Wednesday, January 21, 2009

Different bacteria in the gut 'could cause obesity'

Bacteria in the gut which are crucial to the body's ability to turn food into energy could explain why some people become obese, scientists believe.

Energy is released from food by bacteria in the stomach and the body then stores the energy as fat until it is needed. But researchers say new findings suggest that some people's guts process too much energy, and store too much fat. Over time this can cause weight gain and eventually obesity.

The finding could help scientists better understand why some people are more prone to weight problems than others. Official figures show that almost one in four British adults is now obese, while many more are classed as overweight.

Billions of microbes live in the human gut, thousands of which are linked or could be considered from the same "family". They help the body to digest food, although some of their other functions are not entirely understood by scientists. Scientists looked at the guts of obese patients, those who had recently undergone a gastric band operation and thin people. They found that obese people had different types of bacteria in their stomach than those who were naturally slender. But they also found that a gastric bypass appeared to radically change the composition of bacteria in the gut.

This difference could be one of the reasons why gastric band operations are so effective, according to the scientists, from Arizona State University, the Mayo Clinic, Arizona, and the University of Arizona. Dr Bruce Rittmann, from Arizona State University, said that the combination of different bacteria found in obese patients created a situation of energy release akin to "cars flooding onto (a motorway)". He called for further research into the findings, published in the Proceedings of the National Academy of Science journal, which he said could open up new ways to tackle the growing obesity crisis.

Obesity is calculated using the Body Mass Index (BMI). Experts class a BMI of more than 30 as obese, while more than 25 is overweight and between 19 and 25 considered normal. A person's BMI score is calculated by taking their weight in kilograms and dividing it by the square of their height in metres.


Ignorance and poverty is mainly what kills snakebite victims

Ken Winkler knows his snakes, from rattlesnakes, brown snakes, death adders and taipans to little green tree snakes and even faux snakes like Australia's legless lizards, evolutionary oddballs that just look like snakes. He's treated snakebite victims, studied snake venom, heads the Australian Venom Research Unit at the University of Melbourne and is adamant that the world needs to pay as much attention to snakes as he does.

But has the physician and toxinologist ever been bitten? "Never. I take a low-risk approach. Get your collaborators to handle the snakes," he confesses, pointing to one such collaborator, doctoral student David Williams. A former reptile-keeper and now a researcher at the AVRU's Papua New Guinea Snakebite Research Project in Port Moresby, Williams says it's true he takes the bites for science -- and head office. "I've had four very serious snakebites that could have killed me. It's not the snake's fault. It comes with the (professional) turf."

Few Australians will ever share Williams's experience at the fang end of a serpent. Australia is home to the 11 most venomous snakes in the world and the latest Australian Institute of Health and Welfare statistics show just 1750 people were hospitalised for a dangerous snakebite in 2002-05. That's 2.9 bites per 100,000 Australians. Winkel estimates that just a handful -- perhaps two, three or four -- Australians die each year from snakebite. That's not so elsewhere. Winkel wrote the snakebite section of the World Report on Child Injury Prevention, released last year by the World Health Organisation and the United Nations Children's Fund (UNICEF). He found PNG's annual incidence of snakebite was 561.9 cases per 100,000 people. Nearly 26 per cent of the victims died. Globally, about 5 million people are bitten each year, of whom up to 200,000 will die. Others will be maimed for life, suffering amputated arms and legs.

Most of the victims live in poor tropical countries in Asia, Africa and the Americas. For them snakebite is as serious as malaria or dengue fever. As Williams notes of their predicament, "snakebite is the one illness where you can get out of bed in the morning, go out to work in the garden and be dead by nightfall. It doesn't have to be that way". Winkler agrees. Together they co-convened a clinical toxinology conference last November in Melbourne that attracted diverse international experts, also keen to alleviate the burden of suffering and deaths caused by untreated snakebites.

