Contagious obesity? Identifying the human adenoviruses that may make us fat

There is a lot of good advice to help us avoid becoming obese, such as “Eat less,” and “Exercise.” But here’s a new and surprising piece of advice based on a promising area of obesity research: “Wash your hands.”

There is accumulating evidence that certain viruses may cause obesity, in essence making obesity contagious, according to Leah D. Whigham, the lead researcher in a new study, “Adipogenic potential of multiple human adenoviruses in vivo and in vitro in animals,” in the January issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology published by the American Physiological Society.

The study, by Whigham, Barbara A. Israel and Richard L. Atkinson, of the University of Wisconsin, Madison, found that the human adenovirus Ad-37 causes obesity in chickens. This finding builds on studies that two related viruses, Ad-36 and Ad-5, also cause obesity in animals.

Moreover, Ad-36 has been associated with human obesity, leading researchers to suspect that Ad-37 also may be implicated in human obesity. Whigham said more research is needed to find out if Ad-37 causes obesity in humans. One study was inconclusive, because only a handful of people showed evidence of infection with Ad-37 ? not enough people to draw any conclusions, she said. Ad-37, Ad-36 and Ad-5 are part of a family of approximately 50 viruses known as human adenoviruses.

Researchers now must:

* identify the viruses that cause human obesity
* devise a screening test to identify people who are infected
* develop a vaccine

Screening test and vaccine still a long way off

The Whigham et al. study prompted an editorial in the same issue of AJP-Regulatory, Integrative and Comparative Physiology by Frank Greenway, professor in the Department of Clinical Trials, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge.

“If Ad-36 is responsible for a significant portion of human obesity, the logical therapeutic intervention would be to develop a vaccine to prevent future infections,” Greenway wrote. “If a vaccine were to be developed, one would want to ensure that all the serotypes of human adenoviruses responsible for human obesity were covered in the vaccine.”

“If one could predict the potential of an adenovirus to cause human obesity by using an in vitro assay or even by animal testing, screening of the approximately 50 human adenoviruses might be accelerated, shortening the time required for vaccine formulation,” Greenway wrote. “Human antibody prevalence in obese and lean human populations appears to be the only reliable method to screen adenoviruses for their potential to cause obesity in humans at the present time,” he noted.

Obesity contagion theory slow to catch on

The notion that viruses can cause obesity has been a contentious one among scientists, Whigham said. And yet, there is evidence that factors other than poor diet or lack of exercise may be at work in the obesity epidemic. “The prevalence of obesity has doubled in adults in the United States in the last 30 years and has tripled in children,” the study noted. “With the exception of infectious diseases, no other chronic disease in history has spread so rapidly, and the etiological factors producing this epidemic have not been clearly identified.”

“It makes people feel more comfortable to think that obesity stems from lack of control,” Whigham said. “It’s a big mental leap to think you can catch obesity.” However, other diseases once thought to be the product of environmental factors are now known to stem from infectious agents. For example, ulcers were once thought to be the result of stress, but researchers eventually implicated bacteria, H. pylori, as a cause.

“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 study said. “The role of adenoviruses in the worldwide epidemic of obesity is a critical question that demands additional research.”

Ad-37 third virus implicated in animal obesity

The theory that viruses could play a part in obesity began a few decades ago when Nikhil Dhurandhar, now at Pennington Biomedical Research Center at LSU, noticed that chickens in India infected with the avian adenovirus SMAM-1 had significantly more fat than non-infected chickens. The discovery was intriguing because the explosion of human obesity, even in poor countries, has led to suspicions that overeating and lack of exercise weren’t the only culprits in the rapidly widening human girth. Since then, Ad-36 has been found to be more prevalent in obese humans.

In the current study, Whigham et al. attempted to determine which adenoviruses (in addition to Ad-36 and Ad-5) might be associated with obesity in chickens. The animals were separated into four groups and exposed to either Ad-2, Ad-31, or Ad-37. There was also a control group that was not exposed to any of the viruses. The researchers measured food intake and tracked weight over three weeks before ending the experiment and measuring the chickens’ visceral fat, total body fat, serum lipids, and viral antibodies.

Chickens inoculated with Ad-37 had much more visceral fat and body fat compared with the chickens infected with Ad-2, Ad-31 or the control group, even though they didn’t eat any more. The Ad-37 group was also generally heavier compared to the other three groups, but the difference wasn’t great enough to be significant by scientific standards.

