Study: Fast food high in industrial chemicals

Fast food has never been known for being healthy, but it may be even more harmful than previously thought.

Researchers at George Washington University in the United States have found that eating fast food exposes the body to a class of industrial chemicals called phthalates.

Phthalates are used in the manufacture of plastic food- packaging material.

In the study, people who had eaten fast food had phthalate levels up to 40 per cent higher than those who had not.

"Our findings raise concerns because phthalates have been linked to a number of serious health problems in children and adults," said lead researcher Ami Zota.

For example, studies have suggested that phthalates can damage the reproductive system and lead to infertility.

Other research suggests that these chemicals can leach out of plastic food packaging and contaminate processed food.

In 2008, the US Congress banned the use of phthalates in the production of children's toys because of health concerns.

The researchers obtained data on 8,877 participants' diets in the past 24 hours through detailed questionnaires, and quantified the phthalates in their bodies through urine testing.

The study, published in the journal Environmental Health Perspectives, reported that meat and fast-food grain items, such as bread, cake, pizza and noodles, contributed significantly to phthalate exposure.

Dr Zota said that frequent consumption of fast food is not recommended, owing to its high fat and salt content.

She added: "People concerned about this issue can't go wrong by eating more fruit and vegetables and less fast food. A diet filled with whole foods offers a variety of health benefits that go far beyond the question of phthalates."

Besides food, phthalates also occur in a wide variety of products like toys and perfume.

Brain development linked to attentiveness

Remember the doctor monitoring your growth as a child by taking measurements of height and weight? Maybe he should measure your brain too, scientists say.

Researchers at the University of Michigan mapped the networks of nerve cells in the brains of more than 500 children using magnetic resonance imaging and found that those with underdeveloped networks had difficulty paying attention.

The children's ability to pay attention was measured using a standard test that required them to respond to a sequence of letters and numbers on a computer screen.

"Growth charts enable a family and their physician to quickly spot problematic development and, when necessary, intervene appropriately," said lead researcher Chandra Sripada.

"In the future, we want to provide clinicians with the same sort of guidance about brain development that we can about things like height and weight."

The study was launched after the researchers noticed a knowledge gap in how brain development is related to attention, despite the fact that attention span increases dramatically as a child grows.

The researchers said that separate networks in the brain are responsible for self- reflection and day-dreaming, versus doing cognitively demanding tasks, and that these networks become more distinct from each other with age.

In a person with attention difficulties, the "daydreaming" network turns on periodically and interrupts the other types of network. The researchers said that although the results are promising, much more work is needed before the technique is ready for clinical use.

How gene diversity can curb spread of disease

It is well known that the common agricultural practice of growing large tracts of the same genetic variety of food crop, known as monoculture, increases the risk of a disease wiping out the entire crop. But the reason for this is not clear.

Through experiments where bacterial populations were infected with viruses, a team of researchers from the United States and Europe have found a possible mechanism by which genetic diversity could suppress disease.

When the virus was introduced into a monoculture of bacteria with little genetic variation, it spread rapidly because it was able to evolve fast enough to overcome the similar immune systems throughout the bacterial population.

However, when faced with a genetically diverse bacterial population, the virus could not deal with the great variety of bacterial immune systems it encountered, and died out.

The researchers, who published their study in the journal Nature, said in a statement that their findings were potentially applicable to agriculture and nature conservation.

Compiled by Lin Yangchen