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Bacteria to Clean Arsenic Spills

Scientists have stumbled on a new bacteria that can clean up arsenic spills even in previously inhospitable terrains.

The Giant Mine in Canada is in the sub-arctic region. The presence of over 230,000 tonnes of arsenic-containing dust makes it one of the most polluted places on earth, as well as one of the most inhospitable.

“Water seeps through the mine cracks carrying the arsenic with it as it drips down the walls,” said Thomas Osborne of University College London. “We discovered new types of bacteria living in biofilms on the walls of Giant Mine that consume arsenic compounds contained in the polluted water seeping through.”

Arsenic is toxic to all living cells, and in people causes fatal cancers of the lung, liver, kidney and bladder. It also causes cirrhosis and gangrene, and on a wider scale seriously damages wildlife in fragile environments.

Arsenic contamination is a global problem, with parts of India, Bangladesh, Vietnam, Mexico, Canada, Argentina and the US severely affected.

“Until now, no bacteria have ever been isolated that can thrive in cold temperatures and deal with arsenic contamination. The new bacteria we discovered function at temperatures between minus 20 degrees Celsius and four degrees C,” said Osborne.

“These bacteria also live in a community called a biofilm, which means that we can build them into a new system to clean up contaminated areas by removing the arsenic from soil or drinking water, even in the cold far north and south, or in winter.

“The other exciting possibility that this opens up is that we can isolate the enzyme from these new strains of bacteria and develop an arsenic biosensor to use in cold environments.

“This will warn when traces of arsenic are escaping from areas like mine workings, industrial chemical facilities, or even laboratories, alerting us before pollution manages to get into water courses or drinking water supplies. We could also use it to test newly drilled wells in countries like Bangladesh where water supplies are known to be contaminated.”

Many organisms, including all plants and animals, ultimately get their energy from the sun via photosynthesis. But over the last few decades scientists have discovered more and more microbes that can get their energy directly from breaking down chemical bonds.

This enables them to survive in extraordinary and dark environments such as deep inside the earth or at the bottom of the coldest, deepest oceans, where previously no life was expected to exist at all.

These findings were presented on Monday at the Society for General Microbiology‘s Autumn meeting being held this week at Trinity College, Dublin.

Sources: The Times Of India

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How Safe is Stevia

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The sweetener is banned from food products in the U.S. due to toxicity fears. But the findings of several recent studies suggest otherwise.

Stevia  followers are a diverse bunch, including health nuts and food-industry magnates. The draw? The sweetener is all-natural and naturally calorie-free. But “natural” doesn’t necessarily mean safe, and scientists have long struggled to make sense of early evidence hinting that stevia could be toxic. A series of studies published last month in the journal Food and Chemical Toxicology put that question to the test for one type of stevia-based sweeteners.

CLICK & SEE THE PICTURES OF  STEVIA

Stevia, a South American shrub, has leaves up to 300 times sweeter than table sugar. Extracts have been available as a dietary supplement since 1995. It’s a popular food additive in Japan, Brazil and its native Paraguay, but in the U.S., where the Food and Drug Administration has determined there isn’t sufficient proof it’s nontoxic, stevia is banned from such uses. (Exceptions are made for food and drink items billing themselves as dietary supplements, such as the stevia-sweetened diet drink Zevia.)

FOR THE RECORD:
Stevia sweeteners: An article in Monday’s Health section about no-calorie sweeteners derived from the plant stevia said supermarket sales tests of stevia-derived rebaudioside A (sold as Truvia) were being conducted in New York with the blessing of the Food and Drug Administration. Permission from the FDA was not required for Truvia to be sold. However, Truvia is the subject of an FDA review process that will determine whether the product is safe and allowed to remain on the market. —

The sponsors of the recently published studies — food manufacturer Cargill and the Coca-Cola Co. — hope that in light of recent findings, the agency will reconsider its position on the calorie-free sweetener.