The authors concluded that Ad-37 increases obesity in chickens, but Ad-2 and Ad-31 do not. “Ad-37 is the third human adenovirus to increase adiposity in animals, but not all adenoviruses produce obesity,” the study concluded.

There is still much to learn about how these viruses work, Whigham said. “There are people and animals that get infected and don’t get fat. We don’t know why,” she said. Among the possibilities: the virus hasn’t been in the body long enough to produce the additional fat; or the virus creates a tendency to obesity that must be triggered by overeating, she said.

Mass screening for these viruses is impractical right now because there is no simple blood test available that would quickly identify exposure to a suspect virus, Whigham et al. said. More work is needed to develop such a test, Whigham said.

From APS


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68 thoughts on “Contagious obesity? Identifying the human adenoviruses that may make us fat”

  1. Thank you for your thoughtful comment about the adenovirus. I receive intuitive information from my subconscious and was informed that I had caught a virus from eating chicken and that it was making me fat and to stay away from chicken. Everything I eat has some effect on my body and even though I might not remember it consciously, my subconscious collects millions of bits of information for my use. Thank you for being so intelligent and perceptive.

  2. Your symptoms are consistent with Lyme disease (borrelia infection) or low thyroid or who knows, it could be both. Lyme disease/borrelia is a worldwide infection acquired from tick bites and who knows how else, e.g., mosquitoes. Don’t believe a doctor who says Lyme is not in your area, as I was told a number of times! It easily can be or where you have traveled to. The CDC requirements for reporting are too difficult for most cases to meet. Or-low thyroid. I know, you were tested. Find out if it was only a TSH, which is not helpful in cases where the pituitary is to blame, for example. I went to many, many doctors before I was given thyroid. My TSH was in the “normal” range and my T4 was low normal. I don’t know how they get the ranges they use, but your own symptoms should be taken into consideration. Unfortunately, doctors rely solely on the TSH to the grave detriment of many suffering individuals (www.stopthemadness.com).
    Best wishes in your search for good health.

  3. I was very ill during my first pregnancy with an upper respiratory infection…complication from allergies …and asthmatic bronchitis. I gained 80 lbs, and have tried everything to lose it. I was always able to lose weight quickly and easily before then, and was very thin and athletic . Now even with diet and excercise equal to what I used to do, and more so ..I have not been able to lose, and have gained more over the years..even when dieting! My son also has trouble with his weight, and gains very easily. If it was a virus during my pregnancy with him, than that could explain his problem as well. His 2 sisters are quite thin, and though only slightly younger, they eat as much as he does, without the weight gain.

  4. I believe that the theory or hypothesis link of obesity to a viral infection is stating that it may be the cause of some cases of obesity. And it may be the cause of some cases of obesity that have in the past been presumed to be based on heredity or genetics.

    If there is a virus, which has been proven scientifically be a medical doctor researcher from India, to be linked to cause the symtom of obesity, and that virus is contagous, then family members may expose each other causing them all to come down with the symtom of “obesity”, just like any other virus, such as chicken pox.

  5. Sudden weight gain without a change in diet or exercise is a burden I personally have experienced, when I gained 60 lbs in six months for no apparent reason. In my case it was explained as the onset of an active case of polycystic ovarian disease at the age of 19. I find it interesting that I also have a history of respiratory infections from a very young age. I will be interested to see how this research plays out.

  6. I have an answer to your weight gain that may not have been considered. Remember it may not be the only answer. Probably you were given Antibiotics. Antibiotics are given to animals to fatten them and cause weight gain.

    I personally suspect that the principal issue in the modern epidemic of obesity is actually modern industrial farming. The process strips the food of base nutrients like trace minerals and produces a food which causes malnutrition. Canada has studied this in depth and the data is there. The varieties of foods as well have been altered for this purpose of causing more food demand. Modern Agricultural banking will not fund alternative methods and varieties.

    The basic fact is that animals will not given a balanced diet overeat and become fat in any real quantity. This imbalance of diet is deliberate in modern fatening operations for farming. The cows will never get fat like they do in a feed lot if given a natural decent diet. This fact is plain for the issue of fat people as well. Given what is essentially a feedlot diet they get fat.

    No doubt infections do influence this as well. The other posts on this forum remarking on hygene also are very realistic. This is a complex problem set.

