A new study has found a link between obesity and a type of virus, providing additional evidence that factors other than diet and exercise may be responsible for the increasing numbers of overweight people, Foodfacts.com has learned.
According to the Wall Street Journal, a number of researchers have been exploring whether the virus, known as adenovirus 36, might play a role in the development of obesity. Obesity rates among both children and adults have skyrocketed in the past 30 years. Viruses are one avenue of research that scientists are investigating as a possible environmental factor leading to the growth in obesity rates.
There are more than 50 known types of adenoviruses, which cause respiratory infections or gastrointestinal tract infections. Previous research has shown that adenovirus 36, or AD-36, can infect fat cells. So far, no other type of virus has been shown to affect fat cells.
Animal studies have shown those infected with AD-36 gain weight. Laboratory studies of the virus show it can infect immature fat cells and make them grow more quickly and multiply in greater numbers than normal.
It isn’t clear what role, if any, adenovirus 36 plays in weight gain in humans. At least two previous studies have shown an association with adenovirus 36 and obesity in adults, although a study released about a year ago that involved 300 U.S. military personnel showed similar levels of AD-36 exposure between obese and lean subjects.
Now another team of researchers, led by Jeffrey Schwimmer, a pediatric gastroenterologist at Rady Children’s Hospital and the University of California, both in San Diego, conducted a study involving 124 children ages 8 to 18 years old.
About half of the children were considered obese and half were considered non-obese. Obese children were defined as those having a body mass index in the 95th percentile or greater as calculated using standard growth charts. Samples of blood were taken from all of the children. The blood was tested to see if it contained so-called neutralizing antibodies to the AD-36 virus. Antibodies are developed by the body’s immune system to fight infections from viruses and researchers can test to see which types of antibodies are present in blood. The presence of antibodies indicates a person had been infected with a particular type of virus.
Researchers found neutralizing antibodies specific to AD-36 in 19 of the 124 children. Of those 19 children, 15 were obese. The study findings were published online Monday in the journal Pediatrics. Dr. Schwimmer said the results support a link between AD-36 and higher body weight. Children who tested positive for AD-36 weighed about 50 pounds more than those who tested negative.
Researchers also looked only at obese children and compared those who tested positive for AD-36 antibodies with those who tested negative. Obese children who tested positive weighed about 35 pounds more than obese children who tested negative. They also had significantly larger waist circumferences and waist/height ratios.
Researchers said more studies are needed to determine if AD-36 contributes to obesity. It’s possible that people who are obese are more vulnerable to becoming infected with adenovirus 36. Still, researchers wrote, “If a cause and effect relationship is established it would have considerable implications for the prevention and treatment of childhood obesity.”
The study was funded in part by grants from the National Institutes of Health and the University of California, San Diego.
Source: Wall Street Journal
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