Anti-cancer purple tomato developed

The finding, published in the journal Nature Biotechnology, bolsters the idea that plants can be genetically modified to make people healthier.

Cancer-prone mice fed the modified fruit lived significantly longer than animals fed a standard diet with and without regular tomatoes, Cathie Martin and colleagues at the government-funded John Innes Center in Britain reported.

"The effect was much bigger than we had expected," said Martin, a plant biologist.

The study focused on anthocyanins, a type of antioxidant found in berries such as blackberries and blackcurrants that have been shown to lower risk of cancer, heart disease and some neurological diseases.

While an easy health boost, many people do not eat enough of these fruits, the researchers said.

Using genes that help color the snapdragon flower, the researchers discovered they could get the tomatoes to make anthocyanins -- turning the tomato purple in the process.

Mice genetically engineered to develop cancer lived an average of 182 days when they were fed the purple tomatoes, compared to 142 days for animals on the standard diet.

"It is enormously encouraging to believe that by changing diet, or specific components in the diet, you can improve health in animals and possibly humans," Martin said in a telephone interview.

The researchers cautioned that trials in humans are a long way off and the next step is to investigate how the antioxidants actually affect the tumors to promote better health.

But the findings do bolster research suggesting that people can significantly improve their health by making simple changes to the daily diet, other researchers said.

"It's exciting to see new techniques that could potentially make healthy foods even better for us," said Dr. Lara Bennett, science information officer at Cancer Research UK.

"But it's too early to say whether anthocyanins obtained through diet could help to reduce the risk of cancer."

Red meat primes body for germ

A steady diet of red meat makes the body more susceptible to a virulent form of intestinal bug that can cause bloody diarrhoea and even death, according to a study to be published on Thursday.

- 30 / 10 / 2008 07:22

Researchers in the United States and Australia said persistently eating red meat appears to prime the body for exposure to this potent form of Escherichia coli (E. coli).

The meat naturally contains sugar molecules called Neu5Gc that accumulate in cells lining the intestines and blood vessels.

These molecules also act as a sort of magnet for the toxins exuded by the E. coli strain, thus making it easier for the poisons to enter the blood stream, they said.

"Prior meat eating would set one up for the toxin to bind when it shows up," explained Ajit Varki, a researcher at the University of California at San Diego, one of the study's co-authors.

The Neu5Gc molecule is virtually absent in other foods such as fish, poultry and vegetables and fruits, Varki told AFP in an email exchange.

The investigation, published in the London-based journal Nature, is led by Travis Beddoe of Monash University in Melbourne.

In experiments, the team first tested the affinity of the E. coli bacteria for Neu5Gc using cultured human cells in a lab dish.

"The human samples showed the presence of the Neu5Gc toxin binding sites in the gut and the kidney, the two target organs for the disease," said Varki.

The researchers then confirmed the positive results using genetically modified mice in which the gene which naturally produced Neu5Gc was suppressed.

E. coli is found in the lower intestine of animals and humans. Many of its strains are harmless, but others can cause serious, sometimes fatal health problems.

There are about 75,000 cases of E. coli-related to food poisoning every year in the United States, including an average of 60 fatalities, according to the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.

Most outbreaks have been traced to undercooked ground beef tainted with faecal matter post-slaughter.

E. coli can also be transmitted through unwashed vegetables grown in farmland irrigated by sewage-contaminated water.

AFP