  7. So, which advanced scientific school of thought do you represent, where “shred” is spelt “shread?”

    If you want credibility when dismissing the research of others, you’d be well advised to brush up on basic English.

  8. I agree with you that overweight people may suffer further discrimination because of this announcement. If the science is flawed then I condemn the media attention

    However, if obesity genuinely is virus-bourne, then we need this news to spread. Reducing the spread of the disease will not be helped by a shrouding the facts with well-meaning discretion. In this instance, let’s not let short-term sympathetic objections cloud the objective manner in which we must approach this issue.

  9. While this does make more of an incentive for people to wash their hands and be more hygienic, what does this mean for people who are heavy or obese, and depressed? I know a lot of people who are overweight that have had disgusting experiences of people being extremely rude to them just for the fact of being overweight. Telling the public that obesity is contagious will spur even more shunning and degrading acts towards overweight people.

  10. I don’t know your age or diet history, I
    say this to open the subject of….
    How is your salt intake and potassium? A
    low “k-factor”, according to Dr Richard D.
    Moore M.D., Ph.D. in “The High Blood
    Pressure Solution” can lead to the loss
    of ability to matabolize fat properly.
    In my case, at 57 (two years now 59),
    going on a high potassium, very low sodium
    diet resulted in the loss of 32 pounds and
    it is staying off. I also got off the B.P.
    medication.

  11. I myself became ill, and had what my doctor called “mysterious” symptoms that were unrelated. Some of the symptoms included low fever, respiratory problems, join pain, muscle pain, and exhaustion. I also put on over 20 lbs in one month, with NO change in my diet or exercise level. I had a full workup of almost every blood test, x-ray and the like. They found nothing, thyroid normal, etc… He dismissed the weight gain, and insisted that I must have dramatically changed my diet or exercise to put on that much weight in a month. I was treated for the symptoms(not the weight gain) and told to diet and exercise more. I have been doing additional dieting and exercising for 4 MONTHS now and have only been able to lose about 5 pounds. Suffice it to say, I would like to see much more study in this area.

  12. Assuming this holds up to scrutiny, it will be interesting to ask how such a virus got into the human population. The article implies that this happened recently (else it would not account for a recently-observed statistical uptick in obesity, contradicting the suggestions in the article).

    One might reasonably wonder if the industrialization of the chicken industry since WWII selected for this virus, which then found its way into human beings through the food supply. In other words, perhaps economic pressure to raise nice fat birds cheaply tended to make the virus more prevalent in chickens, increasing the likelyhood of eventual transmission to humans.

  13. The age disparity noted in the frequency of obesity may be linked to the younger citizens being less likely to wash after, well, doing just about anything.
    The current lack of hygiene is not limited to mental…
    The propensity for (re)infection must be greater as a result?

  14. I’m not one to go against scientific studies, but this one really got me interested in what are people thinking. Seriously, if obesity can now be classified as a contagious disease, then we should begin rounding up all the fat people into concentration camps to save the skinny people. Or better yet, have the obese march down to your local social services building and demand disablity because not only is being obese classified as a disease, you are now a detriment to society and should not be allowed into the workplace. Along those same lines, I know a good laywer that would sue for damages because now all the obese people would become xenophobic. And if we want to continue this slippery sloped logic, I know the leader of a small european nation that would love an excuse to terminate the lives of another 3 million people (although the stampede might not be worth it). On a serious note, to say that one can catch obesity is not only dangerous but fool-hardy, perhaps more research should have been done before making a claim as large(pardon the pun) as this. I do hope that the scientists involved get their funding so that they don’t have to scrub the tests after 3 weeks. On a personal note, my wife is large and one of my daughters is large, however, niether myself nor my youngest is large, proving that in the 6 years I’ve been married I have not “caught” fat. Enjoy your cake, and avoid the obese!!

  15. additionally the journal article shows no increase in the weight of the birds, just their fat content. AND they sack the birds 3 weeks after infection. Is that long enough for an immune response to develop to mitigate the consequences of infection? Is it even relevant to humans whatsoever?

  16. One would think that a very thin person would suddenly become obese after “catching” the virus — without changes to their eating or exercise regimen. Is there any evidence to suggest that this is the case? I have never heard of any “mystery” obesity cases which have risen out of no where. Also the obesity epidemic is rising in children even more than adults – why would a virus distinguish between the two (or if the answer is that older generations are resistant, why would that be the case?) Overall the conclusions of this study sound highly questionable even based on anecdotal evidence.

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