Some high-fibre foods, which are sold as low in calories, may actually contain, in the extreme, up to 25 per cent more calories than the label suggests, nutritional experts have said.

It means that some high-fibre foods targeted at people on a diet are actually more fattening than people are led to believe, said Geoffrey Livesey, an independent nutritionist based in Britain who has advised the UN`s Food and Agriculture Organisation.

Dr Livesey told the American Association for the Advancement of Science meeting in Boston that consumers have been unknowingly consuming extra calorie in high-fibre food for decades because the system for assessing calories goes back to the 1970s and even earlier, according to the Independent.

It means that if people follow the daily recommended intake of 18 grams of fibre, they could be consuming more than 250 extra calories each week without realising it, he said.

Food manufacturers and government agencies have consistently misled consumers over many years about the number of calories contained in food, said experts.

Government assessments about the amount of energy in food assume that the caloric value is the same whether the food it cooked or raw, but scientists know that raw food provides fewer calories because the body expends energy breaking it down, said Richard Wrangham of Harvard University.
"There is a lot of misinformation around calories, and it is crucial for the consumer, whether they are on a diet or not, to have the correct information about what they eat," he told the meeting.

The UK's national synchrotron facility - the Diamond Light Source near Oxford - is to become a world centre for studying the structure of viruses and bacteria that cause serious disease.

Diamond uses intense X-rays to reveal the molecular and atomic make-up of objects and materials.

It will now use this capability to image Containment Level 3 pathogens.

These are responsible for illnesses such as Aids, hepatitis and some types of flu.

Level 3 is one step down from the most dangerous types of infectious agent, such as Ebola, which can only be handled in the most secure government facilities.

"Viruses, as you know, are sort of tiny nanomachines and you can't see them in a normal microscope.

"But with the crystallography and X-ray techniques we use, we are able to get about 10,000 times the resolution of the normal light microscope," explained Dave Stuart, the life sciences director at Diamond and a professor of structural biology at Oxford University.

"This takes us from the regime of not being able to see them to being able to see individual atoms.

"And if we can look at 'live' viruses and get an atomic-level description of them, it opens up the possibility of using modern drug-design techniques to produce new pharmaceuticals."

Prof Stuart was speaking in Boston at the annual meeting for the American Association for the Advancement of Science (AAAS).

Diamond has been working for some time to get its "Crystal Lab" ready for Level 3 work, and the Oxford researcher used the US conference to announce that the preparation was now complete.

Synchrotrons work by accelerating electrons in a giant magnetic ring to near light-speeds.

As the particles turn around the circle, they lose energy in the form of exceptionally intense X-rays.

This light is channelled down "beamlines" where it hits targets put in its path.

The way the X-rays scatter off the atoms in these targets reveals their arrangement. This allows scientists to glimpse the shape of virus and bacteria components and get some insight into how they function.

Diamond has already been studying pathogens at lower levels of containment.

A good recent example, says Prof Stuart, is the Human Enterovirus 71 (EV71) that causes hand-foot-and-mouth disease.

The infection is relatively common in infants and children, especially across the Asia-Pacific region, and is characterised by fever, painful sores in the mouth, and unpleasant blisters on the hands, feet and buttocks. There is currently no vaccine or anti-viral treatment available.

A joint UK and Chinese team working at Diamond solved the structure of EV71 last year.

This allowed the researchers to see a kind of breathing motion in the virus that it uses to initiate the infection process. Evident also was the small molecule it picks up from the body's cells to shift itself from one state to another.

"That molecule must be lost to cause an infection, but now that we can see in atomic detail what that molecule looks like, we can try to design a synthetic version that will attach more strongly," Prof Stuart told BBC News.

"That would stop the breathing and stop the infection process."

The British synchrotron's new status makes it now one of only two such facilities in the world where Level 3 study is undertaken; the other being in the US.

This means it will be a major draw for scientists across the world.

Prof Stuart stressed the operations at Diamond would pose no risk to others working on the Harwell site or in the immediate Oxfordshire area.

The pathogens will be brought to the synchrotron in crystal form in double-sealed containers that are not opened during their time at the facility.

They are manipulated robotically inside the Light Source and, what is more, they are destroyed in the very act of shining X-rays on them.

Air pollution and ozone levels may also play a role in precipitating heart attacks, warns fresh research from the US.

Rice University (Houston) statisticians Katherine Ensor and Loren Raun analysed eight years worth of data drawn from Houston's extensive network of air-quality monitors and more than 11,000 concurrent out-of-hospital cardiac arrests (OHCA) logged by Houston Emergency Medical Services (EMS).

"The bottom-line goal is to save lives," Ensor said. "We'd like to contribute to a refined warning system for at-risk individuals. Blanket warnings about air quality may not be good enough. At the same time, we want to enhance our understanding of the health cost of pollution - and celebrate its continuing reduction."

The researchers found a positive correlation between OHCAs and exposure to both fine particulate matter (airborne particles smaller than 2.5 micrograms) and ozone, the American Heart Association journal Circulation, reports.