The result was the Global Snake Bite Initiative. The idea is to borrow from successful international collaborations like the Global Alliance for Vaccines and Immunisations (GAVI). The goal is to create and implement strategies to tackle snakebite, what Winkler and Williams call a "neglected tropical disease", one not even on the radar of WHO, UNICEF and other global players. At the meeting a steering committee was formed and is busy setting up a global network of governments, antivenom producers, scientists, medical experts, agencies like WHO and UNICEF, non-governmental organisations like World Vision and philanthropists. Winkler says they're talking to the Bill and Melinda Gates and Clinton Foundations. He also has his sites trained on major antivenom manufacturers like Melbourne's CSL Ltd. "We hope to have official involvement money on the table and not just for the short-term," he says, noting that CSL supported the November conference.

To help regional experts quickly and cheaply tap into their international colleagues' expertise, the committee created an online resource, a bit like Wikipedia. People can access information and chat with one another, getting and giving advice about local problems in places as diverse as Nigeria, PNG, Mexico, Nepal, India or Bangladesh.

Sometimes the solutions can be astonishingly cheap, says Paul Scuffham, a health economist at Brisbane's Griffith University. "For example, an Australian mining company in PNG used to have about three (staff) deaths per year. They were spending about $3 million per year on antivenom. "Then they spent about $30,000 on boots for staff walking to and from work and nothing on antivenom. They've had no deaths since. That's smart."

According to Scuffham, the new initiative promises to help people on the ground get tips on other cost-effective tactics that can help prevent snakebites, improve the ability of local clinics to identify and treat snakebites and make sure the right antivenom gets to the right place at the right time.

Antivenoms, particularly, are a critical problem for cash-strapped nations, often struggling with internal corruption as well as fraudulent antivenom supplies. Williams recounts incidents of adulterated or out-of-date black-market antivenoms, water sold as antivenom and unscrupulous manufacturers knowingly selling drugs to nations that don't have the snakes for which they were designed. He says a single antivenom that counters the venom of all -- or even many -- snakes is the "holy grail" of toxicologists, specialists in animal venom.

That's where foundations with deep pockets can help make a difference, says Scuffham. Despite the huge unmet need for antivenom, demand has dropped. They're just too expensive. Manufacturers won't, or can't afford to, produce drugs for niche markets at an affordable price. "The idea being floated is that if there's a large injection of funds from an international community like the World Bank to subsidise antivenoms where places can't afford them, that would improve demand, so companies would produce more and stimulate the market," Scuffham explains.

He adds such an approach must be matched with projects to develop local technical, intellectual, administrative and manufacturing skills such that poor nations could develop "country-specific" manufacturing plants that work to international standards. "Whatever happens, it's got to be sustainable and not a windfall to manufacturers that just pushes up the price," Scuffham claims.

Meanwhile, Williams is heading to Geneva in a few weeks to help the WHO expert committee on biological standardisation to put new production guidelines online. Based on his PNG experience, he's also developed a "toxinology toolkit" that regional health officials can use to rapidly assess and tackle their snakebite problem. "Cambodia is the first cab off the rank," Williams says. His work reflects the potential Australia has to help less fortunate neighbours help themselves with a neglected public health issue. "We already have a cure on the shelf," says Williams, pointing to antivenoms. "What we're on about (with the global initiative) is getting that cure into the hands of people who can use it to save lives."



Lena said...

I am very skeptical about gastric bypass surgery as a "cure" for obesity. It is essentially the same type of surgery as the types of gastrectomies given to stomach and esophagal cancer victims, only the information given to fatties and cancer patients is very different. The risks for fatties are glossed over and they are told they will have a fabulous thin, healthy life after surgery. Whereas cancer patients getting the same surgery are told that the very act of resectioning the GI tract can cause death and greatly reduced lifespan, and cause severe vitamin deficiencies and malnutrition and they will have to learn to eat a lot and have frequent pathology tests to monitor nutrient intake. No one who has a cancer gastrectomy is told that the surgery will let them live a long healthy life, simply that it will probably give them more lifespan than if the cancerous tissue was not removed. But I suppose fatties are told the common lie that they could die of being fat any minute now. Even though the statistics say that even the most fat people, with a BMI of over 50, still only have a reduced lifespan of, at the most, two years.

John A said...

Bacteria could cause obesity... Well, maybe, much as the H. Pylori case.

Remember that this is not the sole cause, just as genetic differences are not.

But it may, like genetics, help explain why I tended to put on weight every time a forever-thin colleague opened the desk drawer in which he kept a 2lb box of fudge, even though I never partook.