Researchers including one of an Indian origin have found that the billions of bugs in our guts regulate the immune system and related autoimmune diseases such as rheumatoid arthritis.

Larger-than-normal populations of specific gut bacteria may trigger the development of diseases like rheumatoid arthritis and possibly fuel disease progression in people genetically predisposed to this crippling and confounding condition, say the scientists, at Mayo Clinic and the University of Illinois at Urbana-Champaign.

"A lot of people suspected that gut flora played a role in rheumatoid arthritis, but no one had been able to prove it because they couldn't say which came first - the bacteria or the genes," says senior author Veena Taneja, Ph.D., a Mayo Clinic immunologist.

"Using genomic sequencing technologies, we have been able to show the gut microbiome may be used as a biomarker for predisposition," she said.

The roughly 10 trillion cells that make up the human body have neighbors: mostly bacteria that often help, training the immune system and aiding in digestion, for example.

The bacteria in the intestines, in addition to a relatively small number of other microorganisms (the gut microbiome), outnumber human cells 10-to-1.

Researchers found that hormones and changes related to aging may further modulate the gut immune system and exacerbate inflammatory conditions in genetically susceptible individuals.

Nearly 1 percent of the world's population has rheumatoid arthritis, a disease in which the immune system attacks tissues, inflaming joints and sometimes leading to deadly complications such as heart disease.

Other diseases with suspected gut bacterial ties include type I diabetes and multiple sclerosis.

Researchers with the Mayo Illinois Alliance for Technology Based Healthcare say that identifying new biomarkers in intestinal microbial populations and maintaining a balance in gut bacteria could help physicians stop rheumatoid arthritis before it starts.

"This study is an important advance in our understanding of the immune system disturbances associated with rheumatoid arthritis. While we do not yet know what the causes of this disease are, this study provides important insights into the immune system and its relationship to bacteria of the gut, and how these factors may affect people with genetic susceptibilities to disease," Eric Matteson, M.D., chairman of rheumatology at Mayo Clinic, who was not a study author, said.

Dr. Taneja and her team genetically engineered mice with the human gene HLA-DRB1*0401, a strong indicator of predisposition to rheumatoid arthritis.

A set of control mice were engineered with a different variant of the DRB1 gene, known to promote resistance to rheumatoid arthritis.

Researchers used these mice to compare their immune responses to different bacteria and the effect on rheumatoid arthritis.

"The gut is the largest immune organ in the body," co-author Bryan White, Ph.D., director of the University of Illinois' Microbiome Program in the Division of Biomedical Sciences and a member of the Institute for Genomic Biology, said.

"Because it's presented with multiple insults daily through the introduction of new bacteria, food sources and foreign antigens, the gut is continually teasing out what's good and bad," White said.

The gut has several ways to do this, including the mucosal barrier that prevents organisms - even commensal or "good" bacteria - from crossing the lumen of the gut into the human body.

However, when commensal bacteria breach this barrier, they can trigger autoimmune responses.

The body recognizes them as out of place, and in some way this triggers the body to attack itself, he says.

These mice mimic human gender trends in rheumatoid arthritis, in that females were about three times as likely to generate autoimmune responses and contract the disease.

Researchers believe these "humanized" mice could shed light on why women and other demographic groups are more vulnerable to autoimmune disorders and help guide development of new future therapies.

"The next step for us is to show if bugs in the gut can be manipulated to change the course of disease," Dr. Taneja says.

The study was recently published in PloS ONE.

Are women's breasts getting too big?

That's what one author is saying in a new book Breasts: A Natural and Unnatural History, Medical Daily reported. According to her research, author Florence Williams found that the average bra size for women in the U.S. has increased from 34 B to 36 C a trend that Williams says isn't as good as it sounds.

Williams outlines numerous unpleasant reasons that may be contributing to expanding bra sizes, such as women's expanding waistlines a factor that has been linked with increased risk of breast cancer.

Another culprit behind growing cups is early onset puberty, another precursor for breast cancer, Medical Daily said. According to a 2010 study in Pediatrics, 15 percent of American girls start to get breast tissue when they're only seven years old.

Once a woman develops large breasts, she's put at a greater risk of pollution exposure. Bigger breasts have a much higher concentration of fatty tissue, and according to Medical Daily, the body stores toxic chemicals in its fat cells. This means big breasts could be storing dangerous compounds such as mercury or chemicals found in pesticides and paints.