They found that a daily average increase in particulate matter of six micrograms per day over two days raised the risk of OHCA by 4.6%, with particular impact on those with pre-existing (and not necessarily cardiac-related) health conditions, according to a Houston statement.

For the study, OHCA events were defined as cases where EMS personnel performed chest compressions. Ensor and Raun noted that the patients died in more than 90% of the cases, which occurred more during the hot summer months (55% of total cases).

The researchers also looked at the effects of nitrogen dioxide, sulphur dioxide and carbon monoxide levels, none of which were found to impact the occurrence of OHCA.

These findings were presented at the American Association for the Advancement of Science (AAAS) conference in Boston.

A modest increase in unprotected sex is enough to erode the benefits of other interventions, researchers said

A fall in the proportion of gay and bisexual men using condoms is behind the rise in HIV infections in those groups in the UK, say researchers.

Wider use of anti-retroviral drugs has helped to stop a sharper rise, a study by the Health Protection Agency (HPA) and a number of universities found.

They found a 26% rise, from 1990-2010, in the proportion of men who have sex with men who did not use condoms.

The report said the figures showed it was vital to promote safe sex.

Rates of HIV have been rising in recent years with latest figures showing cases among men who have sex with men (MSM) in the UK reaching an all-time high.

A recent report from the HPA found that nearly half of the 6,280 people diagnosed in the UK in 2011 were MSM.

Overall, one in 20 MSM are infected with HIV.

For this study, researchers analysed data from 1990 to 2010. They concluded that, without the introduction of anti-retroviral drugs to treat those with HIV, infections would be 68% higher in MSM.

Therapy with anti-retrovirals lowers the risk of people with HIV infecting others.

The report suggested the incidence of HIV could be 32% lower if all anti-retroviral treatment were prescribed from the moment of diagnosis rather than when health declined.
Informed choices

Further analysis showed that, if all MSM had stopped using condoms from 2000, rates of HIV in this group would now be 400% higher, the journal PLoS One reported.

The data also showed that the incidence of HIV could have dropped by a quarter if more HIV testing had been done.

But the researchers said the results showed that even a modest increase in unprotected sex was enough to erode the benefits of other interventions.

Study leader Professor Andrew Phillips, from University College London, said: "By better understanding the driving forces behind the trends we've seen in the past, it will allow us to make informed choices to reduce new HIV infections in the future."

Co-author Dr Valerie Delpech, who is head of HIV surveillance at the HPA, said: "Everyone should use a condom when having sex with new or casual partners, until all partners have had a sexual health screen.

"We also encourage men who have sex with men to get an HIV and STI screen at least annually, and every three months if having condomless sex with new or casual partners - and clinicians to take every opportunity to recommend HIV testing to this group."

Sir Nick Partridge, chief executive of the Terrence Higgins Trust, said condom use by gay men had played a key part in containing the spread of HIV in the UK.

"Without it, there would have been 80,000 more gay men with HIV between 2000 and 2010."

He added that the study showed the impact of the combined HIV strategy of promoting condoms, increasing regular HIV testing and encouraging the earlier use of anti-HIV drug therapy.

He added: "At a time when funding for local HIV prevention programmes is under threat, this only reinforces the important role which local authorities can and must play in funding local HIV prevention."

When people lose hope that they will ever get another good night`s sleep, they become at high risk for suicide, according to researchers.

Insomnia and nightmares, which are often confused and may go hand-in-hand, are known risk factors for suicide but just how they contribute was unknown, said Dr. W. Vaughn McCall, Chair of the Medical College of Georgia Department of Psychiatry and Health Behavior at Georgia Regents University.

The new study reaffirms that link and adds the element of hopelessness about sleep that is independent of other types of hopelessness, such as those regarding personal relationships and careers, said McCall, corresponding author of the study.

"It turns out insomnia can lead to a very specific type of hopelessness and hopelessness by itself is a powerful predictor of suicide," he said.

If the findings hold true in larger studies, they wave a red flag about suicide risk and point toward prevention that targets the negative thoughts with pharmaceuticals and psychological intervention.

The finding also is a reminder to physicians that depressed patients who report increased sleep problems should be asked if they are having suicidal thoughts, McCall said.

The scientists used psychometric testing to objectively assess the mental state of 50 depressed patients age 20-80 being treated as an inpatient, outpatient or in the Emergency Department. More than half had attempted suicide and most were taking an anti-depressant. Testing enabled the researchers to filter out other suicide risks such as depression itself and hone in on the relationship between insomnia and suicide risk, asking specific questions about dysfunctional beliefs about sleep such as: Do you think you will ever sleep again?
"It was this dysfunctional thinking, all these negative thoughts about sleep that was the mediating factor that explained why insomnia was linked to suicide," said McCall, who specializes in depression and sleep disorders.

The likelihood of being suicidal at least doubles with insomnia as a symptom, McCall noted.

The finding appeared in Journal of Clinical Sleep Medicine , the journal of the American Academy of Sleep Medicine.