Scientists began studying stevia in the lab roughly 40 years ago, and the first findings gave food safety officials in several countries pause. A 1968 study in female rats showed that drinking a concoction of stevia leaves and stems significantly reduced fertility. A 1985 study, published in the Proceedings of the National Academy of Sciences, showed that steviol, a breakdown product of stevia, might cause genetic mutations. (In Paraguayan traditional medicine, stevia is used to lower blood sugar and as a contraceptive.)

Evidence of genetic and reproductive toxicity was sufficient to inspire a ban on the sweetener in the U.S. since the 1970s. (The 1994 Dietary Supplement Health and Education Act made it legal to sell stevia as a dietary supplement only, as long as it’s not an ingredient in food.) But the research on which the FDA based its long-ago decision may now be out of date. In the last decade, countless studies have revisited stevia, often using purer extracts.

The more-recent research has largely focused on purified forms of the two main chemicals responsible for the stevia plant’s sweetness: stevioside and rebaudioside A. Findings from some studies — still few in number — have resulted in a perhaps overstated claim: that stevia lowers blood pressure.

For example, a 2000 study of 100 adults in Taiwan showed that 250 milligrams of stevioside a day lowered subjects’ blood pressure by 8% to 12% within three months. A 2003 Chinese study in which nearly 170 adults were given 1,500 mg of stevioside daily in three 500 mg doses also reported that subjects’ blood pressure went down. (Both doses are far greater than the amount of stevioside in the few grains of powdered stevia it takes to sweeten a cup of tea.)

Authors of a 2006 report by the World Health Organization acknowledged the promise of the blood pressure studies. The authors also reviewed the dozens of lab and animal studies that had been done on stevioside and rebaudioside A in recent years — and concluded that the compounds appear unlikely to harm DNA or the reproductive system.

The eight studies published in Food and Chemical Toxicology last month went even further. One report showed no reproductive toxicity in rats exposed to the sweetener for two generations, and two human studies showed that 1,000 mg of rebaudioside A per day was safe for healthy adults as well as those with Type 2 diabetes. Rebaudioside A (dubbed Rebiana by Coca-Cola and Cargill) is “safe for human consumption,” three of the study authors wrote. They did not report on stevioside.

These latest findings — should the FDA find them compelling — may be good news for food manufacturers, which have long sought a natural zero-calorie sugar alternative to market to the calorie-conscious public.

But some aren’t convinced it’s good news for consumers just yet. Michael Jacobson, executive director of the Center for Science in the Public Interest Group, a Washington, D.C.-based nutrition advocacy group, said the research still hasn’t quelled concerns about stevia’s genetic toxicity. Although dozens of studies have shown stevia compounds to be harmless, a handful suggest it can damage genetic material. “It’s a warning flag,” he said.

Jacobson added that genetic toxicity may turn out to be attributable to a specific species or component of stevia. Cargill, meanwhile, is certain that at least one stevia component is safe. Rebaudioside A, under the brand name Truvia, is already on store shelves in New York as a test, with the FDA’s blessing. Consumers can expect to see it across the country this fall — if the FDA agrees.

Sources: Los Angles Times

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Are Nanofoods the Next Consumer Nightmare?

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Consumers already worried about genetically engineered or cloned food may soon find another worry in their grocery carts: nano-foods.

Nanotechnology involves the design and manipulation of materials on molecular scales. Companies using nanotechnology say it can enhance the flavor or nutritional effectiveness of food. Food produced by using nanotechnology is quietly coming onto the market, and consumer groups want U.S. authorities to force manufacturers to identify them.

U.S. health officials generally do not place warning labels on products unless there are clear, known reasons for caution or concern. But consumer advocates say uncertainty over health consequences alone is sufficient cause to justify identifying nano-foods.