To make matters worse, the more these chemicals are stored in the breast tissue, the more likely they are to be transferred into

A vaccine which could cut the number of Alzheimer's cases in half has passed its first human trials.

The jab could delay the onset of what is the most common form of dementia by five years and be the first step to a cure.

Scientists in Sweden tested the vaccine called CAD106 on patients aged 50 to 80 over a three-year period.

In three out of four cases it increased the levels of antibodies in their blood, suggesting the vaccine had boosted their immune system.

And those taking part had no serious side-effects.

Authors of the study in the journal Lancet Neurology called it a "promising option in the treatment of people suffering from mild-to-moderate Alzheimer's disease".

Commenting on the research, Thomas Wisniewski, of the New York School of Medicine, said: "Development of immunotherapy that can delay the onset of Alzheimer's disease by five years would reduce the prevalence of the disease by half."

Alzheimer's attacks nerves, brain cells and neurotransmitters which carry messages to and from the brain.

Currently more than 650,000 suffer from the disease in Britain alone.

Dr Simon Ridley, of Alzheimer's Research UK said: "This trial is an important first step.

"Larger scale trials of CAD106 will determine whether it can help people's memory and thinking skills.

"It's likely any new treatment will be most effective when given in the early stages of the disease."

The key to curing unbearable migraine headaches may lie with the people of Norfolk Island, scientists say.

Led by Professor Lyn Griffiths from the University's Griffith Health Institute, the team has identified a new region on the X chromosome that is responsible for playing a role in migraine

The research provides compelling evidence for a new migraine susceptibility gene involved in migraine.

The study also indicated that there may be more than one X chromosomal gene involved and implicated a gene involved in iron regulation in the brain.

All females have two X chromosomes whilst males have an X and a Y chromosome.

"These results provide more support for the role of the X chromosome in migraine and may explain why so many more females suffer from the disorder," Professor Griffiths said.

Tracking down and identifying the various genes that cause migraine is very important as it provides insights to develop better means of diagnosis and more targeted treatments.

"Currently, 12 percent of the population suffers from migraine. Even though we have some very good treatments for this very debilitating disease, they certainly don't work for everyone and can have some adverse side effects. Hence there is a real need to develop new migraine treatments," Griffiths said.

This National Health and Medical Research Council funded work involved a unique population study of the remote Norfolk Island where 80 percent of inhabitants are able to trace their ancestry back to the famous historical event, The Mutiny on the Bounty.

"This population was used due to its unusual pedigree structure in which genetic relationships can be traced through genealogical data to the island's original founders, and also the high incidence of migraine sufferers in this population. It's very useful for gene mapping purposes because of the reduced genetic and environmental diversity," Professor Griffiths said.

A comprehensive chromosome analysis of around 300 Norfolk participants from a large multigenerational Norfolk family, including many who are affected by migraine, was conducted using DNA samples obtained from the islanders.

Drinking eight glasses of water a day to lose weight and stay healthy is a myth, an Australian academic says.

New Zealand recommendations suggest an adequate daily fluid intake is about 2.2 litres for women and 3 litres for men.

However, this includes fluid found in food and beverages.

La Trobe University lecturer Spero Tsindos said people could get their daily fluid intake from fruit, vegetables, juices and even tea and coffee.

"If you're feeling thirsty then drink by all means a beverage. It doesn't have to be water," Tsindos said.

"I'm not saying you shouldn't drink water. I'm saying the need to drink two litres of water on a regular basis is a complete myth.

"We should be telling people that beverages like tea and coffee contribute to a person's fluid needs and, despite their caffeine content, do not lead to dehydration."

He said drinking a large quantity of water in one sitting to reach the daily intake level was pointless because it would not be distributed where it was needed. It would just dilute the urine, he said.

Drinking large amounts of water to lose weight would not work either without a low-calorie diet, he added.

"There is further evidence that water and a well-balanced diet does far more than water alone," Tsindos wrote in The Australian and New Zealand Journal of Public Health, published this week.

"Water is important for health, however, the recommendation of eight glasses of pure water a day appears an overestimation of requirements," he said.

The eight glasses a day notion may have stemmed from guidelines published in the US in 1945, Mr Tsindos wrote.