Appendix explained

Some scientists think they have figured out the real job of the troublesome and seemingly useless appendix: It produces and protects good germs for the gut.

That is the theory from surgeons and immunologists at Duke University Medical School, published online in a scientific journal.

For generations the appendix has been dismissed as superfluous. Doctors could find no function for it. Surgeons removed them routinely. People live fine without them.

And when infected the appendix can turn deadly. It becomes inflamed quickly, and some people die if it is not removed expeditiously.

The function of the appendix seems related to the massive amount of bacteria that populates the human digestive system, according to the study in the Journal of Theoretical Biology. More bacteria inhabit the typical body than human cells. Most of the bacteria are good and help digest food.

But sometimes the flora of bacteria in the intestines die or are purged. Diseases such as cholera or amoebic dysentery would clear the gut of useful bacteria. The appendix's job is to reboot the digestive system in that case.

The appendix "acts as a good safe house for bacteria," said Duke surgery professor Bill Parker, a study co-author. The location of the appendix, just below the normal one-way flow of food and germs in the large intestine in a sort of gut cul-de-sac, helps support the theory, he said.

Also, the worm-shaped organ outgrowth acts as a bacteria factory to cultivate the good germs, Parker said.

That use is not needed in a modern industrialised society, Parker said. If the gut flora dies, they usually can be repopulated easily with germs picked up from other people, he said. But before dense populations in modern times and during epidemics of cholera that affected a whole region, it was not as easy to grow back that bacteria, and the appendix came in handy.

In less developed countries, where the appendix may be still useful, the rate of appendicitis is lower than in the United States, other studies have shown, Parker said.

The appendix, which is about 6 to 10 centimetres long, may be another case of an overly hygienic society triggering an overreaction by the body's immune system, he said.

Even though the appendix seems to have a function, people should still have them removed when they are inflamed because it could turn deadly, Parker said.

Five scientists not connected with the research said that the Duke theory makes sense and raises interesting questions.

The idea "seems by far the most likely" explanation for the function of the appendix, said Brandeis University biochemistry professor Douglas Theobald. "It makes evolutionary sense."

The theory led Gary Huffnagle, a University of Michigan internal medicine and microbiology professor, to wonder about the value of another body part that is often yanked: "I'll bet eventually we'll find the same sort of thing with the tonsils."

Arrest cardiac trouble: quit work

Middle-aged heart attack victims who go back to chronically stressful jobs are twice as likely to suffer a second heart attack or a related problem than those in less taxing jobs, Canadian researchers reported on Tuesday.

The risk is there even after accounting for other heart disease-related factors such as high blood pressure, diabetes, obesity and smoking, the report from Quebec's Laval University concluded.

The study looked at 972 men and women younger than 60 who had suffered a heart attack between 1995 and 1997 and returned to work.

During a follow-up that lasted about six years, 124 suffered a second heart attack, 13 of them fatal, and 82 had unstable angina.

Chronic job strain, defined as high psychological stress and little control over decisions that have to be made, was linked to a two-fold increase in the risk of a second problem, said the study published in this week's Journal of the American Medical Association.

The types of jobs involved were not detailed in the study.

The authors said several, though not all, previous studies have linked job strain to initial heart attacks but only two earlier limited studies had tried to explore the risk of returning to a high-stress job.

The authors, led by Dr Corine Aboa-Eboule, said the risk involved in stressful jobs may be related to the body's response that can lead to inflammation of the artery walls and subsequent formation of blood clots.

It might be thought that failing to develop a healthier post-heart attack lifestyle or not sticking to drug therapy also would be a factor, the study said. But none of the data supported that hypothesis.

"Chronic job strain significantly increased the risk of recurrent [heart problems] among middle-aged patients who returned to work," the study said.

"These results suggest that preventive interventions aimed at reducing job strain might have a significant impact on recurrent ... events," it added.

The study "should be disseminated in cardiac practice and in occupational health services with the aim of reducing job strain for workers returning to work," it concluded.

Fish can help fight diabetes

Get hooked ... fish is a rich source of Omega-3 fatty acids.

A diet rich in fish and other sources of omega-3 fatty acids can help cut the risk that children with a family history of diabetes will develop the disease, US researchers has found.

"It is a relatively large effect," said Jill Norris, whose study appears in the Journal of the American Medical Association.

"It is exciting because it suggests we might be able to develop nutritional interventions to prevent diabetes."

Type 1 diabetes, formerly called juvenile diabetes, is the most common form of diabetes in children. It occurs when the immune system goes haywire and starts attacking insulin-producing cells in the pancreas.

No one knows exactly what triggers this process, but heredity and environmental factors such as diet are thought to play a role.

Several studies in animals have suggested that omega-3 fatty acids - which are found in fish, flaxseed oil, walnuts, soybeans and other foods - may help.

To test whether omega-3 fatty acids offer a potential protective effect, Norris and colleagues at the University of Colorado at Denver studied 1770 children between 1994 and 2006 who were deemed at high risk for diabetes because of genetic tests or because they had a sibling or parent with type 1 diabetes.

Data about their dietary intake were collected in food frequency surveys.

Their blood was tested at least once a year for what is known as islet autoimmunity - the development of antibodies made by the immune system that attack insulin-producing cells in the pancreas. These antibodies are considered a strong predictor of type 1 diabetes.