Sources:
Reuters July 30, 2008

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Healthy Tips

Happiness Keeps the Doctor Away

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Keep humming “Don’t Worry Be Happy“. The 1980s New Age-inspired hit got it right. New research shows being happy can add years to life.

“Happiness does not heal, but happiness protects against falling ill,” says Ruut Veenhoven of Rotterdam‘s Erasmus University in a study to be published next month.

After reviewing 30 studies carried out worldwide over periods ranging from one to 60 years, the Dutch professor said the effects of happiness on longevity were “comparable to that of smoking or not”. That special flair for feeling good, he said, could lengthen life by between 7.5 and 10 years.

The finding brings a vital new piece to a puzzle currently being assembled by researchers worldwide on just what makes us happy – and on the related question of why people blessed with material wealth in developed nations no longer seem satisfied with their lives.

Once the province of poets or philosophers, the notions of happiness and satisfaction have been taken on and dissected, quantified and analysed in the last few years by a growing number of highly serious and respected economists – some of whom dub the new field “hedonics”, or the study of what makes life pleasant, or otherwise.

In Veenhoven’s findings, the strongest effect on longevity was found among a group of US nuns followed through their adult life – perhaps reflecting the feel-good factor from belonging to a close-knit stress-free community with a sense of purpose.

In his paper, Veenhoven first looked at statistics to see whether good cheer impacted on the sick, but concluded that while happiness had helped some cancer patients suffering from a relapse, in general “happiness does not appear to prolong the deathbed”.

Among healthy populations, on the contrary, happiness appeared to protect against falling ill, thus prolonging life. Happy people were more inclined to watch their weight, were more perceptive of symptoms of illness, tended to be more moderate with smoking and drinking and generally lived healthier lives.

They were also more active, more open to the world, more self-confident, made better choices and built more social networks.

Sources: The Times Of India

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Running ‘Can Slow Ageing Process’

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Running on a regular basis can slow the effects of ageing, a study by US researchers shows.

Elderly joggers were half as likely to die prematurely from conditions like cancer than non-runners.

They also enjoyed a healthier life with fewer disabilities, the Stanford University Medical Center team found.

Experts said the findings in Archives of Internal Medicine reinforced the importance that older people exercise regularly.

Survival of the fittest

The work tracked 500 older runners for more than 20 years, comparing them to a similar group of non-runners. All were in their 50s at the start of the study.

Nineteen years into the study, 34% of the non-runners had died compared to only 15% of the runners.

Both groups became more disabled with age, but for the runners the onset of disability started later – an average of 16 years later.

The health gap between the runners and non-runners continued to widen even as the subjects entered their ninth decade of life.

“If you had to pick one thing to make people healthier as they age, it would be aerobic exercise“.…..Says.. Lead author Professor James Fries

Running not only appeared to slow the rate of heart and artery related deaths, but was also associated with fewer early deaths from cancer, neurological disease, infections and other causes.

And there was no evidence that runners were more likely to suffer osteoarthritis or need total knee replacements than non-runners – something scientists have feared.

At the beginning of the study, the runners ran for about four hours a week on average. After 21 years, their weekly running time had reduced to around 76 minutes, but they were still seeing health benefits from taking regular exercise.

Lead author Professor James Fries, from the University of California at Stanford, said: “The study has a very pro-exercise message. If you had to pick one thing to make people healthier as they age, it would be aerobic exercise.

“The health benefits of exercise are greater than we thought.”

Age Concern says many older people do not exercise enough.

Figures show more than 90% of people in the UK over 75 fail to meet international guidelines of half-an-hour moderate intensity exercise at least five times a week.

Gordon Lishman, director general, said: “This research re-confirms the clear benefits of regular exercise for older people.

“Exercise can help older people to stay mobile and independent, ensure a healthy heart, keep weight and stress levels under control, and promote better sleep.

“While younger people are barraged with encouragement to lead healthier lifestyles, the health needs of older people are often overlooked.”

Sources: BBC NEWS:August 11,’08

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