Obesity is a virus?

This is a tale of scientific detection and the triumph of the scientific method. First, Nikhil Dhurandhar of the University of Bombay in India investigated obesity in chickens. I think that this was his PhD thesis. He found that those with an avian adenovirus were more likely to be obese. Further investigation found that humans handling the sick chickens could pick up the virus. More overweight people had the virus than thin people. The trail continued to one or two of the fifty or more human adenoviruses and similar results for people. The idea is gaining credence that a virus causes at least some of cases of human obesity are caused by a virus. Those people, perhaps 10% - 20% of cases, seem to eat no more than thin people, yet they build more fat cells. A signature of virally induced weight gain is low levels of cholesterol, lipids, and triglycerides. The mechanism might be damage to the hypthalamus gland. (I've met several overweight people who say, "It's funny but my cholesterol is normal." And they're not the ones who quietly eat four desserts.) Here's the story...

From LiveScience: Mounting evidence suggests that obesity is contagious.

A human pathogen called the adenovirus Ad-37 causes obesity in chickens, according to a new study led by Leah Whigham of the departments of Medicine and Nutritional Sciences at the University of Wisconsin, Madison.

Previous research found that two related adenoviruses, Ad-36 and Ad-5, cause obesity in animals. Adenoviruses typically cause respiratory infections.

Previous studies have associated Ad-36 human obesity in previous studies. Whigham said that Ad-37 might also be associated, but more research is needed. Whigham said:

"We still need to more definitively establish the link with these adenoviruses and human obesity. We also have no idea how the virus interacts with other factors such as diet and exercise."

The new findings are detailed in the January issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology published by the American Physiological Society. The researchers conclude:

"The nearly simultaneous increase in the prevalence of obesity in most countries of the world is difficult to explain by changes in food intake and exercise alone, and suggest that adenoviruses could have contributed. The role of adenoviruses in the worldwide epidemic of obesity is a critical question that demands additional research."

Richard Atkinson, also of the University of Wisconsin and a member of the research team, studied 500 obese people in 2004 and found that about 30 percent of them had antibodies to the Ad-36 virus, which suggests they may have been exposed to it. (30 January 2006)

See also:

• Many factors contribute to fat pandemic


• International Journal of Obesity, 2 May 2006


• Fact vs. fiction in obesity, Skeptical Inquirer, 23 June 2005


• Obesity virus? DOC News, Diabetes Journals, 1 January 2005


• Is Obesity Contagious? WebMD, 5 August 2004


• Weight gain in one twin


• Infectobesity? Journal of Nutrition, 2001


• Obesity Linked to Virus, CNN 28 May 2000


• Doctor's Guide online, 1997


• Avian adenovirus SMAM-1 and human obesity, Obesity Research, 1997


• Effect of adenovirus infection on adiposity in chicken, Medline, Veterinary Microbiology, 1 June 1992


• Adenovirus, genus Mastadenovirus

Nikhil Dhurandhar now teaches at the Pennington Biomedical Research Center in Louisiana, U.S.A.

Speculation: Maybe the obesity virus damages leptin receptors in the hypothalamus. Leptin decreases appetite in thin people but not in fat people.