Fifty-eight children in the study developed these antibodies.

Overall, the researchers found at-risk children who ate a lot of foods rich in omega-3 were 55 percent less likely to have pancreatic islet autoimmunity.

"This is the first study to show this," Norris said in a telephone interview. "This is all omega-3 fatty acids, not just the kind that are found in fish."

To make sure parents in the study were accurately reporting the children's food intake, Norris and colleagues tested for the presence of omega-3 fatty acids in blood cell membranes of 244 of the children.

In that group, children with omega-3 fatty acids in their blood cell membranes had a 37 percent decreased risk of having islet autoimmunity.

"It is certainly not time to make any recommendations until we can see this in other populations," Norris said, but added that it is a very promising result.

Omega-3 fatty acids interfere with enzymes that play a role in inflammation, a potential trigger for type 1 diabetes.

At least 194 million people in the world have diabetes, and the World Health Organization expects that number to rise to more than 300 million by 2025. Most of these people have type 2 diabetes, which is linked with poor diet and lack of exercise.

People with type 1 diabetes must take insulin injections to control blood sugar levels.

London chef says Aussies can't cook

Chef John Torode has labelled Australian cuisine boring, ordinary and confusing but our head cooks have hit back, saying his criticism is a load of … shish kebab.

A top Australian chef working in the UK has sparked fury with claims London's restaurant scene is superior to that of his former home country.

John Torode, who departed 15 years ago, said while Australians were "in love with themselves about their cuisine" it had become "pretty tired".

The man who fronts the Celebrity Masterchef cooking competition program and runs a leading London restaurant, Smiths of Smithfield, told The Sun-Herald: "Sydney used to be a fantastic, vibrant and fresh place in terms of eating, and it still has some great restaurants, but when I came back in March I was really disappointed. There was no one doing anything very exciting. Nothing seems to have moved on and I had some very ordinary meals.

"Sydney seemed far less egalitarian than Britain, where more and more people are now really into food and can really cook themselves."

Torode said London in particular and the UK in general were "now way, way ahead in terms of food".

"I think Australia has a real problem defining what it is really about in terms of food - a lot of the time it's not fusion, but confusion," he said.

"Australians are in love with themselves about their cuisine but it seems pretty tired when you think about what is coming out of Britain and Europe at the moment, especially in terms of the produce."

The scathing analysis angered some of Sydney's top chefs but was backed by a leading restaurant reviewer.

Simon Thomsen, co-editor of The Sydney Morning Herald Good Food Guide, said: "In some ways I think John has a point. One of the things that we point out in this year's guide is that while there are still some great top restaurants in Sydney, there are lots in the middle that are very tired and indistinguishable from each other.

"It does seem rather samey and tired at the moment - but maybe that is because we've sent all our best chefs over to London to show them how it's done."

Chef Justin North runs the CBD-based Becasse, which was named restaurant of the year in the 2007 Good Food Guide.

"I don't agree with what [Torode] says. Over the last three to four years there has been a massive change in Sydney dining - the range and quality of the produce has improved enormously," North said.

"There is a whole new generation of young Australian chefs who have been travelling and training abroad and who are now coming back here, so I think the scene is very exciting."

A leaner, fitter summer ahead

Slow food ... skip the processed junk and eat well to lose weight.

The weather's warming up so stock the larder with healthy food and throw out those lazy winter habits.

It's the season for dieting, but one former scientist and fat girl has an important message: eating too little can backfire, causing changes in brain chemistry that make it harder to shed weight.

In the early '90s, Dr Amanda Sainsbury-Salis, was so frustrated with diets that didn't work, she used her training as a scientist to solve her own weight problem. Her work in the lab at the Garvan Institute of Medical Research in Sydney showed that restricting kilojoules could activate brain chemicals that caused metabolism to slow down. If restricting food made metabolism slower, she wondered, could eating more food rev it up again?

Searching scientific literature, she found studies that suggested the answer was yes.

She tested the theory the next time she wound up on a weight-loss plateau - that stage when weight loss grinds to a halt, despite sticking to a diet. Instead of persevering with low-kilojoule food, she responded to strong hunger pangs by eating what she felt would be really satisfying - such as bread spread with brie. After three weeks, she'd kept off the two kilograms she'd lost before her weight loss stalled - and dropped another kilogram. "Before, I would have tried to work through the plateau, by eating more vegetables to quash my hunger, and moving more, but I found that the key was to eat satisfying, wholesome food instead," she says. "If I was really hungry and felt like lasagne, that's what I ate."

Sainsbury-Salis - now 28 kilograms lighter - had uncovered what she calls the famine reaction, a survival mechanism that can kick in when the body recognises that it's taking in fewer kilojoules.

"Your body slows down your metabolism, compensating for your lower kilojoule intake and priming you to store fat," she says.

To understand why, it helps to remember that humans didn't evolve in a landscape littered with food outlets, but in an environment with an uncertain food supply - that's why the body can't distinguish between a diet and famine. This explains why Sainsbury-Salis - like many others - found that with every attempt at weight loss, she'd gain weight as her metabolism slowed down.

Still, not everyone who tries to lose weight will have a famine reaction. "Genes play a role. There are some people who have a strong famine reaction and some who never have it, nor struggle with plateaus," she says.