appears regularly on LiveScience.
Article source: http://news.yahoo.com/teens-bulging-bellies-increased-risk-hypertension-112012737.html
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Categories: Fat Loss Diary Tags: Bad Medicine, Biggest Diet Myths, BMI, Christopher Wanjek
Fatty diet may cause new brain cells to sprout
Eating too many burgers and fries? Your brain might show the effects, if new mouse research holds true in humans. Researchers have discovered that a high-fat diet causes new brain cells to sprout in an area of the brain that seems to regulate eating.
Interestingly, if the researchers stopped new brain-cell growth, mice gained less weight and stayed more active, even while eating their “supersize me” diet.
“We really don’t understand the function of these neurons in the normal brain,” study researcher Seth Blackshaw, an associate professor at Johns Hopkins University School of Medicine, told LiveScience. “Our data suggests that these neurons may have an important role in regulating feeding.”
Brain connections
The cells are located in a part of the brain called the median eminence, which lies at the edge of a fluid-filled chamber and therefore outside of the blood-brain barrier (which keeps toxic substances out of the brain), but it extends deep into the hypothalamus. [10 Cool Facts About the Brain]
The hypothalamus plays a role in regulating how our bodies spend the energy they take in and sends out signals to the body through the pituitary gland to control hunger, thirst and behavior.
Because the median eminence is in contact with areas of the body outside the blood-brain barrier, researchers think it may be detecting chemicals in the blood, and transferring signals about the condition of the body into the hypothalamus, which can then make decisions about eating.
Big Mac diet
The researchers wanted to see how brain cells in the median eminence reacted to a high-fat diet, so they put mice on a “Big Mac” diet — which contained 60 percent fat instead of the 35 percent fat in regular mouse chow.
The mice love the high-fat food. They eat and eat and gain tons of weight, as humans would if we could eat only fast food. In the wild, this would be a good thing in times when food is freely available: The mice can fatten up to stay alive when food is scarce.
The researchers saw that on the high-fat diet, creation of new brain cells in the median eminence increased from 1 percent to 5 percent.
Next, the researchers selectively turned off the new brain-cell creation in this region, and compared these mice with the normal mice on a high-fat diet. When new brain-cell growth was turned off, the mice gained 7 percent less weight and were 15 percent more active than the other mice eating the fatty food.
“We have no idea if this happens in any species other than mice. In humans all the cells and the structures are conserved,” Blackshaw said. “I think there’s no reason to assume necessarily that this wouldn’t happen in humans, but I would be very careful into reading too much in these studies.”
Staying thin
If this small connection to the hypothalamus does play a big role in regulating energy intake and use in humans, it could be a potential target for diet-regulating therapies, especially since it is located on the outside of the blood-brain barrier. If the region were inside the blood-brain barrier, that barrier would filter out any “foreign” chemicals used to regulate the growth of new brain cells there.
“The therapeutic potential [is] quite exciting,” Blackshaw said. “The beauty of this region, this median eminence, is that it lies completely outside of the blood-brain barrier. Delivery of therapeutics to target [and] regulate neurons or regulate neurogeneration [the growth of new brain cells] could be made pretty specific.”
The study was published today, March 25, in the journal Nature Neuroscience.
Article source: http://www.foxnews.com/health/2012/03/26/fatty-diet-may-cause-new-brain-cells-to-sprout/
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Categories: Fat Loss Diary Tags: Big Mac, Biggest Diet Myths, Nature Neuroscience, Seth Blackshaw
Fatty diet may cause new brain cells to sprout
Eating too many burgers and fries? Your brain might show the effects, if new mouse research holds true in humans. Researchers have discovered that a high-fat diet causes new brain cells to sprout in an area of the brain that seems to regulate eating.
Interestingly, if the researchers stopped new brain-cell growth, mice gained less weight and stayed more active, even while eating their “supersize me” diet.
“We really don’t understand the function of these neurons in the normal brain,” study researcher Seth Blackshaw, an associate professor at Johns Hopkins University School of Medicine, told LiveScience. “Our data suggests that these neurons may have an important role in regulating feeding.”
Brain connections
The cells are located in a part of the brain called the median eminence, which lies at the edge of a fluid-filled chamber and therefore outside of the blood-brain barrier (which keeps toxic substances out of the brain), but it extends deep into the hypothalamus. [10 Cool Facts About the Brain]
The hypothalamus plays a role in regulating how our bodies spend the energy they take in and sends out signals to the body through the pituitary gland to control hunger, thirst and behavior.
Because the median eminence is in contact with areas of the body outside the blood-brain barrier, researchers think it may be detecting chemicals in the blood, and transferring signals about the condition of the body into the hypothalamus, which can then make decisions about eating.
Big Mac diet
The researchers wanted to see how brain cells in the median eminence reacted to a high-fat diet, so they put mice on a “Big Mac” diet — which contained 60 percent fat instead of the 35 percent fat in regular mouse chow.
The mice love the high-fat food. They eat and eat and gain tons of weight, as humans would if we could eat only fast food. In the wild, this would be a good thing in times when food is freely available: The mice can fatten up to stay alive when food is scarce.
The researchers saw that on the high-fat diet, creation of new brain cells in the median eminence increased from 1 percent to 5 percent.
Next, the researchers selectively turned off the new brain-cell creation in this region, and compared these mice with the normal mice on a high-fat diet. When new brain-cell growth was turned off, the mice gained 7 percent less weight and were 15 percent more active than the other mice eating the fatty food.
“We have no idea if this happens in any species other than mice. In humans all the cells and the structures are conserved,” Blackshaw said. “I think there’s no reason to assume necessarily that this wouldn’t happen in humans, but I would be very careful into reading too much in these studies.”
Staying thin
If this small connection to the hypothalamus does play a big role in regulating energy intake and use in humans, it could be a potential target for diet-regulating therapies, especially since it is located on the outside of the blood-brain barrier. If the region were inside the blood-brain barrier, that barrier would filter out any “foreign” chemicals used to regulate the growth of new brain cells there.
“The therapeutic potential [is] quite exciting,” Blackshaw said. “The beauty of this region, this median eminence, is that it lies completely outside of the blood-brain barrier. Delivery of therapeutics to target [and] regulate neurons or regulate neurogeneration [the growth of new brain cells] could be made pretty specific.”
The study was published today, March 25, in the journal Nature Neuroscience.
Article source: http://www.foxnews.com/health/2012/03/26/fatty-diet-may-cause-new-brain-cells-to-sprout/
Share and Enjoy
Categories: Fat Loss Diary Tags: Big Mac, Biggest Diet Myths, Nature Neuroscience, Seth Blackshaw